refactor package

src/main/kotlin/com/infendro/ktor/migration/Plugin.kt

@@ -0,0 +1,55 @@
+package com.infendro.ktor.migration
+
+import com.infendro.ktor.migration.model.MigrationRepository
+import com.infendro.ktor.migration.model.MigrationTable
+import io.ktor.server.application.*
+import org.jetbrains.exposed.sql.SchemaUtils
+import org.jetbrains.exposed.sql.Transaction
+import org.jetbrains.exposed.sql.transactions.transaction
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
+
+internal val logger: Logger = LoggerFactory.getLogger("Database")
+
+val Migration = createApplicationPlugin(
+    name = "Migration",
+    createConfiguration = { MigrationConfig() },
+) {
+    transaction {
+        SchemaUtils.create(MigrationTable)
+    }
+
+    val (migrations) = pluginConfig
+    for ((name, body) in migrations) {
+        if (MigrationRepository.exists(name))
+            continue
+
+        transaction {
+            try {
+                body()
+                logger.info("""Migration "$name" successful""")
+            } catch (e: Exception) {
+                logger.error("""Migration "$name" failed""")
+                throw e
+            }
+        }
+
+        MigrationRepository.insert(name)
+    }
+}
+
+data class MigrationConfig(
+    internal val migrations: MutableList<Migration> = mutableListOf()
+) {
+    fun migration(
+        name: String,
+        block: Transaction.() -> Unit,
+    ) {
+        migrations += Migration(name, block)
+    }
+
+    data class Migration(
+        val name: String,
+        val body: Transaction.() -> Unit
+    )
+}

src/main/kotlin/com/infendro/ktor/migration/model/Migration.kt

@@ -0,0 +1,16 @@
+package com.infendro.ktor.migration.model
+
+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 MigrationTable : LongIdTable("migration", "id") {
+    val name = text("name")
+}
+
+class MigrationEntity(id: EntityID<Long>) : LongEntity(id) {
+    companion object : LongEntityClass<MigrationEntity>(MigrationTable)
+
+    var name by MigrationTable.name
+}

src/main/kotlin/com/infendro/ktor/migration/model/MigrationRepository.kt

@@ -0,0 +1,22 @@
+package com.infendro.ktor.migration.model
+
+import org.jetbrains.exposed.sql.transactions.transaction
+
+object MigrationRepository {
+    fun exists(
+        name: String,
+    ): Boolean = transaction {
+        MigrationEntity
+            .find { MigrationTable.name eq name }
+            .any()
+    }
+
+    fun insert(
+        name: String,
+    ): Unit = transaction {
+        MigrationEntity
+            .new {
+                this.name = name
+            }
+    }
+}