class SeatCanvasView @JvmOverloads constructor(
    context: Context,
    attrs: AttributeSet? = null
) : View(context, attrs) {

    data class Seat(
        val id: String, val row: Int, val col: Int,
        val type: String, // "lower" | "upper"
        val status: String, // "available" | "held" | "booked" | "selected"
        val fare: Int,
        val gender: String = "any"
    )

    var seats: List<Seat> = emptyList()
        set(value) { field = value; invalidate() }

    var onSeatClick: ((Seat) -> Unit)? = null

    private val paintAvailable = Paint().apply { color = Color.parseColor("#EAF3DE"); isAntiAlias = true }
    private val paintBooked    = Paint().apply { color = Color.parseColor("#E8E8E8"); isAntiAlias = true }
    private val paintSelected  = Paint().apply { color = Color.parseColor("#1D6FEB"); isAntiAlias = true }
    private val paintHeld      = Paint().apply { color = Color.parseColor("#FFF3CD"); isAntiAlias = true }
    private val paintLadies    = Paint().apply { color = Color.parseColor("#FBEAF0"); isAntiAlias = true }
    private val paintText      = Paint().apply { color = Color.WHITE; textSize = 28f; textAlign = Paint.Align.CENTER; isAntiAlias = true }
    private val paintStroke    = Paint().apply { style = Paint.Style.STROKE; strokeWidth = 2f; isAntiAlias = true }

    private val seatW = 90f
    private val seatH = 70f
    private val gap   = 12f
    private val aisleW = 50f

    override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)
        seats.forEach { seat ->
            val left = calculateX(seat.col)
            val top  = calculateY(seat.row)
            val rect = RectF(left, top, left + seatW, top + seatH)

            val paint = when {
                seat.status == "selected"  -> paintSelected
                seat.status == "booked"    -> paintBooked
                seat.status == "held"      -> paintHeld
                seat.gender == "female"    -> paintLadies
                else                       -> paintAvailable
            }

            paintStroke.color = when {
                seat.status == "selected" -> Color.parseColor("#0D47A1")
                seat.status == "booked"   -> Color.parseColor("#BDBDBD")
                else                      -> Color.parseColor("#66BB6A")
            }

            canvas.drawRoundRect(rect, 12f, 12f, paint)
            canvas.drawRoundRect(rect, 12f, 12f, paintStroke)

            val textColor = if (seat.status == "selected") Color.WHITE else Color.parseColor("#333333")
            paintText.color = textColor
            canvas.drawText(seat.id, left + seatW/2, top + seatH/2 + 10f, paintText)
        }
    }

    private fun calculateX(col: Int): Float {
        return if (col <= 1) col * (seatW + gap) + gap
        else col * (seatW + gap) + aisleW + gap
    }

    private fun calculateY(row: Int): Float = row * (seatH + gap) + gap

    override fun onTouchEvent(event: MotionEvent): Boolean {
        if (event.action != MotionEvent.ACTION_UP) return true
        seats.forEach { seat ->
            val left = calculateX(seat.col)
            val top  = calculateY(seat.row)
            if (event.x in left..(left+seatW) && event.y in top..(top+seatH)) {
                if (seat.status != "booked" && seat.status != "held") {
                    onSeatClick?.invoke(seat)
                }
            }
        }
        return true
    }
}