/*

     File: CAUIKeyboardView.mm

 Abstract: 

  Version: 1.1.2

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 */

#import "CAUIKeyboardView.h"

#import "AppDelegate.h"

#import <UIKit/UIGestureRecognizer.h>

#define kWhiteKeyWidthRatio     0.268f

#define kBlackKeyHeightRatio    0.634f

#define kBlackKeyWidthRatio     0.159f

#define kDbKeyOffsetRatio       0.201f

#define kEbKeyOffsetRatio       0.232f

#define kGbKeyOffsetRatio       0.146f

#define kAbKeyOffsetRatio       0.195f

#define kBbKeyOffsetRatio       0.234f

#pragma mark - Utility functions

typedef enum NoteIdentifier {

    C = 0, Db= 1, D = 2, Eb= 3, E = 4, F = 5, Gb= 6, G = 7, Ab= 8, A = 9, Bb= 10, B = 11

} NoteIdentifier;

BOOL IsWhiteKey(NSInteger note) {

    NSInteger value = note % 12;

    switch (value) {

        case 0: case 2: case 4: case 5: case 7: case 9: case 11:

            return YES;

        default:

            return NO;

    }

}

BOOL IsNoteSharp(NSInteger note) {

    NSInteger value = note % 12;

    switch (value) {

        case 0: case 2: case 4: case 5: case 7: case 9: case 11:

            return false;

        case 1: case 3: case 6: case 8: case 10:

            return true;

    }

    return false;

}

NoteIdentifier IdentifierForNote(NSInteger note) {

    NSInteger value = note % 12;

    return (NoteIdentifier)value;

}

NSInteger NumWhiteKeysBetweenNotes(NSInteger startNote, NSInteger endNote) {

    // figure out how many octaves between notes

    if (startNote == endNote)

        return 0;

    NSInteger keys = 0;

    NSInteger octaves = ((endNote - startNote) / 12);

    if (octaves > 0)

        keys = octaves * 7;

    if (IsWhiteKey(startNote))

        keys--;

    NSInteger extraNotes = (endNote - startNote) % 12;

    for (NSInteger indexKey = endNote - extraNotes; indexKey < endNote; indexKey++) {

        if (IsWhiteKey(indexKey))

            keys++;

    }

    return keys;

}

BOOL CGPointInRect(CGPoint aPoint, CGRect aRect) {

    return aPoint.x >= aRect.origin.x &&

    aPoint.x < (aRect.origin.x + aRect.size.width) &&

    aPoint.y >= aRect.origin.y &&

    aPoint.y < (aRect.origin.y + aRect.size.height);

}

#pragma mark - CAUIKeyboardView implementation

@implementation CAUIKeyboardView

@synthesize whiteKeyWidth, whiteKeyHeight, blackKeyWidth, blackKeyHeight;

@synthesize noteDownColor;

@synthesize engine = _engine;

#pragma mark Initialization

- (void) initialize {

    _engine = NULL;

    whiteKeyHeight  = floorf(self.frame.size.height);

    whiteKeyWidth   = roundf(whiteKeyHeight * kWhiteKeyWidthRatio);

    blackKeyHeight  = roundf(whiteKeyHeight * kBlackKeyHeightRatio);

    blackKeyWidth   = roundf(whiteKeyHeight * kBlackKeyWidthRatio);

    dbKeyOffset     = roundf(whiteKeyHeight * kDbKeyOffsetRatio);

    ebKeyOffset     = roundf(whiteKeyHeight * kEbKeyOffsetRatio);

    gbKeyOffset     = roundf(whiteKeyHeight * kGbKeyOffsetRatio);

    abKeyOffset     = roundf(whiteKeyHeight * kAbKeyOffsetRatio);

    bbKeyOffset     = roundf(whiteKeyHeight * kBbKeyOffsetRatio);

    self.noteDownColor = [[UIColor redColor] colorWithAlphaComponent: .7];

    notesDown = [NSMutableSet setWithCapacity: 0];

}

- (id) initWithCoder:(NSCoder *) aDecoder {

    self = [super initWithCoder: aDecoder];

    if (self) 

        [self initialize];

    return self;

}

#pragma mark Utility methods

- (NSInteger) offsetForBlackKey:(NSInteger) note {

    NoteIdentifier identifier = IdentifierForNote(note);

    switch (identifier) {

        case Db:

            return dbKeyOffset;

        case Eb:

            return ebKeyOffset;

        case Gb:

            return gbKeyOffset;

        case Ab:

            return abKeyOffset;

        case Bb:

            return bbKeyOffset;

        default:

            return 0;

    }

}

- (CGRect) noteRectForNote:(NSInteger) note inRect:(CGRect) rect {

    // starting with the starting note, calculate the rect that the note to be drawn is in

    // if the starting note is a sharp, we need to get the previous white key

    // if the starting note is a white key, we can calculate the location of the new note

    CGRect firstNoteRect = CGRectZero;

    CGRect firstWhiteNoteRect = CGRectZero;

    BOOL startingNoteSharp = IsNoteSharp(displayKeyStart);

    firstWhiteNoteRect = CGRectMake(rect.origin.x, rect.origin.y, self.whiteKeyWidth, self.whiteKeyHeight);

    if (startingNoteSharp) {

        firstNoteRect = CGRectMake(rect.origin.x, rect.origin.y, self.blackKeyWidth, self.blackKeyHeight);

        // we need to calculate the starting location of the previous white key

        NSInteger offset = [self offsetForBlackKey: note];

        firstWhiteNoteRect.origin.x -= offset;

    }

    else

        firstNoteRect = firstWhiteNoteRect;

    if (displayKeyStart == note)

        return firstNoteRect;

    // calculate distance in white keys between note and displayKeyStart

    NSInteger whiteInterval = NumWhiteKeysBetweenNotes(displayKeyStart, note) * self.whiteKeyWidth;

    NSInteger lastWhiteStart = firstWhiteNoteRect.origin.x + whiteInterval;

    BOOL endingNoteSharp = IsNoteSharp(note);

    if (!endingNoteSharp)

        return CGRectMake(lastWhiteStart+self.whiteKeyWidth, rect.origin.y, self.whiteKeyWidth, self.whiteKeyHeight);

    else

        return CGRectMake(lastWhiteStart+ [self offsetForBlackKey:note], rect.origin.y, self.blackKeyWidth, self.blackKeyHeight);

}

- (CGFloat) leftEdgeOfNote:(NSInteger) note {

    CGRect rect = [self noteRectForNote: note inRect: self.bounds];

    return rect.origin.x;

}

- (CGFloat) rightEdgeOfNote:(NSInteger) note {

    CGRect rect = [self noteRectForNote: note inRect: self.bounds];

    return rect.origin.x + rect.size.width;

}

- (NSInteger) displayKeyStart {

    return displayKeyStart;

}

- (void) setDisplayKeyStart:(NSInteger) note {

    if (note >= 0 && note < 128 && note != displayKeyStart) {

        displayKeyStart = note;

        [self prepareBackground];

        [self setNeedsDisplay];

    }

}

- (NSInteger) noteAtPoint: (CGPoint) point {

    // check to see which white key we are in

    CGRect firstWhiteNoteRect = CGRectZero;

    BOOL startingNoteSharp = IsNoteSharp(displayKeyStart);

    firstWhiteNoteRect = CGRectMake(self.bounds.origin.x, self.bounds.origin.y, whiteKeyWidth, whiteKeyHeight);

    if (startingNoteSharp) {

        // we need to calculate the starting location of the previous white key

        NSInteger offset = [self offsetForBlackKey: displayKeyStart];

        firstWhiteNoteRect.origin.x -= offset;

    }

    NSInteger whiteNoteNumber = (point.x - firstWhiteNoteRect.origin.x)/whiteKeyWidth;

    NSInteger noteNumber = displayKeyStart + (((float)whiteNoteNumber/7) * 12);

    if (IsNoteSharp(noteNumber))

        noteNumber++;

    if (point.y <= blackKeyHeight) {    // we could be on a black key, so we need to check the black keys surrounding the white key

        // if we are not on a c or and f, check the previous flat

        BOOL foundFlat = NO;

        NoteIdentifier identifier = IdentifierForNote(noteNumber);

        if (identifier != C && identifier != F) {

            if (CGPointInRect(point, [self noteRectForNote:noteNumber-1 inRect:self.bounds])) {

                noteNumber--;

                foundFlat = YES;

            }

        }

        // check the next flat

        if (!foundFlat && CGPointInRect(point, [self noteRectForNote:noteNumber+1 inRect:self.bounds]))

            noteNumber++;

    }

    return noteNumber;

}

#pragma mark Drawing methods

- (UIBezierPath *) bezierPathForNote: (NSInteger) note {

    if (note < 0 || note > 127)

        return nil;

    if (!IsWhiteKey(note))

        return [UIBezierPath bezierPathWithRect: [self noteRectForNote: note inRect: self.bounds]];

    else {

        UIBezierPath *path = [UIBezierPath bezierPath];

        CGFloat edge;

        if (note == 0 || IsWhiteKey(note-1)) { // special case the very first note

            edge = [self leftEdgeOfNote: note] + 1;

            // if the previous key is a white key, then the left edge is the same as the edge of the note

            [path moveToPoint: CGPointMake(edge, whiteKeyHeight-1)];

            [path addLineToPoint: CGPointMake(edge + whiteKeyWidth-1, whiteKeyHeight-1)];

            [path addLineToPoint: CGPointMake(edge + whiteKeyWidth-1, blackKeyHeight)];

            edge = [self leftEdgeOfNote: note+1];

            [path addLineToPoint: CGPointMake(edge, blackKeyHeight)];

            [path addLineToPoint: CGPointMake(edge, 1)];

            edge = [self leftEdgeOfNote: note] + 1;

        } else {

            edge = [self rightEdgeOfNote: note-1];

            [path moveToPoint: CGPointMake(edge, 1)];

            [path addLineToPoint: CGPointMake(edge, blackKeyHeight)];

            edge = [self leftEdgeOfNote: note];

            [path addLineToPoint: CGPointMake(edge, blackKeyHeight)];

            [path addLineToPoint: CGPointMake(edge, whiteKeyHeight-1)];

            [path addLineToPoint: CGPointMake(edge + whiteKeyWidth-1, whiteKeyHeight-1)];

            // if the next key is a white key, then the right edge is the same as the edge of the note

            if (note == 127 || IsWhiteKey(note+1)) {

                edge = [self rightEdgeOfNote: note]-1;

                [path addLineToPoint: CGPointMake(edge, 1)];

            } else {

                [path addLineToPoint: CGPointMake(edge+ whiteKeyWidth-1, blackKeyHeight)];

                edge = [self leftEdgeOfNote: note+1];

                [path addLineToPoint: CGPointMake(edge, blackKeyHeight)];

            }

        }

        [path addLineToPoint: CGPointMake(edge, 1)];

        [path closePath];

        return path;

    }

    return nil;

}

- (void) drawRect:(CGRect) rect {

    [super drawRect: rect];

    CGRect myFrame = self.bounds;

    // prepares the image cache of the keyboard

    if (!imageCache)

        [self prepareBackground];

    [imageCache drawInRect: myFrame];

    [noteDownColor set];

    for (NSNumber *noteDown in notesDown) {

        NSInteger note = [noteDown integerValue];

        if (IsNoteSharp(note))

            UIRectFill([self noteRectForNote: note inRect: self.bounds]);

        else {

            UIBezierPath *path = [self bezierPathForNote: note];

            if (path)

                [path fill];

        }

    }

}

/* We draw the keyboard into a cache for performance reasons so that our draw rect only has to draw the notes that are currently pressed */

- (void) prepareBackground {

    UIGraphicsBeginImageContext(self.bounds.size);

    CGContextRef ctx = UIGraphicsGetCurrentContext();

    displayKeyEnd = 127;

    CGContextSetFillColorWithColor(ctx, [UIColor whiteColor].CGColor);

    CGContextFillRect(ctx, self.bounds);

    CGContextSetFillColorWithColor(ctx, [UIColor blackColor].CGColor);

    CGContextStrokeRect(ctx, self.bounds);

    CGRect noteRect = CGRectZero;

    NSInteger keyIndex, startKey = displayKeyStart;

    if (startKey > 0 == !IsWhiteKey(startKey-1))

        startKey--;

    for (keyIndex = startKey; keyIndex < 128; keyIndex++) {

        if ([notesDown containsObject: @(keyIndex)])

            continue;

        noteRect = [self noteRectForNote: keyIndex inRect: self.bounds];

        if (noteRect.origin.x > self.frame.origin.x + self.frame.size.width) {

            displayKeyEnd = keyIndex-1;

            break;

        }

        if (IsNoteSharp(keyIndex))

            CGContextFillRect(ctx, noteRect);

        else {

            CGContextStrokeRect(ctx, noteRect);

            // draw the note label if this is a C

            NoteIdentifier identifier = IdentifierForNote(keyIndex);

            if (identifier == C) {

                if (!labelAttributes) {

                    UIFont *font = [UIFont systemFontOfSize: 12];

                    NSMutableParagraphStyle *paraStyle = [NSMutableParagraphStyle new];

                    paraStyle.alignment = NSTextAlignmentCenter;

                    labelAttributes = [[NSDictionary alloc] initWithObjectsAndKeys: font, NSFontAttributeName,

                                       paraStyle, NSParagraphStyleAttributeName,

                                       [UIColor grayColor], NSForegroundColorAttributeName, nil];

                }

                NSAttributedString *label = [[NSAttributedString alloc]initWithString:[NSString stringWithFormat: @"C%d", (int)(keyIndex / 12) - 1] attributes: labelAttributes];

                [label drawInRect: CGRectMake(noteRect.origin.x + 1, noteRect.origin.y + self.whiteKeyHeight - 16, noteRect.size.width -2, 12)];

            }

            [[UIColor blackColor] set];

        }

    }

    if (noteRect.origin.x + noteRect.size.width < self.bounds.size.width) {

        CGContextSetFillColorWithColor(ctx, [UIColor darkGrayColor].CGColor);

        CGFloat rightEdge = noteRect.origin.x + noteRect.size.width;

        CGContextFillRect(ctx, CGRectMake(rightEdge, 0, self.bounds.size.width - rightEdge, self.bounds.size.height));

    }

    imageCache = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    [self setNeedsDisplay];

}

#pragma mark Event handling

- (OSStatus) playNote:(UInt32) note velocity: (UInt32) velocity {

    const UInt32 noteOnCommand = kMidiMessage_NoteOn << 4 | 0;

    OSStatus result =  -1;

    if (self.engine){

        AudioUnit au = [self.engine getAudioUnitInstrument];

        result = MusicDeviceMIDIEvent(au, noteOnCommand, note, 100, 0);

    }

    return result;

}

- (OSStatus) stopNote:(UInt32) note {

    const UInt32 noteOffCommand = kMidiMessage_NoteOff << 4 | 0;

    OSStatus result =  -1;

    if (self.engine)

        result = MusicDeviceMIDIEvent([self.engine getAudioUnitInstrument], noteOffCommand, note, 100, 0);

    return result;

}

- (OSStatus) stopAllNotes {

    const UInt32 allNotesOffCommand = kMidiController_AllNotesOff << 4 | 0;

    OSStatus result =  -1;

    if (self.engine)

        result = MusicDeviceMIDIEvent([self.engine getAudioUnitInstrument], allNotesOffCommand, 0, 0, 0);

    return result;

}

- (void) touchesBegan:(NSSet *) touches withEvent:(UIEvent *) event {

    for (UITouch *touch in touches) {

        CGPoint loc = [touch locationInView: self];

        NSNumber * note = @([self noteAtPoint: loc]);

        if (![notesDown containsObject: note])

            [notesDown addObject: note];

        CGRect noteRect = [self noteRectForNote:[note intValue] inRect:self.bounds];

        // generate a 1 to 127 value based on the vertical position of the tap

        NSInteger margin = 6;

        Float32 velocity = 127;

        CGFloat adjustedPoint = loc.y - noteRect.origin.y;

        if (adjustedPoint > noteRect.size.height - margin)

            velocity = 127;

        else if (adjustedPoint > margin) {

            velocity = (adjustedPoint - margin) / (noteRect.size.height - margin * 2);

            velocity = velocity * 127;

        }

        [self playNote: [note unsignedIntValue] velocity: velocity];

    }

    [self setNeedsDisplay];

}

- (void) touchesMoved:(NSSet *) touches withEvent:(UIEvent *) event {

    for (UITouch *touch in touches) {

        CGPoint previousLoc = [touch previousLocationInView: self];

        CGPoint currentLoc  = [touch locationInView: self];

        BOOL previousInView = CGPointInRect(previousLoc, self.bounds);

        BOOL currentInView  = CGPointInRect(currentLoc, self.bounds);

        NSInteger previousNote, currentNote;

        previousNote = previousInView ? [self noteAtPoint: previousLoc] : -1;

        currentNote  = currentInView  ? [self noteAtPoint: currentLoc]  : -1;

        // if the previous and current note match, don't do anything

        // otherwise, if the note has changed, end previous note, and start new note

        if (previousNote != currentNote) {

            if (previousNote > -1) {

                [notesDown removeObject: @(previousNote)];

                // end the note

                OSStatus result = [self stopNote: (UInt32)previousNote];

                if (result != noErr)

                    NSLog(@"Error stopping note %ld: %d", (long)previousNote, (int)result);

            }

            if (currentNote >= -1) {

                if (![notesDown containsObject: @(currentNote)])

                    [notesDown addObject: @(currentNote)];

                // start the new note

                OSStatus result = [self playNote: (UInt32)currentNote velocity: 100];

                if (result != noErr)

                    NSLog(@"Error playing note %ld: %d", (long)currentNote, (int)result);

            }

        }

    }

    [self setNeedsDisplay];

}

- (void) touchesEnded:(NSSet *) touches withEvent:(UIEvent *) event {

    for (UITouch *touch in touches) {

        CGPoint currentLoc  = [touch locationInView: self];

        CGPoint previousLoc = [touch previousLocationInView:self];

        NSNumber *note = @([self noteAtPoint: currentLoc]);

        NSNumber *prevNote = @([self noteAtPoint: previousLoc]);

        if ([notesDown containsObject: note]) {

            [notesDown removeObject: note];

        } else  if ([notesDown containsObject: prevNote]){

            [notesDown removeObject: prevNote];

            note = prevNote;

        }

        // end the note

        OSStatus result = [self stopNote: [note unsignedIntValue]];

        if (result != noErr)

            NSLog(@"Error stopping note %lu: %d", [note unsignedLongValue], (int)result);

    }

    [self setNeedsDisplay];

}

- (void) touchesCancelled:(NSSet *) touches withEvent:(UIEvent *) event {

    [notesDown removeAllObjects];

    [self setNeedsDisplay];

    // end all playing notes

    OSStatus result = [self stopAllNotes];

    if (result != noErr)

        NSLog(@"Error stopping all notes: %d", (int)result);

}

@end