package com.inspection.camera.util

import android.content.Context
import android.graphics.Bitmap
import android.graphics.BitmapFactory
import android.graphics.Canvas
import android.graphics.Paint
import android.graphics.Rect
import android.net.Uri

object PuzzleMerge {
    // Merge up to 4 images into a single 2x2 bitmap
    fun mergeToBitmap(context: Context, imageUris: List<Uri>, targetSize: Int = 1000): Bitmap? {
        if (imageUris.isEmpty()) return null
        val size = targetSize
        val half = size / 2
        val merged = Bitmap.createBitmap(size, size, Bitmap.Config.ARGB_8888)
        val canvas = Canvas(merged)
        val paint = Paint(Paint.ANTI_ALIAS_FLAG)

        val targets = arrayOf(
            Rect(0, 0, half, half),        // TL
            Rect(half, 0, size, half),     // TR
            Rect(0, half, half, size),     // BL
            Rect(half, half, size, size)    // BR
        )

        val toUse = imageUris.take(4)
        for (i in toUse.indices) {
            val bmp = loadBitmap(context, toUse[i], half, half)
            if (bmp != null) {
                val scaled = Bitmap.createScaledBitmap(bmp, half, half, true)
                canvas.drawBitmap(scaled, null, targets[i], paint)
                bmp.recycle()
                scaled.recycle()
            }
        }

        // Optional: fill empty cells with placeholder color if needed
        return merged
    }

    // Load bitmap from URI with sampling to fit within maxW x maxH
    private fun loadBitmap(context: Context, uri: Uri, maxW: Int, maxH: Int): Bitmap? {
        return try {
            val opts = BitmapFactory.Options().apply { inJustDecodeBounds = true }
            context.contentResolver.openInputStream(uri).use { ins ->
                BitmapFactory.decodeStream(ins, null, opts)
            }
            val inSample = maxOf(1, maxOf(opts.outWidth / maxW, opts.outHeight / maxH))
            val opts2 = BitmapFactory.Options().apply { inSampleSize = inSample }
            context.contentResolver.openInputStream(uri).use { ins ->
                BitmapFactory.decodeStream(ins, null, opts2)
            }
        } catch (e: Exception) {
            null
        }
    }
}