/**
 * 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 "RCTProfile.h"

#import <mach/mach.h>

#import <UIKit/UIKit.h>

#import "RCTAssert.h"
#import "RCTDefines.h"
#import "RCTUtils.h"

NSString *const RCTProfileDidStartProfiling = @"RCTProfileDidStartProfiling";
NSString *const RCTProfileDidEndProfiling = @"RCTProfileDidEndProfiling";

#if RCT_DEV

#pragma mark - Prototypes

NSNumber *RCTProfileTimestamp(NSTimeInterval);
NSString *RCTProfileMemory(vm_size_t);
NSDictionary *RCTProfileGetMemoryUsage(void);

#pragma mark - Constants

NSString const *RCTProfileTraceEvents = @"traceEvents";
NSString const *RCTProfileSamples = @"samples";

#pragma mark - Variables

NSDictionary *RCTProfileInfo;
NSUInteger RCTProfileEventID = 0;
NSMutableDictionary *RCTProfileOngoingEvents;
NSTimeInterval RCTProfileStartTime;
NSLock *_RCTProfileLock;

#pragma mark - Macros

#define RCTProfileAddEvent(type, props...) \
[RCTProfileInfo[type] addObject:@{ \
  @"pid": @([[NSProcessInfo processInfo] processIdentifier]), \
  @"tid": RCTCurrentThreadName(), \
  props \
}];

#define CHECK(...) \
if (!RCTProfileIsProfiling()) { \
  return __VA_ARGS__; \
}

#define RCTProfileLock(...) \
[_RCTProfileLock lock]; \
__VA_ARGS__ \
[_RCTProfileLock unlock]

#pragma mark - Private Helpers

NSNumber *RCTProfileTimestamp(NSTimeInterval timestamp)
{
  return @((timestamp - RCTProfileStartTime) * 1e6);
}

NSString *RCTProfileMemory(vm_size_t memory)
{
  double mem = ((double)memory) / 1024 / 1024;
  return [NSString stringWithFormat:@"%.2lfmb", mem];
}

NSDictionary *RCTProfileGetMemoryUsage(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 @{
      @"suspend_count": @(info.suspend_count),
      @"virtual_size": RCTProfileMemory(info.virtual_size),
      @"resident_size": RCTProfileMemory(info.resident_size),
    };
  } else {
    return @{};
  }
}

#pragma mark - Public Functions

BOOL RCTProfileIsProfiling(void)
{
  RCTProfileLock(
    BOOL profiling = RCTProfileInfo != nil;
  );
  return profiling;
}

void RCTProfileInit(void)
{
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    _RCTProfileLock = [[NSLock alloc] init];
  });
  RCTProfileLock(
    RCTProfileStartTime = CACurrentMediaTime();
    RCTProfileOngoingEvents = [[NSMutableDictionary alloc] init];
    RCTProfileInfo = @{
      RCTProfileTraceEvents: [[NSMutableArray alloc] init],
      RCTProfileSamples: [[NSMutableArray alloc] init],
    };
  );

  [[NSNotificationCenter defaultCenter] postNotificationName:RCTProfileDidStartProfiling
                                                      object:nil];
}

NSString *RCTProfileEnd(void)
{
  [[NSNotificationCenter defaultCenter] postNotificationName:RCTProfileDidEndProfiling
                                                      object:nil];

  RCTProfileLock(
    NSString *log = RCTJSONStringify(RCTProfileInfo, NULL);
    RCTProfileEventID = 0;
    RCTProfileInfo = nil;
    RCTProfileOngoingEvents = nil;
  );
  return log;
}

NSNumber *_RCTProfileBeginEvent(void)
{
  CHECK(@0);
  RCTProfileLock(
    NSNumber *eventID = @(++RCTProfileEventID);
    RCTProfileOngoingEvents[eventID] = RCTProfileTimestamp(CACurrentMediaTime());
  );
  return eventID;
}

void _RCTProfileEndEvent(NSNumber *eventID, NSString *name, NSString *categories, id args)
{
  CHECK();
  RCTProfileLock(
    NSNumber *startTimestamp = RCTProfileOngoingEvents[eventID];
    if (startTimestamp) {
      NSNumber *endTimestamp = RCTProfileTimestamp(CACurrentMediaTime());

      RCTProfileAddEvent(RCTProfileTraceEvents,
        @"name": name,
        @"cat": categories,
        @"ph": @"X",
        @"ts": startTimestamp,
        @"dur": @(endTimestamp.doubleValue - startTimestamp.doubleValue),
        @"args": args ?: @[],
      );
      [RCTProfileOngoingEvents removeObjectForKey:eventID];
    }
  );
}

void RCTProfileImmediateEvent(NSString *name, NSTimeInterval timestamp, NSString *scope)
{
  CHECK();
  RCTProfileLock(
    RCTProfileAddEvent(RCTProfileTraceEvents,
      @"name": name,
      @"ts": RCTProfileTimestamp(timestamp),
      @"scope": scope,
      @"ph": @"i",
      @"args": RCTProfileGetMemoryUsage(),
    );
  );
}

NSNumber *_RCTProfileBeginFlowEvent(void)
{
  static NSUInteger flowID = 0;

  CHECK(@0);
  RCTProfileAddEvent(RCTProfileTraceEvents,
    @"name": @"flow",
    @"id": @(++flowID),
    @"cat": @"flow",
    @"ph": @"s",
    @"ts": RCTProfileTimestamp(CACurrentMediaTime()),
  );

  return @(flowID);
}

void _RCTProfileEndFlowEvent(NSNumber *flowID)
{
  CHECK();
  RCTProfileAddEvent(RCTProfileTraceEvents,
    @"name": @"flow",
    @"id": flowID,
    @"cat": @"flow",
    @"ph": @"f",
    @"ts": RCTProfileTimestamp(CACurrentMediaTime()),
  );
}

#endif