#pragma once

#include "Utils.hpp"

#include <algorithm>
#include <cstdint>
#include <glm/glm.hpp>
#include <limits>

class HsvColor;
class RgbaColor {
public:
	uint8_t r;
	uint8_t g;
	uint8_t b;
	uint8_t a;

public:
	constexpr RgbaColor() noexcept
		: r{ 255 }
		, g{ 255 }
		, b{ 255 }
		, a{ 255 } {
	}

	constexpr RgbaColor(float r, float g, float b, float a = 1.0f) noexcept
		: r{ static_cast<uint8_t>(r * 255.0f) }
		, g{ static_cast<uint8_t>(g * 255.0f) }
		, b{ static_cast<uint8_t>(b * 255.0f) }
		, a{ static_cast<uint8_t>(a * 255.0f) } {
	}

	constexpr RgbaColor(int r, int g, int b, int a = 255) noexcept
		: r{ static_cast<uint8_t>(r & 0xFF) }
		, g{ static_cast<uint8_t>(g & 0xFF) }
		, b{ static_cast<uint8_t>(b & 0xFF) }
		, a{ static_cast<uint8_t>(a & 0xFF) } {
	}

	constexpr RgbaColor(uint32_t rgba) noexcept
		: r{ static_cast<uint8_t>((rgba >> 0) & 0xFF) }
		, g{ static_cast<uint8_t>((rgba >> 8) & 0xFF) }
		, b{ static_cast<uint8_t>((rgba >> 16) & 0xFF) }
		, a{ static_cast<uint8_t>((rgba >> 24) & 0xFF) } {
	}

	constexpr uint32_t GetScalar() const noexcept {
		uint32_t res = 0;
		res |= r << 0;
		res |= g << 8;
		res |= b << 16;
		res |= a << 24;
		return res;
	}

	constexpr void SetScalar(uint32_t scalar) noexcept {
		r = (scalar >> 0) & 0xFF;
		g = (scalar >> 8) & 0xFF;
		b = (scalar >> 16) & 0xFF;
		a = (scalar >> 24) & 0xFF;
	}

	constexpr float GetNormalizedRed() const noexcept {
		return r / 255.0f;
	}

	constexpr float GetNormalizedGreen() const noexcept {
		return g / 255.0f;
	}

	constexpr float GetNormalizedBlue() const noexcept {
		return b / 255.0f;
	}

	constexpr float GetNormalizedAlpha() const noexcept {
		return a / 255.0f;
	}

	constexpr glm::ivec4 ToIVec() const noexcept {
		return { r, g, b, a };
	}

	constexpr glm::vec4 ToVec() const noexcept {
		return { GetNormalizedRed(), GetNormalizedGreen(), GetNormalizedBlue(), GetNormalizedAlpha() };
	}

	// Forward declaring because cyclic reference between RgbaColor and HsvColor
	constexpr HsvColor ToHsv() const noexcept;

	friend constexpr bool operator==(const RgbaColor&, const RgbaColor&) noexcept = default;
};

constexpr RgbaColor kXAxisColor(0xFF, 0x80, 0x80, 0xFF);
constexpr RgbaColor kYAxisColor(0x80, 0xFF, 0x80, 0xFF);
constexpr RgbaColor kZAxisColor(0x80, 0x80, 0xFF, 0xFF);

class HsvColor {
public:
	float h;
	float s;
	float v;
	float a;

public:
	constexpr HsvColor() noexcept
		: h{ 0.0f }
		, s{ 0.0f }
		, v{ 1.0f }
		, a{ 1.0f } {
	}

	constexpr HsvColor(float h, float s, float v, float a) noexcept
		: h{ h }
		, s{ s }
		, v{ v }
		, a{ a } {
	}

	// Forward declaring because cyclic reference between RgbaColor and HsvColor
	constexpr RgbaColor ToRgba() const noexcept;
};

constexpr HsvColor RgbaColor::ToHsv() const noexcept {
	float r = GetNormalizedRed();
	float g = GetNormalizedBlue();
	float b = GetNormalizedGreen();
	float a = GetNormalizedAlpha();

	auto p = g < b ? glm::vec4(b, g, -1, 2.0f / 3.0f) : glm::vec4(g, b, 0, -1.0f / 3.0f);
	auto q = r < p.x ? glm::vec4(p.x, p.y, p.w, r) : glm::vec4(r, p.y, p.z, p.x);
	float c = q.x - std::min(q.w, q.y);
	float h = Utils::Abs((q.w - q.y) / (6 * c + std::numeric_limits<float>::epsilon()) + q.z);

	glm::vec3 hcv{ h, c, q.x };
	float s = hcv.y / (hcv.z + std::numeric_limits<float>::epsilon());
	return HsvColor(hcv.x, s, hcv.z, a);
}

constexpr RgbaColor HsvColor::ToRgba() const noexcept {
	float r = Utils::Abs(h * 6 - 3) - 1;
	float g = 2 - Utils::Abs(h * 6 - 2);
	float b = 2 - Utils::Abs(h * 6 - 4);

	auto rgb = glm::vec3{ std::clamp(r, 0.0f, 1.0f), std::clamp(g, 0.0f, 1.0f), std::clamp(b, 0.0f, 1.0f) };
	auto vc = (rgb - glm::vec3{ 0, 0, 0 }) * s + glm::vec3{ 1, 1, 1 } * v;

	return RgbaColor(vc.x, vc.y, vc.z, a);
}