/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

#import "RCTText.h"

#import "RCTShadowText.h"
#import "RCTUtils.h"
#import "UIView+React.h"

@implementation RCTText
{
  NSTextStorage *_textStorage;
  NSMutableArray *_reactSubviews;
}

- (instancetype)initWithFrame:(CGRect)frame
{
  if ((self = [super initWithFrame:frame])) {
    _textStorage = [[NSTextStorage alloc] init];
    _reactSubviews = [NSMutableArray array];

    self.isAccessibilityElement = YES;
    self.accessibilityTraits |= UIAccessibilityTraitStaticText;

    self.opaque = NO;
    self.contentMode = UIViewContentModeRedraw;
  }
  return self;
}

- (void)reactSetFrame:(CGRect)frame
{
  // Text looks super weird if its frame is animated.
  // This disables the frame animation, without affecting opacity, etc.
  [UIView performWithoutAnimation:^{
    [super reactSetFrame:frame];
  }];
}

- (void)insertReactSubview:(UIView *)subview atIndex:(NSInteger)atIndex
{
  [_reactSubviews insertObject:subview atIndex:atIndex];
}

- (void)removeReactSubview:(UIView *)subview
{
  [_reactSubviews removeObject:subview];
}

- (NSMutableArray *)reactSubviews
{
  return _reactSubviews;
}

- (void)setTextStorage:(NSTextStorage *)textStorage
{
  _textStorage = textStorage;
  [self setNeedsDisplay];
}

- (void)drawRect:(CGRect)rect
{
  NSLayoutManager *layoutManager = [_textStorage.layoutManagers firstObject];
  NSTextContainer *textContainer = [layoutManager.textContainers firstObject];
  CGRect textFrame = UIEdgeInsetsInsetRect(self.bounds, _contentInset);
  NSRange glyphRange = [layoutManager glyphRangeForTextContainer:textContainer];
  [layoutManager drawBackgroundForGlyphRange:glyphRange atPoint:textFrame.origin];
  [layoutManager drawGlyphsForGlyphRange:glyphRange atPoint:textFrame.origin];
}

- (NSNumber *)reactTagAtPoint:(CGPoint)point
{
  NSNumber *reactTag = self.reactTag;

  CGFloat fraction;
  NSLayoutManager *layoutManager = [_textStorage.layoutManagers firstObject];
  NSTextContainer *textContainer = [layoutManager.textContainers firstObject];
  NSUInteger characterIndex = [layoutManager characterIndexForPoint:point
                                                    inTextContainer:textContainer
                           fractionOfDistanceBetweenInsertionPoints:&fraction];

  // If the point is not before (fraction == 0.0) the first character and not
  // after (fraction == 1.0) the last character, then the attribute is valid.
  if (_textStorage.length > 0 && (fraction > 0 || characterIndex > 0) && (fraction < 1 || characterIndex < _textStorage.length - 1)) {
    reactTag = [_textStorage attribute:RCTReactTagAttributeName atIndex:characterIndex effectiveRange:NULL];
  }
  return reactTag;
}

#pragma mark - Accessibility

- (NSString *)accessibilityLabel
{
  return _textStorage.string;
}

@end