initial commit

backend/.gitignore

@@ -0,0 +1,9 @@
+# IDE
+/.idea/
+
+# Gradle
+/.gradle/
+/gradle.properties
+
+# Kotlin
+/build/

backend/build.gradle.kts

@@ -0,0 +1,41 @@
+group = "com.infendro.account"
+version = "0.0.1"
+
+application {
+    mainClass.set("com.infendro.account.ApplicationKt")
+}
+
+repositories {
+    maven("https://git.infendro.com/api/packages/Infendro/maven")
+    mavenCentral()
+}
+
+plugins {
+    alias(libs.plugins.kotlin)
+    alias(libs.plugins.ktor)
+    alias(libs.plugins.serialization)
+}
+
+dependencies {
+    implementation(libs.ktor.server)
+    implementation(libs.ktor.server.cio)
+    implementation(libs.ktor.server.auth)
+    implementation(libs.ktor.server.sessions)
+    implementation(libs.ktor.server.resources)
+    implementation(libs.ktor.server.statusPages)
+    implementation(libs.ktor.server.contentNegotiation)
+    implementation(libs.ktor.server.serialization)
+    implementation(libs.ktor.server.validation)
+    implementation(libs.exposed)
+    implementation(libs.exposed.dao)
+    implementation(libs.exposed.jdbc)
+    implementation(libs.postgres)
+    implementation(libs.flyway)
+    implementation(libs.flyway.postgres)
+    implementation(libs.koin)
+    implementation(libs.koin.logger)
+    implementation(libs.otp)
+    implementation(libs.hash)
+    implementation(libs.encoding)
+    implementation(libs.logback)
+}

backend/gradle/libs.versions.toml

@@ -0,0 +1,43 @@
+[versions]
+kotlin = "2.1.21"
+ktor = "3.1.3"
+exposed = "0.60.0"
+postgres = "42.7.5"
+flyway = "11.7.0"
+koin = "4.0.3"
+otp = "1.1.0"
+hash = "1.1.0"
+encoding = "1.1.0"
+logback = "1.5.18"
+
+[plugins]
+kotlin = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }
+ktor = { id = "io.ktor.plugin", version.ref = "ktor" }
+serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }
+
+[libraries]
+ktor-server = { module = "io.ktor:ktor-server-core-jvm", version.ref = "ktor" }
+ktor-server-cio = { module = "io.ktor:ktor-server-cio", version.ref = "ktor" }
+ktor-server-auth = { module = "io.ktor:ktor-server-auth-jvm", version.ref = "ktor" }
+ktor-server-sessions = { module = "io.ktor:ktor-server-sessions-jvm", version.ref = "ktor" }
+ktor-server-resources = { module = "io.ktor:ktor-server-resources", version.ref = "ktor" }
+ktor-server-statusPages = { module = "io.ktor:ktor-server-status-pages", version.ref = "ktor" }
+ktor-server-contentNegotiation = { module = "io.ktor:ktor-server-content-negotiation-jvm", version.ref = "ktor" }
+ktor-server-serialization = { module = "io.ktor:ktor-serialization-kotlinx-json-jvm", version.ref = "ktor" }
+ktor-server-validation = { module = "io.ktor:ktor-server-request-validation", version.ref = "ktor" }
+
+exposed = { module = "org.jetbrains.exposed:exposed-core", version.ref = "exposed" }
+exposed-dao = { module = "org.jetbrains.exposed:exposed-dao", version.ref = "exposed" }
+exposed-jdbc = { module = "org.jetbrains.exposed:exposed-jdbc", version.ref = "exposed" }
+postgres = { module = "org.postgresql:postgresql", version.ref = "postgres" }
+flyway = { module = "org.flywaydb:flyway-core", version.ref = "flyway" }
+flyway-postgres = { module = "org.flywaydb:flyway-database-postgresql", version.ref = "flyway" }
+
+koin = { module = "io.insert-koin:koin-ktor", version.ref = "koin" }
+koin-logger = { module = "io.insert-koin:koin-logger-slf4j", version.ref = "koin" }
+
+otp = { module = "com.infendro:otp", version.ref = "otp" }
+hash = { module = "com.infendro:hash", version.ref = "hash" }
+encoding = { module = "com.infendro:encoding", version.ref = "encoding" }
+
+logback = { module = "ch.qos.logback:logback-classic", version.ref = "logback" }

backend/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.8-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

backend/gradlew

@@ -0,0 +1,249 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

backend/gradlew.bat

@@ -0,0 +1,92 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

backend/settings.gradle.kts

@@ -0,0 +1 @@
+rootProject.name = "backend"

backend/src/main/kotlin/com/infendro/account/Application.kt

@@ -0,0 +1,22 @@
+package com.infendro.account
+
+import com.infendro.account.config.*
+import com.infendro.account.model.initializeDatabase
+import io.ktor.server.application.*
+import io.ktor.server.cio.*
+
+fun main(
+    args: Array<String>,
+) = EngineMain.main(args)
+
+fun Application.module() {
+    configureDatabase()
+    configureDependencyInjection()
+    configureSecurity()
+    configureSerialization()
+    configureValidation()
+    configureRouting()
+    configureException()
+
+    initializeDatabase()
+}

backend/src/main/kotlin/com/infendro/account/config/Config.kt

@@ -0,0 +1,45 @@
+package com.infendro.account.config
+
+import io.ktor.server.config.ApplicationConfig
+
+data class DatabaseConfig(
+    val host: String,
+    val username: String,
+    val password: String,
+) {
+    val url: String
+        get() = "jdbc:postgresql://${host}/account"
+}
+
+data class SecurityConfig(
+    val cookie: CookieConfig,
+)
+
+data class CookieConfig(
+    val domain: String,
+    val path: String,
+    val secure: Boolean,
+)
+
+val ApplicationConfig.database: DatabaseConfig
+    get() {
+        val host = property("database.host").getString()
+        val username = property("database.username").getString()
+        val password = property("database.password").getString()
+
+        return DatabaseConfig(host, username, password)
+    }
+
+val ApplicationConfig.security: SecurityConfig
+    get() {
+        return SecurityConfig(cookie)
+    }
+
+private val ApplicationConfig.cookie: CookieConfig
+    get() {
+        val domain = property("security.cookie.domain").getString()
+        val path = property("security.cookie.path").getString()
+        val secure = property("security.cookie.secure").getString().toBooleanStrict()
+
+        return CookieConfig(domain, path, secure)
+    }

backend/src/main/kotlin/com/infendro/account/config/Database.kt

@@ -0,0 +1,20 @@
+package com.infendro.account.config
+
+import io.ktor.server.application.Application
+import org.flywaydb.core.Flyway
+import org.jetbrains.exposed.sql.Database
+
+fun Application.configureDatabase() {
+    val config = environment.config.database
+
+    Database.connect(
+        url = config.url,
+        user = config.username,
+        password = config.password,
+    )
+
+    val flyway = Flyway.configure()
+        .dataSource(config.url, config.username, config.password)
+        .load()
+    flyway.migrate()
+}

backend/src/main/kotlin/com/infendro/account/config/DependencyInjection.kt

@@ -0,0 +1,34 @@
+package com.infendro.account.config
+
+import com.infendro.account.model.repository.AccessRepository
+import com.infendro.account.model.repository.AccountRepository
+import com.infendro.account.model.repository.InitializationRepository
+import com.infendro.account.model.repository.SessionRepository
+import com.infendro.account.service.AccessService
+import com.infendro.account.service.AccountService
+import com.infendro.account.service.RoleService
+import com.infendro.account.service.SessionService
+import io.ktor.server.application.*
+import org.koin.core.module.dsl.singleOf
+import org.koin.dsl.module
+import org.koin.ktor.plugin.koin
+import org.koin.logger.slf4jLogger
+
+fun Application.configureDependencyInjection() {
+    koin {
+        slf4jLogger()
+        modules(module)
+    }
+}
+
+private val module = module {
+    singleOf(::InitializationRepository)
+    singleOf(::AccessRepository)
+    singleOf(::AccountRepository)
+    singleOf(::SessionRepository)
+
+    singleOf(::AccessService)
+    singleOf(::AccountService)
+    singleOf(::RoleService)
+    singleOf(::SessionService)
+}

backend/src/main/kotlin/com/infendro/account/config/Exception.kt

@@ -0,0 +1,19 @@
+package com.infendro.account.config
+
+import com.infendro.account.exception.StatusException
+import io.ktor.http.HttpStatusCode.Companion.BadRequest
+import io.ktor.server.application.*
+import io.ktor.server.plugins.requestvalidation.*
+import io.ktor.server.plugins.statuspages.*
+import io.ktor.server.response.*
+
+fun Application.configureException() {
+    install(StatusPages) {
+        exception<StatusException> { call, exception ->
+            call.respond(exception.status)
+        }
+        exception<RequestValidationException> { call, _ ->
+            call.respond(BadRequest)
+        }
+    }
+}

backend/src/main/kotlin/com/infendro/account/config/Routing.kt

@@ -0,0 +1,19 @@
+package com.infendro.account.config
+
+import com.infendro.account.routing.access
+import com.infendro.account.routing.account
+import com.infendro.account.routing.role
+import com.infendro.account.routing.session
+import io.ktor.server.application.*
+import io.ktor.server.resources.*
+import io.ktor.server.routing.*
+
+fun Application.configureRouting() {
+    install(Resources)
+    routing {
+        access()
+        account()
+        role()
+        session()
+    }
+}

backend/src/main/kotlin/com/infendro/account/config/Security.kt

@@ -0,0 +1,69 @@
+package com.infendro.account.config
+
+import com.infendro.account.exception.client.UnauthorizedException
+import com.infendro.account.model.Role
+import com.infendro.account.model.entity.AccountEntity
+import com.infendro.account.model.entity.SessionEntity
+import com.infendro.account.model.entity.SessionTable
+import com.infendro.account.model.repository.SessionRepository
+import com.infendro.account.util.Hasher
+import io.ktor.server.application.Application
+import io.ktor.server.application.install
+import io.ktor.server.auth.Authentication
+import io.ktor.server.auth.session
+import io.ktor.server.sessions.*
+import kotlin.time.Duration.Companion.days
+import kotlinx.serialization.Serializable
+import org.jetbrains.exposed.sql.SqlExpressionBuilder.eq
+import org.koin.ktor.ext.inject
+
+@Serializable
+data class AuthenticationSession(
+    val token: String,
+)
+
+data class AuthenticationPrincipal(
+    val account: AccountEntity,
+    val session: SessionEntity,
+) {
+    val role: Role
+        get() = account.role
+}
+
+fun Application.configureSecurity() {
+    val config = environment.config.security
+
+    install(Sessions) {
+        cookie<AuthenticationSession>(
+            "Authentication",
+            SessionStorageMemory(),
+        ) {
+            cookie.domain = config.cookie.domain
+            cookie.path = config.cookie.path
+            cookie.httpOnly = true
+            cookie.secure = config.cookie.secure
+            cookie.extensions["SameSite"] = "Strict"
+            cookie.maxAge = 7.days
+        }
+    }
+    install(Authentication) {
+        session<AuthenticationSession> {
+            validate { authenticationSession ->
+                val sessionRepository by inject<SessionRepository>()
+
+                val session = sessionRepository
+                    .singleOrNull { SessionTable.tokenHash eq Hasher.hash(authenticationSession.token) }
+                    ?: return@validate null
+
+                sessions.set(authenticationSession)
+
+                AuthenticationPrincipal(session.account(), session)
+            }
+            challenge {
+                call.sessions.clear<AuthenticationSession>()
+
+                throw UnauthorizedException()
+            }
+        }
+    }
+}

backend/src/main/kotlin/com/infendro/account/config/Serialization.kt

@@ -0,0 +1,11 @@
+package com.infendro.account.config
+
+import io.ktor.serialization.kotlinx.json.*
+import io.ktor.server.application.*
+import io.ktor.server.plugins.contentnegotiation.*
+
+fun Application.configureSerialization() {
+    install(ContentNegotiation) {
+        json()
+    }
+}

backend/src/main/kotlin/com/infendro/account/config/Validation.kt

@@ -0,0 +1,15 @@
+package com.infendro.account.config
+
+import com.infendro.account.dto.request.validatePostAccountRequest
+import com.infendro.account.dto.request.validatePutAccountCurrentPasswordRequest
+import com.infendro.account.dto.request.validatePutAccountCurrentUsernameRequest
+import io.ktor.server.application.*
+import io.ktor.server.plugins.requestvalidation.*
+
+fun Application.configureValidation() {
+    install(RequestValidation) {
+        validatePostAccountRequest()
+        validatePutAccountCurrentUsernameRequest()
+        validatePutAccountCurrentPasswordRequest()
+    }
+}

backend/src/main/kotlin/com/infendro/account/dto/request/PostAccountRequest.kt

@@ -0,0 +1,30 @@
+package com.infendro.account.dto.request
+
+import com.infendro.account.util.REGEX_PASSWORD
+import com.infendro.account.util.REGEX_USERNAME
+import io.ktor.server.plugins.requestvalidation.RequestValidationConfig
+import io.ktor.server.plugins.requestvalidation.ValidationResult.Invalid
+import io.ktor.server.plugins.requestvalidation.ValidationResult.Valid
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class PostAccountRequest(
+    val username: String,
+    val password: String,
+    val access: PostAccountRequestAccess,
+)
+
+@Serializable
+data class PostAccountRequestAccess(
+    val token: String,
+)
+
+fun RequestValidationConfig.validatePostAccountRequest() {
+    validate<PostAccountRequest> { request ->
+        when {
+            !REGEX_USERNAME.matches(request.username) -> Invalid("")
+            !REGEX_PASSWORD.matches(request.password) -> Invalid("")
+            else -> Valid
+        }
+    }
+}

backend/src/main/kotlin/com/infendro/account/dto/request/PostSessionRequest.kt

@@ -0,0 +1,10 @@
+package com.infendro.account.dto.request
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class PostSessionRequest(
+    val username: String,
+    val password: String,
+    val otp: String,
+)

backend/src/main/kotlin/com/infendro/account/dto/request/PutAccountCurrentPasswordRequest.kt

@@ -0,0 +1,21 @@
+package com.infendro.account.dto.request
+
+import com.infendro.account.util.REGEX_PASSWORD
+import io.ktor.server.plugins.requestvalidation.*
+import io.ktor.server.plugins.requestvalidation.ValidationResult.*
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class PutAccountCurrentPasswordRequest(
+    val password: String,
+    val otp: String,
+)
+
+fun RequestValidationConfig.validatePutAccountCurrentPasswordRequest() {
+    validate<PutAccountCurrentPasswordRequest> { request ->
+        when {
+            !REGEX_PASSWORD.matches(request.password) -> Invalid("")
+            else -> Valid
+        }
+    }
+}

backend/src/main/kotlin/com/infendro/account/dto/request/PutAccountCurrentUsernameRequest.kt

@@ -0,0 +1,21 @@
+package com.infendro.account.dto.request
+
+import com.infendro.account.util.REGEX_USERNAME
+import io.ktor.server.plugins.requestvalidation.*
+import io.ktor.server.plugins.requestvalidation.ValidationResult.*
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class PutAccountCurrentUsernameRequest(
+    val username: String,
+    val otp: String,
+)
+
+fun RequestValidationConfig.validatePutAccountCurrentUsernameRequest() {
+    validate<PutAccountCurrentUsernameRequest> { request ->
+        when {
+            !REGEX_USERNAME.matches(request.username) -> Invalid("")
+            else -> Valid
+        }
+    }
+}

backend/src/main/kotlin/com/infendro/account/dto/request/PutAccountIdRoleRequest.kt

@@ -0,0 +1,9 @@
+package com.infendro.account.dto.request
+
+import com.infendro.account.model.Role
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class PutAccountIdRoleRequest(
+    val role: Role,
+)

backend/src/main/kotlin/com/infendro/account/dto/response/AccessResponse.kt

@@ -0,0 +1,13 @@
+package com.infendro.account.dto.response
+
+import com.infendro.account.model.entity.AccessEntity
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class AccessResponse(
+    val id: Long,
+)
+
+fun AccessEntity.toResponse() = AccessResponse(
+    id = id.value,
+)

backend/src/main/kotlin/com/infendro/account/dto/response/AccountResponse.kt

@@ -0,0 +1,23 @@
+package com.infendro.account.dto.response
+
+import com.infendro.account.model.Role
+import com.infendro.account.model.entity.AccountEntity
+import com.infendro.account.model.entity.SessionEntity
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class AccountResponse(
+    val id: Long,
+    val username: String,
+    val role: Role,
+    val sessions: List<SessionResponse>,
+)
+
+fun AccountEntity.toResponse(): AccountResponse {
+    return AccountResponse(
+        id = id.value,
+        username = username,
+        role = role,
+        sessions = sessions().map(SessionEntity::toResponse),
+    )
+}

backend/src/main/kotlin/com/infendro/account/dto/response/PostAccessResponse.kt

@@ -0,0 +1,8 @@
+package com.infendro.account.dto.response
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class PostAccessResponse(
+    val token: String,
+)

backend/src/main/kotlin/com/infendro/account/dto/response/PostAccountResponse.kt

@@ -0,0 +1,8 @@
+package com.infendro.account.dto.response
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class PostAccountResponse(
+    val secret: String,
+)

backend/src/main/kotlin/com/infendro/account/dto/response/RoleResponse.kt

@@ -0,0 +1,15 @@
+package com.infendro.account.dto.response
+
+import com.infendro.account.model.Role
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class RoleResponse(
+    val role: Role,
+    val children: List<Role>,
+)
+
+fun Role.toResponse() = RoleResponse(
+    role = this,
+    children = children,
+)

backend/src/main/kotlin/com/infendro/account/dto/response/SessionResponse.kt

@@ -0,0 +1,17 @@
+package com.infendro.account.dto.response
+
+import com.infendro.account.model.entity.SessionEntity
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class SessionResponse(
+    val id: Long,
+    val accountId: Long,
+)
+
+fun SessionEntity.toResponse(): SessionResponse {
+    return SessionResponse(
+        id = id.value,
+        accountId = account().id.value,
+    )
+}

backend/src/main/kotlin/com/infendro/account/exception/StatusException.kt

@@ -0,0 +1,7 @@
+package com.infendro.account.exception
+
+import io.ktor.http.HttpStatusCode
+
+abstract class StatusException(
+    val status: HttpStatusCode,
+) : Exception()

backend/src/main/kotlin/com/infendro/account/exception/client/BadRequestException.kt

@@ -0,0 +1,6 @@
+package com.infendro.account.exception.client
+
+import com.infendro.account.exception.StatusException
+import io.ktor.http.HttpStatusCode.Companion.BadRequest
+
+class BadRequestException : StatusException(BadRequest)

backend/src/main/kotlin/com/infendro/account/exception/client/ConflictException.kt

@@ -0,0 +1,6 @@
+package com.infendro.account.exception.client
+
+import com.infendro.account.exception.StatusException
+import io.ktor.http.HttpStatusCode.Companion.Conflict
+
+class ConflictException : StatusException(Conflict)

backend/src/main/kotlin/com/infendro/account/exception/client/ForbiddenException.kt

@@ -0,0 +1,6 @@
+package com.infendro.account.exception.client
+
+import com.infendro.account.exception.StatusException
+import io.ktor.http.HttpStatusCode.Companion.Forbidden
+
+class ForbiddenException : StatusException(Forbidden)

backend/src/main/kotlin/com/infendro/account/exception/client/NotFoundException.kt

@@ -0,0 +1,6 @@
+package com.infendro.account.exception.client
+
+import com.infendro.account.exception.StatusException
+import io.ktor.http.HttpStatusCode.Companion.NotFound
+
+class NotFoundException : StatusException(NotFound)

backend/src/main/kotlin/com/infendro/account/exception/client/UnauthorizedException.kt

@@ -0,0 +1,6 @@
+package com.infendro.account.exception.client
+
+import com.infendro.account.exception.StatusException
+import io.ktor.http.HttpStatusCode.Companion.Unauthorized
+
+class UnauthorizedException : StatusException(Unauthorized)

backend/src/main/kotlin/com/infendro/account/exception/server/InternalServerErrorException.kt

@@ -0,0 +1,6 @@
+package com.infendro.account.exception.server
+
+import com.infendro.account.exception.StatusException
+import io.ktor.http.HttpStatusCode.Companion.InternalServerError
+
+class InternalServerErrorException : StatusException(InternalServerError)

backend/src/main/kotlin/com/infendro/account/exception/server/NotImplementedException.kt

@@ -0,0 +1,6 @@
+package com.infendro.account.exception.server
+
+import com.infendro.account.exception.StatusException
+import io.ktor.http.HttpStatusCode.Companion.NotImplemented
+
+class NotImplementedException : StatusException(NotImplemented)

backend/src/main/kotlin/com/infendro/account/model/Initialization.kt

@@ -0,0 +1,44 @@
+package com.infendro.account.model
+
+import com.infendro.account.model.entity.InitializationTable
+import com.infendro.account.model.repository.AccountRepository
+import com.infendro.account.model.repository.InitializationRepository
+import com.infendro.account.util.SecureHasher
+import io.ktor.server.application.Application
+import org.jetbrains.exposed.sql.SqlExpressionBuilder.eq
+import org.koin.ktor.ext.inject
+
+fun Application.initializeDatabase() {
+    owner()
+}
+
+private fun Application.owner() = initialize("owner") {
+    val accountRepository by inject<AccountRepository>()
+
+    accountRepository.insert {
+        val salt = SecureHasher.generateSalt()
+
+        this.username = "infendro"
+        this.passwordHash = SecureHasher.hash("password", salt)
+        this.passwordSalt = salt
+        this.secret = "deadbeef"
+        this.role = Role.OWNER
+    }
+}
+
+private fun Application.initialize(
+    name: String,
+    block: () -> Unit,
+) {
+    val initializationRepository by inject<InitializationRepository>()
+
+    initializationRepository
+        .singleOrNull { InitializationTable.name eq name }
+        ?.run { return }
+
+    block()
+
+    initializationRepository.insert {
+        this.name = name
+    }
+}

backend/src/main/kotlin/com/infendro/account/model/Role.kt

@@ -0,0 +1,34 @@
+package com.infendro.account.model
+
+enum class Role(
+    val children: List<Role> = listOf(),
+) {
+    USER,
+    OWNER(
+        children = listOf(USER),
+    );
+
+    fun hasChild(
+        role: Role,
+    ): Boolean {
+        return children.contains(role)
+    }
+
+    companion object {
+        val ALL = entries.toList()
+    }
+}
+
+infix fun List<Role>.except(
+    roles: List<Role>,
+): List<Role> {
+    return filterNot { it in roles }
+        .toList()
+}
+
+infix fun List<Role>.except(
+    role: Role,
+): List<Role> {
+    return filterNot { it == role }
+        .toList()
+}

backend/src/main/kotlin/com/infendro/account/model/entity/Access.kt

@@ -0,0 +1,16 @@
+package com.infendro.account.model.entity
+
+import org.jetbrains.exposed.dao.LongEntity
+import org.jetbrains.exposed.dao.LongEntityClass
+import org.jetbrains.exposed.dao.id.EntityID
+import org.jetbrains.exposed.dao.id.LongIdTable
+
+object AccessTable : LongIdTable("access", "id") {
+    val tokenHash = text("token_hash")
+}
+
+class AccessEntity(id: EntityID<Long>) : LongEntity(id) {
+    companion object : LongEntityClass<AccessEntity>(AccessTable)
+
+    var tokenHash by AccessTable.tokenHash
+}

backend/src/main/kotlin/com/infendro/account/model/entity/Account.kt

@@ -0,0 +1,39 @@
+package com.infendro.account.model.entity
+
+import com.infendro.account.model.Role
+import org.jetbrains.exposed.dao.LongEntity
+import org.jetbrains.exposed.dao.LongEntityClass
+import org.jetbrains.exposed.dao.id.EntityID
+import org.jetbrains.exposed.dao.id.LongIdTable
+import org.jetbrains.exposed.sql.transactions.transaction
+
+object AccountTable : LongIdTable("account", "id") {
+    val username = text("username")
+    val passwordHash = text("password_hash")
+    val passwordSalt = text("password_salt")
+    val secret = text("secret")
+    val role = customEnumeration(
+        "role",
+        fromDb = {
+            when (it) {
+                is String -> Role.valueOf(it)
+                else -> throw Error()
+            }
+        },
+        toDb = { it.name }
+    )
+}
+
+class AccountEntity(id: EntityID<Long>) : LongEntity(id) {
+    companion object : LongEntityClass<AccountEntity>(AccountTable)
+
+    var username by AccountTable.username
+    var passwordHash by AccountTable.passwordHash
+    var passwordSalt by AccountTable.passwordSalt
+    var secret by AccountTable.secret
+    var role by AccountTable.role
+
+    val sessions by SessionEntity referrersOn SessionTable.accountId
+
+    fun sessions() = transaction { sessions.toList() }
+}

backend/src/main/kotlin/com/infendro/account/model/entity/Initialization.kt

@@ -0,0 +1,16 @@
+package com.infendro.account.model.entity
+
+import org.jetbrains.exposed.dao.LongEntity
+import org.jetbrains.exposed.dao.LongEntityClass
+import org.jetbrains.exposed.dao.id.EntityID
+import org.jetbrains.exposed.dao.id.LongIdTable
+
+object InitializationTable : LongIdTable("initialization", "id") {
+    val name = text("name")
+}
+
+class InitializationEntity(id: EntityID<Long>) : LongEntity(id) {
+    companion object : LongEntityClass<InitializationEntity>(InitializationTable)
+
+    var name by InitializationTable.name
+}

backend/src/main/kotlin/com/infendro/account/model/entity/Session.kt

@@ -0,0 +1,21 @@
+package com.infendro.account.model.entity
+
+import org.jetbrains.exposed.dao.LongEntity
+import org.jetbrains.exposed.dao.LongEntityClass
+import org.jetbrains.exposed.dao.id.EntityID
+import org.jetbrains.exposed.dao.id.LongIdTable
+import org.jetbrains.exposed.sql.transactions.transaction
+
+object SessionTable : LongIdTable("session", "id") {
+    val tokenHash = text("token_hash")
+    val accountId = reference("account_id", AccountTable.id)
+}
+
+class SessionEntity(id: EntityID<Long>) : LongEntity(id) {
+    companion object : LongEntityClass<SessionEntity>(SessionTable)
+
+    var tokenHash by SessionTable.tokenHash
+    var account by AccountEntity referencedOn SessionTable.accountId
+
+    fun account() = transaction { account }
+}

backend/src/main/kotlin/com/infendro/account/model/repository/AccessRepository.kt

@@ -0,0 +1,5 @@
+package com.infendro.account.model.repository
+
+import com.infendro.account.model.entity.AccessEntity
+
+class AccessRepository : Repository<AccessEntity>(AccessEntity)

backend/src/main/kotlin/com/infendro/account/model/repository/AccountRepository.kt

@@ -0,0 +1,5 @@
+package com.infendro.account.model.repository
+
+import com.infendro.account.model.entity.AccountEntity
+
+class AccountRepository : Repository<AccountEntity>(AccountEntity)

backend/src/main/kotlin/com/infendro/account/model/repository/InitializationRepository.kt

@@ -0,0 +1,5 @@
+package com.infendro.account.model.repository
+
+import com.infendro.account.model.entity.InitializationEntity
+
+class InitializationRepository : Repository<InitializationEntity>(InitializationEntity)

backend/src/main/kotlin/com/infendro/account/model/repository/Repository.kt

@@ -0,0 +1,124 @@
+package com.infendro.account.model.repository
+
+import org.jetbrains.exposed.dao.LongEntity
+import org.jetbrains.exposed.dao.LongEntityClass
+import org.jetbrains.exposed.sql.Op
+import org.jetbrains.exposed.sql.transactions.transaction
+
+abstract class Repository<ENTITY : LongEntity>(
+    private val entityClass: LongEntityClass<ENTITY>,
+) {
+    fun all(): List<ENTITY> = transaction {
+        entityClass.all().toList()
+    }
+
+    fun all(
+        where: Op<Boolean>,
+    ): List<ENTITY> = transaction {
+        entityClass.find(where).toList()
+    }
+
+    fun all(
+        where: () -> Op<Boolean>,
+    ): List<ENTITY> {
+        return all(where())
+    }
+
+    fun single(
+        where: Op<Boolean>,
+    ): ENTITY = transaction {
+        entityClass.find(where).single()
+    }
+
+    fun single(
+        where: () -> Op<Boolean>,
+    ): ENTITY {
+        return single(where())
+    }
+
+    fun singleOrNull(
+        where: Op<Boolean>,
+    ): ENTITY? = transaction {
+        entityClass.find(where).singleOrNull()
+    }
+
+    fun singleOrNull(
+        where: () -> Op<Boolean>,
+    ): ENTITY? {
+        return singleOrNull(where())
+    }
+
+    fun exists(
+        where: Op<Boolean>,
+    ): Boolean {
+        return all(where).isNotEmpty()
+    }
+
+    fun exists(
+        where: () -> Op<Boolean>,
+    ): Boolean {
+        return exists(where())
+    }
+
+    fun insert(
+        block: ENTITY.() -> Unit,
+    ): Unit = transaction {
+        entityClass.new(block)
+    }
+
+    fun update(
+        entity: ENTITY,
+        block: ENTITY.() -> Unit,
+    ): Unit = transaction {
+        entity.block()
+    }
+
+    fun update(
+        entities: Iterable<ENTITY>,
+        block: ENTITY.() -> Unit,
+    ) {
+        for (entity in entities) {
+            update(entity, block)
+        }
+    }
+
+    fun update(
+        where: Op<Boolean>,
+        block: ENTITY.() -> Unit,
+    ) {
+        update(all(where), block)
+    }
+
+    fun update(
+        where: () -> Op<Boolean>,
+        block: ENTITY.() -> Unit,
+    ) {
+        update(where(), block)
+    }
+
+    fun delete(
+        entity: ENTITY,
+    ): Unit = transaction {
+        entity.delete()
+    }
+
+    fun delete(
+        entities: Iterable<ENTITY>,
+    ) {
+        for (entity in entities) {
+            delete(entity)
+        }
+    }
+
+    fun delete(
+        where: Op<Boolean>,
+    ) {
+        delete(all(where))
+    }
+
+    fun delete(
+        where: () -> Op<Boolean>,
+    ) {
+        delete(where())
+    }
+}

backend/src/main/kotlin/com/infendro/account/model/repository/SessionRepository.kt

@@ -0,0 +1,5 @@
+package com.infendro.account.model.repository
+
+import com.infendro.account.model.entity.SessionEntity
+
+class SessionRepository : Repository<SessionEntity>(SessionEntity)

backend/src/main/kotlin/com/infendro/account/routing/Access.kt

@@ -0,0 +1,56 @@
+package com.infendro.account.routing
+
+import com.infendro.account.config.AuthenticationPrincipal
+import com.infendro.account.service.AccessService
+import io.ktor.http.HttpStatusCode.Companion.OK
+import io.ktor.resources.Resource
+import io.ktor.server.auth.authenticate
+import io.ktor.server.auth.principal
+import io.ktor.server.resources.delete
+import io.ktor.server.resources.get
+import io.ktor.server.resources.post
+import io.ktor.server.response.respond
+import io.ktor.server.routing.Routing
+import org.koin.ktor.ext.inject
+
+@Resource("/access")
+private class Access {
+    @Resource("/all")
+    class All(
+        val parent: Access,
+    )
+
+    @Resource("/{id}")
+    class Id(
+        val parent: Access,
+        val id: Long,
+    )
+}
+
+fun Routing.access() {
+    val accessService by inject<AccessService>()
+
+    authenticate {
+        post<Access> {
+            val principal = call.principal<AuthenticationPrincipal>()!!
+
+            accessService.post(principal)
+                .also { call.respond(it) }
+        }
+
+        get<Access.All> {
+            val principal = call.principal<AuthenticationPrincipal>()!!
+
+            accessService.getAll(principal)
+                .also { call.respond(it) }
+        }
+
+        delete<Access.Id> { resource ->
+            val principal = call.principal<AuthenticationPrincipal>()!!
+            val id = resource.id
+
+            accessService.deleteId(principal, id)
+            call.respond(OK)
+        }
+    }
+}

backend/src/main/kotlin/com/infendro/account/routing/Account.kt

@@ -0,0 +1,153 @@
+package com.infendro.account.routing
+
+import com.infendro.account.config.AuthenticationPrincipal
+import com.infendro.account.dto.request.PostAccountRequest
+import com.infendro.account.dto.request.PutAccountCurrentPasswordRequest
+import com.infendro.account.dto.request.PutAccountCurrentUsernameRequest
+import com.infendro.account.dto.request.PutAccountIdRoleRequest
+import com.infendro.account.service.AccountService
+import io.ktor.http.HttpStatusCode.Companion.OK
+import io.ktor.resources.Resource
+import io.ktor.server.auth.authenticate
+import io.ktor.server.auth.principal
+import io.ktor.server.request.receive
+import io.ktor.server.resources.delete
+import io.ktor.server.resources.get
+import io.ktor.server.resources.post
+import io.ktor.server.resources.put
+import io.ktor.server.response.respond
+import io.ktor.server.routing.Routing
+import io.ktor.server.sessions.sessions
+import org.koin.ktor.ext.inject
+
+@Resource("/account")
+private class Account {
+    @Resource("/all")
+    class All(
+        val parent: Account,
+    )
+
+    @Resource("/current")
+    class Current(
+        val parent: Account,
+    ) {
+        @Resource("/username")
+        class Username(
+            val parent: Current,
+        )
+
+        @Resource("/password")
+        class Password(
+            val parent: Current,
+        )
+
+        @Resource("/session")
+        class Session(
+            val parent: Current,
+        ) {
+            @Resource("/all")
+            class All(
+                val parent: Session,
+            )
+
+            @Resource("/{id}")
+            class Id(
+                val parent: Session,
+                val id: Long,
+            )
+        }
+    }
+
+    @Resource("/{id}")
+    class Id(
+        val parent: Account,
+        val id: Long,
+    ) {
+        @Resource("/role")
+        class Role(
+            val parent: Id,
+        )
+    }
+}
+
+fun Routing.account() {
+    val accountService by inject<AccountService>()
+
+    post<Account> {
+        val request = call.receive<PostAccountRequest>()
+
+        accountService.post(request)
+            .also { call.respond(it) }
+    }
+
+    authenticate {
+        get<Account.All> {
+            val principal = call.principal<AuthenticationPrincipal>()!!
+
+            accountService.getAll(principal)
+                .also { call.respond(it) }
+        }
+
+        get<Account.Current> {
+            val principal = call.principal<AuthenticationPrincipal>()!!
+
+            accountService.getCurrent(principal)
+                .also { call.respond(it) }
+        }
+
+        delete<Account.Current> {
+            val principal = call.principal<AuthenticationPrincipal>()!!
+
+            accountService.deleteCurrent(principal)
+            call.respond(OK)
+        }
+
+        put<Account.Current.Username> {
+            val principal = call.principal<AuthenticationPrincipal>()!!
+            val request = call.receive<PutAccountCurrentUsernameRequest>()
+
+            accountService.putCurrentUsername(principal, call.sessions, request)
+            call.respond(OK)
+        }
+
+        put<Account.Current.Password> {
+            val principal = call.principal<AuthenticationPrincipal>()!!
+            val request = call.receive<PutAccountCurrentPasswordRequest>()
+
+            accountService.putCurrentPassword(principal, call.sessions, request)
+            call.respond(OK)
+        }
+
+        get<Account.Current.Session.All> {
+            val principal = call.principal<AuthenticationPrincipal>()!!
+
+            accountService.getCurrentSessionAll(principal)
+                .also { call.respond(it) }
+        }
+
+        delete<Account.Current.Session.Id> { resource ->
+            val principal = call.principal<AuthenticationPrincipal>()!!
+            val id = resource.id
+
+            accountService.deleteCurrentSessionId(principal, call.sessions, id)
+            call.respond(OK)
+        }
+
+        delete<Account.Id> { resource ->
+            val principal = call.principal<AuthenticationPrincipal>()!!
+            val id = resource.id
+
+            accountService.deleteId(principal, id)
+            call.respond(OK)
+        }
+
+        put<Account.Id.Role> { resource ->
+            val principal = call.principal<AuthenticationPrincipal>()!!
+            val id = resource.parent.id
+            val request = call.receive<PutAccountIdRoleRequest>()
+
+            accountService.putIdRole(principal, id, request)
+            call.respond(OK)
+        }
+    }
+}

backend/src/main/kotlin/com/infendro/account/routing/Role.kt

@@ -0,0 +1,25 @@
+package com.infendro.account.routing
+
+import com.infendro.account.service.RoleService
+import io.ktor.resources.Resource
+import io.ktor.server.resources.get
+import io.ktor.server.response.respond
+import io.ktor.server.routing.Routing
+import org.koin.ktor.ext.inject
+
+@Resource("/role")
+private class Role {
+    @Resource("/all")
+    class All(
+        val parent: Role,
+    )
+}
+
+fun Routing.role() {
+    val roleService by inject<RoleService>()
+
+    get<Role.All> {
+        roleService.getAll()
+            .also { call.respond(it) }
+    }
+}

backend/src/main/kotlin/com/infendro/account/routing/Session.kt

@@ -0,0 +1,78 @@
+package com.infendro.account.routing
+
+import com.infendro.account.config.AuthenticationPrincipal
+import com.infendro.account.dto.request.PostSessionRequest
+import com.infendro.account.service.SessionService
+import io.ktor.http.HttpStatusCode.Companion.OK
+import io.ktor.resources.Resource
+import io.ktor.server.auth.authenticate
+import io.ktor.server.auth.principal
+import io.ktor.server.request.receive
+import io.ktor.server.resources.delete
+import io.ktor.server.resources.get
+import io.ktor.server.resources.post
+import io.ktor.server.response.respond
+import io.ktor.server.routing.Routing
+import io.ktor.server.sessions.sessions
+import org.koin.ktor.ext.inject
+
+@Resource("/session")
+private class Session {
+    @Resource("/all")
+    class All(
+        val parent: Session,
+    )
+
+    @Resource("/{id}")
+    class Id(
+        val parent: Session,
+        val id: Long,
+    )
+
+    @Resource("/current")
+    class Current(
+        val parent: Session,
+    )
+}
+
+fun Routing.session() {
+    val sessionService by inject<SessionService>()
+
+    post<Session> {
+        val request = call.receive<PostSessionRequest>()
+
+        sessionService.post(call.sessions, request)
+        call.respond(OK)
+    }
+
+    authenticate {
+        get<Session.All> {
+            val principal = call.principal<AuthenticationPrincipal>()!!
+
+            sessionService.getAll(principal)
+                .also { call.respond(it) }
+        }
+
+        delete<Session.Id> { resource ->
+            val principal = call.principal<AuthenticationPrincipal>()!!
+            val id = resource.id
+
+            sessionService.deleteId(principal, id)
+            call.respond(OK)
+        }
+
+        get<Session.Current> {
+            val principal = call.principal<AuthenticationPrincipal>()!!
+
+            sessionService.getCurrent(principal)
+                .also { call.respond(it) }
+        }
+
+        delete<Session.Current> {
+            val principal = call.principal<AuthenticationPrincipal>()!!
+
+            sessionService.deleteCurrent(principal, call.sessions)
+            call.respond(OK)
+        }
+    }
+}

backend/src/main/kotlin/com/infendro/account/service/AccessService.kt

@@ -0,0 +1,59 @@
+package com.infendro.account.service
+
+import com.infendro.account.config.AuthenticationPrincipal
+import com.infendro.account.dto.response.AccessResponse
+import com.infendro.account.dto.response.PostAccessResponse
+import com.infendro.account.dto.response.toResponse
+import com.infendro.account.exception.client.ForbiddenException
+import com.infendro.account.exception.client.NotFoundException
+import com.infendro.account.model.Role.OWNER
+import com.infendro.account.model.entity.AccessTable
+import com.infendro.account.model.repository.AccessRepository
+import com.infendro.account.util.Hasher
+import com.infendro.account.util.TokenGenerator
+import org.jetbrains.exposed.sql.SqlExpressionBuilder.eq
+
+class AccessService(
+    private val accessRepository: AccessRepository,
+) {
+    fun post(
+        principal: AuthenticationPrincipal,
+    ): PostAccessResponse {
+        if (principal.role != OWNER)
+            throw ForbiddenException()
+
+        val token = TokenGenerator.generate()
+        accessRepository.insert {
+            this.tokenHash = Hasher.hash(token)
+        }
+
+        return PostAccessResponse(
+            token = token
+        )
+    }
+
+    fun getAll(
+        principal: AuthenticationPrincipal,
+    ): List<AccessResponse> {
+        if (principal.role != OWNER)
+            throw ForbiddenException()
+
+        return accessRepository
+            .all()
+            .map { it.toResponse() }
+    }
+
+    fun deleteId(
+        principal: AuthenticationPrincipal,
+        id: Long,
+    ) {
+        if (principal.role != OWNER)
+            throw ForbiddenException()
+
+        val access = accessRepository
+            .singleOrNull { AccessTable.id eq id }
+            ?: throw NotFoundException()
+
+        accessRepository.delete(access)
+    }
+}

backend/src/main/kotlin/com/infendro/account/service/AccountService.kt

@@ -0,0 +1,189 @@
+package com.infendro.account.service
+
+import com.infendro.account.config.AuthenticationPrincipal
+import com.infendro.account.config.AuthenticationSession
+import com.infendro.account.dto.request.PostAccountRequest
+import com.infendro.account.dto.request.PutAccountCurrentPasswordRequest
+import com.infendro.account.dto.request.PutAccountCurrentUsernameRequest
+import com.infendro.account.dto.request.PutAccountIdRoleRequest
+import com.infendro.account.dto.response.AccountResponse
+import com.infendro.account.dto.response.PostAccountResponse
+import com.infendro.account.dto.response.SessionResponse
+import com.infendro.account.dto.response.toResponse
+import com.infendro.account.exception.client.ConflictException
+import com.infendro.account.exception.client.ForbiddenException
+import com.infendro.account.exception.client.NotFoundException
+import com.infendro.account.exception.client.UnauthorizedException
+import com.infendro.account.model.Role.OWNER
+import com.infendro.account.model.Role.USER
+import com.infendro.account.model.entity.AccessTable
+import com.infendro.account.model.entity.AccountEntity
+import com.infendro.account.model.entity.AccountTable
+import com.infendro.account.model.entity.SessionTable
+import com.infendro.account.model.repository.AccessRepository
+import com.infendro.account.model.repository.AccountRepository
+import com.infendro.account.model.repository.SessionRepository
+import com.infendro.account.util.Hasher
+import com.infendro.account.util.OTP
+import com.infendro.account.util.SecureHasher
+import io.ktor.server.sessions.CurrentSession
+import io.ktor.server.sessions.clear
+import org.jetbrains.exposed.sql.SqlExpressionBuilder.eq
+
+class AccountService(
+    private val accessRepository: AccessRepository,
+    private val accountRepository: AccountRepository,
+    private val sessionRepository: SessionRepository,
+) {
+    fun post(
+        request: PostAccountRequest,
+    ): PostAccountResponse {
+        val access = accessRepository
+            .singleOrNull { AccessTable.tokenHash eq Hasher.hash(request.access.token) }
+            ?: throw UnauthorizedException()
+
+        accountRepository
+            .singleOrNull { AccountTable.username eq request.username }
+            ?.run { throw ConflictException() }
+
+        accessRepository.delete(access)
+
+        val secret = OTP.generateSecret()
+        accountRepository.insert {
+            val salt = SecureHasher.generateSalt()
+
+            this.username = request.username
+            this.passwordHash = SecureHasher.hash(request.password, salt)
+            this.passwordSalt = salt
+            this.secret = secret
+            this.role = USER
+        }
+
+        return PostAccountResponse(
+            secret = secret
+        )
+    }
+
+    fun getAll(
+        principal: AuthenticationPrincipal,
+    ): List<AccountResponse> {
+        if (principal.role != OWNER)
+            throw ForbiddenException()
+
+        return accountRepository
+            .all()
+            .map(AccountEntity::toResponse)
+    }
+
+    fun getCurrent(
+        principal: AuthenticationPrincipal,
+    ): AccountResponse {
+        val (account, _) = principal
+
+        return account.toResponse()
+    }
+
+    fun deleteCurrent(
+        principal: AuthenticationPrincipal,
+    ) {
+        if (principal.role == OWNER)
+            throw ForbiddenException()
+
+        accountRepository.delete(principal.account)
+    }
+
+    fun putCurrentUsername(
+        principal: AuthenticationPrincipal,
+        sessions: CurrentSession,
+        request: PutAccountCurrentUsernameRequest,
+    ) {
+        if (!OTP.verify(principal.account.secret, request.otp))
+            throw UnauthorizedException()
+
+        accountRepository.update(principal.account) {
+            this.username = request.username
+        }
+        sessionRepository.delete(principal.account.sessions())
+
+        sessions.clear<AuthenticationSession>()
+
+    }
+
+    fun putCurrentPassword(
+        principal: AuthenticationPrincipal,
+        sessions: CurrentSession,
+        request: PutAccountCurrentPasswordRequest,
+    ) {
+        if (!OTP.verify(principal.account.secret, request.otp))
+            throw UnauthorizedException()
+
+        accountRepository.update(principal.account) {
+            val salt = SecureHasher.generateSalt()
+
+            this.passwordHash = SecureHasher.hash(request.password, salt)
+            this.passwordSalt = salt
+        }
+        sessionRepository.delete(principal.account.sessions())
+
+        sessions.clear<AuthenticationSession>()
+    }
+
+    fun getCurrentSessionAll(
+        principal: AuthenticationPrincipal,
+    ): List<SessionResponse> {
+        return principal.account.sessions()
+            .map { it.toResponse() }
+    }
+
+    fun deleteCurrentSessionId(
+        principal: AuthenticationPrincipal,
+        sessions: CurrentSession,
+        id: Long,
+    ) {
+        val session = sessionRepository
+            .singleOrNull { SessionTable.id eq id }
+            ?: throw NotFoundException()
+
+        if (session.account().id != principal.account.id)
+            throw ForbiddenException()
+
+        sessionRepository.delete(session)
+
+        if (session.id == principal.session.id)
+            sessions.clear<AuthenticationSession>()
+    }
+
+    fun deleteId(
+        principal: AuthenticationPrincipal,
+        id: Long,
+    ) {
+        val account = accountRepository
+            .singleOrNull { AccountTable.id eq id }
+            ?: throw NotFoundException()
+
+        if (!principal.role.hasChild(account.role))
+            throw ForbiddenException()
+
+        accountRepository.delete(account)
+    }
+
+    fun putIdRole(
+        principal: AuthenticationPrincipal,
+        id: Long,
+        request: PutAccountIdRoleRequest,
+    ) {
+        val account = accountRepository
+            .singleOrNull { AccountTable.id eq id }
+            ?: throw NotFoundException()
+
+        if (!principal.role.hasChild(account.role))
+            throw ForbiddenException()
+
+        if (!principal.role.hasChild(request.role))
+            throw ForbiddenException()
+
+        accountRepository.update(account) {
+            role = request.role
+        }
+    }
+}

backend/src/main/kotlin/com/infendro/account/service/RoleService.kt

@@ -0,0 +1,12 @@
+package com.infendro.account.service
+
+import com.infendro.account.dto.response.RoleResponse
+import com.infendro.account.dto.response.toResponse
+import com.infendro.account.model.Role
+
+class RoleService {
+    fun getAll(): List<RoleResponse> {
+        return Role.ALL
+            .map { it.toResponse() }
+    }
+}

backend/src/main/kotlin/com/infendro/account/service/SessionService.kt

@@ -0,0 +1,96 @@
+package com.infendro.account.service
+
+import com.infendro.account.config.AuthenticationPrincipal
+import com.infendro.account.config.AuthenticationSession
+import com.infendro.account.dto.request.PostSessionRequest
+import com.infendro.account.dto.response.SessionResponse
+import com.infendro.account.dto.response.toResponse
+import com.infendro.account.exception.client.ForbiddenException
+import com.infendro.account.exception.client.NotFoundException
+import com.infendro.account.exception.client.UnauthorizedException
+import com.infendro.account.model.Role.USER
+import com.infendro.account.model.entity.AccountTable
+import com.infendro.account.model.entity.SessionTable
+import com.infendro.account.model.repository.AccountRepository
+import com.infendro.account.model.repository.SessionRepository
+import com.infendro.account.util.Hasher
+import com.infendro.account.util.OTP
+import com.infendro.account.util.SecureHasher
+import com.infendro.account.util.TokenGenerator
+import io.ktor.server.sessions.CurrentSession
+import io.ktor.server.sessions.clear
+import io.ktor.server.sessions.set
+import org.jetbrains.exposed.sql.SqlExpressionBuilder.eq
+import org.jetbrains.exposed.sql.SqlExpressionBuilder.inList
+
+class SessionService(
+    private val accountRepository: AccountRepository,
+    private val sessionRepository: SessionRepository,
+) {
+    fun post(
+        sessions: CurrentSession,
+        request: PostSessionRequest,
+    ) {
+        val account = accountRepository
+            .singleOrNull { AccountTable.username eq request.username }
+            ?: throw NotFoundException()
+
+        if (!OTP.verify(account.secret, request.otp))
+            throw UnauthorizedException()
+
+        if (account.passwordHash != SecureHasher.hash(request.password, account.passwordSalt))
+            throw UnauthorizedException()
+
+        val token = TokenGenerator.generate()
+        sessionRepository.insert {
+            this.tokenHash = Hasher.hash(token)
+            this.account = account
+        }
+
+        sessions.set(AuthenticationSession(token))
+    }
+
+    fun getAll(
+        principal: AuthenticationPrincipal,
+    ): List<SessionResponse> {
+        if (principal.role == USER)
+            throw ForbiddenException()
+
+        return accountRepository
+            .all { AccountTable.role inList principal.role.children }
+            .flatMap { it.sessions() }
+            .map { it.toResponse() }
+    }
+
+    fun deleteId(
+        principal: AuthenticationPrincipal,
+        id: Long,
+    ) {
+        if (principal.role == USER)
+            throw ForbiddenException()
+
+        val session = sessionRepository
+            .singleOrNull { SessionTable.id eq id }
+            ?: throw NotFoundException()
+
+        if (session.account().role !in principal.role.children)
+            throw ForbiddenException()
+
+        sessionRepository.delete(session)
+    }
+
+    fun getCurrent(
+        principal: AuthenticationPrincipal,
+    ): SessionResponse {
+        return principal.session.toResponse()
+    }
+
+    fun deleteCurrent(
+        principal: AuthenticationPrincipal,
+        sessions: CurrentSession,
+    ) {
+        sessionRepository.delete(principal.session)
+
+        sessions.clear<AuthenticationSession>()
+    }
+}

backend/src/main/kotlin/com/infendro/account/util/Hasher.kt

@@ -0,0 +1,13 @@
+package com.infendro.account.util
+
+import com.infendro.encoding.Hex
+import com.infendro.hash.SHA256
+
+object Hasher {
+    fun hash(
+        value: String,
+    ): String {
+        val bytes = SHA256.hash(value.toByteArray())
+        return Hex.encode(bytes).toString()
+    }
+}

backend/src/main/kotlin/com/infendro/account/util/OTP.kt

@@ -0,0 +1,31 @@
+package com.infendro.account.util
+
+import com.infendro.encoding.Base32
+import com.infendro.hash.SHA256
+import com.infendro.otp.SecretGenerator
+import com.infendro.otp.TOTP
+import kotlin.time.Clock
+import kotlin.time.Duration.Companion.seconds
+import kotlin.time.ExperimentalTime
+
+@OptIn(ExperimentalTime::class)
+object OTP {
+    private val totp = TOTP(
+        function = SHA256,
+        length = 8,
+        period = 30.seconds,
+    )
+
+    fun verify(
+        secret: String,
+        otp: String,
+    ): Boolean {
+        val bytes = Base32.decode(secret.toByteArray())
+        return totp.verify(bytes, Clock.System.now(), otp)
+    }
+
+    fun generateSecret(): String {
+        val bytes = SecretGenerator.generate(totp.hotp.function)
+        return Base32.encode(bytes).toString()
+    }
+}

backend/src/main/kotlin/com/infendro/account/util/Regex.kt

@@ -0,0 +1,4 @@
+package com.infendro.account.util
+
+val REGEX_USERNAME = """^(?=.{1,32}$)[a-z0-9]+([\-._][a-z0-9]+)*$""".toRegex()
+val REGEX_PASSWORD = """^(?=.{8,}$)[a-zA-Z0-9!"#$%&'()*+,\-./:;<=>?@\[\\\]^_`{|}~]*$""".toRegex()

backend/src/main/kotlin/com/infendro/account/util/SecureHasher.kt

@@ -0,0 +1,26 @@
+package com.infendro.account.util
+
+import com.infendro.encoding.Hex
+import javax.crypto.SecretKeyFactory
+import javax.crypto.spec.PBEKeySpec
+import kotlin.random.Random
+
+// TODO implement PBKDF2
+object SecureHasher {
+    private val factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256")
+    private val random = Random.Default
+
+    fun hash(
+        value: String,
+        salt: String,
+    ): String {
+        val spec = PBEKeySpec(value.toCharArray(), Hex.decode(salt.toByteArray()), 100_000, 256)
+        return factory.generateSecret(spec).encoded
+            .let { Hex.encode(it).toString() }
+    }
+
+    fun generateSalt(): String {
+        return ByteArray(16).also { random.nextBytes(it) }
+            .let { Hex.encode(it).toString() }
+    }
+}

backend/src/main/kotlin/com/infendro/account/util/TokenGenerator.kt

@@ -0,0 +1,15 @@
+package com.infendro.account.util
+
+import com.infendro.encoding.Hex
+import kotlin.random.Random
+
+// TODO implement secure random
+object TokenGenerator {
+    private val random = Random.Default
+
+    fun generate(): String {
+        val bytes = ByteArray(32)
+            .also { random.nextBytes(it) }
+        return Hex.encode(bytes).toString()
+    }
+}

backend/src/main/resources/application.conf

@@ -0,0 +1,20 @@
+ktor {
+    deployment {
+        port = 8080
+    }
+    application {
+        modules = [com.infendro.account.ApplicationKt.module]
+    }
+}
+database {
+    host = ${DATABASE_HOST}
+    username = ${DATABASE_USERNAME}
+    password = ${DATABASE_PASSWORD}
+}
+security {
+    cookie {
+        domain = ${COOKIE_DOMAIN}
+        path = ${COOKIE_PATH}
+        secure = ${COOKIE_SECURE}
+    }
+}

backend/src/main/resources/db/migration/V1__Initial.sql

@@ -0,0 +1,44 @@
+CREATE TABLE initialization
+(
+    id   BIGSERIAL
+        PRIMARY KEY,
+    name TEXT
+        UNIQUE
+        NOT NULL
+);
+
+CREATE TABLE access
+(
+    id         BIGSERIAL
+        PRIMARY KEY,
+    token_hash TEXT
+        NOT NULL
+);
+
+CREATE TABLE account
+(
+    id            BIGSERIAL
+        PRIMARY KEY,
+    username      TEXT
+        UNIQUE
+        NOT NULL,
+    password_hash TEXT
+        NOT NULL,
+    password_salt TEXT
+        NOT NULL,
+    secret        TEXT
+        NOT NULL,
+    role          TEXT
+        NOT NULL
+);
+
+CREATE TABLE session
+(
+    id         BIGSERIAL
+        PRIMARY KEY,
+    token_hash TEXT
+        NOT NULL,
+    account_id BIGINT
+        REFERENCES account (id) ON DELETE CASCADE
+        NOT NULL
+);

backend/src/main/resources/logback.xml

@@ -0,0 +1,10 @@
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%date{YYYY-MM-dd HH:mm:ss.SSS} %highlight(%level) %logger{0} - %message%n</pattern>
+        </encoder>
+    </appender>
+    <root level="INFO">
+        <appender-ref ref="STDOUT"/>
+    </root>
+</configuration>