xtc/src/gui/sequencer_widget.hpp

#ifndef XTC_SEQUENCER_WIDGET_HPP
#define XTC_SEQUENCER_WIDGET_HPP
#include <FL/Fl_Widget.H>
#include "xtc/xtc_audio.h"
#include <memory>
#include <string>
#include <vector>

class SequencerWidget : public Fl_Widget {
  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.
     */
    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 Wave {
        std::string path;
        std::unique_ptr<xtc_waveform, decltype(&xtc_waveform_destroy)> data{nullptr, xtc_waveform_destroy};
    };
    std::vector<Wave> waves_;
    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;
    int scale_ = 48, drag_x_ = 0, mode_ = 0;
    xtc_clip_info original_{};
    /**
     * @brief Converts a screen x coordinate to a bounded timeline tick snapped to a sixteenth note.
     *
     * @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