#pragma once

#include <cstddef>
#include <cstdint>
#include <vector>

class Color
{
public:
    Color() : l{0} {}

    Color(uint8_t l) : l{l} {}

    uint8_t l{}; // luminence

    void Blend(const Color& src, uint8_t alpha)
    {
        l = BlendChannel(l, src.l, alpha);
        // l = alpha;
    }

private:
    static uint8_t BlendChannel(uint8_t a, uint8_t b, uint8_t alpha)
    {
        return static_cast<uint8_t>(
            (static_cast<int>(a) * (255 - static_cast<int>(alpha)) + static_cast<int>(b) * static_cast<int>(alpha)) /
            255);
    }
};

class Bitmap
{
public:
    Bitmap(size_t width, size_t height, const Color& clearColor)
        : m_width(width), m_height(height), m_data(width * height, clearColor)
    {
    }

    // std::span<Color> operator[](size_t row)
    // {
    //     return {&m_data[row * m_width], m_width};
    // };

    // std::span<const Color> operator[](size_t row) const
    // {
    //     return {&m_data[row * m_width], m_width};
    // };

    Color* operator[](size_t row) { return &m_data[row * m_width]; };

    const Color* operator[](size_t row) const { return &m_data[row * m_width]; };

    size_t GetWidth() const { return m_width; }

    size_t GetHeight() const { return m_height; }

    void Put(int x, int y, const Color& color, uint8_t alpha)
    {
        if (x < 0 || y < 0 || x >= m_width || y >= m_height)
            return; // out of bounds

        (*this)[y][x].Blend(color, alpha);
    }

private:
    size_t m_width, m_height;
    std::vector<Color> m_data;
};