#pragma once

#if !defined(BAD_APPLE_OS_PSF_HPP_INCLUDED)
#define BAD_APPLE_OS_PSF_HPP_INCLUDED

#include <stddef.h>
#include <stdint.h>

namespace psf
{
inline const uint32_t MAGIC = 0x864ab572;

struct Header
{
    uint32_t magic;         /* magic bytes to identify PSF */
    uint32_t version;       /* zero */
    uint32_t headersize;    /* offset of bitmaps in file, 32 */
    uint32_t flags;         /* 0 if there's no unicode table */
    uint32_t numglyph;      /* number of glyphs */
    uint32_t bytesperglyph; /* size of each glyph */
    uint32_t height;        /* height in pixels */
    uint32_t width;         /* width in pixels */
};

class Font
{
private:
    const Header* mMemory = nullptr;
    size_t mSize = 0;
public:
    Font() noexcept = default;
    Font(const Font&) = default;
private:
    Font(const Header* memory, size_t size) noexcept : mMemory(memory), mSize(size) {}
public:
    Font& operator=(const Font&) noexcept = default;

    [[nodiscard]] uint32_t getGlyphWidth() const noexcept { return mMemory->width; }
    [[nodiscard]] uint32_t getGlyphHeight() const noexcept { return mMemory->height; }
    template<typename TColor, typename TDrawFn>
    void writeGlyph(char chr, const TColor& fgColor, const TColor& bgColor, TDrawFn draw) const noexcept;
public:
    [[nodiscard]] static bool create(const void* data, size_t size, Font& outFont) noexcept;
};

template<typename TColor, typename TDrawFn>
void Font::writeGlyph(char chr, const TColor& fgColor, const TColor& bgColor, TDrawFn draw) const noexcept
{
    if (chr > mMemory->numglyph) {
        chr = 0;
    }

    const uint8_t* glyphData = reinterpret_cast<const uint8_t*>(mMemory) + mMemory->headersize + chr * mMemory->bytesperglyph;

    for (unsigned y = 0; y < mMemory->height; ++y)
    {
        for (unsigned x = 0; x < mMemory->width; ++x)
        {
            const unsigned idx = y * mMemory->width + x;
            const unsigned byte = idx / 8;
            const unsigned bit = idx % 8;

            if (glyphData[byte] & (0b10000000 >> bit))
            {
                draw(x, y, fgColor);
            }
            else
            {
                draw(x, y, bgColor);
            }
        }
    }
}
}

#endif // !defined(BAD_APPLE_OS_PSF_HPP_INCLUDED)