/**
 * libra3assets - read (and write) Red Alert 3's built-in resource files.
 *
 * The primary module interface re-exports every partition:
 *
 * - `:error`   - the `asset_error` exception family
 * - `:bytes`   - bounds-checked little-/big-endian readers and writers
 * - `:refpack` - EA's RefPack codec (decompress and compress)
 * - `:big`     - `BIG4` archives (`Data\*.big`), read and write
 * - `:binary`  - compiled `BinaryAsset` streams (`*.bin` + `.manifest`)
 * - `:csf`     - SAGE `.csf` string tables
 * - `:map`     - SAGE `.map` containers (`CkMp`), read and write
 *
 * Nothing here reads game data on its own: callers point the library at their
 * own installation (`RA3_GAME_DIR` / `C:\Red Alert 3`).
 */
export module ra3.assets;

export import :error;
export import :bytes;
export import :refpack;
export import :big;
export import :binary;
export import :csf;
export import :map;

import std;

export namespace ra3::assets {

    /**
     * Locate a Red Alert 3 installation.
     *
     * Resolution order: the explicit argument, then `$RA3_GAME_DIR`, then the
     * default `C:\Red Alert 3`. A directory qualifies only if it has a `Data`
     * subdirectory.
     */
    [[nodiscard]] inline auto find_game_dir(const std::optional<std::filesystem::path> &explicit_dir = std::nullopt) -> std::optional<std::filesystem::path> {
        const auto qualifies = [](const std::filesystem::path &candidate) {
            std::error_code ec;
            return !candidate.empty() && std::filesystem::is_directory(candidate / "Data", ec);
        };

        if (explicit_dir && qualifies(*explicit_dir)) return explicit_dir;
        if (const auto *env = std::getenv("RA3_GAME_DIR"); env != nullptr && *env != '\0') {
            const std::filesystem::path candidate{env};
            if (qualifies(candidate)) return candidate;
        }
        const std::filesystem::path default_dir{"C:/Red Alert 3"};
        if (qualifies(default_dir)) return default_dir;
        return std::nullopt;
    }

    /** Every `Data\*.big` archive in an installation, sorted by name. */
    [[nodiscard]] inline auto list_archives(const std::filesystem::path &game_dir) -> std::vector<std::filesystem::path> {
        std::vector<std::filesystem::path> archives;
        std::error_code ec;
        for (const auto &entry: std::filesystem::directory_iterator(game_dir / "Data", ec)) {
            if (entry.is_regular_file() && entry.path().extension() == ".big") archives.push_back(entry.path());
        }
        std::ranges::sort(archives);
        return archives;
    }

} // namespace ra3::assets