// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#import "components/cronet/ios/Cronet.h"

#include <memory>

#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/mac/bundle_locations.h"
#include "base/mac/scoped_block.h"
#include "base/memory/ptr_util.h"
#include "base/memory/scoped_vector.h"
#include "base/strings/sys_string_conversions.h"
#include "base/synchronization/lock.h"
#include "components/cronet/ios/cronet_environment.h"
#include "components/cronet/url_request_context_config.h"
#include "ios/net/crn_http_protocol_handler.h"
#include "ios/net/empty_nsurlcache.h"
#include "net/cert/cert_verifier.h"
#include "net/url_request/url_request_context_getter.h"

namespace {

class CronetHttpProtocolHandlerDelegate;

// Currently there is one and only one instance of CronetEnvironment,
// which is leaked at the shutdown. We should consider allowing multiple
// instances if that makes sense in the future.
base::LazyInstance<std::unique_ptr<cronet::CronetEnvironment>>::Leaky
    gChromeNet = LAZY_INSTANCE_INITIALIZER;

BOOL gHttp2Enabled = YES;
BOOL gQuicEnabled = NO;
cronet::URLRequestContextConfig::HttpCacheType gHttpCache =
    cronet::URLRequestContextConfig::HttpCacheType::DISK;
ScopedVector<cronet::URLRequestContextConfig::QuicHint> gQuicHints;
NSString* gUserAgent = nil;
BOOL gUserAgentPartial = NO;
NSString* gSslKeyLogFileName = nil;
RequestFilterBlock gRequestFilterBlock = nil;
std::unique_ptr<CronetHttpProtocolHandlerDelegate> gHttpProtocolHandlerDelegate;
NSURLCache* gPreservedSharedURLCache = nil;
BOOL gEnableTestCertVerifierForTesting = FALSE;

// CertVerifier, which allows any certificates for testing.
class TestCertVerifier : public net::CertVerifier {
  int Verify(const RequestParams& params,
             net::CRLSet* crl_set,
             net::CertVerifyResult* verify_result,
             const net::CompletionCallback& callback,
             std::unique_ptr<Request>* out_req,
             const net::NetLogWithSource& net_log) override {
    net::Error result = net::OK;
    verify_result->verified_cert = params.certificate();
    verify_result->cert_status = net::MapNetErrorToCertStatus(result);
    return result;
  }
};

// net::HTTPProtocolHandlerDelegate for Cronet.
class CronetHttpProtocolHandlerDelegate
    : public net::HTTPProtocolHandlerDelegate {
 public:
  CronetHttpProtocolHandlerDelegate(net::URLRequestContextGetter* getter,
                                    RequestFilterBlock filter)
      : getter_(getter), filter_(filter, base::scoped_policy::RETAIN) {}

  void SetRequestFilterBlock(RequestFilterBlock filter) {
    base::AutoLock auto_lock(lock_);
    filter_.reset(filter, base::scoped_policy::RETAIN);
  }

 private:
  // net::HTTPProtocolHandlerDelegate implementation:
  bool CanHandleRequest(NSURLRequest* request) override {
    base::AutoLock auto_lock(lock_);
    if (filter_) {
      RequestFilterBlock block = filter_.get();
      return block(request);
    }
    return true;
  }

  bool IsRequestSupported(NSURLRequest* request) override {
    NSString* scheme = [[request URL] scheme];
    if (!scheme)
      return false;
    return [scheme caseInsensitiveCompare:@"data"] == NSOrderedSame ||
           [scheme caseInsensitiveCompare:@"http"] == NSOrderedSame ||
           [scheme caseInsensitiveCompare:@"https"] == NSOrderedSame;
  }

  net::URLRequestContextGetter* GetDefaultURLRequestContext() override {
    return getter_.get();
  }

  scoped_refptr<net::URLRequestContextGetter> getter_;
  base::mac::ScopedBlock<RequestFilterBlock> filter_;
  base::Lock lock_;
};

}  // namespace

@implementation Cronet

+ (void)configureCronetEnvironmentForTesting:
    (cronet::CronetEnvironment*)cronetEnvironment {
  if (gEnableTestCertVerifierForTesting) {
    std::unique_ptr<TestCertVerifier> test_cert_verifier =
        base::MakeUnique<TestCertVerifier>();
    cronetEnvironment->set_mock_cert_verifier(std::move(test_cert_verifier));
  }
}

+ (NSString*)getAcceptLanguages {
  // Use the framework bundle to search for resources.
  NSBundle* frameworkBundle = [NSBundle bundleForClass:self];
  NSString* bundlePath =
      [frameworkBundle pathForResource:@"cronet_resources" ofType:@"bundle"];
  NSBundle* bundle = [NSBundle bundleWithPath:bundlePath];
  NSString* acceptLanguages = NSLocalizedStringWithDefaultValue(
      @"IDS_ACCEPT_LANGUAGES", @"Localizable", bundle, @"en-US,en",
      @"These values are copied from Chrome's .xtb files, so the same "
       "values are used in the |Accept-Language| header. Key name matches "
       "Chrome's.");
  if (acceptLanguages == Nil)
    acceptLanguages = @"";
  return acceptLanguages;
}

+ (void)checkNotStarted {
  CHECK(gChromeNet == NULL) << "Cronet is already started.";
}

+ (void)setHttp2Enabled:(BOOL)http2Enabled {
  [self checkNotStarted];
  gHttp2Enabled = http2Enabled;
}

+ (void)setQuicEnabled:(BOOL)quicEnabled {
  [self checkNotStarted];
  gQuicEnabled = quicEnabled;
}

+ (void)addQuicHint:(NSString*)host port:(int)port altPort:(int)altPort {
  [self checkNotStarted];
  gQuicHints.push_back(new cronet::URLRequestContextConfig::QuicHint(
      base::SysNSStringToUTF8(host), port, altPort));
}

+ (void)setUserAgent:(NSString*)userAgent partial:(BOOL)partial {
  [self checkNotStarted];
  gUserAgent = userAgent;
  gUserAgentPartial = partial;
}

+ (void)setSslKeyLogFileName:(NSString*)sslKeyLogFileName {
  [self checkNotStarted];
  gSslKeyLogFileName = sslKeyLogFileName;
}

+ (void)setHttpCacheType:(HttpCacheType)httpCacheType {
  [self checkNotStarted];
  switch (httpCacheType) {
    case DISABLED:
      gHttpCache = cronet::URLRequestContextConfig::HttpCacheType::DISABLED;
      break;
    case DISK:
      gHttpCache = cronet::URLRequestContextConfig::HttpCacheType::DISK;
      break;
    case MEMORY:
      gHttpCache = cronet::URLRequestContextConfig::HttpCacheType::MEMORY;
      break;
    default:
      DCHECK(NO) << "Invalid HTTP cache type: " << httpCacheType;
  }
}

+ (void)setRequestFilterBlock:(RequestFilterBlock)block {
  if (gHttpProtocolHandlerDelegate.get())
    gHttpProtocolHandlerDelegate.get()->SetRequestFilterBlock(block);
  else
    gRequestFilterBlock = block;
}

+ (void)startInternal {
  cronet::CronetEnvironment::Initialize();
  std::string user_agent = base::SysNSStringToUTF8(gUserAgent);
  gChromeNet.Get().reset(
      new cronet::CronetEnvironment(user_agent, gUserAgentPartial));
  gChromeNet.Get()->set_accept_language(
      base::SysNSStringToUTF8([self getAcceptLanguages]));

  gChromeNet.Get()->set_http2_enabled(gHttp2Enabled);
  gChromeNet.Get()->set_quic_enabled(gQuicEnabled);
  gChromeNet.Get()->set_http_cache(gHttpCache);
  gChromeNet.Get()->set_ssl_key_log_file_name(
      base::SysNSStringToUTF8(gSslKeyLogFileName));
  for (const auto* quicHint : gQuicHints) {
    gChromeNet.Get()->AddQuicHint(quicHint->host, quicHint->port,
                                  quicHint->alternate_port);
  }

  [self configureCronetEnvironmentForTesting:gChromeNet.Get().get()];
  gChromeNet.Get()->Start();
  gHttpProtocolHandlerDelegate.reset(new CronetHttpProtocolHandlerDelegate(
      gChromeNet.Get()->GetURLRequestContextGetter(), gRequestFilterBlock));
  net::HTTPProtocolHandlerDelegate::SetInstance(
      gHttpProtocolHandlerDelegate.get());
  gRequestFilterBlock = nil;
}

+ (void)start {
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    if (![NSThread isMainThread]) {
      dispatch_sync(dispatch_get_main_queue(), ^(void) {
        [self startInternal];
      });
    } else {
      [self startInternal];
    }
  });
}

+ (void)registerHttpProtocolHandler {
  if (gPreservedSharedURLCache == nil) {
    gPreservedSharedURLCache = [NSURLCache sharedURLCache];
  }
  // Disable the default cache.
  [NSURLCache setSharedURLCache:[EmptyNSURLCache emptyNSURLCache]];
  // Register the chrome http protocol handler to replace the default one.
  BOOL success =
      [NSURLProtocol registerClass:[CRNPauseableHTTPProtocolHandler class]];
  DCHECK(success);
}

+ (void)unregisterHttpProtocolHandler {
  // Set up SharedURLCache preserved in registerHttpProtocolHandler.
  if (gPreservedSharedURLCache != nil) {
    [NSURLCache setSharedURLCache:gPreservedSharedURLCache];
    gPreservedSharedURLCache = nil;
  }
  [NSURLProtocol unregisterClass:[CRNPauseableHTTPProtocolHandler class]];
}

+ (void)installIntoSessionConfiguration:(NSURLSessionConfiguration*)config {
  config.protocolClasses = @[ [CRNPauseableHTTPProtocolHandler class] ];
}

+ (NSString*)getNetLogPathForFile:(NSString*)fileName {
  return [[[[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory
                                                   inDomains:NSUserDomainMask]
      lastObject] URLByAppendingPathComponent:fileName] path];
}

+ (BOOL)startNetLogToFile:(NSString*)fileName logBytes:(BOOL)logBytes {
  if (gChromeNet.Get().get() && [fileName length] &&
      ![fileName isAbsolutePath]) {
    return gChromeNet.Get()->StartNetLog(
        base::SysNSStringToUTF8([self getNetLogPathForFile:fileName]),
        logBytes);
  }

  return NO;
}

+ (void)stopNetLog {
  if (gChromeNet.Get().get()) {
    gChromeNet.Get()->StopNetLog();
  }
}

+ (NSString*)getUserAgent {
  if (!gChromeNet.Get().get()) {
    return nil;
  }

  return [NSString stringWithCString:gChromeNet.Get()->user_agent().c_str()
                            encoding:[NSString defaultCStringEncoding]];
}

+ (stream_engine*)getGlobalEngine {
  DCHECK(gChromeNet.Get().get());
  if (gChromeNet.Get().get()) {
    static stream_engine engine;
    engine.obj = gChromeNet.Get()->GetURLRequestContextGetter();
    return &engine;
  }
  return nil;
}

+ (NSData*)getGlobalMetricsDeltas {
  if (!gChromeNet.Get().get()) {
    return nil;
  }
  std::vector<uint8_t> deltas(gChromeNet.Get()->GetHistogramDeltas());
  return [NSData dataWithBytes:deltas.data() length:deltas.size()];
}

+ (void)enableTestCertVerifierForTesting {
  gEnableTestCertVerifierForTesting = YES;
}

+ (void)setHostResolverRulesForTesting:(NSString*)hostResolverRulesForTesting {
  DCHECK(gChromeNet.Get().get());
  gChromeNet.Get()->SetHostResolverRules(
      base::SysNSStringToUTF8(hostResolverRulesForTesting));
}

// This is a non-public dummy method that prevents the linker from stripping out
// the otherwise non-referenced methods from 'bidirectional_stream.cc'.
+ (void)preventStrippingCronetBidirectionalStream {
  bidirectional_stream_create(NULL, 0, 0);
}

@end