#include "ProjectBrowserModelInternal.h"

#include <algorithm>
#include <cctype>
#include <cwctype>
#include <initializer_list>
#include <system_error>

namespace XCEngine::UI::Editor::App::ProjectBrowserModelInternal {

namespace {

std::string BuildUtf8String(std::u8string_view value) {
    std::string result = {};
    result.reserve(value.size());
    for (const char8_t character : value) {
        result.push_back(static_cast<char>(character));
    }
    return result;
}

std::u8string BuildU8String(std::string_view value) {
    std::u8string result = {};
    result.reserve(value.size());
    for (const char character : value) {
        result.push_back(static_cast<char8_t>(character));
    }
    return result;
}

} // namespace

std::string ToLowerCopy(std::string value) {
    std::transform(
        value.begin(),
        value.end(),
        value.begin(),
        [](unsigned char character) {
            return static_cast<char>(std::tolower(character));
        });
    return value;
}

std::string PathToUtf8String(const std::filesystem::path& path) {
    return BuildUtf8String(path.u8string());
}

std::filesystem::path BuildPathFromUtf8(std::string_view value) {
    return std::filesystem::path(BuildU8String(value));
}

std::string NormalizePathSeparators(std::string value) {
    std::replace(value.begin(), value.end(), '\\', '/');
    return value;
}

std::string BuildRelativeItemId(
    const std::filesystem::path& path,
    const std::filesystem::path& assetsRoot) {
    const std::filesystem::path relative =
        std::filesystem::relative(path, assetsRoot.parent_path());
    const std::string normalized =
        NormalizePathSeparators(PathToUtf8String(relative.lexically_normal()));
    return normalized.empty() ? std::string(kAssetsRootId) : normalized;
}

std::string BuildRelativeProjectPath(
    const std::filesystem::path& path,
    const std::filesystem::path& projectRoot) {
    if (projectRoot.empty() || path.empty()) {
        return {};
    }

    const std::filesystem::path relative =
        std::filesystem::relative(path, projectRoot);
    const std::string normalized =
        NormalizePathSeparators(PathToUtf8String(relative.lexically_normal()));
    return normalized;
}

std::string BuildAssetDisplayName(const std::filesystem::path& path, bool directory) {
    if (directory) {
        return PathToUtf8String(path.filename());
    }

    const std::string filename = PathToUtf8String(path.filename());
    const std::size_t extensionOffset = filename.find_last_of('.');
    if (extensionOffset == std::string::npos || extensionOffset == 0u) {
        return filename;
    }

    return filename.substr(0u, extensionOffset);
}

std::string BuildAssetNameWithExtension(const std::filesystem::path& path, bool directory) {
    return directory
        ? PathToUtf8String(path.filename())
        : PathToUtf8String(path.filename());
}

bool IsMetaFile(const std::filesystem::path& path) {
    return ToLowerCopy(path.extension().string()) == ".meta";
}

bool HasChildDirectories(const std::filesystem::path& folderPath) {
    std::error_code errorCode = {};
    const std::filesystem::directory_iterator end = {};
    for (std::filesystem::directory_iterator iterator(folderPath, errorCode);
         !errorCode && iterator != end;
         iterator.increment(errorCode)) {
        if (iterator->is_directory(errorCode)) {
            return true;
        }
    }

    return false;
}

std::vector<std::filesystem::path> CollectSortedChildDirectories(
    const std::filesystem::path& folderPath) {
    std::vector<std::filesystem::path> paths = {};
    std::error_code errorCode = {};
    const std::filesystem::directory_iterator end = {};
    for (std::filesystem::directory_iterator iterator(folderPath, errorCode);
         !errorCode && iterator != end;
         iterator.increment(errorCode)) {
        if (iterator->is_directory(errorCode)) {
            paths.push_back(iterator->path());
        }
    }

    std::sort(
        paths.begin(),
        paths.end(),
        [](const std::filesystem::path& lhs, const std::filesystem::path& rhs) {
            return ToLowerCopy(PathToUtf8String(lhs.filename())) <
                ToLowerCopy(PathToUtf8String(rhs.filename()));
        });
    return paths;
}

std::wstring MakePathKey(const std::filesystem::path& path) {
    std::wstring key = path.lexically_normal().generic_wstring();
    std::transform(key.begin(), key.end(), key.begin(), ::towlower);
    return key;
}

bool IsSameOrDescendantPath(
    const std::filesystem::path& path,
    const std::filesystem::path& ancestor) {
    const std::wstring pathKey = MakePathKey(path);
    std::wstring ancestorKey = MakePathKey(ancestor);
    if (pathKey.empty() || ancestorKey.empty()) {
        return false;
    }

    if (pathKey == ancestorKey) {
        return true;
    }

    if (ancestorKey.back() != L'/') {
        ancestorKey += L'/';
    }
    return pathKey.rfind(ancestorKey, 0) == 0;
}

std::string TrimAssetName(std::string_view name) {
    const auto first =
        std::find_if_not(name.begin(), name.end(), [](unsigned char character) {
            return std::isspace(character) != 0;
        });
    if (first == name.end()) {
        return {};
    }

    const auto last =
        std::find_if_not(name.rbegin(), name.rend(), [](unsigned char character) {
            return std::isspace(character) != 0;
        }).base();
    return std::string(first, last);
}

bool HasInvalidAssetName(std::string_view name) {
    if (name.empty() || name == "." || name == "..") {
        return true;
    }

    return name.find_first_of("\\/:*?\"<>|") != std::string_view::npos;
}

std::filesystem::path MakeUniqueFolderPath(
    const std::filesystem::path& parentPath,
    std::string_view preferredName) {
    std::filesystem::path candidatePath =
        parentPath / BuildPathFromUtf8(preferredName);
    if (!std::filesystem::exists(candidatePath)) {
        return candidatePath;
    }

    for (std::size_t suffix = 1u;; ++suffix) {
        candidatePath =
            parentPath / BuildPathFromUtf8(
                std::string(preferredName) + " " + std::to_string(suffix));
        if (!std::filesystem::exists(candidatePath)) {
            return candidatePath;
        }
    }
}

std::filesystem::path MakeUniqueFilePath(
    const std::filesystem::path& parentPath,
    const std::filesystem::path& preferredFileName) {
    std::filesystem::path candidatePath = parentPath / preferredFileName;
    if (!std::filesystem::exists(candidatePath)) {
        return candidatePath;
    }

    const std::wstring stem = preferredFileName.stem().wstring();
    const std::wstring extension = preferredFileName.extension().wstring();
    for (std::size_t suffix = 1u;; ++suffix) {
        candidatePath =
            parentPath /
            std::filesystem::path(
                stem + L" " + std::to_wstring(suffix) + extension);
        if (!std::filesystem::exists(candidatePath)) {
            return candidatePath;
        }
    }
}

std::string BuildRenamedEntryName(
    const std::filesystem::path& sourcePath,
    std::string_view requestedName) {
    if (std::filesystem::is_directory(sourcePath)) {
        return std::string(requestedName);
    }

    const std::filesystem::path requestedPath =
        BuildPathFromUtf8(requestedName);
    if (requestedPath.has_extension()) {
        return PathToUtf8String(requestedPath.filename());
    }

    return std::string(requestedName) + PathToUtf8String(sourcePath.extension());
}

std::filesystem::path GetMetaSidecarPath(const std::filesystem::path& assetPath) {
    return std::filesystem::path(assetPath.native() + std::filesystem::path(L".meta").native());
}

void RemoveMetaSidecarIfPresent(const std::filesystem::path& assetPath) {
    std::error_code errorCode = {};
    std::filesystem::remove_all(GetMetaSidecarPath(assetPath), errorCode);
}

namespace {

std::filesystem::path MakeCaseOnlyRenameTempPath(const std::filesystem::path& sourcePath) {
    const std::filesystem::path parentPath = sourcePath.parent_path();
    const std::wstring sourceStem = sourcePath.filename().wstring();

    for (std::size_t suffix = 0u;; ++suffix) {
        std::wstring tempName = sourceStem + L".xc_tmp_rename";
        if (suffix > 0u) {
            tempName += std::to_wstring(suffix);
        }

        const std::filesystem::path tempPath = parentPath / tempName;
        if (!std::filesystem::exists(tempPath)) {
            return tempPath;
        }
    }
}

bool MatchesExtension(
    std::wstring_view extension,
    std::initializer_list<std::wstring_view> candidates) {
    for (const std::wstring_view candidate : candidates) {
        if (extension == candidate) {
            return true;
        }
    }

    return false;
}

} // namespace

bool RenamePathCaseAware(
    const std::filesystem::path& sourcePath,
    const std::filesystem::path& destPath) {
    if (MakePathKey(sourcePath) != MakePathKey(destPath)) {
        if (std::filesystem::exists(destPath)) {
            return false;
        }

        std::filesystem::rename(sourcePath, destPath);
        return true;
    }

    if (sourcePath.filename() == destPath.filename()) {
        return true;
    }

    const std::filesystem::path tempPath = MakeCaseOnlyRenameTempPath(sourcePath);
    std::filesystem::rename(sourcePath, tempPath);
    std::filesystem::rename(tempPath, destPath);
    return true;
}

void MoveMetaSidecarIfPresent(
    const std::filesystem::path& sourcePath,
    const std::filesystem::path& destPath) {
    const std::filesystem::path sourceMetaPath = GetMetaSidecarPath(sourcePath);
    if (!std::filesystem::exists(sourceMetaPath)) {
        return;
    }

    const std::filesystem::path destMetaPath = GetMetaSidecarPath(destPath);
    RenamePathCaseAware(sourceMetaPath, destMetaPath);
}

bool MovePathWithOptionalMeta(
    const std::filesystem::path& sourcePath,
    const std::filesystem::path& destinationPath) {
    std::error_code errorCode = {};
    const std::filesystem::path sourceMetaPath = GetMetaSidecarPath(sourcePath);
    const std::filesystem::path destinationMetaPath = GetMetaSidecarPath(destinationPath);
    const bool moveMeta = std::filesystem::exists(sourceMetaPath, errorCode);
    if (errorCode) {
        return false;
    }

    std::filesystem::rename(sourcePath, destinationPath, errorCode);
    if (errorCode) {
        return false;
    }

    if (!moveMeta) {
        return true;
    }

    std::filesystem::rename(sourceMetaPath, destinationMetaPath, errorCode);
    if (!errorCode) {
        return true;
    }

    std::error_code rollbackError = {};
    std::filesystem::rename(destinationPath, sourcePath, rollbackError);
    return false;
}

ProjectBrowserModel::ItemKind ResolveItemKind(
    const std::filesystem::path& path,
    bool directory) {
    if (directory) {
        return ProjectBrowserModel::ItemKind::Folder;
    }

    std::wstring extension = path.extension().wstring();
    std::transform(extension.begin(), extension.end(), extension.begin(), ::towlower);

    if (MatchesExtension(extension, { L".xc", L".unity", L".scene" })) {
        return ProjectBrowserModel::ItemKind::Scene;
    }
    if (MatchesExtension(extension, { L".fbx", L".obj", L".gltf", L".glb" })) {
        return ProjectBrowserModel::ItemKind::Model;
    }
    if (extension == L".mat") {
        return ProjectBrowserModel::ItemKind::Material;
    }
    if (MatchesExtension(extension, {
            L".png", L".jpg", L".jpeg", L".tga", L".bmp", L".gif",
            L".psd", L".hdr", L".pic", L".ppm", L".pgm", L".pbm",
            L".pnm", L".dds", L".ktx", L".ktx2", L".webp" })) {
        return ProjectBrowserModel::ItemKind::Texture;
    }
    if (MatchesExtension(extension, { L".cs", L".cpp", L".c", L".h", L".hpp" })) {
        return ProjectBrowserModel::ItemKind::Script;
    }

    return ProjectBrowserModel::ItemKind::File;
}

bool CanOpenItemKind(ProjectBrowserModel::ItemKind kind) {
    return kind == ProjectBrowserModel::ItemKind::Folder ||
        kind == ProjectBrowserModel::ItemKind::Scene;
}

bool CanPreviewItemKind(ProjectBrowserModel::ItemKind kind) {
    return kind == ProjectBrowserModel::ItemKind::Texture;
}

} // namespace XCEngine::UI::Editor::App::ProjectBrowserModelInternal