//
//  FKPhotoClipView.m
//  FirstLink
//
//  Created by ascii on 16/6/13.
//  Copyright © 2016年 FirstLink. All rights reserved.
//

#import "FKPhotoClipView.h"

@implementation FKPhotoClipGridView

- (id)init {
    self = [super init];
    if (self) {
        [self configInitData];
        
        self.layer.borderWidth = self.width;
        self.layer.borderColor = self.color.CGColor;
    }
    return self;
}

- (id)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        [self configInitData];
    }
    return self;
}

- (void)configInitData {
    self.color  = [UIColor whiteColor];
    self.width  = 1;
    self.row    = 2;
    self.column = 2;
}

- (void)drawRect:(CGRect)rect {
    [super drawRect:rect];
    
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    CGContextSetStrokeColorWithColor(context, self.color.CGColor);
    CGContextSetLineWidth(context, self.width);
    
    // draw row line
    int distance = (int)(CGRectGetHeight(self.frame)/((float)(self.row + 1)));
    for (int idx = 0; idx < self.row; idx++) {
        CGContextMoveToPoint(context, 0.0f, distance*(idx+1));
        CGContextAddLineToPoint(context, CGRectGetWidth(self.frame), distance*(idx+1));
    }
    
    // draw column line
    distance = (int)(CGRectGetWidth(self.frame)/((float)(self.column + 1)));
    for (int idx = 0; idx < self.column; idx++) {
        CGContextMoveToPoint(context, distance*(idx+1), 0.0f);
        CGContextAddLineToPoint(context, distance*(idx+1), CGRectGetHeight(self.frame));
    }
    
    CGContextStrokePath(context);
}

@end


#pragma mark - FKPhotoClipView


@interface FKPhotoClipView ()

@property (nonatomic, strong) UIImage             *sourceImage;

@property (nonatomic, strong) UIScrollView        *scrollView;
@property (nonatomic, strong) UIImageView         *imageView;
@property (nonatomic, strong) FKPhotoClipGridView *gridView;

@end

@implementation FKPhotoClipView

/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    // Drawing code
}
*/

- (instancetype)initWithImage:(UIImage *)image {
    self = [super init];
    if (self) {
        [self setImage:image];
        
        self.clipsToBounds = YES;
        [self addSubview:self.scrollView];
        [self.scrollView addSubview:self.imageView];
        [self addSubview:self.gridView];
    }
    return self;
}

- (void)setImage:(UIImage *)image {
    _sourceImage = [image copy];
    self.imageView.image = _sourceImage;
}

- (UIImage *)getClipImage {
    CGRect rectInImageView = CGRectMake(self.scrollView.contentOffset.x
                                        , self.scrollView.contentOffset.y
                                        , CGRectGetWidth(self.gridView.frame)
                                        , CGRectGetHeight(self.gridView.frame));
    CGFloat scale          = CGRectGetWidth(self.imageView.frame)/self.sourceImage.size.width;
    CGRect rectInImage     = CGRectMake((int)(CGRectGetMinX(rectInImageView)/scale)
                                    , (int)(CGRectGetMinY(rectInImageView)/scale)
                                    , (int)(CGRectGetWidth(rectInImageView)/scale)
                                    , (int)(CGRectGetHeight(rectInImageView)/scale));
    
    CGImageRef suourceImageRef = CGImageCreateWithImageInRect(self.sourceImage.CGImage, rectInImage);
    CGRect subBounds = CGRectMake(0, 0, CGImageGetWidth(suourceImageRef), CGImageGetHeight(suourceImageRef));
    
    UIGraphicsBeginImageContext(subBounds.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextDrawImage(context, subBounds, suourceImageRef);
    UIImage* subImage = [UIImage imageWithCGImage:suourceImageRef];
    UIGraphicsEndImageContext();
    
    return subImage;
}

- (void)drawRect:(CGRect)rect {
    [super drawRect:rect];
    
    if (self.sourceImage) {
        self.gridView.frame         = self.bounds;
        self.scrollView.frame       = self.bounds;
        
        [self setVisableViewContentSize:[self minVisableViewSize]];
        [self setVisableViewCenterAnimated:NO];
    }
}

#pragma mark - Method

- (CGSize)minVisableViewSize {
    CGFloat length  = CGRectGetWidth(self.frame);
    CGFloat width   = self.sourceImage.size.width;
    CGFloat height  = self.sourceImage.size.height;
    CGFloat minSide = MIN(width, height);
    
    return CGSizeMake(ceilf(width*length/minSide), ceilf(height*length/minSide));
}

- (void)setVisableViewContentSize:(CGSize)size {
    // +1是为了保证scrollView可滑动
    self.scrollView.contentSize = size;
    self.imageView.frame        = CGRectMake(0, 0, size.width + 1, size.height + 1);
}

- (void)scaleVisableViewToMinSize:(CGSize)size {
    CGSize minSize = [self minVisableViewSize];
    if (size.width < minSize.width || size.height < minSize.height) {
        __weak FKPhotoClipView *weakSelf = self;
        [UIView animateWithDuration:0.3
                         animations:^
         {
             // +1是为了保证scrollView可滑动
             weakSelf.scrollView.contentSize = minSize;
             weakSelf.imageView.frame        = CGRectMake(0, 0, minSize.width + 1, minSize.height + 1);
         } completion:^(BOOL finished)
         {
             [weakSelf setVisableViewCenterAnimated:NO];
         }];
    }
}

- (void)setVisableViewCenterAnimated:(BOOL)animated {
    CGFloat centerOffsetX = (self.scrollView.contentSize.width/2) - (self.scrollView.bounds.size.width/2);
    CGFloat centerOffsetY = (self.scrollView.contentSize.height/2) - (self.scrollView.bounds.size.width/2);
    [self.scrollView setContentOffset:CGPointMake(centerOffsetX, centerOffsetY) animated:animated];
}

- (void)setVisableViewContentOffsetScale:(CGFloat)scale {
    CGFloat centerOffsetX = (self.scrollView.contentOffset.x*scale);
    CGFloat centerOffsetY = (self.scrollView.contentOffset.y*scale);
    [self.scrollView setContentOffset:CGPointMake(centerOffsetX, centerOffsetY) animated:NO];
}

#pragma mark - Action

- (void)pinchViewGesture:(UIPinchGestureRecognizer *)pinchGestureRecognizer {
    if (pinchGestureRecognizer.state == UIGestureRecognizerStateBegan || pinchGestureRecognizer.state == UIGestureRecognizerStateChanged || pinchGestureRecognizer.state == UIGestureRecognizerStateEnded) {
        UIView *view                 = self.imageView;
        CGFloat scale                = pinchGestureRecognizer.scale;
        view.transform               = CGAffineTransformScale(view.transform, scale, scale);
        pinchGestureRecognizer.scale = 1;
        
        if (pinchGestureRecognizer.state == UIGestureRecognizerStateEnded) {
            [self scaleVisableViewToMinSize:view.frame.size];
        } else {
            [self setVisableViewContentSize:view.frame.size];
            [self setVisableViewContentOffsetScale:scale];
        }
    }
}

#pragma mark - Property

- (UIScrollView *)scrollView{
    if (!_scrollView) {
        _scrollView                                = [[UIScrollView alloc] init];
        _scrollView.backgroundColor                = [UIColor blackColor];
        _scrollView.showsHorizontalScrollIndicator = NO;
        _scrollView.showsVerticalScrollIndicator   = NO;
    }
    return _scrollView;
}

- (UIImageView *)imageView {
    if (!_imageView) {
        _imageView = [UIImageView new];
        _imageView.userInteractionEnabled = YES;
        
        UIPinchGestureRecognizer *gesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchViewGesture:)];
        [_imageView addGestureRecognizer:gesture];
    }
    return _imageView;
}

- (FKPhotoClipGridView *)gridView {
    if (!_gridView) {
        _gridView = [FKPhotoClipGridView new];
        _gridView.userInteractionEnabled = NO;
        _gridView.backgroundColor = [UIColor colorWithWhite:0 alpha:0];
    }
    return _gridView;
}

@end