#include "Composition/EditorWindowWorkspaceStore.h"

#include <algorithm>
#include <utility>

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

namespace {

UIEditorWindowWorkspaceState BuildWindowState(
    std::string_view windowId,
    const UIEditorWorkspaceController& workspaceController) {
    UIEditorWindowWorkspaceState state = {};
    state.windowId = std::string(windowId);
    state.workspace = workspaceController.GetWorkspace();
    state.session = workspaceController.GetSession();
    return state;
}

std::string ResolveFallbackWindowId(const UIEditorWindowWorkspaceSet& windowSet) {
    if (!windowSet.primaryWindowId.empty() &&
        FindUIEditorWindowWorkspaceState(windowSet, windowSet.primaryWindowId) != nullptr) {
        return windowSet.primaryWindowId;
    }

    return windowSet.windows.empty() ? std::string() : windowSet.windows.front().windowId;
}

void UpsertWindowState(
    UIEditorWindowWorkspaceSet& windowSet,
    UIEditorWindowWorkspaceState windowState) {
    if (UIEditorWindowWorkspaceState* existing =
            FindMutableUIEditorWindowWorkspaceState(windowSet, windowState.windowId);
        existing != nullptr) {
        *existing = std::move(windowState);
        return;
    }

    windowSet.windows.push_back(std::move(windowState));
}

} // namespace

EditorWindowWorkspaceStore::EditorWindowWorkspaceStore(UIEditorPanelRegistry panelRegistry)
    : m_panelRegistry(std::move(panelRegistry)) {}

UIEditorWindowWorkspaceController EditorWindowWorkspaceStore::BuildMutationController() const {
    return UIEditorWindowWorkspaceController(m_panelRegistry, m_windowSet);
}

bool EditorWindowWorkspaceStore::RegisterWindowProjection(
    std::string_view windowId,
    bool primary,
    const UIEditorWorkspaceController& workspaceController,
    std::string& outError) {
    UIEditorWindowWorkspaceSet nextWindowSet = m_windowSet;
    UpsertWindowState(nextWindowSet, BuildWindowState(windowId, workspaceController));

    if (primary) {
        if (!nextWindowSet.primaryWindowId.empty() && nextWindowSet.primaryWindowId != windowId) {
            outError =
                "Cannot register a second primary window '" + std::string(windowId) +
                "' while '" + nextWindowSet.primaryWindowId + "' is still primary.";
            return false;
        }
        nextWindowSet.primaryWindowId = std::string(windowId);
    } else if (nextWindowSet.primaryWindowId.empty()) {
        outError =
            "Cannot register detached window '" + std::string(windowId) +
            "' before the primary window exists.";
        return false;
    }

    if (nextWindowSet.activeWindowId.empty() ||
        FindUIEditorWindowWorkspaceState(nextWindowSet, nextWindowSet.activeWindowId) == nullptr) {
        nextWindowSet.activeWindowId = ResolveFallbackWindowId(nextWindowSet);
    }

    if (!ValidateWindowSet(nextWindowSet, outError)) {
        return false;
    }

    ReplaceWindowSet(std::move(nextWindowSet));
    outError.clear();
    return true;
}

bool EditorWindowWorkspaceStore::CommitWindowProjection(
    std::string_view windowId,
    const UIEditorWorkspaceController& workspaceController,
    std::string& outError) {
    UIEditorWindowWorkspaceSet nextWindowSet = m_windowSet;
    UIEditorWindowWorkspaceState* existingWindow =
        FindMutableUIEditorWindowWorkspaceState(nextWindowSet, windowId);
    if (existingWindow == nullptr) {
        outError = "Window '" + std::string(windowId) + "' is not registered in the workspace store.";
        return false;
    }

    existingWindow->workspace = workspaceController.GetWorkspace();
    existingWindow->session = workspaceController.GetSession();

    if (nextWindowSet.activeWindowId.empty() ||
        FindUIEditorWindowWorkspaceState(nextWindowSet, nextWindowSet.activeWindowId) == nullptr) {
        nextWindowSet.activeWindowId = ResolveFallbackWindowId(nextWindowSet);
    }

    if (!ValidateWindowSet(nextWindowSet, outError)) {
        return false;
    }

    ReplaceWindowSet(std::move(nextWindowSet));
    outError.clear();
    return true;
}

bool EditorWindowWorkspaceStore::ValidateWindowSet(
    const UIEditorWindowWorkspaceSet& windowSet,
    std::string& outError) const {
    const UIEditorWindowWorkspaceValidationResult validation =
        ValidateUIEditorWindowWorkspaceSet(m_panelRegistry, windowSet);
    if (!validation.IsValid()) {
        outError = validation.message;
        return false;
    }

    outError.clear();
    return true;
}

void EditorWindowWorkspaceStore::ReplaceWindowSet(UIEditorWindowWorkspaceSet windowSet) {
    m_windowSet = std::move(windowSet);
}

void EditorWindowWorkspaceStore::RemoveWindow(std::string_view windowId, bool primary) {
    if (m_windowSet.windows.empty()) {
        return;
    }

    if (primary || m_windowSet.primaryWindowId == windowId) {
        m_windowSet = {};
        return;
    }

    m_windowSet.windows.erase(
        std::remove_if(
            m_windowSet.windows.begin(),
            m_windowSet.windows.end(),
            [windowId](const UIEditorWindowWorkspaceState& state) {
                return state.windowId == windowId;
            }),
        m_windowSet.windows.end());

    if (m_windowSet.windows.empty()) {
        m_windowSet = {};
        return;
    }

    if (FindUIEditorWindowWorkspaceState(m_windowSet, m_windowSet.primaryWindowId) == nullptr) {
        m_windowSet.primaryWindowId = ResolveFallbackWindowId(m_windowSet);
    }

    if (m_windowSet.activeWindowId == windowId ||
        FindUIEditorWindowWorkspaceState(m_windowSet, m_windowSet.activeWindowId) == nullptr) {
        m_windowSet.activeWindowId = ResolveFallbackWindowId(m_windowSet);
    }
}

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