/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2020 - Raw Material Software Limited

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 6 End-User License
   Agreement and JUCE Privacy Policy (both effective as of the 16th June 2020).

   End User License Agreement: www.juce.com/juce-6-licence
   Privacy Policy: www.juce.com/juce-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

//==============================================================================
/**
    A component that displays a piano keyboard, whose notes can be clicked on.

    This component will mimic a physical midi keyboard, showing the current state of
    a MidiKeyboardState object. When the on-screen keys are clicked on, it will play these
    notes by calling the noteOn() and noteOff() methods of its MidiKeyboardState object.

    Another feature is that the computer keyboard can also be used to play notes. By
    default it maps the top two rows of a standard qwerty keyboard to the notes, but
    these can be remapped if needed. It will only respond to keypresses when it has
    the keyboard focus, so to disable this feature you can call setWantsKeyboardFocus (false).

    The component is also a ChangeBroadcaster, so if you want to be informed when the
    keyboard is scrolled, you can register a ChangeListener for callbacks.

    @see MidiKeyboardState

    @tags{Audio}
*/
class JUCE_API  MidiKeyboardComponent  : public Component,
                                         public MidiKeyboardState::Listener,
                                         public ChangeBroadcaster,
                                         private Timer
{
public:
    //==============================================================================
    /** The direction of the keyboard.
        @see setOrientation
    */
    enum Orientation
    {
        horizontalKeyboard,
        verticalKeyboardFacingLeft,
        verticalKeyboardFacingRight,
    };

    /** Creates a MidiKeyboardComponent.

        @param state        the midi keyboard model that this component will represent
        @param orientation  whether the keyboard is horizontal or vertical
    */
    MidiKeyboardComponent (MidiKeyboardState& state,
                           Orientation orientation);

    /** Destructor. */
    ~MidiKeyboardComponent() override;

    //==============================================================================
    /** Changes the velocity used in midi note-on messages that are triggered by clicking
        on the component.

        Values are 0 to 1.0, where 1.0 is the heaviest.

        @see setMidiChannel
    */
    void setVelocity (float velocity, bool useMousePositionForVelocity);

    /** Changes the midi channel number that will be used for events triggered by clicking
        on the component.

        The channel must be between 1 and 16 (inclusive). This is the channel that will be
        passed on to the MidiKeyboardState::noteOn() method when the user clicks the component.

        Although this is the channel used for outgoing events, the component can display
        incoming events from more than one channel - see setMidiChannelsToDisplay()

        @see setVelocity
    */
    void setMidiChannel (int midiChannelNumber);

    /** Returns the midi channel that the keyboard is using for midi messages.
        @see setMidiChannel
    */
    int getMidiChannel() const noexcept                             { return midiChannel; }

    /** Sets a mask to indicate which incoming midi channels should be represented by
        key movements.

        The mask is a set of bits, where bit 0 = midi channel 1, bit 1 = midi channel 2, etc.

        If the MidiKeyboardState has a key down for any of the channels whose bits are set
        in this mask, the on-screen keys will also go down.

        By default, this mask is set to 0xffff (all channels displayed).

        @see setMidiChannel
    */
    void setMidiChannelsToDisplay (int midiChannelMask);

    /** Returns the current set of midi channels represented by the component.
        This is the value that was set with setMidiChannelsToDisplay().
    */
    int getMidiChannelsToDisplay() const noexcept                   { return midiInChannelMask; }

    //==============================================================================
    /** Changes the width used to draw the white keys. */
    void setKeyWidth (float widthInPixels);

    /** Returns the width that was set by setKeyWidth(). */
    float getKeyWidth() const noexcept                              { return keyWidth; }

    /** Changes the width used to draw the buttons that scroll the keyboard up/down in octaves. */
    void setScrollButtonWidth (int widthInPixels);

    /** Returns the width that was set by setScrollButtonWidth(). */
    int getScrollButtonWidth() const noexcept                       { return scrollButtonWidth; }

    /** Changes the keyboard's current direction. */
    void setOrientation (Orientation newOrientation);

    /** Returns the keyboard's current direction. */
    Orientation getOrientation() const noexcept                     { return orientation; }

    /** Sets the range of midi notes that the keyboard will be limited to.

        By default the range is 0 to 127 (inclusive), but you can limit this if you
        only want a restricted set of the keys to be shown.

        Note that the values here are inclusive and must be between 0 and 127.
    */
    void setAvailableRange (int lowestNote,
                            int highestNote);

    /** Returns the first note in the available range.
        @see setAvailableRange
    */
    int getRangeStart() const noexcept                              { return rangeStart; }

    /** Returns the last note in the available range.
        @see setAvailableRange
    */
    int getRangeEnd() const noexcept                                { return rangeEnd; }

    /** If the keyboard extends beyond the size of the component, this will scroll
        it to show the given key at the start.

        Whenever the keyboard's position is changed, this will use the ChangeBroadcaster
        base class to send a callback to any ChangeListeners that have been registered.
    */
    void setLowestVisibleKey (int noteNumber);

    /** Returns the number of the first key shown in the component.
        @see setLowestVisibleKey
    */
    int getLowestVisibleKey() const noexcept                        { return (int) firstKey; }

    /** Sets the length of the black notes as a proportion of the white note length. */
    void setBlackNoteLengthProportion (float ratio) noexcept;

    /** Returns the length of the black notes as a proportion of the white note length. */
    float getBlackNoteLengthProportion() const noexcept             { return blackNoteLengthRatio; }

    /** Returns the absolute length of the black notes.
        This will be their vertical or horizontal length, depending on the keyboard's orientation.
    */
    float getBlackNoteLength() const noexcept;

    /** Sets the width of the black notes as a proportion of the white note width. */
    void setBlackNoteWidthProportion (float ratio) noexcept;

    /** Returns the width of the black notes as a proportion of the white note width. */
    float getBlackNoteWidthProportion() const noexcept             { return blackNoteWidthRatio; }

    /** Returns the absolute width of the black notes.
        This will be their vertical or horizontal width, depending on the keyboard's orientation.
    */
    float getBlackNoteWidth() const noexcept                       { return keyWidth * blackNoteWidthRatio; }

    /** If set to true, then scroll buttons will appear at either end of the keyboard
        if there are too many notes to fit them all in the component at once.
    */
    void setScrollButtonsVisible (bool canScroll);

    /** Sets width of scroll buttons */
    void setScrollButtonsWidth (int width);

    /** Returns width of scroll buttons */
    int getScrollButtonsWidth () const { return scrollButtonWidth; }

    //==============================================================================
    /** A set of colour IDs to use to change the colour of various aspects of the keyboard.

        These constants can be used either via the Component::setColour(), or LookAndFeel::setColour()
        methods.

        @see Component::setColour, Component::findColour, LookAndFeel::setColour, LookAndFeel::findColour
    */
    enum ColourIds
    {
        whiteNoteColourId               = 0x1005000,
        blackNoteColourId               = 0x1005001,
        keySeparatorLineColourId        = 0x1005002,
        mouseOverKeyOverlayColourId     = 0x1005003,  /**< This colour will be overlaid on the normal note colour. */
        keyDownOverlayColourId          = 0x1005004,  /**< This colour will be overlaid on the normal note colour. */
        textLabelColourId               = 0x1005005,
        upDownButtonBackgroundColourId  = 0x1005006,
        upDownButtonArrowColourId       = 0x1005007,
        shadowColourId                  = 0x1005008
    };

    /** Returns the position within the component of the left-hand edge of a key.

        Depending on the keyboard's orientation, this may be a horizontal or vertical
        distance, in either direction.
    */
    float getKeyStartPosition (int midiNoteNumber) const;

    /** Returns the total width needed to fit all the keys in the available range. */
    float getTotalKeyboardWidth() const noexcept;

    /** Returns the key at a given coordinate. */
    int getNoteAtPosition (Point<float> position);

    //==============================================================================
    /** Deletes all key-mappings.
        @see setKeyPressForNote
    */
    void clearKeyMappings();

    /** Maps a key-press to a given note.

        @param key                  the key that should trigger the note
        @param midiNoteOffsetFromC  how many semitones above C the triggered note should
                                    be. The actual midi note that gets played will be
                                    this value + (12 * the current base octave). To change
                                    the base octave, see setKeyPressBaseOctave()
    */
    void setKeyPressForNote (const KeyPress& key,
                             int midiNoteOffsetFromC);

    /** Removes any key-mappings for a given note.
        For a description of what the note number means, see setKeyPressForNote().
    */
    void removeKeyPressForNote (int midiNoteOffsetFromC);

    /** Changes the base note above which key-press-triggered notes are played.

        The set of key-mappings that trigger notes can be moved up and down to cover
        the entire scale using this method.

        The value passed in is an octave number between 0 and 10 (inclusive), and
        indicates which C is the base note to which the key-mapped notes are
        relative.
    */
    void setKeyPressBaseOctave (int newOctaveNumber);

    /** This sets the octave number which is shown as the octave number for middle C.

        This affects only the default implementation of getWhiteNoteText(), which
        passes this octave number to MidiMessage::getMidiNoteName() in order to
        get the note text. See MidiMessage::getMidiNoteName() for more info about
        the parameter.

        By default this value is set to 3.

        @see getOctaveForMiddleC
    */
    void setOctaveForMiddleC (int octaveNumForMiddleC);

    /** This returns the value set by setOctaveForMiddleC().
        @see setOctaveForMiddleC
    */
    int getOctaveForMiddleC() const noexcept            { return octaveNumForMiddleC; }

    //==============================================================================
    /** @internal */
    void paint (Graphics&) override;
    /** @internal */
    void resized() override;
    /** @internal */
    void mouseMove (const MouseEvent&) override;
    /** @internal */
    void mouseDrag (const MouseEvent&) override;
    /** @internal */
    void mouseDown (const MouseEvent&) override;
    /** @internal */
    void mouseUp (const MouseEvent&) override;
    /** @internal */
    void mouseEnter (const MouseEvent&) override;
    /** @internal */
    void mouseExit (const MouseEvent&) override;
    /** @internal */
    void mouseWheelMove (const MouseEvent&, const MouseWheelDetails&) override;
    /** @internal */
    void timerCallback() override;
    /** @internal */
    bool keyStateChanged (bool isKeyDown) override;
    /** @internal */
    bool keyPressed (const KeyPress&) override;
    /** @internal */
    void focusLost (FocusChangeType) override;
    /** @internal */
    void handleNoteOn (MidiKeyboardState*, int midiChannel, int midiNoteNumber, float velocity) override;
    /** @internal */
    void handleNoteOff (MidiKeyboardState*, int midiChannel, int midiNoteNumber, float velocity) override;
    /** @internal */
    void colourChanged() override;

protected:
    //==============================================================================
    /** Draws a white note in the given rectangle.

        isOver indicates whether the mouse is over the key, isDown indicates whether the key is
        currently pressed down.

        When doing this, be sure to note the keyboard's orientation.
    */
    virtual void drawWhiteNote (int midiNoteNumber,
                                Graphics& g, Rectangle<float> area,
                                bool isDown, bool isOver,
                                Colour lineColour, Colour textColour);

    /** Draws a black note in the given rectangle.

        isOver indicates whether the mouse is over the key, isDown indicates whether the key is
        currently pressed down.

        When doing this, be sure to note the keyboard's orientation.
    */
    virtual void drawBlackNote (int midiNoteNumber,
                                Graphics& g, Rectangle<float> area,
                                bool isDown, bool isOver,
                                Colour noteFillColour);

    /** Allows text to be drawn on the white notes.
        By default this is used to label the C in each octave, but could be used for other things.
        @see setOctaveForMiddleC
    */
    virtual String getWhiteNoteText (int midiNoteNumber);

    /** Draws the up and down buttons that scroll the keyboard up/down in octaves. */
    virtual void drawUpDownButton (Graphics& g, int w, int h,
                                   bool isMouseOver,
                                   bool isButtonPressed,
                                   bool movesOctavesUp);

    /** Callback when the mouse is clicked on a key.

        You could use this to do things like handle right-clicks on keys, etc.

        Return true if you want the click to trigger the note, or false if you
        want to handle it yourself and not have the note played.

        @see mouseDraggedToKey
    */
    virtual bool mouseDownOnKey (int midiNoteNumber, const MouseEvent& e);

    /** Callback when the mouse is dragged from one key onto another.

        Return true if you want the drag to trigger the new note, or false if you
        want to handle it yourself and not have the note played.

        @see mouseDownOnKey
    */
    virtual bool mouseDraggedToKey (int midiNoteNumber, const MouseEvent& e);

    /** Callback when the mouse is released from a key.
        @see mouseDownOnKey
    */
    virtual void mouseUpOnKey (int midiNoteNumber, const MouseEvent& e);

    /** Calculates the position of a given midi-note.

        This can be overridden to create layouts with custom key-widths.

        @param midiNoteNumber   the note to find
        @param keyWidth         the desired width in pixels of one key - see setKeyWidth()
        @returns                the start and length of the key along the axis of the keyboard
    */
    virtual Range<float> getKeyPosition (int midiNoteNumber, float keyWidth) const;

    /** Returns the rectangle for a given key if within the displayable range */
    Rectangle<float> getRectangleForKey (int midiNoteNumber) const;


private:
    //==============================================================================
    struct UpDownButton;

    MidiKeyboardState& state;
    float blackNoteLengthRatio = 0.7f;
    float blackNoteWidthRatio = 0.7f;
    float xOffset = 0;
    float keyWidth = 16.0f;
    int scrollButtonWidth = 12;
    Orientation orientation;

    int midiChannel = 1, midiInChannelMask = 0xffff;
    float velocity = 1.0f;

    Array<int> mouseOverNotes, mouseDownNotes;
    BigInteger keysPressed, keysCurrentlyDrawnDown;
    std::atomic<bool> noPendingUpdates { true };

    int rangeStart = 0, rangeEnd = 127;
    float firstKey = 12 * 4.0f;
    bool canScroll = true, useMousePositionForVelocity = true;
    std::unique_ptr<Button> scrollDown, scrollUp;

    Array<KeyPress> keyPresses;
    Array<int> keyPressNotes;
    int keyMappingOctave = 6, octaveNumForMiddleC = 3;

    Range<float> getKeyPos (int midiNoteNumber) const;
    int xyToNote (Point<float>, float& mousePositionVelocity);
    int remappedXYToNote (Point<float>, float& mousePositionVelocity) const;
    void resetAnyKeysInUse();
    void updateNoteUnderMouse (Point<float>, bool isDown, int fingerNum);
    void updateNoteUnderMouse (const MouseEvent&, bool isDown);
    void repaintNote (int midiNoteNumber);
    void setLowestVisibleKeyFloat (float noteNumber);

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (MidiKeyboardComponent)
};

} // namespace juce
