#include "core/resources/palette_loader.hpp"

#include <algorithm>
#include <cstddef>
#include <cstdint>
#include <filesystem>
#include <sstream>
#include <stdexcept>
#include <string>

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

namespace Resource::PaletteLoader {

    auto parseJasc(const std::vector<std::uint8_t>& bytes) -> Palette {
        std::string content(bytes.begin(), bytes.end());
        std::istringstream stream(content);
        std::string line;

        // Capçalera: "JASC-PAL" / "0100" / count.
        std::getline(stream, line);
        if (!line.starts_with("JASC-PAL")) {
            throw std::runtime_error("PaletteLoader: fitxer no és JASC-PAL");
        }
        std::getline(stream, line);  // versió, ignorada per ara
        std::getline(stream, line);
        int declared_count = 0;
        try {
            declared_count = std::stoi(line);
        } catch (...) {
            throw std::runtime_error("PaletteLoader: count JASC-PAL invàlid");
        }

        Palette palette{};
        const std::size_t MAX = std::min(static_cast<std::size_t>(declared_count), palette.size());
        std::size_t i = 0;
        while (i < MAX && std::getline(stream, line)) {
            if (line.empty()) { continue; }
            std::istringstream ls(line);
            int r = 0;
            int g = 0;
            int b = 0;
            ls >> r >> g >> b;
            palette[i] = 0xFF000000U | (static_cast<std::uint32_t>(r & 0xFF) << 16) | (static_cast<std::uint32_t>(g & 0xFF) << 8) | static_cast<std::uint32_t>(b & 0xFF);
            ++i;
        }
        return palette;
    }

    auto loadFromFile(const std::string& file_path) -> Palette {
        auto ext = std::filesystem::path(file_path).extension().string();
        std::ranges::transform(ext, ext.begin(), [](unsigned char c) { return std::tolower(c); });

        auto bytes = Resource::Helper::loadFile(file_path);
        if (bytes.empty()) {
            throw std::runtime_error("PaletteLoader: no s'ha pogut llegir " + file_path);
        }

        if (ext == ".pal") { return parseJasc(bytes); }
        if (ext == ".gif") { return loadPaletteFromGif(file_path); }
        throw std::runtime_error("PaletteLoader: format de paleta no suportat: " + ext);
    }

}  // namespace Resource::PaletteLoader