#include "paint_renderer/compositor.h"
#include "test_harness.h"

#include <cmath>
#include <vector>

using pp::foundation::StatusCode;
using pp::paint::BlendMode;
using pp::paint::Rgba;
using pp::paint_renderer::LayerCompositeView;
using pp::paint_renderer::composite_layer;
using pp::renderer::Extent2D;

namespace {

bool near(float a, float b)
{
    return std::fabs(a - b) < 0.0001F;
}

void composites_visible_layer_with_opacity(pp::tests::Harness& h)
{
    std::vector<Rgba> destination {
        Rgba { .r = 0.2F, .g = 0.4F, .b = 0.6F, .a = 0.5F },
    };
    const std::vector<Rgba> foreground {
        Rgba { .r = 0.8F, .g = 0.2F, .b = 0.1F, .a = 0.5F },
    };

    const auto status = composite_layer(
        destination,
        Extent2D { .width = 1, .height = 1 },
        LayerCompositeView {
            .pixels = foreground,
            .opacity = 0.5F,
            .visible = true,
            .blend_mode = BlendMode::normal,
        });

    PP_EXPECT(h, status.ok());
    PP_EXPECT(h, near(destination[0].a, 0.625F));
    PP_EXPECT(h, near(destination[0].r, 0.44F));
    PP_EXPECT(h, near(destination[0].g, 0.32F));
    PP_EXPECT(h, near(destination[0].b, 0.4F));
}

void invisible_and_zero_opacity_layers_are_noops(pp::tests::Harness& h)
{
    const Rgba original { .r = 0.1F, .g = 0.2F, .b = 0.3F, .a = 0.4F };
    std::vector<Rgba> destination { original };
    const std::vector<Rgba> foreground {
        Rgba { .r = 1.0F, .g = 1.0F, .b = 1.0F, .a = 1.0F },
    };

    PP_EXPECT(h, composite_layer(
        destination,
        Extent2D { .width = 1, .height = 1 },
        LayerCompositeView { .pixels = foreground, .opacity = 1.0F, .visible = false }).ok());
    PP_EXPECT(h, near(destination[0].r, original.r));
    PP_EXPECT(h, near(destination[0].g, original.g));
    PP_EXPECT(h, near(destination[0].b, original.b));
    PP_EXPECT(h, near(destination[0].a, original.a));

    PP_EXPECT(h, composite_layer(
        destination,
        Extent2D { .width = 1, .height = 1 },
        LayerCompositeView { .pixels = foreground, .opacity = 0.0F, .visible = true }).ok());
    PP_EXPECT(h, near(destination[0].r, original.r));
    PP_EXPECT(h, near(destination[0].g, original.g));
    PP_EXPECT(h, near(destination[0].b, original.b));
    PP_EXPECT(h, near(destination[0].a, original.a));
}

void rejects_invalid_sizes_and_opacity(pp::tests::Harness& h)
{
    std::vector<Rgba> destination(2);
    const std::vector<Rgba> foreground(1);

    const auto mismatched = composite_layer(
        destination,
        Extent2D { .width = 2, .height = 1 },
        LayerCompositeView { .pixels = foreground });
    const auto bad_opacity = composite_layer(
        destination,
        Extent2D { .width = 2, .height = 1 },
        LayerCompositeView { .pixels = destination, .opacity = 1.5F });
    const auto bad_extent = composite_layer(
        destination,
        Extent2D { .width = 0, .height = 1 },
        LayerCompositeView { .pixels = destination });

    PP_EXPECT(h, !mismatched.ok());
    PP_EXPECT(h, mismatched.code == StatusCode::invalid_argument);
    PP_EXPECT(h, !bad_opacity.ok());
    PP_EXPECT(h, bad_opacity.code == StatusCode::out_of_range);
    PP_EXPECT(h, !bad_extent.ok());
    PP_EXPECT(h, bad_extent.code == StatusCode::invalid_argument);
}

}

int main()
{
    pp::tests::Harness harness;
    harness.run("composites_visible_layer_with_opacity", composites_visible_layer_with_opacity);
    harness.run("invisible_and_zero_opacity_layers_are_noops", invisible_and_zero_opacity_layers_are_noops);
    harness.run("rejects_invalid_sizes_and_opacity", rejects_invalid_sizes_and_opacity);
    return harness.finish();
}