#include "ProjectBrowserModel.h"
#include <filesystem>
#include <string>
#include <string_view>
#include <vector>
#include <algorithm>
#include <cctype>
#include <cwctype>
#include <initializer_list>
#include <system_error>
#include <fstream>

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

inline constexpr std::string_view kAssetsRootId = "Assets";

std::string ToLowerCopy(std::string value);
std::string PathToUtf8String(const std::filesystem::path& path);
std::filesystem::path BuildPathFromUtf8(std::string_view value);
std::string NormalizePathSeparators(std::string value);
std::string BuildRelativeItemId(
    const std::filesystem::path& path,
    const std::filesystem::path& assetsRoot);
std::string BuildRelativeProjectPath(
    const std::filesystem::path& path,
    const std::filesystem::path& projectRoot);
std::string BuildAssetDisplayName(const std::filesystem::path& path, bool directory);
std::string BuildAssetNameWithExtension(const std::filesystem::path& path, bool directory);
bool IsMetaFile(const std::filesystem::path& path);
bool HasChildDirectories(const std::filesystem::path& folderPath);
std::vector<std::filesystem::path> CollectSortedChildDirectories(
    const std::filesystem::path& folderPath);
std::wstring MakePathKey(const std::filesystem::path& path);
bool IsSameOrDescendantPath(
    const std::filesystem::path& path,
    const std::filesystem::path& ancestor);
std::string TrimAssetName(std::string_view name);
bool HasInvalidAssetName(std::string_view name);
std::filesystem::path MakeUniqueFolderPath(
    const std::filesystem::path& parentPath,
    std::string_view preferredName);
std::filesystem::path MakeUniqueFilePath(
    const std::filesystem::path& parentPath,
    const std::filesystem::path& preferredFileName);
std::string BuildRenamedEntryName(
    const std::filesystem::path& sourcePath,
    std::string_view requestedName);
std::filesystem::path GetMetaSidecarPath(const std::filesystem::path& assetPath);
void RemoveMetaSidecarIfPresent(const std::filesystem::path& assetPath);
bool RenamePathCaseAware(
    const std::filesystem::path& sourcePath,
    const std::filesystem::path& destPath);
void MoveMetaSidecarIfPresent(
    const std::filesystem::path& sourcePath,
    const std::filesystem::path& destPath);
bool MovePathWithOptionalMeta(
    const std::filesystem::path& sourcePath,
    const std::filesystem::path& destinationPath);
ProjectBrowserModel::ItemKind ResolveItemKind(
    const std::filesystem::path& path,
    bool directory);
bool CanOpenItemKind(ProjectBrowserModel::ItemKind kind);
bool CanPreviewItem(
    const std::filesystem::path& path,
    ProjectBrowserModel::ItemKind kind,
    bool directory);

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

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

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 CanPreviewItem(
    const std::filesystem::path& path,
    ProjectBrowserModel::ItemKind kind,
    bool directory) {
    if (directory || kind != ProjectBrowserModel::ItemKind::Texture) {
        return false;
    }

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

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

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


namespace {

bool IsSameOrDescendantFolderId(
    std::string_view candidateId,
    std::string_view ancestorId) {
    if (candidateId == ancestorId) {
        return true;
    }

    if (candidateId.size() <= ancestorId.size() ||
        candidateId.substr(0u, ancestorId.size()) != ancestorId) {
        return false;
    }

    return candidateId[ancestorId.size()] == '/';
}

std::string RemapMovedFolderId(
    std::string_view itemId,
    std::string_view sourceFolderId,
    std::string_view destinationFolderId) {
    if (!IsSameOrDescendantFolderId(itemId, sourceFolderId)) {
        return std::string(itemId);
    }

    if (itemId == sourceFolderId) {
        return std::string(destinationFolderId);
    }

    std::string remapped = std::string(destinationFolderId);
    remapped += std::string(itemId.substr(sourceFolderId.size()));
    return remapped;
}

bool IsSameOrDescendantItemId(
    std::string_view candidateId,
    std::string_view ancestorId) {
    if (candidateId == ancestorId) {
        return true;
    }

    if (candidateId.size() <= ancestorId.size() ||
        candidateId.substr(0u, ancestorId.size()) != ancestorId) {
        return false;
    }

    return candidateId[ancestorId.size()] == '/';
}

std::string RemapMovedItemId(
    std::string_view itemId,
    std::string_view sourceItemId,
    std::string_view destinationItemId) {
    if (!IsSameOrDescendantItemId(itemId, sourceItemId)) {
        return std::string(itemId);
    }

    if (itemId == sourceItemId) {
        return std::string(destinationItemId);
    }

    std::string remapped = std::string(destinationItemId);
    remapped += std::string(itemId.substr(sourceItemId.size()));
    return remapped;
}

} // namespace

void ProjectBrowserModel::Initialize(const std::filesystem::path& repoRoot) {
    m_assetsRootPath = (repoRoot / "project/Assets").lexically_normal();
    std::error_code errorCode = {};
    if (!std::filesystem::exists(m_assetsRootPath, errorCode)) {
        std::filesystem::create_directories(m_assetsRootPath / "Scenes", errorCode);
    }
    Refresh();
}

void ProjectBrowserModel::SetFolderIcon(const ::XCEngine::UI::UITextureHandle& icon) {
    m_folderIcon = icon;
    if (!m_assetsRootPath.empty()) {
        RefreshFolderTree();
    }
}

void ProjectBrowserModel::Refresh() {
    RefreshFolderTree();
    EnsureValidCurrentFolder();
    RefreshAssetList();
}

bool ProjectBrowserModel::Empty() const {
    return m_treeItems.empty();
}

std::filesystem::path ProjectBrowserModel::GetProjectRootPath() const {
    return m_assetsRootPath.empty()
        ? std::filesystem::path()
        : m_assetsRootPath.parent_path();
}

const std::filesystem::path& ProjectBrowserModel::GetAssetsRootPath() const {
    return m_assetsRootPath;
}

const std::vector<ProjectBrowserModel::FolderEntry>& ProjectBrowserModel::GetFolderEntries() const {
    return m_folderEntries;
}

const std::vector<Widgets::UIEditorTreeViewItem>& ProjectBrowserModel::GetTreeItems() const {
    return m_treeItems;
}

const std::vector<ProjectBrowserModel::AssetEntry>& ProjectBrowserModel::GetAssetEntries() const {
    return m_assetEntries;
}

const std::string& ProjectBrowserModel::GetCurrentFolderId() const {
    return m_currentFolderId;
}

bool ProjectBrowserModel::IsAssetsRoot(std::string_view itemId) const {
    return itemId == kAssetsRootId;
}

const ProjectBrowserModel::FolderEntry* ProjectBrowserModel::FindFolderEntry(
    std::string_view itemId) const {
    for (const FolderEntry& entry : m_folderEntries) {
        if (entry.itemId == itemId) {
            return &entry;
        }
    }

    return nullptr;
}

const ProjectBrowserModel::AssetEntry* ProjectBrowserModel::FindAssetEntry(
    std::string_view itemId) const {
    for (const AssetEntry& entry : m_assetEntries) {
        if (entry.itemId == itemId) {
            return &entry;
        }
    }

    return nullptr;
}

std::optional<std::filesystem::path> ProjectBrowserModel::ResolveItemAbsolutePath(
    std::string_view itemId) const {
    if (itemId.empty() || m_assetsRootPath.empty()) {
        return std::nullopt;
    }

    const std::filesystem::path rootPath = m_assetsRootPath.parent_path();
    const std::filesystem::path candidatePath =
        (rootPath / std::filesystem::path(std::string(itemId))).lexically_normal();
    if (!IsSameOrDescendantPath(candidatePath, m_assetsRootPath)) {
        return std::nullopt;
    }

    return candidatePath;
}

std::string ProjectBrowserModel::BuildProjectRelativePath(std::string_view itemId) const {
    const std::optional<std::filesystem::path> absolutePath =
        ResolveItemAbsolutePath(itemId);
    if (!absolutePath.has_value()) {
        return {};
    }

    return BuildRelativeProjectPath(absolutePath.value(), GetProjectRootPath());
}

bool ProjectBrowserModel::CreateFolder(
    std::string_view parentFolderId,
    std::string_view requestedName,
    std::string* createdFolderId) {
    if (createdFolderId != nullptr) {
        createdFolderId->clear();
    }

    const FolderEntry* parentFolder = FindFolderEntry(parentFolderId);
    if (parentFolder == nullptr) {
        return false;
    }

    try {
        const std::string trimmedName = TrimAssetName(requestedName);
        if (HasInvalidAssetName(trimmedName)) {
            return false;
        }

        const std::filesystem::path newFolderPath =
            MakeUniqueFolderPath(parentFolder->absolutePath, trimmedName);
        if (!std::filesystem::create_directory(newFolderPath)) {
            return false;
        }

        RefreshFolderTree();
        EnsureValidCurrentFolder();
        RefreshAssetList();
        if (createdFolderId != nullptr) {
            *createdFolderId = BuildRelativeItemId(newFolderPath, m_assetsRootPath);
        }
        return true;
    } catch (...) {
        return false;
    }
}

bool ProjectBrowserModel::CreateMaterial(
    std::string_view parentFolderId,
    std::string_view requestedName,
    std::string* createdItemId) {
    if (createdItemId != nullptr) {
        createdItemId->clear();
    }

    const FolderEntry* parentFolder = FindFolderEntry(parentFolderId);
    if (parentFolder == nullptr) {
        return false;
    }

    try {
        const std::string trimmedName = TrimAssetName(requestedName);
        if (HasInvalidAssetName(trimmedName)) {
            return false;
        }

        std::filesystem::path requestedPath =
            BuildPathFromUtf8(trimmedName);
        if (!requestedPath.has_extension()) {
            requestedPath.replace_extension(".mat");
        }

        const std::filesystem::path materialPath =
            MakeUniqueFilePath(parentFolder->absolutePath, requestedPath);
        std::ofstream output(materialPath, std::ios::out | std::ios::trunc);
        if (!output.is_open()) {
            return false;
        }

        output <<
            "{\n"
            "  \"renderQueue\": \"geometry\",\n"
            "  \"renderState\": {\n"
            "    \"cull\": \"none\",\n"
            "    \"depthTest\": true,\n"
            "    \"depthWrite\": true,\n"
            "    \"depthFunc\": \"less\",\n"
            "    \"blendEnable\": false,\n"
            "    \"srcBlend\": \"one\",\n"
            "    \"dstBlend\": \"zero\",\n"
            "    \"srcBlendAlpha\": \"one\",\n"
            "    \"dstBlendAlpha\": \"zero\",\n"
            "    \"blendOp\": \"add\",\n"
            "    \"blendOpAlpha\": \"add\",\n"
            "    \"colorWriteMask\": 15\n"
            "  }\n"
            "}\n";
        output.close();
        if (!output.good()) {
            return false;
        }

        RefreshFolderTree();
        EnsureValidCurrentFolder();
        RefreshAssetList();
        if (createdItemId != nullptr) {
            *createdItemId = BuildRelativeItemId(materialPath, m_assetsRootPath);
        }
        return true;
    } catch (...) {
        return false;
    }
}

bool ProjectBrowserModel::RenameItem(
    std::string_view itemId,
    std::string_view newName,
    std::string* renamedItemId) {
    if (renamedItemId != nullptr) {
        renamedItemId->clear();
    }

    if (itemId.empty() || IsAssetsRoot(itemId)) {
        return false;
    }

    const std::optional<std::filesystem::path> sourcePath =
        ResolveItemAbsolutePath(itemId);
    if (!sourcePath.has_value()) {
        return false;
    }

    try {
        const std::string trimmedName = TrimAssetName(newName);
        if (HasInvalidAssetName(trimmedName) ||
            !std::filesystem::exists(sourcePath.value())) {
            return false;
        }

        const std::string targetName =
            BuildRenamedEntryName(sourcePath.value(), trimmedName);
        if (HasInvalidAssetName(targetName)) {
            return false;
        }

        const std::filesystem::path destinationPath =
            (sourcePath->parent_path() / BuildPathFromUtf8(targetName))
                .lexically_normal();
        const std::string destinationItemId =
            BuildRelativeItemId(destinationPath, m_assetsRootPath);

        if (!RenamePathCaseAware(sourcePath.value(), destinationPath)) {
            return false;
        }
        MoveMetaSidecarIfPresent(sourcePath.value(), destinationPath);

        if (std::filesystem::is_directory(destinationPath)) {
            m_currentFolderId = RemapMovedItemId(
                m_currentFolderId,
                itemId,
                destinationItemId);
        }
        RefreshFolderTree();
        EnsureValidCurrentFolder();
        RefreshAssetList();
        if (renamedItemId != nullptr) {
            *renamedItemId = destinationItemId;
        }
        return true;
    } catch (...) {
        return false;
    }
}

bool ProjectBrowserModel::DeleteItem(std::string_view itemId) {
    if (itemId.empty() || IsAssetsRoot(itemId)) {
        return false;
    }

    const std::optional<std::filesystem::path> sourcePath =
        ResolveItemAbsolutePath(itemId);
    if (!sourcePath.has_value()) {
        return false;
    }

    try {
        if (!std::filesystem::exists(sourcePath.value())) {
            return false;
        }

        if (std::filesystem::is_directory(sourcePath.value()) &&
            IsSameOrDescendantFolderId(m_currentFolderId, itemId)) {
            m_currentFolderId =
                BuildRelativeItemId(sourcePath->parent_path(), m_assetsRootPath);
        }

        std::filesystem::remove_all(sourcePath.value());
        RemoveMetaSidecarIfPresent(sourcePath.value());
        RefreshFolderTree();
        EnsureValidCurrentFolder();
        RefreshAssetList();
        return true;
    } catch (...) {
        return false;
    }
}

bool ProjectBrowserModel::CanMoveItemToFolder(
    std::string_view itemId,
    std::string_view targetFolderId) const {
    if (itemId.empty() || targetFolderId.empty() || IsAssetsRoot(itemId)) {
        return false;
    }

    const std::optional<std::filesystem::path> sourcePath =
        ResolveItemAbsolutePath(itemId);
    const FolderEntry* targetFolder = FindFolderEntry(targetFolderId);
    if (!sourcePath.has_value() || targetFolder == nullptr) {
        return false;
    }

    std::error_code errorCode = {};
    if (!std::filesystem::exists(sourcePath.value(), errorCode) || errorCode) {
        return false;
    }

    const std::filesystem::path destinationPath =
        (targetFolder->absolutePath / sourcePath->filename()).lexically_normal();
    if (destinationPath == sourcePath->lexically_normal()) {
        return false;
    }

    if (std::filesystem::exists(destinationPath, errorCode) || errorCode) {
        return false;
    }

    if (std::filesystem::is_directory(sourcePath.value(), errorCode)) {
        if (errorCode) {
            return false;
        }
        if (IsSameOrDescendantPath(targetFolder->absolutePath, sourcePath.value())) {
            return false;
        }
    }

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

    return !errorCode;
}

bool ProjectBrowserModel::MoveItemToFolder(
    std::string_view itemId,
    std::string_view targetFolderId,
    std::string* movedItemId) {
    if (movedItemId != nullptr) {
        movedItemId->clear();
    }

    if (!CanMoveItemToFolder(itemId, targetFolderId)) {
        return false;
    }

    const std::optional<std::filesystem::path> sourcePath =
        ResolveItemAbsolutePath(itemId);
    const FolderEntry* targetFolder = FindFolderEntry(targetFolderId);
    if (!sourcePath.has_value() || targetFolder == nullptr) {
        return false;
    }

    try {
        const std::filesystem::path destinationPath =
            (targetFolder->absolutePath / sourcePath->filename()).lexically_normal();
        const std::string destinationItemId =
            BuildRelativeItemId(destinationPath, m_assetsRootPath);
        if (!MovePathWithOptionalMeta(sourcePath.value(), destinationPath)) {
            return false;
        }

        if (std::filesystem::is_directory(destinationPath)) {
            m_currentFolderId = RemapMovedItemId(
                m_currentFolderId,
                itemId,
                destinationItemId);
        }
        RefreshFolderTree();
        EnsureValidCurrentFolder();
        RefreshAssetList();
        if (movedItemId != nullptr) {
            *movedItemId = destinationItemId;
        }
        return true;
    } catch (...) {
        return false;
    }
}

std::optional<std::string> ProjectBrowserModel::GetParentFolderId(std::string_view itemId) const {
    const FolderEntry* folderEntry = FindFolderEntry(itemId);
    if (folderEntry == nullptr || itemId == kAssetsRootId) {
        return std::nullopt;
    }

    const std::filesystem::path parentPath = folderEntry->absolutePath.parent_path();
    if (parentPath.empty() || parentPath == folderEntry->absolutePath) {
        return std::nullopt;
    }

    return BuildRelativeItemId(parentPath, m_assetsRootPath);
}

bool ProjectBrowserModel::CanReparentFolder(
    std::string_view sourceFolderId,
    std::string_view targetParentId) const {
    if (sourceFolderId.empty() ||
        targetParentId.empty() ||
        sourceFolderId == kAssetsRootId) {
        return false;
    }

    const FolderEntry* sourceFolder = FindFolderEntry(sourceFolderId);
    const FolderEntry* targetFolder = FindFolderEntry(targetParentId);
    if (sourceFolder == nullptr || targetFolder == nullptr) {
        return false;
    }

    if (IsSameOrDescendantFolderId(targetParentId, sourceFolderId)) {
        return false;
    }

    const std::optional<std::string> currentParentId = GetParentFolderId(sourceFolderId);
    if (currentParentId.has_value() && currentParentId.value() == targetParentId) {
        return false;
    }

    const std::filesystem::path destinationPath =
        targetFolder->absolutePath / sourceFolder->absolutePath.filename();
    if (destinationPath.lexically_normal() == sourceFolder->absolutePath.lexically_normal()) {
        return false;
    }

    std::error_code errorCode = {};
    if (std::filesystem::exists(destinationPath, errorCode)) {
        return false;
    }
    if (errorCode) {
        return false;
    }

    const std::filesystem::path sourceMetaPath = GetMetaSidecarPath(sourceFolder->absolutePath);
    const std::filesystem::path destinationMetaPath = GetMetaSidecarPath(destinationPath);
    const bool sourceMetaExists = std::filesystem::exists(sourceMetaPath, errorCode);
    if (errorCode) {
        return false;
    }
    if (sourceMetaExists && std::filesystem::exists(destinationMetaPath, errorCode)) {
        return false;
    }

    return !errorCode;
}

bool ProjectBrowserModel::ReparentFolder(
    std::string_view sourceFolderId,
    std::string_view targetParentId,
    std::string* movedFolderId) {
    if (!CanReparentFolder(sourceFolderId, targetParentId)) {
        return false;
    }

    const FolderEntry* sourceFolder = FindFolderEntry(sourceFolderId);
    const FolderEntry* targetFolder = FindFolderEntry(targetParentId);
    if (sourceFolder == nullptr || targetFolder == nullptr) {
        return false;
    }

    const std::filesystem::path destinationPath =
        (targetFolder->absolutePath / sourceFolder->absolutePath.filename()).lexically_normal();
    const std::string destinationFolderId =
        BuildRelativeItemId(destinationPath, m_assetsRootPath);

    if (!MovePathWithOptionalMeta(sourceFolder->absolutePath, destinationPath)) {
        return false;
    }

    m_currentFolderId = RemapMovedFolderId(
        m_currentFolderId,
        sourceFolderId,
        destinationFolderId);
    RefreshFolderTree();
    EnsureValidCurrentFolder();
    RefreshAssetList();

    if (movedFolderId != nullptr) {
        *movedFolderId = destinationFolderId;
    }
    return true;
}

bool ProjectBrowserModel::MoveFolderToRoot(
    std::string_view sourceFolderId,
    std::string* movedFolderId) {
    if (sourceFolderId.empty() || sourceFolderId == kAssetsRootId) {
        return false;
    }

    const FolderEntry* sourceFolder = FindFolderEntry(sourceFolderId);
    if (sourceFolder == nullptr) {
        return false;
    }

    const std::optional<std::string> currentParentId = GetParentFolderId(sourceFolderId);
    if (!currentParentId.has_value() || currentParentId.value() == kAssetsRootId) {
        return false;
    }

    const std::filesystem::path destinationPath =
        (m_assetsRootPath / sourceFolder->absolutePath.filename()).lexically_normal();
    if (destinationPath == sourceFolder->absolutePath.lexically_normal()) {
        return false;
    }

    std::error_code errorCode = {};
    if (std::filesystem::exists(destinationPath, errorCode)) {
        return false;
    }
    if (errorCode) {
        return false;
    }

    const std::filesystem::path sourceMetaPath = GetMetaSidecarPath(sourceFolder->absolutePath);
    const std::filesystem::path destinationMetaPath = GetMetaSidecarPath(destinationPath);
    const bool sourceMetaExists = std::filesystem::exists(sourceMetaPath, errorCode);
    if (errorCode) {
        return false;
    }
    if (sourceMetaExists && std::filesystem::exists(destinationMetaPath, errorCode)) {
        return false;
    }
    if (errorCode) {
        return false;
    }

    const std::string destinationFolderId =
        BuildRelativeItemId(destinationPath, m_assetsRootPath);
    if (!MovePathWithOptionalMeta(sourceFolder->absolutePath, destinationPath)) {
        return false;
    }

    m_currentFolderId = RemapMovedFolderId(
        m_currentFolderId,
        sourceFolderId,
        destinationFolderId);
    RefreshFolderTree();
    EnsureValidCurrentFolder();
    RefreshAssetList();

    if (movedFolderId != nullptr) {
        *movedFolderId = destinationFolderId;
    }
    return true;
}

bool ProjectBrowserModel::NavigateToFolder(std::string_view itemId) {
    if (itemId.empty() || FindFolderEntry(itemId) == nullptr || itemId == m_currentFolderId) {
        return false;
    }

    m_currentFolderId = std::string(itemId);
    EnsureValidCurrentFolder();
    RefreshAssetList();
    return true;
}

std::vector<ProjectBrowserModel::BreadcrumbSegment> ProjectBrowserModel::BuildBreadcrumbSegments() const {
    std::vector<BreadcrumbSegment> segments = {};
    if (m_currentFolderId.empty()) {
        segments.push_back(BreadcrumbSegment{ std::string(kAssetsRootId), std::string(kAssetsRootId), true });
        return segments;
    }

    std::string cumulativeFolderId = {};
    std::size_t segmentStart = 0u;
    while (segmentStart < m_currentFolderId.size()) {
        const std::size_t separator = m_currentFolderId.find('/', segmentStart);
        const std::size_t segmentLength =
            separator == std::string_view::npos
                ? m_currentFolderId.size() - segmentStart
                : separator - segmentStart;
        if (segmentLength > 0u) {
            std::string label = std::string(m_currentFolderId.substr(segmentStart, segmentLength));
            if (cumulativeFolderId.empty()) {
                cumulativeFolderId = label;
            } else {
                cumulativeFolderId += "/";
                cumulativeFolderId += label;
            }

            segments.push_back(BreadcrumbSegment{
                std::move(label),
                cumulativeFolderId,
                false
            });
        }
        if (separator == std::string_view::npos) {
            break;
        }
        segmentStart = separator + 1u;
    }

    if (segments.empty()) {
        segments.push_back(BreadcrumbSegment{ std::string(kAssetsRootId), std::string(kAssetsRootId), true });
        return segments;
    }

    segments.back().current = true;
    return segments;
}

void ProjectBrowserModel::EnsureValidCurrentFolder() {
    if (m_currentFolderId.empty()) {
        m_currentFolderId = std::string(kAssetsRootId);
    }

    if (FindFolderEntry(m_currentFolderId) == nullptr) {
        m_currentFolderId = m_treeItems.empty()
            ? std::string()
            : m_treeItems.front().itemId;
    }
}

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

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


void ProjectBrowserModel::RefreshAssetList() {
    EnsureValidCurrentFolder();

    m_assetEntries.clear();
    const FolderEntry* currentFolder = FindFolderEntry(m_currentFolderId);
    if (currentFolder == nullptr) {
        return;
    }

    std::vector<std::filesystem::directory_entry> entries = {};
    std::error_code errorCode = {};
    const std::filesystem::directory_iterator end = {};
    for (std::filesystem::directory_iterator iterator(currentFolder->absolutePath, errorCode);
         !errorCode && iterator != end;
         iterator.increment(errorCode)) {
        if (!iterator->exists(errorCode) || IsMetaFile(iterator->path())) {
            continue;
        }
        if (!iterator->is_directory(errorCode) && !iterator->is_regular_file(errorCode)) {
            continue;
        }

        entries.push_back(*iterator);
    }

    std::sort(
        entries.begin(),
        entries.end(),
        [](const std::filesystem::directory_entry& lhs, const std::filesystem::directory_entry& rhs) {
            const bool lhsDirectory = lhs.is_directory();
            const bool rhsDirectory = rhs.is_directory();
            if (lhsDirectory != rhsDirectory) {
                return lhsDirectory && !rhsDirectory;
            }

            return ToLowerCopy(PathToUtf8String(lhs.path().filename())) <
                ToLowerCopy(PathToUtf8String(rhs.path().filename()));
        });

    for (const std::filesystem::directory_entry& entry : entries) {
        AssetEntry assetEntry = {};
        assetEntry.itemId = BuildRelativeItemId(entry.path(), m_assetsRootPath);
        assetEntry.absolutePath = entry.path();
        assetEntry.nameWithExtension =
            BuildAssetNameWithExtension(entry.path(), entry.is_directory());
        assetEntry.displayName = BuildAssetDisplayName(entry.path(), entry.is_directory());
        assetEntry.extensionLower = ToLowerCopy(PathToUtf8String(entry.path().extension()));
        assetEntry.kind = ResolveItemKind(entry.path(), entry.is_directory());
        assetEntry.directory = entry.is_directory();
        assetEntry.canOpen = CanOpenItemKind(assetEntry.kind);
        assetEntry.canPreview =
            CanPreviewItem(entry.path(), assetEntry.kind, assetEntry.directory);
        m_assetEntries.push_back(std::move(assetEntry));
    }
}

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

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


void ProjectBrowserModel::RefreshFolderTree() {
    m_folderEntries.clear();
    m_treeItems.clear();

    if (m_assetsRootPath.empty() || !std::filesystem::exists(m_assetsRootPath)) {
        return;
    }

    const auto appendFolderRecursive =
        [&](auto&& self, const std::filesystem::path& folderPath, std::uint32_t depth) -> void {
        const std::string itemId = BuildRelativeItemId(folderPath, m_assetsRootPath);

        FolderEntry folderEntry = {};
        folderEntry.itemId = itemId;
        folderEntry.absolutePath = folderPath;
        folderEntry.label = PathToUtf8String(folderPath.filename());
        m_folderEntries.push_back(folderEntry);

        Widgets::UIEditorTreeViewItem item = {};
        item.itemId = itemId;
        item.label = folderEntry.label;
        item.depth = depth;
        item.forceLeaf = !HasChildDirectories(folderPath);
        item.leadingIcon = m_folderIcon;
        m_treeItems.push_back(std::move(item));

        const std::vector<std::filesystem::path> childFolders =
            CollectSortedChildDirectories(folderPath);
        for (const std::filesystem::path& childPath : childFolders) {
            self(self, childPath, depth + 1u);
        }
    };

    appendFolderRecursive(appendFolderRecursive, m_assetsRootPath, 0u);
}

std::vector<std::string> ProjectBrowserModel::CollectCurrentFolderAncestorIds() const {
    return BuildAncestorFolderIds(m_currentFolderId);
}

std::vector<std::string> ProjectBrowserModel::BuildAncestorFolderIds(
    std::string_view itemId) const {
    std::vector<std::string> ancestors = {};
    const FolderEntry* folderEntry = FindFolderEntry(itemId);
    if (folderEntry == nullptr) {
        return ancestors;
    }

    std::filesystem::path path = folderEntry->absolutePath;
    while (true) {
        ancestors.push_back(BuildRelativeItemId(path, m_assetsRootPath));
        if (path == m_assetsRootPath) {
            break;
        }
        path = path.parent_path();
    }

    std::reverse(ancestors.begin(), ancestors.end());
    return ancestors;
}

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