#include "core/rendering/text.hpp"

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iostream>
#include <sstream>
#include <string>

#include "core/jail/jfile.hpp"

// Forward declarations de gif.h (inclòs des de jdraw8.cpp, no es pot incloure dos vegades)
struct rgb;
extern unsigned char* LoadGif(unsigned char* data, unsigned short* w, unsigned short* h);

Text::Text(const char* fnt_file, const char* gif_file) {
    loadBitmap(gif_file);
    loadFont(fnt_file);
}

Text::~Text() {
    if (bitmap_) free(bitmap_);
}

// --- UTF-8 ---

auto Text::nextCodepoint(const char*& ptr) -> uint32_t {
    auto byte = static_cast<uint8_t>(*ptr);
    if (byte == 0) return 0;

    uint32_t cp = 0;
    int extra = 0;

    if (byte < 0x80) {
        cp = byte;
    } else if ((byte & 0xE0) == 0xC0) {
        cp = byte & 0x1F;
        extra = 1;
    } else if ((byte & 0xF0) == 0xE0) {
        cp = byte & 0x0F;
        extra = 2;
    } else if ((byte & 0xF8) == 0xF0) {
        cp = byte & 0x07;
        extra = 3;
    } else {
        ptr++;
        return 0xFFFD;
    }

    ptr++;
    for (int i = 0; i < extra; i++) {
        auto cont = static_cast<uint8_t>(*ptr);
        if ((cont & 0xC0) != 0x80) return 0xFFFD;
        cp = (cp << 6) | (cont & 0x3F);
        ptr++;
    }

    return cp;
}

// --- Càrrega de font ---

void Text::loadFont(const char* fnt_file) {
    int filesize = 0;
    char* buffer = file_getfilebuffer(fnt_file, filesize, true);
    if (!buffer) {
        std::cerr << "Text: unable to load font file: " << fnt_file << '\n';
        return;
    }

    std::istringstream stream(std::string(buffer, filesize));
    free(buffer);

    std::string line;
    int glyph_index = 0;

    while (std::getline(stream, line)) {
        // Ignora comentaris i línies buides
        if (line.empty() || line[0] == '#') continue;

        // Elimina comentaris inline
        auto comment_pos = line.find('#');
        if (comment_pos != std::string::npos) {
            line = line.substr(0, comment_pos);
        }

        // Parseja directives
        if (line.find("box_width") == 0) {
            sscanf(line.c_str(), "box_width %d", &box_width_);
            continue;
        }
        if (line.find("box_height") == 0) {
            sscanf(line.c_str(), "box_height %d", &box_height_);
            continue;
        }
        if (line.find("columns") == 0) {
            sscanf(line.c_str(), "columns %d", &columns_);
            continue;
        }
        if (line.find("cell_spacing") == 0) {
            sscanf(line.c_str(), "cell_spacing %d", &cell_spacing_);
            continue;
        }
        if (line.find("row_spacing") == 0) {
            sscanf(line.c_str(), "row_spacing %d", &row_spacing_);
            continue;
        }

        // Línies de glifos: "codepoint width"
        uint32_t codepoint = 0;
        int visual_width = 0;
        if (sscanf(line.c_str(), "%u %d", &codepoint, &visual_width) == 2) {
            int col = glyph_index % columns_;
            int row = glyph_index / columns_;

            GlyphInfo glyph{};
            glyph.x = col * (box_width_ + cell_spacing_) + cell_spacing_;
            glyph.y = row * (box_height_ + (row_spacing_ > 0 ? row_spacing_ : cell_spacing_)) + cell_spacing_;
            glyph.w = visual_width;

            glyphs_[codepoint] = glyph;
            glyph_index++;
        }
    }

    std::cout << "Text: loaded font with " << glyphs_.size() << " glyphs (" << box_width_ << "x" << box_height_ << ")\n";
}

void Text::loadBitmap(const char* gif_file) {
    int filesize = 0;
    char* buffer = file_getfilebuffer(gif_file, filesize);
    if (!buffer) {
        std::cerr << "Text: unable to load bitmap: " << gif_file << '\n';
        return;
    }

    // Extrau dimensions del header GIF (bytes 6-7 = width, 8-9 = height, little-endian)
    auto* raw = reinterpret_cast<unsigned char*>(buffer);
    int w = raw[6] | (raw[7] << 8);
    int h = raw[8] | (raw[9] << 8);

    unsigned short gw = 0, gh = 0;
    Uint8* pixels = LoadGif(raw, &gw, &gh);
    if (!pixels) {
        std::cerr << "Text: unable to decode GIF: " << gif_file << '\n';
        free(buffer);
        return;
    }

    bitmap_width_ = w;
    bitmap_height_ = h;
    bitmap_ = pixels;

    free(buffer);
    std::cout << "Text: bitmap loaded " << w << "x" << h << '\n';
}

// --- Renderitzat ---

void Text::draw(Uint32* pixel_data, int x, int y, const char* text, Uint32 color) const {
    if (!bitmap_ || !pixel_data) return;

    const char* ptr = text;
    int cursor_x = x;

    while (*ptr) {
        uint32_t cp = nextCodepoint(ptr);
        if (cp == 0) break;

        auto it = glyphs_.find(cp);
        if (it == glyphs_.end()) {
            it = glyphs_.find('?');
            if (it == glyphs_.end()) {
                cursor_x += box_width_;
                continue;
            }
        }

        const auto& glyph = it->second;

        // Pinta glifo pixel a pixel
        for (int gy = 0; gy < box_height_; gy++) {
            int dst_y = y + gy;
            if (dst_y < 0 || dst_y >= SCREEN_HEIGHT) continue;

            for (int gx = 0; gx < glyph.w; gx++) {
                int dst_x = cursor_x + gx;
                if (dst_x < 0 || dst_x >= SCREEN_WIDTH) continue;

                int src_x = glyph.x + gx;
                int src_y = glyph.y + gy;

                if (src_x >= bitmap_width_ || src_y >= bitmap_height_) continue;

                Uint8 pixel = bitmap_[src_x + src_y * bitmap_width_];
                // Píxel no transparent (índex 0 és fons típicament)
                if (pixel != 0) {
                    pixel_data[dst_x + dst_y * SCREEN_WIDTH] = color;
                }
            }
        }

        cursor_x += glyph.w + 1;  // +1 kerning
    }
}

void Text::drawCentered(Uint32* pixel_data, int y, const char* text, Uint32 color) const {
    int w = width(text);
    int x = (SCREEN_WIDTH - w) / 2;
    draw(pixel_data, x, y, text, color);
}

auto Text::width(const char* text) const -> int {
    const char* ptr = text;
    int w = 0;
    bool first = true;

    while (*ptr) {
        uint32_t cp = nextCodepoint(ptr);
        if (cp == 0) break;

        auto it = glyphs_.find(cp);
        if (it == glyphs_.end()) {
            it = glyphs_.find('?');
        }

        if (!first) w += 1;  // kerning
        first = false;

        if (it != glyphs_.end()) {
            w += it->second.w;
        } else {
            w += box_width_;
        }
    }

    return w;
}
