PokeGoalsHelper/app/src/main/java/com/quillstudios/pokegoalshelper/capture/ScreenCaptureManagerImpl.kt

package com.quillstudios.pokegoalshelper.capture

import android.app.Activity
import android.content.Context
import android.content.Intent
import android.graphics.PixelFormat
import android.hardware.display.DisplayManager
import android.hardware.display.VirtualDisplay
import android.media.Image
import android.media.ImageReader
import android.media.projection.MediaProjection
import android.media.projection.MediaProjectionManager
import android.os.Handler
import android.util.DisplayMetrics
import android.util.Log
import android.view.WindowManager

/**
 * Implementation of ScreenCaptureManager that handles MediaProjection-based screen capture.
 * Extracted from ScreenCaptureService for better separation of concerns.
 */
class ScreenCaptureManagerImpl(
    private val context: Context,
    private val handler: Handler
) : ScreenCaptureManager
{
    companion object
    {
        private const val TAG = "ScreenCaptureManager"
        private const val BUFFER_COUNT = 3
    }

    private var mediaProjectionManager: MediaProjectionManager? = null
    private var mediaProjection: MediaProjection? = null
    private var virtualDisplay: VirtualDisplay? = null
    private var imageReader: ImageReader? = null
    
    private var screenWidth = 0
    private var screenHeight = 0
    private var screenDensity = 0
    
    private var imageCallback: ((Image) -> Unit)? = null
    private var isActive = false

    init
    {
        mediaProjectionManager = context.getSystemService(Context.MEDIA_PROJECTION_SERVICE) as MediaProjectionManager
        initializeScreenMetrics()
    }

    private fun initializeScreenMetrics()
    {
        val display_metrics = DisplayMetrics()
        val window_manager = context.getSystemService(Context.WINDOW_SERVICE) as WindowManager
        window_manager.defaultDisplay.getMetrics(display_metrics)

        screenWidth = display_metrics.widthPixels
        screenHeight = display_metrics.heightPixels
        screenDensity = display_metrics.densityDpi

        Log.d(TAG, "Screen metrics initialized: ${screenWidth}x${screenHeight}, density: $screenDensity")
    }

    private val mediaProjectionCallback = object : MediaProjection.Callback()
    {
        override fun onStop()
        {
            Log.d(TAG, "MediaProjection stopped")
            stopCapture()
        }

        override fun onCapturedContentResize(width: Int, height: Int)
        {
            Log.d(TAG, "Screen size changed: ${width}x${height}")
        }

        override fun onCapturedContentVisibilityChanged(isVisible: Boolean)
        {
            Log.d(TAG, "Content visibility changed: $isVisible")
        }
    }

    private val onImageAvailableListener = ImageReader.OnImageAvailableListener { reader ->
        try
        {
            val captured_image = reader.acquireLatestImage()
            if (captured_image != null)
            {
                imageCallback?.invoke(captured_image)
            }
        }
        catch (e: Exception)
        {
            Log.e(TAG, "Error in onImageAvailableListener", e)
        }
    }

    override fun startCapture(resultData: Intent): Boolean
    {
        if (isActive)
        {
            Log.w(TAG, "Capture already active")
            return true
        }

        try
        {
            Log.d(TAG, "Starting screen capture")

            mediaProjection = mediaProjectionManager?.getMediaProjection(Activity.RESULT_OK, resultData)
            if (mediaProjection == null)
            {
                Log.e(TAG, "Failed to get MediaProjection")
                return false
            }

            Log.d(TAG, "Registering MediaProjection callback")
            mediaProjection?.registerCallback(mediaProjectionCallback, handler)

            Log.d(TAG, "Creating ImageReader: ${screenWidth}x${screenHeight}")
            imageReader = ImageReader.newInstance(screenWidth, screenHeight, PixelFormat.RGBA_8888, BUFFER_COUNT)
            imageReader?.setOnImageAvailableListener(onImageAvailableListener, handler)

            Log.d(TAG, "Creating VirtualDisplay")
            virtualDisplay = mediaProjection?.createVirtualDisplay(
                "ScreenCapture",
                screenWidth,
                screenHeight,
                screenDensity,
                DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
                imageReader?.surface,
                null,
                null
            )

            if (virtualDisplay == null)
            {
                Log.e(TAG, "Failed to create VirtualDisplay")
                cleanupResources()
                return false
            }

            isActive = true
            Log.d(TAG, "Screen capture started successfully")
            return true
        }
        catch (e: Exception)
        {
            Log.e(TAG, "Error starting screen capture", e)
            cleanupResources()
            return false
        }
    }

    override fun stopCapture()
    {
        if (!isActive)
        {
            Log.d(TAG, "Capture not active, nothing to stop")
            return
        }

        Log.d(TAG, "Stopping screen capture")
        cleanupResources()
        isActive = false
        Log.d(TAG, "Screen capture stopped")
    }

    private fun cleanupResources()
    {
        try
        {
            virtualDisplay?.release()
            imageReader?.close()
            mediaProjection?.unregisterCallback(mediaProjectionCallback)
            mediaProjection?.stop()
        }
        catch (e: Exception)
        {
            Log.e(TAG, "Error during cleanup", e)
        }
        finally
        {
            virtualDisplay = null
            imageReader = null
            mediaProjection = null
        }
    }

    override fun setImageCallback(callback: (Image) -> Unit)
    {
        this.imageCallback = callback
        Log.d(TAG, "Image callback set")
    }

    override fun isCapturing(): Boolean = isActive

    override fun getScreenDimensions(): Pair<Int, Int>?
    {
        return if (screenWidth > 0 && screenHeight > 0)
        {
            Pair(screenWidth, screenHeight)
        }
        else
        {
            null
        }
    }
    
    override fun getMediaProjection(): MediaProjection?
    {
        return mediaProjection
    }
    
    override fun getScreenDensity(): Int
    {
        return screenDensity
    }

    override fun release()
    {
        Log.d(TAG, "Releasing ScreenCaptureManager")
        stopCapture()
        imageCallback = null
        mediaProjectionManager = null
    }
}