package org.schabi.newpipe.util.image;

import static org.junit.Assert.assertEquals;
import static org.schabi.newpipe.extractor.Image.HEIGHT_UNKNOWN;
import static org.schabi.newpipe.extractor.Image.WIDTH_UNKNOWN;
import static org.schabi.newpipe.util.image.ImageStrategy.choosePreferredImage;
import static org.schabi.newpipe.util.image.ImageStrategy.estimatePixelCount;

import org.junit.Test;
import org.schabi.newpipe.extractor.Image;
import org.schabi.newpipe.extractor.Image.ResolutionLevel;

import java.util.List;

public class ImageStrategyTest {

    private static final List<ResolutionLevel> RESOLUTION_LEVELS = List.of(
            ResolutionLevel.LOW, ResolutionLevel.MEDIUM, ResolutionLevel.HIGH);

    private Image img(final int height, final int width) {
        return new Image("", height, width, ResolutionLevel.UNKNOWN);
    }

    private Image img(final String url, final ResolutionLevel resolutionLevel) {
        return new Image(url, HEIGHT_UNKNOWN, WIDTH_UNKNOWN, resolutionLevel);
    }

    private Image img(final String url,
                      final int height,
                      final int width,
                      final ResolutionLevel resolutionLevel) {
        return new Image(url, height, width, resolutionLevel);
    }

    private void assertChoosePreferredImage(final String low,
                                            final String medium,
                                            final String high,
                                            final List<Image> images) {
        assertEquals(low, choosePreferredImage(images, PreferredImageQuality.LOW));
        assertEquals(medium, choosePreferredImage(images, PreferredImageQuality.MEDIUM));
        assertEquals(high, choosePreferredImage(images, PreferredImageQuality.HIGH));
    }


    // CHECKSTYLE:OFF
    @Test
    public void testEstimatePixelCountAllKnown() {
        assertEquals(20000.0, estimatePixelCount(img(100, 200),  1.0), 0.0);
        assertEquals(20000.0, estimatePixelCount(img(100, 200), 12.0), 0.0);
        assertEquals(  100.0, estimatePixelCount(img(100,   1), 12.0), 0.0);
        assertEquals(  100.0, estimatePixelCount(img(  1, 100),  0.5), 0.0);
    }

    @Test
    public void testEstimatePixelCountHeightUnknown() {
        assertEquals( 10000.0, estimatePixelCount(img(HEIGHT_UNKNOWN, 100),  1.0    ), 0.0);
        assertEquals( 20000.0, estimatePixelCount(img(HEIGHT_UNKNOWN, 200),  2.0    ), 0.0);
        assertEquals(    10.0, estimatePixelCount(img(HEIGHT_UNKNOWN,   1),  0.1    ), 0.0);
        assertEquals(230400.0, estimatePixelCount(img(HEIGHT_UNKNOWN, 640), 16.0/9.0), 0.0);
    }

    @Test
    public void testEstimatePixelCountWidthUnknown() {
        assertEquals( 10000.0, estimatePixelCount(img(100, WIDTH_UNKNOWN),  1.0    ), 0.0);
        assertEquals( 20000.0, estimatePixelCount(img(200, WIDTH_UNKNOWN),  0.5    ), 0.0);
        assertEquals(    12.0, estimatePixelCount(img(  1, WIDTH_UNKNOWN), 12.0    ), 0.0);
        assertEquals(230400.0, estimatePixelCount(img(360, WIDTH_UNKNOWN), 16.0/9.0), 0.0);
    }

    @Test
    public void testEstimatePixelCountAllUnknown() {
        assertEquals(0.0, estimatePixelCount(img(HEIGHT_UNKNOWN, WIDTH_UNKNOWN),  1.0    ), 0.0);
        assertEquals(0.0, estimatePixelCount(img(HEIGHT_UNKNOWN, WIDTH_UNKNOWN), 12.0    ), 0.0);
        assertEquals(0.0, estimatePixelCount(img(HEIGHT_UNKNOWN, WIDTH_UNKNOWN),  0.1    ), 0.0);
        assertEquals(0.0, estimatePixelCount(img(HEIGHT_UNKNOWN, WIDTH_UNKNOWN), 16.0/9.0), 0.0);
    }
    // CHECKSTYLE:ON


    @Test
    public void testChoosePreferredImageAllKnown() {
        // the resolution level of the images is more important than the actual resolution
        assertChoosePreferredImage("a", "b", "c", List.of(
                img("a", 1, 1, ResolutionLevel.LOW),
                img("b", 200, 200, ResolutionLevel.MEDIUM),
                img("c", 10000, 10000, ResolutionLevel.HIGH)
        ));
        assertChoosePreferredImage("a", "b", "c", List.of(
                img("a", 10000, 10000, ResolutionLevel.LOW),
                img("b", 200, 200, ResolutionLevel.MEDIUM),
                img("c", 1, 1, ResolutionLevel.HIGH)
        ));

        assertChoosePreferredImage("b", "c", "d", List.of(
                img("a", 2, 1, ResolutionLevel.LOW),
                img("b", 50, 25, ResolutionLevel.LOW),
                img("c", 200, 100, ResolutionLevel.LOW),
                img("d", 300, 150, ResolutionLevel.LOW)
        ));

        assertChoosePreferredImage("c", "d", "d", List.of(
                img("a", 2, 1, ResolutionLevel.MEDIUM),
                img("b", 50, 25, ResolutionLevel.MEDIUM),
                img("c", 60, 30, ResolutionLevel.MEDIUM),
                img("d", 300, 150, ResolutionLevel.MEDIUM)
        ));
    }

    @Test
    public void testChoosePreferredImageSomeKnown() {
        // the resolution level of the images is more important than the actual resolution
        assertChoosePreferredImage("a", "b", "c", List.of(
                img("a", 1, WIDTH_UNKNOWN, ResolutionLevel.LOW),
                img("b", HEIGHT_UNKNOWN, 200, ResolutionLevel.MEDIUM),
                img("c", 10000, WIDTH_UNKNOWN, ResolutionLevel.HIGH)
        ));
        assertChoosePreferredImage("a", "b", "c", List.of(
                img("a", HEIGHT_UNKNOWN, 10000, ResolutionLevel.LOW),
                img("b", 200, WIDTH_UNKNOWN, ResolutionLevel.MEDIUM),
                img("c", HEIGHT_UNKNOWN, 1, ResolutionLevel.HIGH)
        ));

        assertChoosePreferredImage("b", "c", "d", List.of(
                img("a", HEIGHT_UNKNOWN, 1, ResolutionLevel.HIGH),
                img("b", 50, WIDTH_UNKNOWN, ResolutionLevel.HIGH),
                img("c", HEIGHT_UNKNOWN, 120, ResolutionLevel.HIGH),
                img("d", 340, WIDTH_UNKNOWN, ResolutionLevel.HIGH)
        ));

        assertChoosePreferredImage("c", "d", "d", List.of(
                img("a", 2, WIDTH_UNKNOWN, ResolutionLevel.MEDIUM),
                img("b", HEIGHT_UNKNOWN, 50, ResolutionLevel.MEDIUM),
                img("c", 60, WIDTH_UNKNOWN, ResolutionLevel.MEDIUM),
                img("d", HEIGHT_UNKNOWN, 340, ResolutionLevel.MEDIUM)
        ));
    }

    @Test
    public void testChoosePreferredImageMixed() {
        for (final ResolutionLevel resolutionLevel : RESOLUTION_LEVELS) {
            assertChoosePreferredImage("d", "b", "c", List.of(
                    img("a", ResolutionLevel.UNKNOWN),
                    img("b", 200, 100, resolutionLevel),
                    img("c", 400, WIDTH_UNKNOWN, resolutionLevel),
                    img("d", HEIGHT_UNKNOWN, 50, resolutionLevel),
                    img("e", resolutionLevel)
            ));
        }
        for (final ResolutionLevel resolutionLevel : RESOLUTION_LEVELS) {
            assertChoosePreferredImage("b", "b", "b", List.of(
                    img("a", ResolutionLevel.UNKNOWN),
                    img("b", 200, 100, resolutionLevel),
                    img("e", resolutionLevel)
            ));
        }
        assertChoosePreferredImage("b", "b", "e", List.of(
                img("a", ResolutionLevel.UNKNOWN),
                img("b", 200, 100, ResolutionLevel.LOW),
                img("e", ResolutionLevel.HIGH)
        ));
    }

    @Test
    public void testChoosePreferredImageAllUnknown() {
        assertChoosePreferredImage("b", "c", "d", List.of(
                img("a", ResolutionLevel.UNKNOWN),
                img("b", ResolutionLevel.LOW),
                img("c", ResolutionLevel.MEDIUM),
                img("d", ResolutionLevel.HIGH)
        ));
        assertChoosePreferredImage("c", "c", "d", List.of(
                img("a", ResolutionLevel.UNKNOWN),
                img("c", ResolutionLevel.MEDIUM),
                img("d", ResolutionLevel.HIGH)
        ));
        assertChoosePreferredImage("b", "c", "c", List.of(
                img("a", ResolutionLevel.UNKNOWN),
                img("b", ResolutionLevel.LOW),
                img("c", ResolutionLevel.MEDIUM)
        ));

        // UNKNOWN is avoided as much as possible
        assertChoosePreferredImage("d", "d", "d", List.of(
                img("a", ResolutionLevel.UNKNOWN),
                img("d", ResolutionLevel.HIGH)
        ));
        assertChoosePreferredImage("b", "b", "b", List.of(
                img("a", ResolutionLevel.UNKNOWN),
                img("b", ResolutionLevel.LOW)
        ));
        assertChoosePreferredImage("a", "a", "a", List.of(
                img("a", ResolutionLevel.UNKNOWN)
        ));
    }
}