#ifndef XTC_SEQUENCER_WIDGET_HPP
#define XTC_SEQUENCER_WIDGET_HPP
#include <FL/Fl_Group.H>
#include <FL/Fl_Choice.H>
#include "xtc/xtc_plugin.h"
#include "xtc/xtc_editing.h"
#include <array>
#include "xtc/xtc_audio.h"
#include <memory>
#include <string>
#include <vector>

class SequencerWidget : public Fl_Group {
  public:
    /**
     * @brief Prepares a model edit using the widget's opaque callback context.
     *
     * @return XTC_OK to allow the edit, or an error to cancel it.
     */
    using LoopSelect = xtc_result (*)(void *,uint64_t,uint64_t);
    LoopSelect loop_select = nullptr;
    uint64_t new_clip_ticks = 3840;
    int header_width() const {return header_width_;}
    void header_width(int width);
    int header_left() const;
    int zoom_level() const { return scale_; }
    xtc_result set_zoom(int scale);
    void loop_region(uint64_t start,uint64_t end,bool enabled) { loop_begin_=start; loop_end_=end; loop_enabled_=enabled; redraw(); }
    using OpenClip = void (*)(void *);
    using InstrumentSelect = void (*)(void *, uint64_t, const xtc_plugin_spec *, bool);
    OpenClip open_clip = nullptr;
    InstrumentSelect instrument_select = nullptr;
    Fl_Choice *instrument_choice(uint64_t track) const;
    void refresh_instruments();
    bool select(uint64_t track, uint64_t clip = UINT64_MAX);
    xtc_result merge_midi();
    xtc_result duplicate_track(const char *name);
    void duplicate_track_dialog();
    xtc_result ripple_time(uint64_t length,bool remove);
    void ripple_dialog(bool remove);
    xtc_result marker(const char *name); /* NULL removes at cursor. */
    void marker_dialog();
    bool toggle_clip(uint64_t clip);
    void select_all_clips();
    bool clip_selected(uint64_t clip) const;
    std::vector<uint64_t> selected_clips() const;
    xtc_result transform_selection(xtc_clip_operation operation,int64_t amount);
    xtc_result transform_midi(const xtc_midi_transform &edit);
    void swing_dialog();
    void gate_dialog();
    void scale_dialog();
    void velocity_dialog();
    void humanize_dialog();
    xtc_result make_chord(const std::vector<int> &intervals);
    void chord_dialog();
    xtc_result arpeggiate(uint64_t step,unsigned int gate,bool descending);
    void arpeggio_dialog();
    void fades_dialog();
    xtc_result repeat_selection(unsigned int copies);
    void repeat_dialog();
    xtc_result copy_selection();
    xtc_result paste_selection();
    xtc_result nudge_selection(int direction);
    xtc_result duplicate_selection();
    xtc_result split_selection();
    xtc_result audio_properties(float gain, uint64_t fade_in, uint64_t fade_out);
    void audio_properties_dialog();
    void refresh_waveforms();
    size_t waveform_count() const { return waves_.size(); }

    xtc_result rename_selection(const char *name);
    xtc_result move_track(int direction);
    xtc_result grid(uint64_t ticks);
    uint64_t grid() const { return grid_; }
    using BeforeEdit = xtc_result (*)(void *);
    BeforeEdit before_edit = nullptr;

    /**
     * @brief Returns the selected track identifier, or UINT64_MAX when none is selected.
     * @return Stable track identifier, or UINT64_MAX if no track is selected.
     */
    uint64_t selected_track() const
    {
        return track_;
    }

    /**
     * @brief Returns the selected clip identifier, or UINT64_MAX when none is selected.
     * @return Stable clip identifier, or UINT64_MAX if no clip is selected.
     */
    uint64_t selected_clip() const
    {
        return clip_;
    }

    /**
     * @brief Requests a transport seek using an opaque context and musical tick.
     *
     * @return XTC_OK on success, or a transport error.
     */
    using Seek = xtc_result (*)(void *, uint64_t);
    /**
     * @brief Constructs the timeline widget with a borrowed project and seek callback.
     *
     * @param x Left coordinate in pixels.
     * @param y Top coordinate in pixels.
     * @param project Borrowed project; must outlive the widget's use of it.
     * @param seek Callback used to request a transport seek.
     * @param context Opaque callback context.
     */
    SequencerWidget(int x, int y, xtc_project *project, Seek seek, void *context);
    /**
     * @brief Replaces the borrowed project and refreshes the widget's displayed state.
     *
     * @param project Borrowed project; must outlive the widget's use of it.
     * @param reset Whether to clear selection, cursor, and drag state.
     */
    void set_project(xtc_project *project, bool reset = true);

    /**
     * @brief Returns the timeline cursor position in musical ticks.
     * @return Cursor position in musical ticks.
     */
    uint64_t position() const
    {
        return cursor_;
    }

    /**
     * @brief Moves the timeline cursor to the supplied musical tick and requests a redraw.
     *
     * @param tick Musical position in ticks.
     */
    void position(uint64_t tick)
    {
        cursor_ = tick;
        redraw();
    }

    /**
     * @brief Creates and selects a track through the arrangement edit hook.
     * @return XTC_OK on success, or an error code describing the failure.
     */
    xtc_result add_track();
    /**
     * @brief Creates and selects a one-bar silent region at the timeline cursor.
     * @return XTC_OK on success, or an error code describing the failure.
     */
    xtc_result add_region();
    /**
     * @brief Creates and selects a one-bar MIDI clip at the timeline cursor.
     * @return XTC_OK on success, or an error code describing the failure.
     */
    xtc_result add_midi_clip();
    /**
     * @brief Removes the selected clip, or the selected track when no clip is selected.
     * @return XTC_OK on success, or an error code describing the failure.
     */
    xtc_result delete_selection();
    /**
     * @brief Adjusts timeline zoom within its supported bounds and updates the scroll extent.
     *
     * @param direction Zoom direction; positive zooms in, nonpositive zooms out.
     */
    void zoom(int direction);

    /**
     * @brief Returns the borrowed project currently displayed by the widget.
     * @return Borrowed project pointer.
     */
    xtc_project *project() const
    {
        return project_;
    }

    /**
     * @brief Handles FLTK input events and delegates unhandled events to the base widget.
     *
     * @param event FLTK event code.
     * @return Nonzero if the event was handled, zero otherwise.
     */
    int handle(int event) override;

  protected:
    /**
     * @brief Draws the widget's current model, selection, and interaction feedback.
     */
    void draw() override;

  private:
    struct TrackChoice { Fl_Choice *widget = nullptr; uint64_t track = UINT64_MAX; };
    std::array<TrackChoice,XTC_PROJECT_MAX_TRACKS> track_choices_{};
    std::vector<xtc_plugin_spec> catalog_;
    static void instrument_callback(Fl_Widget *, void *);
    struct Wave {
        std::string path;
        std::unique_ptr<xtc_waveform, decltype(&xtc_waveform_destroy)> data{nullptr, xtc_waveform_destroy};
    };
    std::vector<Wave> waves_;
    std::vector<uint64_t> selection_;
    std::unique_ptr<xtc_clipboard,decltype(&xtc_clipboard_destroy)> clipboard_{nullptr,xtc_clipboard_destroy};
    void draw_waveform(const xtc_clip_info &clip, int left, int top);
    xtc_project *project_;
    Seek seek_;
    void *context_;
    uint64_t track_ = UINT64_MAX, clip_ = UINT64_MAX, cursor_ = 0, grid_ = 240;
    uint64_t loop_begin_=0,loop_end_=3840,loop_anchor_=0,loop_preview_=0;
    bool loop_enabled_=false;
    int scale_ = 48, drag_x_ = 0, mode_ = 0;
    int header_width_=180,header_drag_x_=0,header_drag_original_=180;
    xtc_clip_info original_{};
    /**
     * @brief Converts a screen x coordinate to a bounded timeline tick snapped to the selected grid.
     *
     * @param px Screen x coordinate in pixels.
     * @return Snapped tick within the supported project range.
     */
    uint64_t tick(int px) const;
    /**
     * @brief Reports an edit result, refreshes the widget, and notifies listeners on success.
     *
     * @param result Result of the attempted operation.
     */
    void changed(xtc_result result);
    /**
     * @brief Resizes the timeline's scrollable area to fit its tracks and clip ends.
     */
    void extent();
};
#endif