/*
 * Copyright (C) 2025 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.launcher3.graphics

import android.graphics.Matrix
import android.graphics.Matrix.ScaleToFit.FILL
import android.graphics.Path
import android.graphics.Path.Direction
import android.graphics.Rect
import android.graphics.RectF
import android.graphics.Region
import android.platform.uiautomatorhelpers.DeviceHelpers.context
import android.view.View
import androidx.core.graphics.PathParser
import androidx.test.ext.junit.runners.AndroidJUnit4
import androidx.test.filters.SmallTest
import com.android.launcher3.graphics.ShapeDelegate.Circle
import com.android.launcher3.graphics.ShapeDelegate.Companion.AREA_CALC_SIZE
import com.android.launcher3.graphics.ShapeDelegate.Companion.AREA_DIFF_THRESHOLD
import com.android.launcher3.graphics.ShapeDelegate.Companion.areaDiffCalculator
import com.android.launcher3.graphics.ShapeDelegate.Companion.pickBestShape
import com.android.launcher3.graphics.ShapeDelegate.GenericPathShape
import com.android.launcher3.graphics.ShapeDelegate.RoundedSquare
import com.android.launcher3.icons.GraphicsUtils
import com.android.launcher3.views.ClipPathView
import com.google.common.truth.Truth.assertThat
import org.junit.Test
import org.junit.runner.RunWith

@SmallTest
@RunWith(AndroidJUnit4::class)
class ShapeDelegateTest {

    @Test
    fun `areaDiffCalculator increases with outwards shape`() {
        val diffCalculator =
            areaDiffCalculator(
                Path().apply {
                    addCircle(
                        AREA_CALC_SIZE / 2f,
                        AREA_CALC_SIZE / 2f,
                        AREA_CALC_SIZE / 2f,
                        Direction.CW,
                    )
                }
            )
        assertThat(diffCalculator(Circle())).isLessThan(AREA_DIFF_THRESHOLD)
        assertThat(diffCalculator(Circle())).isLessThan(diffCalculator(RoundedSquare(.9f)))
        assertThat(diffCalculator(RoundedSquare(.9f)))
            .isLessThan(diffCalculator(RoundedSquare(.8f)))
        assertThat(diffCalculator(RoundedSquare(.8f)))
            .isLessThan(diffCalculator(RoundedSquare(.7f)))
        assertThat(diffCalculator(RoundedSquare(.7f)))
            .isLessThan(diffCalculator(RoundedSquare(.6f)))
        assertThat(diffCalculator(RoundedSquare(.6f)))
            .isLessThan(diffCalculator(RoundedSquare(.5f)))
    }

    @Test
    fun `areaDiffCalculator increases with inwards shape`() {
        val diffCalculator = areaDiffCalculator(roundedRectPath(0.5f))
        assertThat(diffCalculator(RoundedSquare(.5f))).isLessThan(AREA_DIFF_THRESHOLD)
        assertThat(diffCalculator(RoundedSquare(.5f)))
            .isLessThan(diffCalculator(RoundedSquare(.6f)))
        assertThat(diffCalculator(RoundedSquare(.5f)))
            .isLessThan(diffCalculator(RoundedSquare(.4f)))
    }

    @Test
    fun `pickBestShape picks circle`() {
        val r = AREA_CALC_SIZE / 2
        val pathStr = "M 50 0 a 50 50 0 0 1 0 100 a 50 50 0 0 1 0 -100"
        val path = Path().apply { addCircle(r.toFloat(), r.toFloat(), r.toFloat(), Direction.CW) }
        assertThat(pickBestShape(path, pathStr)).isInstanceOf(Circle::class.java)
    }

    @Test
    fun `pickBestShape picks rounded rect`() {
        val factor = 0.5f
        var shape = pickBestShape(roundedRectPath(factor), roundedRectString(factor))
        assertThat(shape).isInstanceOf(RoundedSquare::class.java)
        assertThat((shape as RoundedSquare).radiusRatio).isEqualTo(factor)

        val factor2 = 0.2f
        shape = pickBestShape(roundedRectPath(factor2), roundedRectString(factor2))
        assertThat(shape).isInstanceOf(RoundedSquare::class.java)
        assertThat((shape as RoundedSquare).radiusRatio).isEqualTo(factor2)
    }

    @Test
    fun `pickBestShape picks generic shape`() {
        val path = cookiePath(Rect(0, 0, AREA_CALC_SIZE, AREA_CALC_SIZE))
        val pathStr = FOUR_SIDED_COOKIE
        val shape = pickBestShape(path, pathStr)
        assertThat(shape).isInstanceOf(GenericPathShape::class.java)

        val diffCalculator = areaDiffCalculator(path)
        assertThat(diffCalculator(shape)).isLessThan(AREA_DIFF_THRESHOLD)
    }

    @Test
    fun `generic shape creates smooth animation`() {
        val shape = GenericPathShape(FOUR_SIDED_COOKIE)
        val target = TestClipView()
        val anim =
            shape.createRevealAnimator(
                target,
                Rect(0, 0, AREA_CALC_SIZE, AREA_CALC_SIZE),
                Rect(0, 0, AREA_CALC_SIZE, AREA_CALC_SIZE),
                AREA_CALC_SIZE * .25f,
                false,
            )

        // Verify that the start rect is similar to initial path
        anim.setCurrentFraction(0f)
        assertThat(
                getAreaDiff(
                    target.currentClip!!,
                    cookiePath(Rect(0, 0, AREA_CALC_SIZE, AREA_CALC_SIZE)),
                )
            )
            .isLessThan(AREA_CALC_SIZE)

        // Verify that end rect is similar to end path
        anim.setCurrentFraction(1f)
        assertThat(getAreaDiff(target.currentClip!!, roundedRectPath(0.5f)))
            .isLessThan(AREA_CALC_SIZE)

        // Ensure that when running animation, area increases smoothly. We run the animation over
        // [steps] and verify increase of max 5 times the linear diff increase
        val steps = 1000
        val incrementalDiff =
            getAreaDiff(
                cookiePath(Rect(0, 0, AREA_CALC_SIZE, AREA_CALC_SIZE)),
                roundedRectPath(0.5f),
            ) * 5 / steps
        var lastPath = cookiePath(Rect(0, 0, AREA_CALC_SIZE, AREA_CALC_SIZE))
        for (progress in 1..steps) {
            anim.setCurrentFraction(progress / 1000f)
            val currentPath = Path(target.currentClip!!)
            assertThat(getAreaDiff(lastPath, currentPath)).isLessThan(incrementalDiff)
            lastPath = currentPath
        }
        assertThat(getAreaDiff(lastPath, roundedRectPath(0.5f))).isLessThan(AREA_CALC_SIZE)
    }

    private fun roundedRectPath(factor: Float) =
        Path().apply {
            val r = factor * AREA_CALC_SIZE / 2
            addRoundRect(
                0f,
                0f,
                AREA_CALC_SIZE.toFloat(),
                AREA_CALC_SIZE.toFloat(),
                r,
                r,
                Direction.CW,
            )
        }

    private fun roundedRectString(factor: Float): String {
        val s = 100f
        val r = (factor * s / 2)
        val t = s - r
        return "M $r 0 " +
            "L $t 0 " +
            "A $r $r 0 0 1 $s $r " +
            "L $s $t " +
            "A $r $r 0 0 1 $t $s " +
            "L $r $s " +
            "A $r $r 0 0 1 0 $t " +
            "L 0 $r " +
            "A $r $r 0 0 1 $r 0 Z"
    }

    private fun getAreaDiff(p1: Path, p2: Path): Int {
        val fullRegion = Region(0, 0, AREA_CALC_SIZE, AREA_CALC_SIZE)
        val iconRegion = Region().apply { setPath(p1, fullRegion) }
        val shapeRegion = Region().apply { setPath(p2, fullRegion) }
        shapeRegion.op(iconRegion, Region.Op.XOR)
        return GraphicsUtils.getArea(shapeRegion)
    }

    class TestClipView : View(context), ClipPathView {

        var currentClip: Path? = null

        override fun setClipPath(clipPath: Path?) {
            currentClip = clipPath
        }
    }

    companion object {
        const val FOUR_SIDED_COOKIE =
            "M63.605 3C84.733 -6.176 106.176 15.268 97 36.395L95.483 39.888C92.681 46.338 92.681 53.662 95.483 60.112L97 63.605C106.176 84.732 84.733 106.176 63.605 97L60.112 95.483C53.662 92.681 46.338 92.681 39.888 95.483L36.395 97C15.267 106.176 -6.176 84.732 3 63.605L4.517 60.112C7.319 53.662 7.319 46.338 4.517 39.888L3 36.395C -6.176 15.268 15.267 -6.176 36.395 3L39.888 4.517C46.338 7.319 53.662 7.319 60.112 4.517L63.605 3Z"

        private fun cookiePath(bounds: Rect) =
            PathParser.createPathFromPathData(FOUR_SIDED_COOKIE).apply {
                transform(
                    Matrix().apply { setRectToRect(RectF(0f, 0f, 100f, 100f), RectF(bounds), FILL) }
                )
            }
    }
}