package de.steamwar.commands.world

import com.github.ajalt.clikt.core.CliktCommand
import de.steamwar.db.Database
import de.steamwar.sql.SteamwarUser
import de.steamwar.sql.SteamwarWorld
import de.steamwar.sql.UserConfig
import org.jetbrains.exposed.v1.jdbc.transactions.transaction
import java.io.File
import java.sql.SQLException
import java.util.UUID

class MigrationCommand : CliktCommand(name = "migrate") {
    private val userWorldPattern = Regex("""userworlds(\d+)""")
    private val builderWorldPattern = Regex("""builder(\d+)""")
    private val trailingVersionPattern = Regex("""(\d+)$""")

    override fun run() {
        Database.ensureConnected()

        val bau = migrateBauWorlds()
        val builder = migrateBuilderWorlds()
        val arena = migrateArenaWorlds()
        migrateBauLockConfig()
        migrateBauweltMembers()

        echo("Imported ${bau.imported} build worlds, skipped ${bau.skipped}, missing users ${bau.missingOwner}.")
        echo("Imported ${builder.imported} builder worlds, skipped ${builder.skipped}.")
        echo("Imported ${arena.imported} arena worlds, skipped ${arena.skipped}.")
        echo("World migration completed.")
    }

    private fun migrateBauWorlds(): MigrationStats {
        val stats = MigrationStats()
        val worldsRoot = File("/worlds")
        worldsRoot.listFiles { file -> file.isDirectory && userWorldPattern.matches(file.name) }
            ?.forEach { versionFolder ->
                val version = userWorldPattern.matchEntire(versionFolder.name)!!.groupValues[1].toInt()
                versionFolder.listFiles { file -> file.isDirectory && isWorldDirectory(file) }
                    ?.sortedBy { it.name }
                    ?.forEach { legacyWorld ->
                        val owner = legacyWorld.ownerUser()
                        if (owner == null) {
                            stats.missingOwner++
                            echo("Skipped build world ${legacyWorld.path}: no matching user.")
                            return@forEach
                        }

                        val lockState = UserConfig.getConfig(owner.id.value, BAU_LOCK_CONFIG_NAME)
                        val world = SteamwarWorld.getOrCreateBauWorld(owner, owner.userName, version, legacyWorld)
                        if (world.lockState == null && lockState != null) {
                            world.changeLockState(lockState)
                        }
                        stats.imported++
                    }
            } ?: run {
            stats.skipped++
            echo("Skipped build worlds: /worlds does not exist.")
        }
        return stats
    }

    private fun migrateBuilderWorlds(): MigrationStats {
        val stats = MigrationStats()
        val worldsRoot = File("/worlds")
        worldsRoot.listFiles { file -> file.isDirectory && builderWorldPattern.matches(file.name) }
            ?.forEach { versionFolder ->
                val version = builderWorldPattern.matchEntire(versionFolder.name)!!.groupValues[1].toInt()
                versionFolder.listFiles { file -> file.isDirectory && isWorldDirectory(file) }
                    ?.sortedBy { it.name }
                    ?.forEach { legacyWorld ->
                        SteamwarWorld.getOrCreateBuilderWorld(legacyWorld.name, version, legacyWorld)
                        stats.imported++
                    }
            } ?: run {
            stats.skipped++
            echo("Skipped builder worlds: /worlds does not exist.")
        }
        return stats
    }

    private fun migrateArenaWorlds(): MigrationStats {
        val stats = MigrationStats()
        val configs = parseGameModeConfigs(File("/configs/GameModes"))
        if (configs.isEmpty()) {
            stats.skipped++
            echo("Skipped arena worlds: no game mode configs found in /configs/GameModes.")
            return stats
        }

        for (config in configs) {
            val version = trailingVersionPattern.find(config.serverFolder)?.value?.toIntOrNull()
            if (version == null) {
                stats.skipped++
                echo("Skipped arena mode ${config.modeName}: server folder '${config.serverFolder}' has no version suffix.")
                continue
            }

            val arenaRoot = File("/servers/${config.serverFolder}/arenas")
            for (map in config.maps) {
                val legacyWorld = File(arenaRoot, map)
                if (!isWorldDirectory(legacyWorld)) {
                    stats.skipped++
                    continue
                }

                SteamwarWorld.getOrCreateArenaWorld(config.modeName, map, version, legacyWorld)
                stats.imported++
            }
        }

        return stats
    }

    private fun migrateBauLockConfig() {
        transaction(Database.db) {
            exec(
                """
                UPDATE `world` w
                JOIN `UserConfig` uc ON uc.`User` = w.`Owner` AND uc.`Config` = 'baulockstate'
                SET w.`LockState` = uc.`Value`
                WHERE w.`Owner` IS NOT NULL AND w.`LockState` IS NULL
                """.trimIndent()
            )
        }
    }

    private fun migrateBauweltMembers() {
        if (!columnExists("BauweltMember", "WorldID") || !columnExists("BauweltMember", "BauweltID")) {
            echo("Skipped BauweltMember data migration: expected WorldID and BauweltID columns are not both present.")
            return
        }

        execIgnore(
            """
            INSERT IGNORE INTO `BauweltMember` (`WorldID`, `MemberID`, `Build`, `WorldEdit`, `World`)
            SELECT w.`id`, bm.`MemberID`, bm.`Build`, bm.`WorldEdit`, bm.`World`
            FROM `BauweltMember` bm
            JOIN `world` w ON w.`Owner` = bm.`BauweltID` AND w.`Deleted` = 0
            """.trimIndent(),
            "Skipped BauweltMember data migration"
        )
    }

    private fun parseGameModeConfigs(configRoot: File): List<ArenaMigrationConfig> {
        if (!configRoot.isDirectory) return emptyList()

        return configRoot.listFiles { file -> file.isFile && file.extension == "yml" && !file.name.endsWith(".kits.yml") }
            ?.mapNotNull { file ->
                val server = parseServerBlock(file)
                val folder = server.folder ?: return@mapNotNull null
                ArenaMigrationConfig(file.nameWithoutExtension, folder, server.maps)
            }
            ?: emptyList()
    }

    private fun parseServerBlock(file: File): ParsedServerBlock {
        var inServer = false
        var inMaps = false
        var folder: String? = null
        val maps = mutableListOf<String>()

        file.readLines().forEach { line ->
            val trimmed = line.trim()
            if (trimmed.isEmpty() || trimmed.startsWith("#")) return@forEach

            val indent = line.indexOfFirst { !it.isWhitespace() }.let { if (it == -1) 0 else it }
            if (indent == 0) {
                inServer = trimmed == "Server:"
                inMaps = false
                return@forEach
            }

            if (!inServer) return@forEach

            when {
                indent <= 2 && trimmed.startsWith("Folder:") -> folder = trimmed.substringAfter(":").cleanYamlValue()
                indent <= 2 && trimmed.startsWith("Maps:") -> {
                    val value = trimmed.substringAfter(":").trim()
                    inMaps = true
                    if (value.startsWith("[") && value.endsWith("]")) {
                        maps += value.removePrefix("[").removeSuffix("]")
                            .split(",")
                            .map { it.cleanYamlValue() }
                            .filter { it.isNotEmpty() }
                        inMaps = false
                    }
                }
                inMaps && trimmed.startsWith("-") -> maps += trimmed.removePrefix("-").cleanYamlValue()
                inMaps && indent <= 2 -> inMaps = false
            }
        }

        return ParsedServerBlock(folder, maps)
    }

    private fun File.ownerUser(): SteamwarUser? {
        name.toIntOrNull()?.let { return SteamwarUser.byId(it) }
        return runCatching { SteamwarUser.get(UUID.fromString(name)) }.getOrNull()
    }

    private fun isWorldDirectory(file: File): Boolean =
        file.isDirectory && (File(file, "level.dat").isFile || File(file, "region").isDirectory)

    private fun String.cleanYamlValue(): String =
        trim().trim('"').trim('\'')

    private fun columnExists(table: String, column: String): Boolean =
        transaction(Database.db) {
            exec("SHOW COLUMNS FROM `$table` LIKE '$column'") { result -> result.next() } ?: false
        }

    private fun execIgnore(sql: String, prefix: String) {
        try {
            transaction(Database.db) {
                exec(sql)
            }
        } catch (e: SQLException) {
            echo("$prefix: ${e.message}")
        }
    }

    private data class MigrationStats(
        var imported: Int = 0,
        var skipped: Int = 0,
        var missingOwner: Int = 0,
    )

    private data class ArenaMigrationConfig(
        val modeName: String,
        val serverFolder: String,
        val maps: List<String>,
    )

    private data class ParsedServerBlock(
        val folder: String?,
        val maps: List<String>,
    )

    private companion object {
        private const val BAU_LOCK_CONFIG_NAME = "baulockstate"
    }
}