#include "Project/EditorProjectRuntime.h"

#include "State/EditorSelectionStamp.h"

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

namespace {

using AssetCommandTarget = EditorProjectRuntime::AssetCommandTarget;
using EditCommandTarget = EditorProjectRuntime::EditCommandTarget;

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()] == '/';
}

void PopulateAssetCommandTargetFromAsset(
    AssetCommandTarget& target,
    const ProjectBrowserModel& browserModel,
    const ProjectBrowserModel::AssetEntry& asset,
    const ProjectBrowserModel::FolderEntry* containerFolder) {
    target.subjectAsset = &asset;
    target.subjectItemId = asset.itemId;
    target.subjectPath = asset.absolutePath;
    target.subjectDisplayName = asset.displayName;
    target.subjectRelativePath =
        browserModel.BuildProjectRelativePath(asset.itemId);
    target.showInExplorerSelectTarget = true;
    target.containerFolder = containerFolder;
}

void PopulateAssetCommandTargetFromFolder(
    AssetCommandTarget& target,
    const ProjectBrowserModel& browserModel,
    const ProjectBrowserModel::FolderEntry& folder) {
    target.subjectFolder = &folder;
    target.subjectItemId = folder.itemId;
    target.subjectPath = folder.absolutePath;
    target.subjectDisplayName = folder.label;
    target.subjectRelativePath =
        browserModel.BuildProjectRelativePath(folder.itemId);
    target.showInExplorerSelectTarget = false;
    target.containerFolder = &folder;
}

EditCommandTarget BuildEditCommandTarget(
    const ProjectBrowserModel::AssetEntry& asset) {
    EditCommandTarget target = {};
    target.itemId = asset.itemId;
    target.absolutePath = asset.absolutePath;
    target.displayName = asset.displayName;
    target.itemKind = asset.kind;
    target.directory = asset.directory;
    return target;
}

EditCommandTarget BuildEditCommandTarget(
    const ProjectBrowserModel& browserModel,
    const ProjectBrowserModel::FolderEntry& folder) {
    EditCommandTarget target = {};
    target.itemId = folder.itemId;
    target.absolutePath = folder.absolutePath;
    target.displayName = folder.label;
    target.itemKind = ProjectBrowserModel::ItemKind::Folder;
    target.directory = true;
    target.assetsRoot = browserModel.IsAssetsRoot(folder.itemId);
    return target;
}

} // namespace

bool EditorProjectRuntime::Initialize(const std::filesystem::path& repoRoot) {
    m_browserModel.Initialize(repoRoot);
    m_selection = {};
    m_pendingSceneOpenPath.reset();
    return true;
}

void EditorProjectRuntime::SetFolderIcon(const ::XCEngine::UI::UITextureHandle& icon) {
    m_browserModel.SetFolderIcon(icon);
}

void EditorProjectRuntime::Refresh() {
    m_browserModel.Refresh();
    RevalidateSelection();
}

const ProjectBrowserModel& EditorProjectRuntime::GetBrowserModel() const {
    return m_browserModel;
}

ProjectBrowserModel& EditorProjectRuntime::GetBrowserModel() {
    return m_browserModel;
}

bool EditorProjectRuntime::HasSelection() const {
    return m_selection.kind == EditorSelectionKind::ProjectItem &&
        !m_selection.itemId.empty();
}

const EditorSelectionState& EditorProjectRuntime::GetSelection() const {
    return m_selection;
}

std::uint64_t EditorProjectRuntime::GetSelectionStamp() const {
    return m_selection.stamp;
}

bool EditorProjectRuntime::SetSelection(std::string_view itemId) {
    const ProjectBrowserModel::AssetEntry* asset = FindAssetEntry(itemId);
    if (asset == nullptr) {
        return false;
    }

    const bool changed =
        m_selection.kind != EditorSelectionKind::ProjectItem ||
        m_selection.itemId != asset->itemId ||
        m_selection.absolutePath != asset->absolutePath ||
        m_selection.directory != asset->directory;
    ApplySelection(*asset, !changed);
    return changed;
}

void EditorProjectRuntime::ClearSelection() {
    m_selection = {};
    m_selection.stamp = GenerateEditorSelectionStamp();
}

bool EditorProjectRuntime::NavigateToFolder(std::string_view itemId) {
    if (!m_browserModel.NavigateToFolder(itemId)) {
        return false;
    }

    ClearSelection();
    return true;
}

bool EditorProjectRuntime::OpenItem(std::string_view itemId) {
    const ProjectBrowserModel::AssetEntry* asset = FindAssetEntry(itemId);
    if (asset == nullptr) {
        return false;
    }

    if (asset->directory) {
        return NavigateToFolder(asset->itemId);
    }

    if (!asset->canOpen) {
        return false;
    }

    if (asset->kind == ProjectBrowserModel::ItemKind::Scene &&
        !asset->absolutePath.empty()) {
        m_pendingSceneOpenPath = asset->absolutePath;
        return true;
    }

    return false;
}

std::optional<std::filesystem::path> EditorProjectRuntime::ConsumePendingSceneOpenPath() {
    if (!m_pendingSceneOpenPath.has_value()) {
        return std::nullopt;
    }

    std::optional<std::filesystem::path> result = m_pendingSceneOpenPath;
    m_pendingSceneOpenPath.reset();
    return result;
}

const ProjectBrowserModel::FolderEntry* EditorProjectRuntime::FindFolderEntry(
    std::string_view itemId) const {
    return m_browserModel.FindFolderEntry(itemId);
}

const ProjectBrowserModel::AssetEntry* EditorProjectRuntime::FindAssetEntry(
    std::string_view itemId) const {
    return m_browserModel.FindAssetEntry(itemId);
}

EditorProjectRuntime::AssetCommandTarget
EditorProjectRuntime::ResolveAssetCommandTarget(
    std::string_view explicitItemId,
    bool forceCurrentFolder) const {
    AssetCommandTarget target = {};
    target.currentFolder = FindFolderEntry(m_browserModel.GetCurrentFolderId());

    const ProjectBrowserModel::AssetEntry* explicitAsset =
        explicitItemId.empty() ? nullptr : FindAssetEntry(explicitItemId);
    const ProjectBrowserModel::FolderEntry* explicitFolder =
        explicitItemId.empty() ? nullptr : FindFolderEntry(explicitItemId);

    if (!forceCurrentFolder && explicitAsset != nullptr) {
        PopulateAssetCommandTargetFromAsset(
            target,
            m_browserModel,
            *explicitAsset,
            explicitAsset->directory
                ? FindFolderEntry(explicitAsset->itemId)
                : target.currentFolder);
        return target;
    }

    if (!forceCurrentFolder && explicitFolder != nullptr) {
        PopulateAssetCommandTargetFromFolder(
            target,
            m_browserModel,
            *explicitFolder);
        return target;
    }

    if (forceCurrentFolder) {
        if (target.currentFolder != nullptr) {
            PopulateAssetCommandTargetFromFolder(
                target,
                m_browserModel,
                *target.currentFolder);
        }
        return target;
    }

    if (HasSelection()) {
        if (const ProjectBrowserModel::AssetEntry* selectedAsset =
                FindAssetEntry(m_selection.itemId);
            selectedAsset != nullptr) {
            PopulateAssetCommandTargetFromAsset(
                target,
                m_browserModel,
                *selectedAsset,
                selectedAsset->directory
                    ? FindFolderEntry(selectedAsset->itemId)
                    : target.currentFolder);
            return target;
        }
    }

    if (target.currentFolder != nullptr) {
        PopulateAssetCommandTargetFromFolder(
            target,
            m_browserModel,
            *target.currentFolder);
    }
    return target;
}

std::optional<EditorProjectRuntime::EditCommandTarget>
EditorProjectRuntime::ResolveEditCommandTarget(
    std::string_view explicitItemId,
    bool forceCurrentFolder) const {
    if (forceCurrentFolder) {
        return std::nullopt;
    }

    if (!explicitItemId.empty()) {
        if (const ProjectBrowserModel::AssetEntry* asset =
                FindAssetEntry(explicitItemId);
            asset != nullptr) {
            return BuildEditCommandTarget(*asset);
        }

        if (const ProjectBrowserModel::FolderEntry* folder =
                FindFolderEntry(explicitItemId);
            folder != nullptr) {
            return BuildEditCommandTarget(m_browserModel, *folder);
        }

        return std::nullopt;
    }

    if (HasSelection()) {
        if (const ProjectBrowserModel::AssetEntry* selectedAsset =
                FindAssetEntry(m_selection.itemId);
            selectedAsset != nullptr) {
            return BuildEditCommandTarget(*selectedAsset);
        }
    }

    if (const ProjectBrowserModel::FolderEntry* currentFolder =
            FindFolderEntry(m_browserModel.GetCurrentFolderId());
        currentFolder != nullptr) {
        return BuildEditCommandTarget(m_browserModel, *currentFolder);
    }

    return std::nullopt;
}

bool EditorProjectRuntime::CreateFolder(
    std::string_view parentFolderId,
    std::string_view requestedName,
    std::string* createdFolderId) {
    const bool created =
        m_browserModel.CreateFolder(parentFolderId, requestedName, createdFolderId);
    RevalidateSelection();
    return created;
}

bool EditorProjectRuntime::CreateMaterial(
    std::string_view parentFolderId,
    std::string_view requestedName,
    std::string* createdItemId) {
    const bool created =
        m_browserModel.CreateMaterial(parentFolderId, requestedName, createdItemId);
    RevalidateSelection();
    return created;
}

bool EditorProjectRuntime::RenameItem(
    std::string_view itemId,
    std::string_view newName,
    std::string* renamedItemId) {
    std::string resolvedRenamedItemId = {};
    std::string* renameOutput =
        renamedItemId != nullptr ? renamedItemId : &resolvedRenamedItemId;
    if (!m_browserModel.RenameItem(itemId, newName, renameOutput)) {
        return false;
    }

    if (SelectionTargetsItem(itemId)) {
        if (!renameOutput->empty() && !SetSelection(*renameOutput)) {
            ClearSelection();
        }
    } else {
        RevalidateSelection();
    }
    return true;
}

bool EditorProjectRuntime::DeleteItem(std::string_view itemId) {
    const bool selectionAffected = SelectionTargetsItem(itemId);
    if (!m_browserModel.DeleteItem(itemId)) {
        return false;
    }

    if (selectionAffected) {
        ClearSelection();
    } else {
        RevalidateSelection();
    }
    return true;
}

bool EditorProjectRuntime::CanMoveItemToFolder(
    std::string_view itemId,
    std::string_view targetFolderId) const {
    return m_browserModel.CanMoveItemToFolder(itemId, targetFolderId);
}

bool EditorProjectRuntime::MoveItemToFolder(
    std::string_view itemId,
    std::string_view targetFolderId,
    std::string* movedItemId) {
    const bool selectionAffected = SelectionTargetsItem(itemId);
    if (!m_browserModel.MoveItemToFolder(itemId, targetFolderId, movedItemId)) {
        return false;
    }

    if (selectionAffected) {
        ClearSelection();
    } else {
        RevalidateSelection();
    }
    return true;
}

std::optional<std::string> EditorProjectRuntime::GetParentFolderId(
    std::string_view itemId) const {
    return m_browserModel.GetParentFolderId(itemId);
}

bool EditorProjectRuntime::CanReparentFolder(
    std::string_view sourceFolderId,
    std::string_view targetParentId) const {
    return m_browserModel.CanReparentFolder(sourceFolderId, targetParentId);
}

bool EditorProjectRuntime::ReparentFolder(
    std::string_view sourceFolderId,
    std::string_view targetParentId,
    std::string* movedFolderId) {
    const bool selectionAffected = SelectionTargetsItem(sourceFolderId);
    if (!m_browserModel.ReparentFolder(sourceFolderId, targetParentId, movedFolderId)) {
        return false;
    }

    if (selectionAffected) {
        ClearSelection();
    } else {
        RevalidateSelection();
    }
    return true;
}

bool EditorProjectRuntime::MoveFolderToRoot(
    std::string_view sourceFolderId,
    std::string* movedFolderId) {
    const bool selectionAffected = SelectionTargetsItem(sourceFolderId);
    if (!m_browserModel.MoveFolderToRoot(sourceFolderId, movedFolderId)) {
        return false;
    }

    if (selectionAffected) {
        ClearSelection();
    } else {
        RevalidateSelection();
    }
    return true;
}

void EditorProjectRuntime::ApplySelection(
    const ProjectBrowserModel::AssetEntry& asset,
    bool preserveStamp) {
    const std::uint64_t previousStamp = m_selection.stamp;
    m_selection = {};
    m_selection.kind = EditorSelectionKind::ProjectItem;
    m_selection.itemId = asset.itemId;
    m_selection.displayName = asset.displayName.empty()
        ? asset.nameWithExtension
        : asset.displayName;
    m_selection.absolutePath = asset.absolutePath;
    m_selection.directory = asset.directory;
    m_selection.stamp = preserveStamp && previousStamp != 0u
        ? previousStamp
        : GenerateEditorSelectionStamp();
}

void EditorProjectRuntime::RevalidateSelection() {
    if (!HasSelection()) {
        return;
    }

    const ProjectBrowserModel::AssetEntry* asset = FindAssetEntry(m_selection.itemId);
    if (asset == nullptr) {
        ClearSelection();
        return;
    }

    ApplySelection(*asset, true);
}

bool EditorProjectRuntime::SelectionTargetsItem(std::string_view itemId) const {
    return HasSelection() && IsSameOrDescendantItemId(m_selection.itemId, itemId);
}

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