1 files changed, 68 insertions, 0 deletions
diff --git a/src/main/kotlin/moe/nea/ledger/database/DBUpgrade.kt b/src/main/kotlin/moe/nea/ledger/database/DBUpgrade.kt
new file mode 100644
index 0000000..7d1782a
--- /dev/null
+++ b/src/main/kotlin/moe/nea/ledger/database/DBUpgrade.kt
@@ -0,0 +1,68 @@
+package moe.nea.ledger.database
+
+import java.sql.Connection
+
+interface DBUpgrade {
+	val toVersion: Long
+	val fromVersion get() = toVersion - 1
+	fun performUpgrade(connection: Connection)
+
+	companion object {
+
+		fun performUpgrades(
+			connection: Connection,
+			upgrades: Iterable<DBUpgrade>,
+		) {
+			for (upgrade in upgrades) {
+				upgrade.performUpgrade(connection)
+			}
+		}
+
+		fun performUpgradeChain(
+			connection: Connection,
+			from: Long, to: Long,
+			upgrades: Iterable<DBUpgrade>,
+			afterEach: (newVersion: Long) -> Unit,
+		) {
+			val table = buildLookup(upgrades)
+			for (version in (from + 1)..(to)) {
+				val currentUpgrades = table[version] ?: listOf()
+				println("Scheduled ${currentUpgrades.size} upgrades to reach DB version $version")
+				performUpgrades(connection, currentUpgrades)
+				afterEach(version)
+			}
+		}
+
+		fun buildLookup(upgrades: Iterable<DBUpgrade>): Map<Long, List<DBUpgrade>> {
+			return upgrades.groupBy { it.toVersion }
+		}
+
+		fun createTable(to: Long, table: Table, vararg columns: Column<*>): DBUpgrade {
+			require(columns.all { it in table.columns })
+			return of("Create table ${table}", to) {
+				table.createIfNotExists(it, columns.toList())
+			}
+		}
+
+		fun addColumns(to: Long, table: Table, vararg columns: Column<*>): DBUpgrade {
+			return of("Add columns to table $table", to) {
+				table.alterTableAddColumns(it, columns.toList())
+			}
+		}
+
+		fun of(name: String, to: Long, block: (Connection) -> Unit): DBUpgrade {
+			return object : DBUpgrade {
+				override val toVersion: Long
+					get() = to
+
+				override fun performUpgrade(connection: Connection) {
+					block(connection)
+				}
+
+				override fun toString(): String {
+					return name
+				}
+			}
+		}
+	}
+}
+\ No newline at end of file