plugins {
    alias(libs.plugins.android.application)
    alias(libs.plugins.kotlin.android)		// ⇐ kotlin-gradle-plugin
    :
//    id("com.google.devtools.ksp") version "2.0.20-1.0.24"
    id("com.google.devtools.ksp") version "2.0.0-1.0.23"
//    id("com.google.devtools.ksp") version "1.9.0-1.0.13"
}
    :

dependencies {
    :
    val room_version = "2.6.1"

    implementation ("androidx.room:room-runtime:$room_version")

    // To use Kotlin Symbol Processing (KSP)
    ksp ("androidx.room:room-compiler:$room_version")
    // optional - Kotlin Extensions and Coroutines support for Room
    implementation ("androidx.room:room-ktx:$room_version")
    :
}

@Entity
data class Player(
    @PrimaryKey(autoGenerate = true) val id: Int,
    val name: String,
    val score: Int
)

@Entity(tableName = "player")		// 別名：Player⇒player
data class Player(
    @PrimaryKey(autoGenerate = true) val id: Int,
    @ColumnInfo(name = "name") val playerName: String,	// 別名：palyerName⇒name
    @ColumnInfo(name = "score") val bestScore: Int		// 別名：bestScore⇒score
)

@Dao
interface PlayerDao {

    @Query("SELECT * FROM Player ORDER BY bestScore DESC LIMIT :num")
    fun fetchTopX(num: Int): List<Player>  // 「:引数」でSQLへ引数を受け渡し

    @Insert
    fun insert(player: Player)	// playerを追加、idは自動作成
	
	@Delete
	fun delete(player: Player)	// player.idを持つRowを削除
	
	@Update
	fun update(player: Player)	// player.idを持つRowをplayerの値で置き換え
}

@Database(entities = arrayOf(Player::class), version = 1) // ポイント1,2
abstract class GameDb : RoomDatabase() {

    abstract fun playerDao(): PlayerDao					  // ポイント3

    companion object {
        @Volatile                                         // ポイント5
        private var instance: GameDb? = null              // ポイント6
        fun getDatabase(context: Context): GameDb {
            return instance ?: synchronized(this) {       // ポイント5,6
                val _instans = Room.databaseBuilder(      // ポイント4
                    context,            // アプリのContext
                    GameDb::class.java, // 自身のクラス
                    "Game.db"           // データベース名
                )
//                    .createFromAsset("databases/Game.db")
                    .build()
                instance = _instans                       // ポイント6
                _instans
            }
        }
    }
}

class RankingActivity : ComponentActivity() {

    private lateinit var gameDb: GameDb
    private lateinit var playerFlow: MutableStateFlow<List<Player>>

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContent {
            GameaTheme {
                Scaffold(
                    modifier = Modifier.fillMaxSize(),
                    floatingActionButton = {
                        FloatingActionButton(
                            onClick = {
                                lifecycleScope.launch(Dispatchers.Default) {
                                    gameDb.playerDao().insert(randomPlayer())
                                    playerFlow.value = gameDb.playerDao().fetchTopX(10)
                                }
                            },
                            modifier = Modifier.padding(15.dp)
                        ) { Icon(Icons.Default.Add, contentDescription = "Add") }
                    }
                ) { innerPadding ->
                    Box(
                        modifier = Modifier.padding(innerPadding).fillMaxSize(),
                        contentAlignment = Alignment.Center
                    ) {
                        RankingPanel(playerFlow.asStateFlow())
                    }
                }
            }
        }

        gameDb = (application as MyApplication).gameDb
        playerFlow = MutableStateFlow<List<Player>>(listOf<Player>())
        lifecycleScope.launch(Dispatchers.Default) {
            val _list = gameDb.playerDao().fetchTopX(10)
            playerFlow.value = _list
        }
    }

    override fun onDestroy() {
        super.onDestroy()
        gameDb.close()
    }
}

@Composable
fun RankingPanel(playerFlow: StateFlow<List<Player>>) {
    val _players = playerFlow.collectAsState().value
    LazyColumn {
        items(items = _players, key = { it.id }) {
            Text(
                text = "%-8s  %06d".format(it.name, it.bestScore),
                fontSize = 20.sp,
                fontFamily = FontFamily.Monospace,
                fontWeight = FontWeight.Bold
            )
        }
    }
}