package com.bartsent.simpleresizer

import android.graphics.Bitmap
import android.graphics.BitmapFactory
import android.graphics.Color
import androidx.test.ext.junit.runners.AndroidJUnit4
import androidx.test.platform.app.InstrumentationRegistry
import com.bartsent.simpleresizer.lib.getScaledInstance
import org.junit.Assert
import org.junit.Test
import org.junit.runner.RunWith

@RunWith(AndroidJUnit4::class)
class ResizerTest {
    val ORIG_TILE_SIZE = 576
    val WIDTH_IN_TILES = 8
    val HEIGHT_IN_TILES = 6
    val CSTEP = 0x55

    var count = 0

    @Test
    fun canLoadImage() {
        val image = getBitmap()
        Assert.assertNotNull(image)
        checkBitmap(image, WIDTH_IN_TILES * ORIG_TILE_SIZE, HEIGHT_IN_TILES * ORIG_TILE_SIZE)
    }

    @Test
    fun resizeVertical() {
        val image = getBitmap()
        val newWidth = image.width
        val newHeight = image.height / 2
        checkBitmap(image.getScaledInstance(newWidth, newHeight), newWidth, newHeight)
    }

    @Test
    fun resizeHorizontal() {
        val image = getBitmap()
        val newWidth = image.width / 2
        val newHeight = image.height
        checkBitmap(image.getScaledInstance(newWidth, newHeight), newWidth, newHeight)
    }

    @Test
    fun resizeBoth() {
        val image = getBitmap()
        val newWidth = image.width / 2
        val newHeight = image.height / 2
        checkBitmap(image.getScaledInstance(newWidth, newHeight), newWidth, newHeight)
    }

    fun getBitmap(): Bitmap =
        InstrumentationRegistry.getInstrumentation().context.assets.open("testimage.png").use {
            BitmapFactory.decodeStream(it)
        }

    fun getColor(): Int {
        count += 1
        val b = (count and 0x3)*CSTEP
        val temp = count shr 2
        val g = (temp and 0x3)*CSTEP
        val r = ((temp shr 2) and 0x3)*CSTEP
        return Color.rgb(r, g, b)
    }

    fun resetColor() {
        count = 0
    }

    fun checkBitmap(image: Bitmap, width: Int, height: Int) {
        Assert.assertEquals("width", width, image.width)
        Assert.assertEquals("height", height, image.height)
        val tileWidth = image.width / WIDTH_IN_TILES
        val tileHeight = image.height / HEIGHT_IN_TILES
        val tw2 = tileWidth / 2
        val th2 = tileHeight / 2
        resetColor()
        for (x in 0 until WIDTH_IN_TILES) {
            val xoff = tw2 + x * tileWidth
            for (y in 0 until HEIGHT_IN_TILES) {
                val yoff = th2 + y * tileHeight
                Assert.assertEquals("color @ tile $x, $y", getColor(), image.getPixel(xoff, yoff))
            }
        }
    }
}