// SPDX-License-Identifier: MPL-2.0

#include "sequa/platform/layout.hpp"

#include <doctest/doctest.h>

#include <chrono>
#include <filesystem>
#include <fstream>
#include <string>
#include <system_error>

namespace sequa::platform::testing {

// Dossier temporaire propre à un test, supprimé à la fin.
class TempDir {
public:
    TempDir()
        : path_(std::filesystem::temp_directory_path()
                / ("sequa-layout-" + std::to_string(std::chrono::steady_clock::now().time_since_epoch().count()) + "-"
                   + std::to_string(++counter_)))
    {
        std::filesystem::create_directories(path_);
    }
    ~TempDir()
    {
        std::error_code ignored;
        std::filesystem::remove_all(path_, ignored);
    }
    TempDir(const TempDir&) = delete;
    TempDir& operator=(const TempDir&) = delete;

    [[nodiscard]] const std::filesystem::path& path() const noexcept { return path_; }

private:
    inline static int counter_ = 0;
    std::filesystem::path path_;
};

// Écrit un fichier repère vide.
inline void touch(const std::filesystem::path& file)
{
    std::ofstream out(file);
    REQUIRE(out.good());
}

// Fonction dont l'adresse sert à module_path.
inline void function_in_test_executable() {}

} // namespace sequa::platform::testing

TEST_SUITE("sequa::platform::layout") {

TEST_CASE("find_root finds marker in start directory itself") {
    using namespace sequa::platform;
    using namespace sequa::platform::testing;

    TempDir tmp;
    const auto root = tmp.path();
    std::error_code ec;
    std::filesystem::create_directories(root / "core", ec);
    REQUIRE(!ec);
    std::filesystem::create_directories(root / "render", ec);
    REQUIRE(!ec);

    // Créer le fichier repère
    const auto marker = root / root_marker;
    std::filesystem::create_directories(marker.parent_path(), ec);
    REQUIRE(!ec);
    touch(marker);

    const auto found = find_root(root);
    REQUIRE(found.has_value());
    CHECK(std::filesystem::equivalent(found.value(), root));
}

TEST_CASE("find_root finds marker two levels up from nested directory") {
    using namespace sequa::platform;
    using namespace sequa::platform::testing;

    TempDir tmp;
    const auto root = tmp.path();
    const auto nested = root / "a" / "b" / "c";
    std::error_code ec;
    std::filesystem::create_directories(nested, ec);
    REQUIRE(!ec);

    // Créer le fichier repère à la racine
    const auto marker = root / root_marker;
    touch(marker);

    const auto found = find_root(nested);
    REQUIRE(found.has_value());
    CHECK(std::filesystem::equivalent(found.value(), root));
}

TEST_CASE("find_root returns nullopt when marker absent") {
    using namespace sequa::platform;
    using namespace sequa::platform::testing;

    TempDir tmp;
    const auto root = tmp.path();
    const auto nested = root / "a" / "b";
    std::error_code ec;
    std::filesystem::create_directories(nested, ec);
    REQUIRE(!ec);

    const auto found = find_root(nested);
    CHECK_FALSE(found.has_value());
}

TEST_CASE("Layout paths match expected structure") {
    using namespace sequa::platform;
    using namespace sequa::platform::testing;

    TempDir tmp;
    const auto root = tmp.path();

    Layout layout(root);

    CHECK(layout.root() == root);
    CHECK(layout.core_executable() == root / "core" / executable_name("sequa-core"));
    CHECK(layout.render_executable() == root / "render" / executable_name("sequa-render"));
    CHECK(layout.studio_executable() == root / "studio" / executable_name("sequa-studio"));
    CHECK(layout.ui_dir() == root / "studio" / "ui");
    CHECK(layout.engine_dir("godot") == root / "engines" / "godot");
}

TEST_CASE("adapter_library returns correct filename and rejects invalid names") {
    using namespace sequa::platform;
    using namespace sequa::platform::testing;

    TempDir tmp;
    const auto root = tmp.path();
    Layout layout(root);

    // Nom valide
    const auto godot_adapter = layout.adapter_library("godot");
    REQUIRE(godot_adapter.has_value());
    CHECK(godot_adapter.value() == root / "engines" / "godot" / module_name("sequa_godot_adapter"));

    // Nom invalide : contient des caractères non autorisés
    CHECK_FALSE(layout.adapter_library("../x").has_value());
    CHECK_FALSE(layout.adapter_library("").has_value());
    CHECK_FALSE(layout.adapter_library("Godot").has_value()); // majuscule
    CHECK_FALSE(layout.adapter_library("godot-1").has_value()); // tiret
    CHECK_FALSE(layout.adapter_library("godot ").has_value()); // espace
}

TEST_CASE("executable_name and module_name per platform") {
    using namespace sequa::platform;

#if defined(_WIN32)
    CHECK(executable_name("sequa-core") == "sequa-core.exe");
    CHECK(module_name("sequa_godot_adapter") == "sequa_godot_adapter.dll");
#else
    CHECK(executable_name("sequa-core") == "sequa-core");
    CHECK(module_name("sequa_godot_adapter") == "sequa_godot_adapter.so");
#endif
}

TEST_CASE("current_executable returns non-empty existing path") {
    using namespace sequa::platform;

    const auto exe = current_executable();
    CHECK_FALSE(exe.empty());
    std::error_code ec;
    CHECK(std::filesystem::exists(exe, ec));
    CHECK(!ec);
}

TEST_CASE("module_path of a function in this test equals current_executable") {
    using namespace sequa::platform;

    const auto exe = current_executable();
    REQUIRE_FALSE(exe.empty());

    // Adresse d'une fonction locale pour tester module_path
    const auto mod = module_path(reinterpret_cast<const void*>(&testing::function_in_test_executable));
    REQUIRE_FALSE(mod.empty());

    std::error_code ec;
    CHECK(std::filesystem::equivalent(exe, mod, ec));
    CHECK(!ec);
}

TEST_CASE("is_valid_engine_name accepts valid names and rejects invalid ones") {
    using namespace sequa::platform;

    CHECK(is_valid_engine_name("godot"));
    CHECK(is_valid_engine_name("debug"));
    CHECK(is_valid_engine_name("engine_123"));
    CHECK(is_valid_engine_name("a"));

    CHECK_FALSE(is_valid_engine_name(""));
    CHECK_FALSE(is_valid_engine_name("Godot"));
    CHECK_FALSE(is_valid_engine_name("godot-1"));
    CHECK_FALSE(is_valid_engine_name("godot "));
    CHECK_FALSE(is_valid_engine_name("godot.engine"));
    CHECK_FALSE(is_valid_engine_name("../godot"));
    CHECK_FALSE(is_valid_engine_name("godot/evil"));
}

TEST_CASE("path_from_utf8 and path_to_utf8 keep non-ASCII characters") {
    using namespace sequa::platform;

    const std::string utf8 = "C:/Users/Am\xC3\xA9lie/SEQUA"; // « é » en UTF-8
    const auto path = path_from_utf8(utf8);
    CHECK(path.filename() == path_from_utf8("SEQUA"));
    CHECK(path_to_utf8(path) == utf8);
    CHECK(path.u8string() == u8"C:/Users/Amélie/SEQUA");
}

TEST_CASE("utf8_arguments drops the program name") {
    using namespace sequa::platform;

    char program[] = "sequa-layout-tests";
    char* argv[] = {program, nullptr};
    const auto args = utf8_arguments(1, argv);
#if !defined(_WIN32)
    CHECK(args.empty());
#else
    // Sous Windows, la vraie ligne de commande du test (arguments de doctest éventuels).
    CHECK(args.size() < 64);
#endif
}

} // TEST_SUITE