#ifndef XTC_MAIN_WINDOW_HPP
#define XTC_MAIN_WINDOW_HPP

#include <FL/Fl_Double_Window.H>
#include <memory>
#include <string>
#include "xtc/xtc_project.h"
#include "xtc/xtc_backend.h"
#include "xtc/xtc_mixer.h"
#include "xtc/xtc_plugin.h"

class GraphWidget;
class MixerWidget;
class PianoRollWidget;
class SequencerWidget;
class Fl_Box;
class Fl_Button;
class Fl_Tabs;

class MainWindow : public Fl_Double_Window {
  public:
    /* Control-thread plugin commands, transactional model adoption. */
    xtc_result add_plugin(const char *path, unsigned int index, size_t *id = nullptr);
    xtc_result set_plugin_control(size_t id, unsigned int port, float value);
    /**
     * @brief Constructs the window, its widgets, and the initial project.
     *
     * Creates an empty project and undo history, opens the audio backend, and
     * schedules the periodic status timer. Throws std::runtime_error when the
     * initial project or history cannot be created.
     *
     * @param prompt_unsaved Whether open, new, and close actions ask before
     *        discarding unsaved changes.
     */
    explicit MainWindow(bool prompt_unsaved = true);
    /**
     * @brief Removes the status timer and releases backend and recording state.
     *
     * A backend that fails to close is intentionally retained with its recorder
     * until process exit so active callbacks never observe freed state.
     */
    ~MainWindow() override;
    /**
     * @brief Deleted copy constructor; a window uniquely owns its project and backend.
     */
    MainWindow(const MainWindow &) = delete;
    /**
     * @brief Deleted copy assignment; a window uniquely owns its project and backend.
     */
    MainWindow &operator=(const MainWindow &) = delete;
    using Fl_Double_Window::show;
    /**
     * @brief Handles FLTK events for the window.
     *
     * Space without Ctrl/Alt/Meta toggles the audio engine and is consumed.
     *
     * @param event FLTK event code, such as FL_SHORTCUT.
     * @return 1 when Space was consumed; otherwise the Fl_Double_Window result.
     */
    int handle(int event) override;

    /**
     * @brief Applies one undo or redo step from the project history.
     *
     * The selected snapshot is installed without resetting history and then
     * accepted, leaving the window marked dirty.
     *
     * @param redo True to redo, false to undo.
     * @return XTC_OK on success, XTC_ERR_INVALID_STATE while recording,
     *         XTC_ERR_NOT_FOUND when no step is available, or another error from
     *         checkout, install, or accept.
     */
    xtc_result undo(bool redo = false);

    /**
     * @brief Returns the mixer tab widget owned by the window.
     *
     * @return Borrowed mixer widget, or nullptr before construction completes.
     */
    MixerWidget *mixer() const
    {
        return mixer_;
    }

    /**
     * @brief Shows the piano roll for the selected MIDI clip.
     *
     * The piano-roll window is created on first use and reused afterwards.
     *
     * @return XTC_OK on success, or XTC_ERR_INVALID_STATE when the selected clip
     *         does not exist or is not MIDI.
     */
    xtc_result open_piano_roll();

    /**
     * @brief Returns the piano-roll editor widget.
     *
     * @return Borrowed widget, or nullptr until open_piano_roll() first succeeds.
     */
    PianoRollWidget *piano_roll() const
    {
        return piano_;
    }

    /**
     * @brief Imports a WAV file as an audio clip in a cloned project.
     *
     * Stops the engine first, creates an "Audio" track when none is selected,
     * and places the clip at the sequencer cursor. The clone replaces the live
     * project only after every step succeeds.
     *
     * @param path Path to the WAV file to import.
     * @return XTC_OK on success, or an error from the engine stop, clone, import,
     *         or backend preparation.
     */
    xtc_result import_audio(const char *path);
    /**
     * @brief Starts recording JACK input to a WAV file.
     *
     * Requires a connected backend and no active recording. The engine is
     * stopped, the current position and selected track are remembered, and a
     * stereo recorder at the engine sample rate is attached before starting.
     * Failure leaves the window without a recorder.
     *
     * @param path Destination WAV path chosen by the user.
     * @return XTC_OK when recording started, XTC_ERR_INVALID_STATE when
     *         disconnected or already recording, or another backend or recorder
     *         error.
     */
    xtc_result record_audio(const char *path);
    /**
     * @brief Saves the current project to a path and updates the window title.
     *
     * On success the path is remembered and the unsaved marker is cleared.
     *
     * @param path Destination project path; nullptr is invalid.
     * @return XTC_OK on success, XTC_ERR_INVALID_ARGUMENT for nullptr,
     *         XTC_ERR_INVALID_STATE while recording, or the save error.
     */
    xtc_result save_project(const char *path);
    /**
     * @brief Loads a project from a path and makes it the current project.
     *
     * The file is loaded into a candidate project and installed only on success.
     *
     * @param path Source project path; nullptr is invalid.
     * @return XTC_OK on success, XTC_ERR_INVALID_ARGUMENT for nullptr, or an
     *         error from loading or installing the project.
     */
    xtc_result open_project(const char *path);

    /** Creates a fresh untitled project; the File menu checks unsaved changes first.
     * On failure the current document remains owned by the window. */
    xtc_result new_project();
    /** Requests a playback fade/stop; the timer completes deactivation after
     * callback acknowledgement. Recording must use immediate Stop instead.
     * Returns request acceptance or the backend failure. */
    xtc_result pause_playback();
    /** Stops playback and seeks to zero. Refuses during recording. A failed
     * stop/seek is reported without moving the displayed cursor to zero. */
    xtc_result return_to_start();

  private:
    MixerWidget *mixer_ = nullptr;
    std::unique_ptr<xtc_history, decltype(&xtc_history_destroy)> history_{nullptr, xtc_history_destroy};
    /**
     * @brief FLTK menu callback for the Undo and Redo menu items.
     *
     * The selected menu label starting with "Redo" chooses redo; all other
     * labels undo. Failures other than XTC_ERR_NOT_FOUND are shown in the window.
     *
     * @param widget Fl_Menu_Bar whose selected item triggered the callback.
     * @param context MainWindow * owning the menu and history.
     */
    static void history_callback(Fl_Widget * widget, void * context);
    std::unique_ptr<xtc_project, decltype(&xtc_project_destroy)> project_{nullptr, xtc_project_destroy};
    std::unique_ptr<Fl_Double_Window> piano_window_;
    PianoRollWidget *piano_ = nullptr;
    /**
     * @brief FLTK callback for the Piano roll menu item and button.
     *
     * Refuses to open the editor while recording and asks the user to select a
     * MIDI clip when open_piano_roll() fails.
     *
     * @param widget Unused triggering widget.
     * @param context MainWindow * owning the piano roll.
     */
    static void piano_callback(Fl_Widget * widget, void *context);
    /**
     * @brief FLTK callback for the Panic menu item and button.
     *
     * When the backend is connected, sends a panic request that silences held
     * instrument notes and reports failures.
     *
     * @param widget Unused triggering widget.
     * @param context MainWindow * owning the backend.
     */
    static void panic_callback(Fl_Widget * widget, void *context);
    SequencerWidget *sequencer_ = nullptr;
    xtc_recorder *recorder_ = nullptr;
    std::string recording_path_;
    uint64_t recording_tick_ = 0, recording_track_ = UINT64_MAX;
    /**
     * @brief Finalizes the active recording and adds the take to the project.
     *
     * Must run only after the engine has stopped, so no audio callback can
     * reference the recorder ring. The recorder is detached, finished, and
     * destroyed. A failed finalize or empty take is reported and not added. If
     * the subsequent import fails, the saved WAV path is reported for recovery.
     */
    void finish_recording();
    /**
     * @brief Hook called by arrangement widgets before mutating the project.
     *
     * Refuses edits while recording. When connected, stops the engine so the
     * mutation cannot race the audio thread, then refreshes the status display.
     *
     * @param context MainWindow * passed as the widget owner context.
     * @return XTC_OK when disconnected or the stop succeeded,
     *         XTC_ERR_INVALID_STATE while recording, or the backend stop error.
     */
    static xtc_result before_arrangement_edit(void *context);
    /**
     * @brief FLTK callback for the audio import, record, and relink commands.
     *
     * The triggering widget supplies the menu label; the Record button uses the
     * "Record WAV" default. A native file chooser selects the file, after which
     * the selected clip is relinked, recording starts, or a WAV is imported.
     * Failures are reported in the window.
     *
     * @param widget Triggering Fl_Menu_Bar or Fl_Button; menu labels select the
     *        action.
     * @param context MainWindow * owning the project and sequencer.
     */
    static void audio_file_callback(Fl_Widget * widget, void *context);
    bool dirty_ = false, prompt_unsaved_ = true;
    std::string path_;
    /**
     * @brief Asks whether unsaved changes may be discarded.
     *
     * @return True when the project is clean, prompting is disabled, or the user
     *         chose Discard; false when the user cancels.
     */
    bool discard_changes();
    /**
     * @brief Records the current project in history and marks the window dirty.
     *
     * Dependent widgets are refreshed with the current project and graph, and
     * the title gains the unsaved marker. A history failure is reported.
     */
    void mark_dirty();
    /**
     * @brief Installs a candidate project as the active project.
     *
     * Rejected while recording. Optionally builds fresh undo history, stops and
     * prepares the connected backend, or validates offline audio and MIDI plans
     * when disconnected. On success the window takes ownership of candidate,
     * rebinds widgets, resets the graph layout, clears the dirty flag, and shows
     * any missing-asset warning. On failure ownership stays with the caller.
     *
     * @param candidate Project to install; must be non-null.
     * @param reset_history True to discard existing undo/redo history and start
     *        from candidate.
     * @return XTC_OK on success, XTC_ERR_INVALID_STATE while recording, or an
     *         error from history creation, the backend, or offline planning.
     */
    xtc_result install_project(xtc_project *candidate, bool reset_history = true);
    /**
     * @brief Hook used by the sequencer to seek the audio engine.
     *
     * Does nothing when the backend is disconnected. Otherwise reads the engine
     * sample rate, converts the tick position to samples, and seeks the backend.
     *
     * @param context MainWindow * passed as the sequencer owner context.
     * @param tick Target timeline position in project ticks.
     * @return XTC_OK when disconnected or the seek succeeded, or the status,
     *         conversion, or backend seek error.
     */
    static xtc_result seek(void *context, uint64_t tick);
    /**
     * @brief FLTK menu callback for the File/New, Open, Save, and Save As items.
     *
     * Reads the action from the selected menu label, confirms discarding unsaved
     * changes for New and Open, and uses a native file chooser unless Save can
     * reuse the remembered path. Refuses file operations while recording and
     * reports failures in the window.
     *
     * @param widget Triggering Fl_Menu_Bar whose selected label names the action.
     * @param context MainWindow * owning the project and file path.
     */
    static void plugin_callback(Fl_Widget *widget, void *context);
    xtc_result install_plugin_graph(xtc_graph *graph);
    static void file_callback(Fl_Widget * widget, void *context);
    GraphWidget *graph_widget_ = nullptr;
    Fl_Box *graph_state_ = nullptr;
    xtc_backend *backend_ = nullptr;
    std::string project_issue_;
    bool ready_ = false;
    bool running_ = false;
    bool closing_ = false;
    Fl_Button *record_ = nullptr;
    Fl_Button *play_ = nullptr;
    Fl_Button *stop_ = nullptr;
    Fl_Button *pause_ = nullptr;
    Fl_Button *home_ = nullptr;
    Fl_Box *indicator_ = nullptr;
    Fl_Box *status_ = nullptr;
    Fl_Box *error_ = nullptr;
    Fl_Tabs *tabs_ = nullptr;

    /**
     * @brief Edit handler passed to the modular graph widget.
     *
     * Applies the edit to a candidate graph, clones the project around it, and
     * submits the new graph to the engine when connected. The live project is
     * replaced only after every step succeeds.
     *
     * @param context MainWindow * passed as the graph widget owner context.
     * @param edit Graph edit to apply.
     * @param out_added_id Optional output receiving the new node ID when the edit
     *        adds a node; untouched otherwise or when nullptr.
     * @return XTC_OK on success, XTC_ERR_INVALID_STATE while recording, or an
     *         error from the graph, project, or backend operation.
     */
    static xtc_result edit_graph(void *context, const xtc_graph_edit &edit, size_t *out_added_id);
    /**
     * @brief Opens the JACK backend and submits the current graph.
     *
     * Uses the default backend configuration and leaves the engine stopped.
     * Failure is reported and leaves the backend disconnected; a handle that
     * opened but failed to accept the graph is retained for reconnect.
     */
    void open_backend();
    /**
     * @brief Starts the audio engine with the current project.
     *
     * Does nothing when already running. Reports an error when disconnected.
     * Otherwise prepares the project and starts the engine. Missing or
     * unreadable audio is reported as a warning after a successful start.
     */
    void start_engine();
    /**
     * @brief Requests a graceful playback stop, or immediately finalizes recording.
     *
     * Does nothing when disconnected. Failures are reported in the window.
     */
    void stop_engine();
    /**
     * @brief Closes and reopens the JACK backend, leaving the engine stopped.
     *
     * Refuses to run while recording. If closing fails the existing handle is
     * retained for a later retry and the failure is reported.
     */
    void reconnect_engine();
    /**
     * @brief Polls the backend and updates labels, meters, and button states.
     *
     * When disconnected, shows offline text and disables transport controls.
     * Otherwise updates the sequencer position, mixer peaks, status line, and
     * error indicators from the latest engine status, then collects backend
     * work.
     */
    void refresh_status();
    /**
     * @brief Attempts to close the window after discarding unsaved changes.
     *
     * Refuses while recording. On success closes the backend, removes the status
     * timer, hides the piano-roll window, and hides this window.
     *
     * @return True when the window closed; false when recording is active, the
     *         user cancels discarding, or the backend cannot close.
     */
    bool close_window();
    /**
     * @brief Shows an operation failure and a context-sensitive hint.
     *
     * @param operation Human-readable operation name; names containing
     *        "Project" select a file and permission hint.
     * @param result Failing result code whose name is included in the message.
     */
    void report_error(const char *operation, xtc_result result);
    /**
     * @brief FLTK callback for the Play menu item and button.
     *
     * @param widget Unused triggering widget.
     * @param context MainWindow * whose engine is started.
     */
    static void play_callback(Fl_Widget * widget, void *context);
    /**
     * @brief FLTK callback for the Stop menu item and button.
     *
     * @param widget Unused triggering widget.
     * @param context MainWindow * whose engine is stopped.
     */
    static void stop_callback(Fl_Widget * widget, void *context);
    /**
     * @brief FLTK callback for the Reconnect menu item and button.
     *
     * @param widget Unused triggering widget.
     * @param context MainWindow * whose backend is reopened.
     */
    static void reconnect_callback(Fl_Widget * widget, void *context);
    /**
     * @brief FLTK callback for the window close box, File/Quit, and close events.
     *
     * @param widget Unused triggering widget or window.
     * @param context MainWindow * whose close is requested; a refused close
     *        simply leaves the window open.
     */
    static void close_callback(Fl_Widget * widget, void *context);
    /**
     * @brief FLTK menu callback that selects a tab page in the main window.
     *
     * @param widget Triggering menu item; window() must return the MainWindow.
     * @param view Fl_Widget * tab page to make current, not the MainWindow.
     */
    static void view_callback(Fl_Widget *widget, void *view);
    /**
     * @brief FLTK help callback that shows the application name and version.
     *
     * @param widget Unused triggering widget.
     * @param context Unused callback context.
     */
    static void about_callback(Fl_Widget * widget, void * context);
    /**
     * @brief FLTK timeout callback that refreshes status and supervises recording.
     *
     * While recording, drains the recorder and stops the engine if draining
     * fails or the backend reports a lost server, sample-rate change, or
     * processing error. Reschedules itself every 0.1 seconds until closing.
     *
     * @param context MainWindow * registered with Fl::add_timeout().
     */
    static void timer_callback(void *context);
};

#endif