#include "engine_paths.hpp"

#include <algorithm>
#include <filesystem>
#include <sstream>
#include <stack>
#include <utility>
#include <array>

#include <typedefs.hpp>
#include <util/stringutil.hpp>
#include "WorldFiles.hpp"

/**
 * @brief ENUM for accessing folder and file names
 */
enum F_F_NAME{
    SCREENSHOTS_FOLDER,
    CONTENT_FOLDER,
    CONTROLS_FILE,
    SETTINGS_FILE,

    COUNT
};

/**
 * @brief array for get file or folder name by enum `F_F_NAME`
 * 
 * example:
 * `std::filesystem::path settings = f_f_names[SETTINGS_FILE];`
 */
static std::array<std::string, F_F_NAME::COUNT> f_f_names{
        "screenshots",
        "content",
        "controls.toml",
        "settings.toml"
};

static std::filesystem::path toCanonic(std::filesystem::path path) {
    std::stack<std::string> parts;
    path = path.lexically_normal();
    do {
        parts.push(path.filename().u8string());
        path = path.parent_path();
    } while (!path.empty());

    path = fs::u8path("");
    
    while (!parts.empty()) {
        const std::string part = parts.top();
        parts.pop();
        if (part == ".") {
            continue;
        }
        if (part == "..") {
            throw files_access_error("entry point reached");
        }

        path = path / std::filesystem::path(part);
    }
    return path;
}


void EnginePaths::prepare() {
    std::filesystem::path contentFolder = userFilesFolder / std::filesystem::path(f_f_names[CONTENT_FOLDER]);
    if (!fs::is_directory(contentFolder)) {
        fs::create_directories(contentFolder);
    }
}

std::filesystem::path EnginePaths::getUserFilesFolder() const {
    return userFilesFolder;
}

std::filesystem::path EnginePaths::getResourcesFolder() const {
    return resourcesFolder;
}

std::filesystem::path EnginePaths::getNewScreenshotFile(const std::string& ext) {
    std::filesystem::path folder = userFilesFolder / std::filesystem::path(f_f_names[SCREENSHOTS_FOLDER]);
    if (!fs::is_directory(folder)) {
        fs::create_directory(folder);
    }

    auto t = std::time(nullptr);
    auto tm = *std::localtime(&t);

    const char* format = "%Y-%m-%d_%H-%M-%S";
    std::stringstream ss;
    ss << std::put_time(&tm, format);
    std::string datetimestr = ss.str();

    std::filesystem::path filename =
        folder / fs::u8path("screenshot-" + datetimestr + "." + ext);
    uint index = 0;
    while (fs::exists(filename)) {
        filename = folder / fs::u8path(
                                "screenshot-" + datetimestr + "-" +
                                std::to_string(index) + "." + ext
                            );
        index++;
    }
    return filename;
}

std::filesystem::path EnginePaths::getWorldsFolder() {
    return userFilesFolder / std::filesystem::path("worlds");
}

std::filesystem::path EnginePaths::getCurrentWorldFolder() {
    return currentWorldFolder;
}

std::filesystem::path EnginePaths::getWorldFolderByName(const std::string& name) {
    return getWorldsFolder() / std::filesystem::path(name);
}

std::filesystem::path EnginePaths::getControlsFile() {
    return userFilesFolder / std::filesystem::path(f_f_names[CONTROLS_FILE]);
}

std::filesystem::path EnginePaths::getSettingsFile() {
    return userFilesFolder / std::filesystem::path(f_f_names[SETTINGS_FILE]);
}

std::vector<std::filesystem::path> EnginePaths::scanForWorlds() {
    std::vector<std::filesystem::path> folders;

    std::filesystem::path folder = getWorldsFolder();
    if (!fs::is_directory(folder)) return folders;

    for (const auto& entry : fs::directory_iterator(folder)) {
        if (!entry.is_directory()) {
            continue;
        }
        const std::filesystem::path& worldFolder = entry.path();
        std::filesystem::path worldFile = worldFolder / fs::u8path(WorldFiles::WORLD_FILE);
        if (!fs::is_regular_file(worldFile)) {
            continue;
        }
        folders.push_back(worldFolder);
    }
    std::sort(folders.begin(), folders.end(), [](std::filesystem::path a, std::filesystem::path b) {
        a = a / fs::u8path(WorldFiles::WORLD_FILE);
        b = b / fs::u8path(WorldFiles::WORLD_FILE);
        return fs::last_write_time(a) > fs::last_write_time(b);
    });
    return folders;
}

void EnginePaths::setUserFilesFolder(std::filesystem::path folder) {
    this->userFilesFolder = std::move(folder);
}

void EnginePaths::setResourcesFolder(std::filesystem::path folder) {
    this->resourcesFolder = std::move(folder);
}

void EnginePaths::setCurrentWorldFolder(std::filesystem::path folder) {
    this->currentWorldFolder = std::move(folder);
}

void EnginePaths::setContentPacks(std::vector<ContentPack>* contentPacks) {
    this->contentPacks = contentPacks;
}

std::filesystem::path EnginePaths::resolve(const std::string& path, bool throwErr) {
    size_t separator = path.find(':');
    if (separator == std::string::npos) {
        throw files_access_error("no entry point specified");
    }
    std::string prefix = path.substr(0, separator);
    std::string filename = path.substr(separator + 1);
    filename = toCanonic(fs::u8path(filename)).u8string();

    if (prefix == "res" || prefix == "core") {
        return resourcesFolder / fs::u8path(filename);
    }
    if (prefix == "user") {
        return userFilesFolder / fs::u8path(filename);
    }
    if (prefix == "world") {
        return currentWorldFolder / fs::u8path(filename);
    }

    if (contentPacks) {
        for (auto& pack : *contentPacks) {
            if (pack.id == prefix) {
                return pack.folder / fs::u8path(filename);
            }
        }
    }
    if (throwErr) {
        throw files_access_error("unknown entry point '" + prefix + "'");
    }
    return std::filesystem::path(filename);
}


ResPaths::ResPaths(std::filesystem::path mainRoot, std::vector<PathsRoot> roots)
    : mainRoot(std::move(mainRoot)), roots(std::move(roots)) {
}

std::filesystem::path ResPaths::find(const std::string& filename) const {
    for (int i = roots.size() - 1; i >= 0; i--) {
        auto& root = roots[i];
        std::filesystem::path file = root.path / fs::u8path(filename);
        if (fs::exists(file)) {
            return file;
        }
    }
    return mainRoot / fs::u8path(filename);
}

std::string ResPaths::findRaw(const std::string& filename) const {
    for (int i = roots.size() - 1; i >= 0; i--) {
        auto& root = roots[i];
        if (fs::exists(root.path / std::filesystem::path(filename))) {
            return root.name + ":" + filename;
        }
    }
    auto resDir = mainRoot;
    if (fs::exists(resDir / std::filesystem::path(filename))) {
        return "core:" + filename;
    }
    throw std::runtime_error("could not to find file " + util::quote(filename));
}

std::vector<std::string> ResPaths::listdirRaw(const std::string& folderName
) const {
    std::vector<std::string> entries;
    for (int i = roots.size() - 1; i >= 0; i--) {
        auto& root = roots[i];
        std::filesystem::path folder = root.path / fs::u8path(folderName);
        if (!fs::is_directory(folder)) continue;
        for (const auto& entry : fs::directory_iterator(folder)) {
            auto name = entry.path().filename().u8string();
            entries.emplace_back(root.name + ":" + folderName + "/" + name);
        }
    }
    {
        std::filesystem::path folder = mainRoot / fs::u8path(folderName);
        if (!fs::is_directory(folder)) return entries;
        for (const auto& entry : fs::directory_iterator(folder)) {
            auto name = entry.path().filename().u8string();
            entries.emplace_back("core:" + folderName + "/" + name);
        }
    }
    return entries;
}

std::vector<std::filesystem::path> ResPaths::listdir(const std::string& folderName) const {
    std::vector<std::filesystem::path> entries;
    for (int i = roots.size() - 1; i >= 0; i--) {
        auto& root = roots[i];
        std::filesystem::path folder = root.path / fs::u8path(folderName);
        if (!fs::is_directory(folder)) continue;
        for (const auto& entry : fs::directory_iterator(folder)) {
            entries.push_back(entry.path());
        }
    }
    {
        std::filesystem::path folder = mainRoot / fs::u8path(folderName);
        if (!fs::is_directory(folder)) return entries;
        for (const auto& entry : fs::directory_iterator(folder)) {
            entries.push_back(entry.path());
        }
    }
    return entries;
}

const std::filesystem::path& ResPaths::getMainRoot() const {
    return mainRoot;
}