//
//  WKWebView+Post.m
//  TLChat
//
//  Created by 李伯坤 on 17/9/10.
//  Copyright © 2017年 李伯坤. All rights reserved.
//

#import "WKWebView+Post.h"
#import <objc/runtime.h>

@implementation WKWebView (Post)

+ (void)load
{
    Class class = [self class];
    SEL originalSelector = @selector(loadRequest:);
    SEL swizzledSelector = @selector(post_loadRequest:);
    Method originalMethod = class_getInstanceMethod(class, originalSelector);
    Method swizzledMethod = class_getInstanceMethod(class, swizzledSelector);
    BOOL success = class_addMethod(class, originalSelector, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod));
    if (success) {
        class_replaceMethod(class, swizzledSelector, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod));
    }
    else {
        method_exchangeImplementations(originalMethod, swizzledMethod);
    }
}

- (WKNavigation *)post_loadRequest:(NSURLRequest *)request
{
    if ([[request.HTTPMethod uppercaseString] isEqualToString:@"POST"]){
        NSString *url = request.URL.absoluteString;
        NSString *params = [[NSString alloc] initWithData:request.HTTPBody encoding:NSUTF8StringEncoding];
        if ([params containsString:@"="]) {
            params = [params stringByReplacingOccurrencesOfString:@"=" withString:@"\":\""];
            params = [params stringByReplacingOccurrencesOfString:@"&" withString:@"\",\""];
            params = [NSString stringWithFormat:@"{\"%@\"}", params];
        }
        else {
            params = @"{}";
        }
        NSString *postJavaScript = [NSString stringWithFormat:@"\
                             var url = '%@';\
                             var params = %@;\
                             var form = document.createElement('form');\
                             form.setAttribute('method', 'post');\
                             form.setAttribute('action', url);\
                             for(var key in params) {\
                             if(params.hasOwnProperty(key)) {\
                             var hiddenField = document.createElement('input');\
                             hiddenField.setAttribute('type', 'hidden');\
                             hiddenField.setAttribute('name', key);\
                             hiddenField.setAttribute('value', params[key]);\
                             form.appendChild(hiddenField);\
                             }\
                             }\
                             document.body.appendChild(form);\
                             form.submit();", url, params];
        __weak typeof(self) wself = self;
        [self evaluateJavaScript:postJavaScript completionHandler:^(id object, NSError * _Nullable error) {
            if (error && [wself.navigationDelegate respondsToSelector:@selector(webView:didFailProvisionalNavigation:withError:)]) {
                dispatch_async(dispatch_get_main_queue(), ^{
                    [wself.navigationDelegate webView:wself didFailProvisionalNavigation:nil withError:error];
                });
            }
        }];
    }
    else {
       return [self post_loadRequest:request];
    }
    
    return nil;
}

@end