#include "core/rendering/text.hpp"

#include <SDL3/SDL.h>

#include <cstddef>
#include <iostream>
#include <sstream>
#include <stdexcept>
#include <string>

#include "core/rendering/sprite/sprite.hpp"
#include "core/rendering/surface.hpp"
#include "core/resources/resource_helper.hpp"
#include "utils/utils.hpp"

// Decodifica el pròxim codepoint UTF-8 de la cadena i avança 'pos' al byte
// següent. Retorna U+FFFD davant seqüències malformades perquè el caller
// seguisca dibuixant (cau al glif '?' més endavant).
auto Text::nextCodepoint(const std::string& s, std::size_t& pos) -> std::uint32_t {
    auto c = static_cast<unsigned char>(s[pos]);
    std::uint32_t cp = 0;
    std::size_t extra = 0;

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

    pos++;
    for (std::size_t i = 0; i < extra && pos < s.size(); ++i, ++pos) {
        auto cb = static_cast<unsigned char>(s[pos]);
        if ((cb & 0xC0) != 0x80) { return 0xFFFD; }
        cp = (cp << 6) | (cb & 0x3F);
    }
    return cp;
}

// Format .fnt: claus "box_width/box_height/columns/cell_spacing/row_spacing"
// i una línia per glif amb "codepoint_decimal amplada_visual". Els glifs
// s'ordenen al png per ordre d'aparició al .fnt (glyph_index).
auto Text::loadTextFile(const std::string& file_path) -> std::shared_ptr<File> {
    auto tf = std::make_shared<File>();

    auto file_data = Resource::Helper::loadFile(file_path);
    if (file_data.empty()) {
        std::cerr << "Error: Fitxer no trobat " << getFileName(file_path) << '\n';
        throw std::runtime_error("Fitxer no trobat: " + getFileName(file_path));
    }

    std::string content(file_data.begin(), file_data.end());
    std::istringstream stream(content);
    std::string line;
    int glyph_index = 0;

    while (std::getline(stream, line)) {
        if (!line.empty() && line.back() == '\r') { line.pop_back(); }
        if (line.empty() || line[0] == '#') { continue; }

        std::istringstream ls(line);
        std::string key;
        ls >> key;

        if (key == "box_width") {
            ls >> tf->box_width;
        } else if (key == "box_height") {
            ls >> tf->box_height;
        } else if (key == "columns") {
            ls >> tf->columns;
        } else if (key == "cell_spacing") {
            ls >> tf->cell_spacing;
        } else if (key == "row_spacing") {
            ls >> tf->row_spacing;
        } else {
            std::uint32_t codepoint = 0;
            int width = 0;
            try {
                codepoint = static_cast<std::uint32_t>(std::stoul(key));
                ls >> width;
            } catch (...) {
                continue;
            }
            Offset off{};
            const int ROW_SP = tf->row_spacing > 0 ? tf->row_spacing : tf->cell_spacing;
            off.x = ((glyph_index % tf->columns) * (tf->box_width + tf->cell_spacing)) + tf->cell_spacing;
            off.y = ((glyph_index / tf->columns) * (tf->box_height + ROW_SP)) + tf->cell_spacing;
            off.w = width;
            tf->offset[codepoint] = off;
            ++glyph_index;
        }
    }

    printWithDots("Text File : ", getFileName(file_path), "[ LOADED ]");
    return tf;
}

Text::Text(const std::shared_ptr<Surface>& surface, const std::string& text_file) {
    auto tf = loadTextFile(text_file);
    box_height_ = tf->box_height;
    box_width_ = tf->box_width;
    offset_ = tf->offset;
    sprite_ = std::make_unique<Sprite>(surface, SDL_FRect{.x = 0.0F, .y = 0.0F, .w = static_cast<float>(box_width_), .h = static_cast<float>(box_height_)});
}

Text::Text(const std::shared_ptr<Surface>& surface, const std::shared_ptr<File>& text_file)
    : sprite_(std::make_unique<Sprite>(surface, SDL_FRect{.x = 0.0F, .y = 0.0F, .w = static_cast<float>(text_file->box_width), .h = static_cast<float>(text_file->box_height)})),
      box_width_(text_file->box_width),
      box_height_(text_file->box_height),
      offset_(text_file->offset) {
}

// Dibuixa la cadena amb la tinta per defecte. Els glifs amb codepoint no
// registrat es substitueixen pel glif '?'.
void Text::write(int x, int y, const std::string& text, int kerning, int length) {
    writeColored(x, y, text, DEFAULT_TEXT_COLOR, kerning, length);
}

void Text::writeColored(int x, int y, const std::string& text, Uint8 color, int kerning, int length) {
    int shift = 0;
    int glyphs_done = 0;
    std::size_t pos = 0;

    sprite_->setY(static_cast<float>(y));
    while (pos < text.size()) {
        if (length != -1 && glyphs_done >= length) { break; }
        std::uint32_t cp = nextCodepoint(text, pos);
        if (const Offset* off = resolveGlyph(cp); off != nullptr) {
            sprite_->setClip(static_cast<float>(off->x), static_cast<float>(off->y), static_cast<float>(box_width_), static_cast<float>(box_height_));
            sprite_->setX(static_cast<float>(x + shift));
            sprite_->render(INK_COLOR_INDEX, color);
            shift += off->w + kerning;
        }
        ++glyphs_done;
    }
}

void Text::writeDX(Uint8 flags, int x, int y, const std::string& text, int kerning, Uint8 text_color, Uint8 shadow_distance, Uint8 shadow_color, int length) {
    const bool CENTERED = ((flags & CENTER_FLAG) == CENTER_FLAG);
    const bool SHADOWED = ((flags & SHADOW_FLAG) == SHADOW_FLAG);
    const bool COLORED = ((flags & COLOR_FLAG) == COLOR_FLAG);
    const bool STROKED = ((flags & STROKE_FLAG) == STROKE_FLAG);
    const bool STROKED_4 = ((flags & STROKE4_FLAG) == STROKE4_FLAG);

    if (CENTERED) { x -= (Text::length(text, kerning) / 2); }

    if (SHADOWED) {
        writeColored(x + shadow_distance, y + shadow_distance, text, shadow_color, kerning, length);
    }

    if (STROKED_4) {
        const int MAX_DIST = static_cast<int>(shadow_distance);
        for (int dist = 1; dist <= MAX_DIST; ++dist) {
            writeColored(x + dist, y, text, shadow_color, kerning, length);
            writeColored(x - dist, y, text, shadow_color, kerning, length);
            writeColored(x, y + dist, text, shadow_color, kerning, length);
            writeColored(x, y - dist, text, shadow_color, kerning, length);
        }
    }

    if (STROKED) {
        const int MAX_DIST = static_cast<int>(shadow_distance);
        for (int dist = 1; dist <= MAX_DIST; ++dist) {
            for (int dy = -dist; dy <= dist; ++dy) {
                for (int dx = -dist; dx <= dist; ++dx) {
                    writeColored(x + dx, y + dy, text, shadow_color, kerning, length);
                }
            }
        }
    }

    if (COLORED) {
        writeColored(x, y, text, text_color, kerning, length);
    } else {
        write(x, y, text, kerning, length);
    }
}

// Amplada fixa per dígits: cada '0'-'9' ocupa digit_cell_w centrat dins de
// la cel·la; la resta de glifs avancen amb la seua amplada natural. Emprat
// pel comptador de temps de l'overlay RenderInfo per a que els dígits no
// balleteigen quan canvien.
void Text::writeMonoDigits(int x, int y, const std::string& text, Uint8 color, int digit_cell_w, int kerning) {
    int shift = 0;
    std::size_t pos = 0;

    sprite_->setY(static_cast<float>(y));
    while (pos < text.size()) {
        std::uint32_t cp = nextCodepoint(text, pos);
        const Offset* off = resolveGlyph(cp);
        if (off == nullptr) { continue; }

        const bool IS_DIGIT = (cp >= '0' && cp <= '9');
        const int GLYPH_W = off->w;
        const int CELL_W = IS_DIGIT ? digit_cell_w : GLYPH_W;
        const int GLYPH_X = IS_DIGIT ? x + shift + ((CELL_W - GLYPH_W) / 2) : x + shift;

        sprite_->setClip(static_cast<float>(off->x),
            static_cast<float>(off->y),
            static_cast<float>(box_width_),
            static_cast<float>(box_height_));
        sprite_->setX(static_cast<float>(GLYPH_X));
        sprite_->render(INK_COLOR_INDEX, color);

        shift += CELL_W + kerning;
    }
}

auto Text::lengthMonoDigits(const std::string& text, int digit_cell_w, int kerning) const -> int {
    int shift = 0;
    std::size_t pos = 0;

    while (pos < text.size()) {
        std::uint32_t cp = nextCodepoint(text, pos);
        const Offset* off = resolveGlyph(cp);
        if (off == nullptr) { continue; }

        const bool IS_DIGIT = (cp >= '0' && cp <= '9');
        shift += (IS_DIGIT ? digit_cell_w : off->w) + kerning;
    }

    return shift > 0 ? shift - kerning : 0;
}

auto Text::length(const std::string& text, int kerning) const -> int {
    int shift = 0;
    std::size_t pos = 0;

    while (pos < text.size()) {
        std::uint32_t cp = nextCodepoint(text, pos);
        if (const Offset* off = resolveGlyph(cp); off != nullptr) {
            shift += off->w + kerning;
        }
    }

    return shift > 0 ? shift - kerning : 0;
}

auto Text::resolveGlyph(std::uint32_t cp) const -> const Offset* {
    auto it = offset_.find(cp);
    if (it == offset_.end()) { it = offset_.find('?'); }
    return (it != offset_.end()) ? &it->second : nullptr;
}