//
//  YH_H5URLProtocol.m
//  YH_Mall
//
//  Created by jhsonzhi on 16/4/13.
//  Copyright © 2016年 YOHO. All rights reserved.
//

#import "YH_H5URLProtocol.h"
#import "YH_HttpDNS.h"

static NSString * const URLProtocolHandledKey = @"URLProtocolHandledKey";

static NSObject *H5CachingSupportedSchemesMonitor;
static NSSet *H5CachingSupportedSchemes;

@interface YH_H5URLProtocol () <NSURLConnectionDataDelegate>
@property (nonatomic, readwrite, strong) NSURLConnection *connection;

@end

@implementation YH_H5URLProtocol

+ (void)initialize
{
    if (self == [YH_H5URLProtocol class])
    {
        static dispatch_once_t onceToken;
        dispatch_once(&onceToken, ^{
            H5CachingSupportedSchemesMonitor = [NSObject new];
        });
        
        [self setSupportedSchemes:[NSSet setWithArray:@[@"http",@"https"]]];
    }
}

+ (NSSet *)supportedSchemes {
    NSSet *supportedSchemes;
    @synchronized(H5CachingSupportedSchemesMonitor)
    {
        supportedSchemes = H5CachingSupportedSchemes;
    }
    return supportedSchemes;
}

+ (void)setSupportedSchemes:(NSSet *)supportedSchemes
{
    @synchronized(H5CachingSupportedSchemesMonitor)
    {
        H5CachingSupportedSchemes = supportedSchemes;
    }
}

+ (BOOL)canInitWithRequest:(NSURLRequest *)request
{
    if ([NSURLProtocol propertyForKey:URLProtocolHandledKey inRequest:request]) {
        return NO;
    }
    
    NSURL *requestURL = [request URL];
    if (![[self supportedSchemes] containsObject:[requestURL scheme]]) {
        return NO;
    }
    NSString * webViewType = [request valueForHTTPHeaderField:@"X-YH-Request-DNS-H5"];
    if ([webViewType hasSuffix:@"iOS"]){
        return  YES;
    }

    return NO;
}

+ (NSURLRequest *)canonicalRequestForRequest:(NSURLRequest *)request {
    
    return request;
}



- (void)startLoading
{
    NSMutableURLRequest * request = [self.request mutableCopy];
    // 表示该请求已经被处理，防止无限循环
    [NSURLProtocol setProperty:@(YES) forKey:URLProtocolHandledKey inRequest:request];
    NSLog(@">>>>>>>>loading URL:%@",request.URL.absoluteString);
    self.connection = [NSURLConnection connectionWithRequest:request delegate:self];
    
}

- (void)stopLoading
{
    [self.connection cancel];
    self.connection = nil;
}

#pragma mark - NSURLConnectionDelegate
- (BOOL)evaluateServerTrust:(SecTrustRef)serverTrust
                  forDomain:(NSString *)domain
{
    /*
     * 创建证书校验策略
     */
    NSMutableArray *policies = [NSMutableArray array];
    if (domain) {
        [policies addObject:(__bridge_transfer id)SecPolicyCreateSSL(true, (__bridge CFStringRef)domain)];
    } else {
        [policies addObject:(__bridge_transfer id)SecPolicyCreateBasicX509()];
    }
    
    /*
     * 绑定校验策略到服务端的证书上
     */
    SecTrustSetPolicies(serverTrust, (__bridge CFArrayRef)policies);
    
    
    /*
     * 评估当前serverTrust是否可信任，
     * 官方建议在result = kSecTrustResultUnspecified 或 kSecTrustResultProceed
     * 的情况下serverTrust可以被验证通过，https://developer.apple.com/library/ios/technotes/tn2232/_index.html
     * 关于SecTrustResultType的详细信息请参考SecTrust.h
     */
    SecTrustResultType result;
    SecTrustEvaluate(serverTrust, &result);
    
    return (result == kSecTrustResultUnspecified || result == kSecTrustResultProceed);
}

/*
 * NSURLConnection
 */
- (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{
    if (!challenge) {
        return;
    }
    
    /*
     * URL里面的host在使用HTTPDNS的情况下被设置成了IP，此处从HTTP Header中获取真实域名
     */
    NSString* host = [[self.request allHTTPHeaderFields] objectForKey:@"Host"];
    if (!host) {
        host = self.request.URL.host;
    }
    
    /*
     * 判断challenge的身份验证方法是否是NSURLAuthenticationMethodServerTrust（HTTPS模式下会进行该身份验证流程），
     * 在没有配置身份验证方法的情况下进行默认的网络请求流程。
     */
    if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust])
    {
        if ([self evaluateServerTrust:challenge.protectionSpace.serverTrust forDomain:host]) {
            /*
             * 验证完以后，需要构造一个NSURLCredential发送给发起方
             */
            NSURLCredential *credential = [NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust];
            [[challenge sender] useCredential:credential forAuthenticationChallenge:challenge];
        } else {
            /*
             * 验证失败，取消这次验证流程
             */
            [[challenge sender] cancelAuthenticationChallenge:challenge];
        }
    } else {
        /*
         * 对于其他验证方法直接进行处理流程
         */
        [[challenge sender] continueWithoutCredentialForAuthenticationChallenge:challenge];
    }
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    [self.client URLProtocol:self didReceiveResponse:response cacheStoragePolicy:NSURLCacheStorageNotAllowed];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [self.client URLProtocol:self didLoadData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    [self.client URLProtocolDidFinishLoading:self];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    [self.client URLProtocol:self didFailWithError:error];
}

@end