import java.util.UUID
import java.sql.{Connection, DriverManager}

case class Task(id: UUID, title: String, completed: Boolean)

object TaskStore:
  private val dbPath = sys.env.getOrElse("DB_PATH", "./tasks.db")
  private val url = s"jdbc:sqlite:$dbPath"

  Class.forName("org.sqlite.JDBC")

  private def connect(): Connection = DriverManager.getConnection(url)

  // Initialize schema and pre-seed if empty
  locally {
    val conn = connect()
    try
      val stmt = conn.createStatement()
      stmt.execute(
        "CREATE TABLE IF NOT EXISTS tasks (id TEXT PRIMARY KEY, title TEXT NOT NULL, completed INTEGER NOT NULL DEFAULT 0)"
      )
      val rs = stmt.executeQuery("SELECT COUNT(*) FROM tasks")
      val count = rs.getInt(1)
      if count == 0 then
        val samples = List(
          "Deploy Scala app to Clouderized",
          "Set up CI/CD with Gitea Actions",
          "Configure custom domain"
        )
        val ps = conn.prepareStatement("INSERT INTO tasks (id, title, completed) VALUES (?, ?, 0)")
        samples.foreach { title =>
          ps.setString(1, UUID.randomUUID().toString)
          ps.setString(2, title)
          ps.executeUpdate()
        }
    finally conn.close()
  }

  def all(): List[Task] =
    val conn = connect()
    try
      val rs = conn.createStatement().executeQuery("SELECT id, title, completed FROM tasks ORDER BY title")
      val buf = collection.mutable.ListBuffer.empty[Task]
      while rs.next() do
        buf += Task(UUID.fromString(rs.getString("id")), rs.getString("title"), rs.getInt("completed") == 1)
      buf.toList
    finally conn.close()

  def add(title: String): Task =
    val id = UUID.randomUUID()
    val conn = connect()
    try
      val ps = conn.prepareStatement("INSERT INTO tasks (id, title, completed) VALUES (?, ?, 0)")
      ps.setString(1, id.toString)
      ps.setString(2, title.trim)
      ps.executeUpdate()
      Task(id, title.trim, false)
    finally conn.close()

  def toggle(id: UUID): Unit =
    val conn = connect()
    try
      val ps = conn.prepareStatement(
        "UPDATE tasks SET completed = CASE WHEN completed = 1 THEN 0 ELSE 1 END WHERE id = ?"
      )
      ps.setString(1, id.toString)
      ps.executeUpdate()
    finally conn.close()

  def delete(id: UUID): Unit =
    val conn = connect()
    try
      val ps = conn.prepareStatement("DELETE FROM tasks WHERE id = ?")
      ps.setString(1, id.toString)
      ps.executeUpdate()
    finally conn.close()

  def get(id: UUID): Option[Task] =
    val conn = connect()
    try
      val ps = conn.prepareStatement("SELECT id, title, completed FROM tasks WHERE id = ?")
      ps.setString(1, id.toString)
      val rs = ps.executeQuery()
      if rs.next() then
        Some(Task(UUID.fromString(rs.getString("id")), rs.getString("title"), rs.getInt("completed") == 1))
      else None
    finally conn.close()