/**
 * 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 "RCTDefines.h"

#if RCT_DEV

#import <dlfcn.h>

#import <mach/mach.h>

#import "RCTBridge.h"
#import "RCTDevMenu.h"
#import "RCTFPSGraph.h"
#import "RCTInvalidating.h"
#import "RCTJavaScriptExecutor.h"
#import "RCTRootView.h"
#import "RCTSparseArray.h"
#import "RCTUIManager.h"

static NSString *const RCTPerfMonitorKey = @"RCTPerfMonitorKey";

typedef BOOL (*RCTJSCSetOptionType)(const char *);

static BOOL RCTJSCSetOption(const char *option)
{
  static RCTJSCSetOptionType setOption;
  static dispatch_once_t onceToken;

  dispatch_once(&onceToken, ^{
    setOption = dlsym(RTLD_DEFAULT, "_ZN3JSC7Options9setOptionEPKc");
    setOption("logGC=1");
  });

  if (setOption) {
    return setOption(option);
  } else {
    return NO;
  }
}

static vm_size_t RCTGetResidentMemorySize(void)
{
  struct task_basic_info info;
  mach_msg_type_number_t size = sizeof(info);
  kern_return_t kerr = task_info(mach_task_self(),
                                 TASK_BASIC_INFO,
                                 (task_info_t)&info,
                                 &size);
  if (kerr != KERN_SUCCESS) {
    return 0;
  }

  return info.resident_size;
}

@class RCTDevMenuItem;

@interface RCTPerfMonitor : NSObject <RCTBridgeModule, RCTInvalidating>

@property (nonatomic, strong, readonly) RCTDevMenuItem *devMenuItem;
@property (nonatomic, strong, readonly) UIPanGestureRecognizer *gestureRecognizer;
@property (nonatomic, strong, readonly) UIView *container;
@property (nonatomic, strong, readonly) UILabel *memory;
@property (nonatomic, strong, readonly) UILabel *heap;
@property (nonatomic, strong, readonly) UILabel *views;
@property (nonatomic, strong, readonly) RCTFPSGraph *jsGraph;
@property (nonatomic, strong, readonly) RCTFPSGraph *uiGraph;
@property (nonatomic, strong, readonly) UILabel *jsGraphLabel;
@property (nonatomic, strong, readonly) UILabel *uiGraphLabel;

@end

@implementation RCTPerfMonitor {
  RCTDevMenuItem *_devMenuItem;
  UIPanGestureRecognizer *_gestureRecognizer;
  UIView *_container;
  UILabel *_memory;
  UILabel *_heap;
  UILabel *_views;
  UILabel *_uiGraphLabel;
  UILabel *_jsGraphLabel;

  RCTFPSGraph *_uiGraph;
  RCTFPSGraph *_jsGraph;

  CADisplayLink *_uiDisplayLink;
  CADisplayLink *_jsDisplayLink;

  NSUInteger _heapSize;

  dispatch_queue_t _queue;
  dispatch_io_t _io;
  int _stderr;
  int _pipe[2];
  NSString *_remaining;
}

@synthesize bridge = _bridge;

RCT_EXPORT_MODULE()

- (void)invalidate
{
  [self hide];
}

- (RCTDevMenuItem *)devMenuItem
{
  if (!_devMenuItem) {
    __weak __typeof__(self) weakSelf = self;
    _devMenuItem =
      [RCTDevMenuItem toggleItemWithKey:RCTPerfMonitorKey
                                  title:@"Show Monitor"
                          selectedTitle:@"Hide Monitor"
                                handler:
                                ^(BOOL selected) {
                                  if (selected) {
                                    [weakSelf show];
                                  } else {
                                    [weakSelf hide];
                                  }
                                }];
  }

  return _devMenuItem;
}

- (UIPanGestureRecognizer *)gestureRecognizer
{
  if (!_gestureRecognizer) {
    _gestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self
                                                                 action:@selector(gesture:)];
  }

  return _gestureRecognizer;
}

- (UIView *)container
{
  if (!_container) {
    _container = [[UIView alloc] initWithFrame:CGRectMake(10, 25, 180, 50)];
    _container.backgroundColor = UIColor.whiteColor;
    _container.layer.borderWidth = 2;
    _container.layer.borderColor = [UIColor grayColor].CGColor;
    [_container addGestureRecognizer:self.gestureRecognizer];
  }

  return _container;
}

- (UILabel *)memory
{
  if (!_memory) {
    _memory = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 44, 50)];
    _memory.font = [UIFont systemFontOfSize:12];
    _memory.numberOfLines = 3;
    _memory.textAlignment = NSTextAlignmentCenter;
  }

  return _memory;
}

- (UILabel *)heap
{
  if (!_heap) {
    _heap = [[UILabel alloc] initWithFrame:CGRectMake(44, 0, 44, 50)];
    _heap.font = [UIFont systemFontOfSize:12];
    _heap.numberOfLines = 3;
    _heap.textAlignment = NSTextAlignmentCenter;
  }

  return _heap;
}

- (UILabel *)views
{
  if (!_views) {
    _views = [[UILabel alloc] initWithFrame:CGRectMake(88, 0, 44, 50)];
    _views.font = [UIFont systemFontOfSize:12];
    _views.numberOfLines = 3;
    _views.textAlignment = NSTextAlignmentCenter;
  }

  return _views;
}

- (RCTFPSGraph *)uiGraph
{
  if (!_uiGraph) {
    _uiGraph = [[RCTFPSGraph alloc] initWithFrame:CGRectMake(134, 14, 40, 30)
                                            color:[UIColor lightGrayColor]];
  }
  return _uiGraph;
}

- (RCTFPSGraph *)jsGraph
{
  if (!_jsGraph) {
    _jsGraph = [[RCTFPSGraph alloc] initWithFrame:CGRectMake(178, 14, 40, 30)
                                            color:[UIColor lightGrayColor]];
  }
  return _jsGraph;
}

- (UILabel *)uiGraphLabel
{
  if (!_uiGraphLabel) {
    _uiGraphLabel = [[UILabel alloc] initWithFrame:CGRectMake(134, 3, 40, 10)];
    _uiGraphLabel.font = [UIFont systemFontOfSize:11];
    _uiGraphLabel.textAlignment = NSTextAlignmentCenter;
    _uiGraphLabel.text = @"UI";
  }

  return _uiGraphLabel;
}

- (UILabel *)jsGraphLabel
{
  if (!_jsGraphLabel) {
    _jsGraphLabel = [[UILabel alloc] initWithFrame:CGRectMake(178, 3, 38, 10)];
    _jsGraphLabel.font = [UIFont systemFontOfSize:11];
    _jsGraphLabel.textAlignment = NSTextAlignmentCenter;
    _jsGraphLabel.text = @"JS";
  }

  return _jsGraphLabel;
}

- (dispatch_queue_t)methodQueue
{
  return dispatch_get_main_queue();
}

- (void)setBridge:(RCTBridge *)bridge
{
  _bridge = bridge;

  [_bridge.devMenu addItem:self.devMenuItem];
}

- (void)show
{
  if (_container) {
    return;
  }

  [self.container addSubview:self.memory];
  [self.container addSubview:self.heap];
  [self.container addSubview:self.views];
  [self.container addSubview:self.uiGraph];
  [self.container addSubview:self.uiGraphLabel];

  [self redirectLogs];

  RCTJSCSetOption("logGC=1");

  [self updateStats];

  UIWindow *window = [UIApplication sharedApplication].delegate.window;
  [window addSubview:self.container];


  _uiDisplayLink = [CADisplayLink displayLinkWithTarget:self
                                               selector:@selector(threadUpdate:)];
  [_uiDisplayLink addToRunLoop:[NSRunLoop mainRunLoop]
                       forMode:NSRunLoopCommonModes];

  id<RCTJavaScriptExecutor> executor = [_bridge valueForKey:@"javaScriptExecutor"];
  if ([executor isKindOfClass:NSClassFromString(@"RCTContextExecutor")]) {
    self.container.frame = (CGRect) {
      self.container.frame.origin, {
        self.container.frame.size.width + 44,
        self.container.frame.size.height
      }
    };
    [self.container addSubview:self.jsGraph];
    [self.container addSubview:self.jsGraphLabel];
    [executor executeBlockOnJavaScriptQueue:^{
      _jsDisplayLink = [CADisplayLink displayLinkWithTarget:self
                                                   selector:@selector(threadUpdate:)];
      [_jsDisplayLink addToRunLoop:[NSRunLoop currentRunLoop]
                           forMode:NSRunLoopCommonModes];
    }];
  }
}

- (void)hide
{
  if (!_container) {
    return;
  }

  [self.container removeFromSuperview];
  _container = nil;
  _jsGraph = nil;
  _uiGraph = nil;

  RCTJSCSetOption("logGC=0");

  [self stopLogs];

  [_uiDisplayLink invalidate];
  [_jsDisplayLink invalidate];

  _uiDisplayLink = nil;
  _jsDisplayLink = nil;
}

- (void)redirectLogs
{
  _stderr = dup(STDERR_FILENO);

  if (pipe(_pipe) != 0) {
    return;
  }

  dup2(_pipe[1], STDERR_FILENO);
  close(_pipe[1]);

  __weak __typeof__(self) weakSelf = self;
  _queue = dispatch_queue_create("com.facebook.react.RCTPerfMonitor", DISPATCH_QUEUE_SERIAL);
  _io = dispatch_io_create(
    DISPATCH_IO_STREAM,
    _pipe[0],
    _queue,
    ^(__unused int error) {});

  dispatch_io_set_low_water(_io, 20);

  dispatch_io_read(
    _io,
    0,
    SIZE_MAX,
    _queue,
    ^(__unused bool done, dispatch_data_t data, __unused int error) {
      if (!data) {
        return;
    }

      dispatch_data_apply(
        data,
        ^bool(
          __unused dispatch_data_t region,
          __unused size_t offset,
          const void *buffer,
          size_t size
        ) {
          write(_stderr, buffer, size);

          NSString *log = [[NSString alloc] initWithBytes:buffer
                                                   length:size
                                                 encoding:NSUTF8StringEncoding];
          [weakSelf parse:log];
          return true;
        });
    });
}

- (void)stopLogs
{
  dup2(_stderr, STDERR_FILENO);
  dispatch_io_close(_io, 0);
}

- (void)parse:(NSString *)log
{
  static NSRegularExpression *GCRegex;
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    NSString *pattern = @"\\[GC: (Eden|Full)Collection, (?:Skipped copying|Did copy), ([\\d\\.]+) (\\wb), ([\\d.]+) (\\ws)\\]";
    GCRegex = [NSRegularExpression regularExpressionWithPattern:pattern
                                                        options:0
                                                          error:nil];
  });

  if (_remaining) {
    log = [_remaining stringByAppendingString:log];
    _remaining = nil;
  }

  NSArray *lines = [log componentsSeparatedByString:@"\n"];
  if (lines.count == 1) { // no newlines
    _remaining = log;
    return;
  }

  for (NSString *line in lines) {
    NSTextCheckingResult *match = [GCRegex firstMatchInString:line options:0 range:NSMakeRange(0, line.length)];
    if (match) {
      NSString *heapSizeStr = [line substringWithRange:[match rangeAtIndex:2]];
      _heapSize = [heapSizeStr integerValue];
    }
  }
}

- (void)updateStats
{
  RCTSparseArray *views = [_bridge.uiManager valueForKey:@"viewRegistry"];
  NSUInteger viewCount = views.count;
  NSUInteger visibleViewCount = 0;
  for (UIView *view in views.allObjects) {
    if (view.window || view.superview.window) {
      visibleViewCount++;
    }
  }

  double mem = (double)RCTGetResidentMemorySize() / 1024 / 1024;
  self.memory.text  =[NSString stringWithFormat:@"RAM\n%.2lf\nMB", mem];
  self.heap.text = [NSString stringWithFormat:@"JSC\n%.2lf\nMB", (double)_heapSize / 1024];
  self.views.text = [NSString stringWithFormat:@"Views\n%lu\n%lu", (unsigned long)visibleViewCount, (unsigned long)viewCount];

  __weak __typeof__(self) weakSelf = self;
  dispatch_after(
    dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)),
    dispatch_get_main_queue(),
    ^{
      __strong __typeof__(weakSelf) strongSelf = weakSelf;
      if (strongSelf && strongSelf->_container.superview) {
        [strongSelf updateStats];
      }
    });
}

- (void)gesture:(UIPanGestureRecognizer *)gestureRecognizer
{
  CGPoint translation = [gestureRecognizer translationInView:self.container.superview];
  self.container.center = CGPointMake(
    self.container.center.x + translation.x,
    self.container.center.y + translation.y
  );
  [gestureRecognizer setTranslation:CGPointMake(0, 0)
                             inView:self.container.superview];
}

- (void)threadUpdate:(CADisplayLink *)displayLink
{
  RCTFPSGraph *graph = displayLink == _jsDisplayLink ? _jsGraph : _uiGraph;
  [graph onTick:displayLink.timestamp];
}

@end

#endif