EMASCurlWeb/EMASCurlWebDataTask.m

//
//  EMASCurlWebDataTask.m
//  EMASCurl
//
//  Created by xuyecan on 2025/2/5.
//

#import "EMASCurlWebDataTask.h"
#import "EMASCurlWebUtils.h"
#import "EMASCurlWebLogger.h"
#import "NSCachedURLResponse+EMASCurl.h"

NSInteger const kEMASCurlGetRequestRetryLimit = 0;

@interface EMASCurlNetworkDataTask ()

@property (nonatomic, assign) BOOL isCancelled;
@property (nonatomic, assign) RequestTaskIdentifier requestID;
@property (nonatomic, strong) NSHTTPURLResponse *receivedResponse;
@property (nonatomic, strong) NSMutableData *receivedData;

@end

@implementation EMASCurlNetworkDataTask

- (instancetype)initWithRequest:(NSURLRequest *)request {
    self = [super init];
    if (self) {
        _originalRequest = request;
        _currentRetryCount = 0;
        _isCancelled = NO;
        _canCache = YES;
        _requestID = -1;
        _receivedData = [NSMutableData data];
    }
    return self;
}

#pragma mark - Public Methods

- (void)resume {
    if (self.isCancelled) {
        return;
    }

    // 检查是否可用缓存
    if (![self prepareRequestAndTryCache]) {
        return;
    }

    // 设置请求优先级对应的超时时间
    NSMutableURLRequest *mutableRequest = [self.originalRequest mutableCopy];

    // 强制不使用系统缓存
    mutableRequest.cachePolicy = NSURLRequestReloadIgnoringLocalCacheData;
    self.originalRequest = [mutableRequest copy];

    // 发起网络请求
    EMASCurlWeak(self)
    self.requestID = [self.networkManagerWeakRef
                      startWithRequest:self.originalRequest
                      responseCallback:^(NSURLResponse * _Nonnull response) {
        EMASCurlStrong(self)
        [self handleResponse:response];
    }
        dataCallback:^(NSData * _Nonnull data) {
        EMASCurlStrong(self)
        [self handleData:data];
    } successCallback:^{
        EMASCurlStrong(self)
        [self handleSuccess];
    } failCallback:^(NSError * _Nonnull error) {
        EMASCurlStrong(self)
        [self handleFailure:error];
    } redirectCallback:^(NSURLResponse * _Nonnull resp, NSURLRequest * _Nonnull newReq, EMASCurlNetRedirectDecisionCallback decisionCb) {
        EMASCurlStrong(self)
        [self handleRedirect:resp newRequest:newReq decisionCallback:decisionCb];
    }];
}

- (void)cancel {
    if (self.isCancelled) {
        return;
    }
    self.isCancelled = YES;
    [self.networkManagerWeakRef cancelWithRequestIdentifier:self.requestID];
    if (self.cancelHandler) {
        self.cancelHandler();
    }
}

#pragma mark - Cache & Request Preparation

// 检查缓存是否可用并尝试直接返回缓存内容
- (BOOL)prepareRequestAndTryCache {
    // 不使用缓存的情况
    BOOL isGetMethod = [[self.originalRequest.HTTPMethod uppercaseString] isEqualToString:@"GET"];
    if (!isGetMethod) {
        self.canCache = NO;
    }
    NSString *mainURL = self.originalRequest.mainDocumentURL.absoluteString;
    NSString *requestURL = self.originalRequest.URL.absoluteString;
    if ([EMASCurlWebUtils isValidStr:mainURL] &&
        [EMASCurlWebUtils isEqualURLA:requestURL withURLB:mainURL]) {
        self.canCache = NO;
    }
    if (!self.canCache) {
        return YES;
    }

    // 有缓存能力则获取缓存
    NSCachedURLResponse *cachedResponse = [self.httpCacheWeakRef getCachedResponseWithRequest:self.originalRequest];
    if (cachedResponse && ![cachedResponse emas_isExpired]) {
        if (self.responseCallback) {
            self.responseCallback(cachedResponse.response);
        }
        if (self.dataCallback) {
            self.dataCallback(cachedResponse.data);
        }
        if (self.successCallback) {
            self.successCallback();
        }
        return NO;
    }

    // 如果缓存已过期，则设置If-None-Match/If-Modified-Since
    if (cachedResponse && [cachedResponse emas_isExpired]) {
        NSMutableURLRequest *tmpRequest = [self.originalRequest mutableCopy];
        if (cachedResponse.emas_etag) {
            [tmpRequest setValue:cachedResponse.emas_etag forHTTPHeaderField:@"If-None-Match"];
        }
        if (cachedResponse.emas_lastModified) {
            [tmpRequest setValue:cachedResponse.emas_lastModified forHTTPHeaderField:@"If-Modified-Since"];
        }
        self.originalRequest = [tmpRequest copy];
    }
    return YES;
}

#pragma mark - Callback Handling

// 处理响应回调
- (void)handleResponse:(NSURLResponse *)response {
    if (!self.canCache || ![response isKindOfClass:[NSHTTPURLResponse class]]) {
        if (self.responseCallback) {
            self.responseCallback(response);
        }
        return;
    }

    self.receivedResponse = (NSHTTPURLResponse *)response;

    // 如果 304 不立即回调 responseCallback，等 successCallback 时再处理
    if (self.receivedResponse.statusCode != 304
        || ![self.httpCacheWeakRef getCachedResponseWithRequest:self.originalRequest]) {

        if (self.responseCallback) {
            self.responseCallback(response);
        }
    }
}

// 处理数据回调
- (void)handleData:(NSData *)data {
    [self.receivedData appendData:data];
    if (self.dataCallback) {
        self.dataCallback(data);
    }
}

// 处理成功回调
- (void)handleSuccess {
    if (!self.canCache) {
        if (self.successCallback) {
            self.successCallback();
        }
        return;
    }

    // 如果 304, 则尝试使用缓存
    if (self.receivedResponse.statusCode == 304 && [self.httpCacheWeakRef getCachedResponseWithRequest:self.originalRequest]) {
        NSCachedURLResponse *cachedResponse = [self.httpCacheWeakRef
                                               updateCachedResponseWithURLResponse:self.receivedResponse
                                               request:self.originalRequest];
        if (self.responseCallback) {
            self.responseCallback(cachedResponse.response);
        }
        if (self.dataCallback) {
            self.dataCallback(cachedResponse.data);
        }
        if (self.successCallback) {
            self.successCallback();
        }
        return;
    }

    [self.httpCacheWeakRef cacheWithHTTPURLResponse:self.receivedResponse
                                               data:self.receivedData
                                            request:self.originalRequest];

    if (self.successCallback) {
        self.successCallback();
    }
}

// 处理失败回调
- (void)handleFailure:(NSError *)error {
    // 重试条件：超时错误且为GET请求，并且未超出重试次数
    BOOL isTimeout = (error.code == -1001);
    BOOL isGetMethod = [[self.originalRequest.HTTPMethod uppercaseString] isEqualToString:@"GET"];
    if (isTimeout && isGetMethod && self.currentRetryCount < kEMASCurlGetRequestRetryLimit) {
        EMASCurlCacheLog(@"Request failed and we retry, url: %@, error: %@", self.originalRequest.URL.absoluteString, error);
        [self performRetry];
        return;
    }
    if (self.failCallback) {
        EMASCurlCacheLog(@"Request failed and we give up, url: %@, error: %@", self.originalRequest.URL.absoluteString, error);
        self.failCallback(error);
    }
}

// 处理重定向回调
- (void)handleRedirect:(NSURLResponse *)response
            newRequest:(NSURLRequest *)redirectRequest
     decisionCallback:(EMASCurlNetRedirectDecisionCallback)decisionCallback {
    // 直接透传给上层
    if (self.redirectCallback) {
        self.redirectCallback(response, redirectRequest, decisionCallback);
    } else {
        decisionCallback(YES);
    }
}

#pragma mark - Internal Retry

- (void)performRetry {
    self.currentRetryCount++;

    // 先取消当前任务
    [self cancel];

    if (self.retryHandler) {
        self.retryHandler();
    }
}

@end