#include "paint/stroke.h"
#include "test_harness.h"

#include <array>
#include <cmath>
#include <limits>

using pp::foundation::StatusCode;
using pp::paint::StrokePoint;
using pp::paint::StrokeSamplingConfig;
using pp::paint::max_stroke_samples;
using pp::paint::sample_stroke;

namespace {

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

void samples_straight_line_at_fixed_spacing(pp::tests::Harness& h)
{
    const std::array points {
        StrokePoint { .x = 0.0F, .y = 0.0F, .pressure = 0.25F },
        StrokePoint { .x = 10.0F, .y = 0.0F, .pressure = 0.75F },
    };

    const auto result = sample_stroke(points, StrokeSamplingConfig { .spacing = 2.5F });
    PP_EXPECT(h, result.ok());
    PP_EXPECT(h, result.value().size() == 5U);
    PP_EXPECT(h, near(result.value()[0].x, 0.0F));
    PP_EXPECT(h, near(result.value()[1].x, 2.5F));
    PP_EXPECT(h, near(result.value()[2].x, 5.0F));
    PP_EXPECT(h, near(result.value()[3].x, 7.5F));
    PP_EXPECT(h, near(result.value()[4].x, 10.0F));
    PP_EXPECT(h, near(result.value()[2].pressure, 0.5F));
    PP_EXPECT(h, near(result.value()[4].distance, 10.0F));
}

void carries_spacing_across_segments(pp::tests::Harness& h)
{
    const std::array points {
        StrokePoint { .x = 0.0F, .y = 0.0F, .pressure = 1.0F },
        StrokePoint { .x = 3.0F, .y = 0.0F, .pressure = 1.0F },
        StrokePoint { .x = 3.0F, .y = 4.0F, .pressure = 0.0F },
    };

    const auto result = sample_stroke(points, StrokeSamplingConfig { .spacing = 2.0F });
    PP_EXPECT(h, result.ok());
    PP_EXPECT(h, result.value().size() == 5U);
    PP_EXPECT(h, near(result.value()[1].x, 2.0F));
    PP_EXPECT(h, near(result.value()[1].y, 0.0F));
    PP_EXPECT(h, near(result.value()[2].x, 3.0F));
    PP_EXPECT(h, near(result.value()[2].y, 1.0F));
    PP_EXPECT(h, near(result.value()[3].x, 3.0F));
    PP_EXPECT(h, near(result.value()[3].y, 3.0F));
    PP_EXPECT(h, near(result.value()[4].distance, 7.0F));
}

void can_skip_endpoint_and_clamps_pressure(pp::tests::Harness& h)
{
    const std::array points {
        StrokePoint { .x = 0.0F, .y = 0.0F, .pressure = -1.0F },
        StrokePoint { .x = 5.0F, .y = 0.0F, .pressure = 2.0F },
    };

    const auto result = sample_stroke(
        points,
        StrokeSamplingConfig {
            .spacing = 2.0F,
            .include_endpoint = false,
        });
    PP_EXPECT(h, result.ok());
    PP_EXPECT(h, result.value().size() == 3U);
    PP_EXPECT(h, near(result.value()[0].pressure, 0.0F));
    PP_EXPECT(h, near(result.value()[2].pressure, 1.0F));
    PP_EXPECT(h, near(result.value()[2].distance, 4.0F));
}

void skips_zero_length_segments_without_resetting_spacing(pp::tests::Harness& h)
{
    const std::array points {
        StrokePoint { .x = 0.0F, .y = 0.0F, .pressure = 0.2F },
        StrokePoint { .x = 0.0F, .y = 0.0F, .pressure = 0.8F },
        StrokePoint { .x = 6.0F, .y = 0.0F, .pressure = 0.8F },
        StrokePoint { .x = 6.0F, .y = 0.0F, .pressure = 0.1F },
        StrokePoint { .x = 6.0F, .y = 4.0F, .pressure = 0.1F },
    };

    const auto result = sample_stroke(points, StrokeSamplingConfig { .spacing = 3.0F });
    PP_EXPECT(h, result.ok());
    PP_EXPECT(h, result.value().size() == 5U);
    PP_EXPECT(h, near(result.value()[1].x, 3.0F));
    PP_EXPECT(h, near(result.value()[1].y, 0.0F));
    PP_EXPECT(h, near(result.value()[2].x, 6.0F));
    PP_EXPECT(h, near(result.value()[2].y, 0.0F));
    PP_EXPECT(h, near(result.value()[3].x, 6.0F));
    PP_EXPECT(h, near(result.value()[3].y, 3.0F));
    PP_EXPECT(h, near(result.value()[4].distance, 10.0F));
}

void samples_large_stroke_with_deterministic_count(pp::tests::Harness& h)
{
    const std::array points {
        StrokePoint { .x = 0.0F, .y = 0.0F, .pressure = 0.0F },
        StrokePoint { .x = 1000.0F, .y = 0.0F, .pressure = 1.0F },
    };

    const auto result = sample_stroke(
        points,
        StrokeSamplingConfig {
            .spacing = 1.0F,
            .max_samples = 1001U,
        });
    PP_EXPECT(h, result.ok());
    PP_EXPECT(h, result.value().size() == 1001U);
    PP_EXPECT(h, near(result.value()[0].distance, 0.0F));
    PP_EXPECT(h, near(result.value()[500].x, 500.0F));
    PP_EXPECT(h, near(result.value()[500].pressure, 0.5F));
    PP_EXPECT(h, near(result.value().back().x, 1000.0F));
    PP_EXPECT(h, near(result.value().back().distance, 1000.0F));
}

void rejects_invalid_sampling_inputs(pp::tests::Harness& h)
{
    const std::array one_point {
        StrokePoint { .x = 0.0F, .y = 0.0F },
    };
    const std::array zero_length {
        StrokePoint { .x = 1.0F, .y = 1.0F },
        StrokePoint { .x = 1.0F, .y = 1.0F },
    };
    const std::array non_finite {
        StrokePoint { .x = 0.0F, .y = 0.0F },
        StrokePoint { .x = std::nanf(""), .y = 1.0F },
    };
    const std::array non_finite_pressure {
        StrokePoint { .x = 0.0F, .y = 0.0F },
        StrokePoint { .x = 1.0F, .y = 1.0F, .pressure = std::nanf("") },
    };
    const std::array valid {
        StrokePoint { .x = 0.0F, .y = 0.0F },
        StrokePoint { .x = 10.0F, .y = 0.0F },
    };

    const auto missing_points = sample_stroke(one_point, StrokeSamplingConfig {});
    const auto bad_spacing = sample_stroke(valid, StrokeSamplingConfig { .spacing = 0.0F });
    const auto infinite_spacing = sample_stroke(
        valid,
        StrokeSamplingConfig { .spacing = std::numeric_limits<float>::infinity() });
    const auto bad_limit = sample_stroke(valid, StrokeSamplingConfig { .max_samples = max_stroke_samples + 1U });
    const auto no_distance = sample_stroke(zero_length, StrokeSamplingConfig {});
    const auto bad_point = sample_stroke(non_finite, StrokeSamplingConfig {});
    const auto bad_pressure = sample_stroke(non_finite_pressure, StrokeSamplingConfig {});
    const auto too_many = sample_stroke(valid, StrokeSamplingConfig { .spacing = 1.0F, .max_samples = 2U });

    PP_EXPECT(h, !missing_points.ok());
    PP_EXPECT(h, missing_points.status().code == StatusCode::invalid_argument);
    PP_EXPECT(h, !bad_spacing.ok());
    PP_EXPECT(h, bad_spacing.status().code == StatusCode::invalid_argument);
    PP_EXPECT(h, !infinite_spacing.ok());
    PP_EXPECT(h, infinite_spacing.status().code == StatusCode::invalid_argument);
    PP_EXPECT(h, !bad_limit.ok());
    PP_EXPECT(h, bad_limit.status().code == StatusCode::out_of_range);
    PP_EXPECT(h, !no_distance.ok());
    PP_EXPECT(h, no_distance.status().code == StatusCode::invalid_argument);
    PP_EXPECT(h, !bad_point.ok());
    PP_EXPECT(h, bad_point.status().code == StatusCode::invalid_argument);
    PP_EXPECT(h, !bad_pressure.ok());
    PP_EXPECT(h, bad_pressure.status().code == StatusCode::invalid_argument);
    PP_EXPECT(h, !too_many.ok());
    PP_EXPECT(h, too_many.status().code == StatusCode::out_of_range);
}

}

int main()
{
    pp::tests::Harness harness;
    harness.run("samples_straight_line_at_fixed_spacing", samples_straight_line_at_fixed_spacing);
    harness.run("carries_spacing_across_segments", carries_spacing_across_segments);
    harness.run("can_skip_endpoint_and_clamps_pressure", can_skip_endpoint_and_clamps_pressure);
    harness.run("skips_zero_length_segments_without_resetting_spacing", skips_zero_length_segments_without_resetting_spacing);
    harness.run("samples_large_stroke_with_deterministic_count", samples_large_stroke_with_deterministic_count);
    harness.run("rejects_invalid_sampling_inputs", rejects_invalid_sampling_inputs);
    return harness.finish();
}