package com.example.jnicpp.bowling

import android.content.Context
import android.graphics.Canvas
import android.graphics.Matrix
import android.graphics.Paint
import android.util.AttributeSet
import android.view.View
import androidx.core.content.ContextCompat
import com.example.jnicpp.R
import com.google.mlkit.vision.pose.Pose

/**
 * Draws the 33 ML Kit pose landmarks and connecting skeleton lines on top of
 * the camera preview. The landmark topology and the coordinate mapping math
 * (analysis-image pixels -> view pixels, replicating `PreviewView`'s
 * `FILL_CENTER` scaling) live in [PoseSkeletonRenderer], shared with
 * [CameraXController]'s baked-into-the-recorded-video overlay so both paths
 * can't drift apart.
 */
class PoseOverlayView @JvmOverloads constructor(
    context: Context,
    attrs: AttributeSet? = null
) : View(context, attrs) {

    private val jointPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
        color = ContextCompat.getColor(context, R.color.skeleton_joint)
        style = Paint.Style.FILL
    }
    private val bonePaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
        color = ContextCompat.getColor(context, R.color.skeleton_bone)
        style = Paint.Style.STROKE
        strokeWidth = PoseSkeletonRenderer.STROKE_WIDTH
    }
    private val anglePaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
        color = ContextCompat.getColor(context, R.color.white)
        style = Paint.Style.FILL
        textSize = 36f
        isFakeBoldText = true
        // Readable regardless of what's behind it (skin, clothing, wall) --
        // the skeleton paints get away without this since a line/dot has a
        // consistent look, but small text needs the contrast.
        setShadowLayer(4f, 0f, 0f, ContextCompat.getColor(context, R.color.black))
    }

    private var pose: Pose? = null
    private var angles: PoseAngles? = null
    private var isFrontCamera = false

    // Source image size and rotation, as last reported by the analyzer --
    // fed straight into PoseSkeletonRenderer.computeTransform on every
    // size/frame change.
    private var sourceWidth = 0
    private var sourceHeight = 0
    private var sourceRotationDegrees = 0

    private var transform = Matrix()

    /** Called from the main thread with the latest analyzer result, or null to clear. */
    fun update(frame: PoseAnalyzer.PoseFrameResult?) {
        pose = frame?.pose
        angles = frame?.angles
        if (frame != null) {
            isFrontCamera = frame.isFrontCamera
            sourceWidth = frame.imageWidth
            sourceHeight = frame.imageHeight
            sourceRotationDegrees = frame.rotationDegrees
        }
        recomputeTransform()
        invalidate()
    }

    fun clear() {
        pose = null
        angles = null
        invalidate()
    }

    override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
        super.onSizeChanged(w, h, oldw, oldh)
        recomputeTransform()
    }

    private fun recomputeTransform() {
        transform = PoseSkeletonRenderer.computeTransform(
            sourceWidth = sourceWidth,
            sourceHeight = sourceHeight,
            sourceRotationDegrees = sourceRotationDegrees,
            targetWidth = width,
            targetHeight = height,
            // Front camera preview is mirrored; flip the x axis about the
            // view's center so the overlay matches what's on screen.
            mirror = isFrontCamera
        )
    }

    override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)
        val currentPose = pose ?: return
        PoseSkeletonRenderer.draw(canvas, currentPose, transform, bonePaint, jointPaint)
        angles?.let { PoseSkeletonRenderer.drawAngleLabels(canvas, currentPose, it, transform, anglePaint) }
    }
}