/*
 Copyright 2017 Vector Creations Ltd
 Copyright 2018 New Vector Ltd

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */

#import "WidgetViewController.h"

#import "AppDelegate.h"
#import "IntegrationManagerViewController.h"
#import "Riot-Swift.h"

NSString *const kJavascriptSendResponseToPostMessageAPI = @"riotIOS.sendResponse('%@', %@);";

@interface WidgetViewController () <ServiceTermsModalCoordinatorBridgePresenterDelegate>

@property (nonatomic, strong) ServiceTermsModalCoordinatorBridgePresenter *serviceTermsModalCoordinatorBridgePresenter;
@property (nonatomic, strong) NSString *widgetUrl;

@end

@implementation WidgetViewController
@synthesize widget;

- (instancetype)initWithUrl:(NSString*)widgetUrl forWidget:(Widget*)theWidget
{
    // The opening of the url is delayed in viewWillAppear where we will check
    // the widget permission
    self = [super initWithURL:nil];
    if (self)
    {
        self.widgetUrl = widgetUrl;
        widget = theWidget;
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    webView.scrollView.bounces = NO;

    // Disable opacity so that the webview background uses the current interface theme
    webView.opaque = NO;

    if (widget)
    {
        self.navigationItem.title = widget.name ? widget.name : widget.type;
    }
}

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];

    // Check widget permission before opening the widget
    [self checkWidgetPermissionWithCompletion:^(BOOL granted) {
        if (granted)
        {
            self.URL = self.widgetUrl;
        }
        else
        {
            [self withdrawViewControllerAnimated:YES completion:nil];
        }
    }];
}

- (void)showErrorAsAlert:(NSError*)error
{
    NSString *title = [error.userInfo valueForKey:NSLocalizedFailureReasonErrorKey];
    NSString *msg = [error.userInfo valueForKey:NSLocalizedDescriptionKey];
    if (!title)
    {
        if (msg)
        {
            title = msg;
            msg = nil;
        }
        else
        {
            title = [NSBundle mxk_localizedStringForKey:@"error"];
        }
    }

    __weak __typeof__(self) weakSelf = self;

    UIAlertController *alert = [UIAlertController alertControllerWithTitle:title message:msg preferredStyle:UIAlertControllerStyleAlert];
    [alert addAction:[UIAlertAction actionWithTitle:[NSBundle mxk_localizedStringForKey:@"ok"]
                                              style:UIAlertActionStyleDefault
                                            handler:^(UIAlertAction * action) {

                                                typeof(self) self = weakSelf;

                                                if (self)
                                                {
                                                    // Leave this widget VC
                                                    [self withdrawViewControllerAnimated:YES completion:nil];
                                                }

                                            }]];

    [self presentViewController:alert animated:YES completion:nil];
}


#pragma mark - Widget Permission

- (void)checkWidgetPermissionWithCompletion:(void (^)(BOOL granted))completion
{
    MXSession *session = widget.mxSession;

    if ([widget.widgetEvent.sender isEqualToString:session.myUser.userId])
    {
        // No need of more permission check if the user created the widget
        completion(YES);
        return;
    }

    // Check permission in user Riot settings
    __block RiotSharedSettings *sharedSettings = [[RiotSharedSettings alloc] initWithSession:session];

    WidgetPermission permission = [sharedSettings permissionForWidget:widget];
    if (permission == WidgetPermissionGranted)
    {
        completion(YES);
    }
    else
    {
        // Note: ask permission again if the user previously declined it
        [self askPermissionWithCompletion:^(BOOL granted) {
            // Update the settings in user account data in parallel
            [sharedSettings setPermissionForWidget:self.widget
                                        permission:granted ? WidgetPermissionGranted : WidgetPermissionDeclined
                                           success:^
             {
                 sharedSettings = nil;
             }
                                           failure:^(NSError * _Nullable error)
             {
                 NSLog(@"[WidgetVC] setPermissionForWidget failed. Error: %@", error);
                 sharedSettings = nil;
             }];

            completion(granted);
        }];
    }
}

- (void)askPermissionWithCompletion:(void (^)(BOOL granted))completion
{
    // TODO: Implement the design
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Load Widget"
                                                                   message:@"blabla"
                                                            preferredStyle:UIAlertControllerStyleAlert];

    [alert addAction:[UIAlertAction actionWithTitle:[NSBundle mxk_localizedStringForKey:@"continue"]
                                              style:UIAlertActionStyleDefault
                                            handler:^(UIAlertAction * action) {
                                                completion(YES);
                                            }]];

    [alert addAction:[UIAlertAction actionWithTitle:NSLocalizedStringFromTable(@"decline", @"Vector", nil)
                                              style:UIAlertActionStyleCancel
                                            handler:^(UIAlertAction * action) {
                                                completion(NO);
                                            }]];

    [self presentViewController:alert animated:YES completion:nil];
}


#pragma mark - WKNavigationDelegate

- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation
{
    [self enableDebug];

    // Setup js code
    NSString *path = [[NSBundle mainBundle] pathForResource:@"postMessageAPI" ofType:@"js"];
    NSString *js = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
    [webView evaluateJavaScript:js completionHandler:nil];

    [self stopActivityIndicator];

    // Check connectivity
    if ([AppDelegate theDelegate].isOffline)
    {
        // The web page may be in the cache, so its loading will be successful
        // but we cannot go further, it often leads to a blank screen.
        // So, display an error so that the user can escape.
        NSError *error = [NSError errorWithDomain:NSURLErrorDomain
                                             code:NSURLErrorNotConnectedToInternet
                                         userInfo:@{
                                                    NSLocalizedDescriptionKey : NSLocalizedStringFromTable(@"network_offline_prompt", @"Vector", nil)
                                                    }];
        [self showErrorAsAlert:error];
    }
}

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler
{
    NSString *urlString = navigationAction.request.URL.absoluteString;

    // TODO: We should use the WebKit PostMessage API and the
    // `didReceiveScriptMessage` delegate to manage the JS<->Native bridge
    if ([urlString hasPrefix:@"js:"])
    {
        // Listen only to the scheme of the JS<->Native bridge
        NSString *jsonString = [[[urlString componentsSeparatedByString:@"js:"] lastObject] stringByRemovingPercentEncoding];
        NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];

        NSError *error;
        NSDictionary *parameters = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers
                                                                     error:&error];
        if (!error)
        {
            // Retrieve the js event payload data
            NSDictionary *eventData;
            MXJSONModelSetDictionary(eventData, parameters[@"event.data"]);

            NSString *requestId;
            MXJSONModelSetString(requestId, eventData[@"_id"]);

            if (requestId)
            {
                [self onPostMessageRequest:requestId data:eventData];
            }
            else
            {
                NSLog(@"[WidgetVC] shouldStartLoadWithRequest: ERROR: Missing request id in postMessage API %@", parameters);
            }
        }

        decisionHandler(WKNavigationActionPolicyCancel);
        return;
    }

    if (navigationAction.navigationType == WKNavigationTypeLinkActivated)
    {
        // Open links outside the app
        [[UIApplication sharedApplication] openURL:navigationAction.request.URL];
        decisionHandler(WKNavigationActionPolicyCancel);
        return;
    }

    decisionHandler(WKNavigationActionPolicyAllow);
}

- (void)webView:(WKWebView *)webView didFailNavigation:(WKNavigation *)navigation withError:(NSError *)error
{
    // Filter out the users's scalar token
    NSString *errorDescription = error.description;
    errorDescription = [self stringByReplacingScalarTokenInString:errorDescription byScalarToken:@"..."];

    NSLog(@"[WidgetVC] didFailLoadWithError: %@", errorDescription);

    [self stopActivityIndicator];
    [self showErrorAsAlert:error];
}

- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler {

    if ([navigationResponse.response isKindOfClass:[NSHTTPURLResponse class]])
    {
        NSHTTPURLResponse * response = (NSHTTPURLResponse *)navigationResponse.response;
        if (response.statusCode != 200)
        {
            NSLog(@"[WidgetVC] decidePolicyForNavigationResponse: statusCode: %@", @(response.statusCode));
        }

        if (response.statusCode == 403 && [[WidgetManager sharedManager] isScalarUrl:self.URL forUser:self.widget.mxSession.myUser.userId])
        {
            [self fixScalarToken];
        }
    }
    decisionHandler(WKNavigationResponsePolicyAllow);
}

#pragma mark - postMessage API

- (void)onPostMessageRequest:(NSString*)requestId data:(NSDictionary*)requestData
{
    NSString *action;
    MXJSONModelSetString(action, requestData[@"action"]);

    if ([@"m.sticker" isEqualToString:action])
    {
        // Extract the sticker event content and send it as is

        // The key should be "data" according to https://docs.google.com/document/d/1uPF7XWY_dXTKVKV7jZQ2KmsI19wn9-kFRgQ1tFQP7wQ/edit?usp=sharing
        // TODO: Fix it once spec is finalised
        NSDictionary *widgetData;
        NSDictionary *stickerContent;
        MXJSONModelSetDictionary(widgetData, requestData[@"widgetData"]);
        if (widgetData)
        {
            MXJSONModelSetDictionary(stickerContent, widgetData[@"content"]);
        }

        if (stickerContent)
        {
            // Let the data source manage the sending cycle
            [_roomDataSource sendEventOfType:kMXEventTypeStringSticker content:stickerContent success:nil failure:nil];
        }
        else
        {
            NSLog(@"[WidgetVC] onPostMessageRequest: ERROR: Invalid content for m.sticker: %@", requestData);
        }

        // Consider we are done with the sticker picker widget
        [self withdrawViewControllerAnimated:YES completion:nil];
    }
    else if ([@"integration_manager_open" isEqualToString:action])
    {
        NSDictionary *widgetData;
        NSString *integType, *integId;
        MXJSONModelSetDictionary(widgetData, requestData[@"widgetData"]);
        if (widgetData)
        {
            MXJSONModelSetString(integType, widgetData[@"integType"]);
            MXJSONModelSetString(integId, widgetData[@"integId"]);
        }

        if (integType && integId)
        {
            // Open the integration manager requested page
            IntegrationManagerViewController *modularVC = [[IntegrationManagerViewController alloc]
                                                           initForMXSession:self.roomDataSource.mxSession
                                                           inRoom:self.roomDataSource.roomId
                                                           screen:[IntegrationManagerViewController screenForWidget:integType]
                                                           widgetId:integId];

            [self presentViewController:modularVC animated:NO completion:nil];
        }
        else
        {
            NSLog(@"[WidgetVC] onPostMessageRequest: ERROR: Invalid content for integration_manager_open: %@", requestData);
        }
    }
    else
    {
        NSLog(@"[WidgetVC] onPostMessageRequest: ERROR: Unsupported action: %@: %@", action, requestData);
    }
}

- (void)sendBoolResponse:(BOOL)response toRequest:(NSString*)requestId
{
    // Convert BOOL to "true" or "false"
    NSString *js = [NSString stringWithFormat:kJavascriptSendResponseToPostMessageAPI,
                    requestId,
                    response ? @"true" : @"false"];

    [webView evaluateJavaScript:js completionHandler:nil];
}

- (void)sendIntegerResponse:(NSUInteger)response toRequest:(NSString*)requestId
{
    NSString *js = [NSString stringWithFormat:kJavascriptSendResponseToPostMessageAPI,
                    requestId,
                    @(response)];

    [webView evaluateJavaScript:js completionHandler:nil];
}

- (void)sendNSObjectResponse:(NSObject*)response toRequest:(NSString*)requestId
{
    NSString *jsString;

    if (response)
    {
        // Convert response into a JS object through a JSON string
        NSData *jsonData = [NSJSONSerialization dataWithJSONObject:response
                                                           options:0
                                                             error:0];
        NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];

        jsString = [NSString stringWithFormat:@"JSON.parse('%@')", jsonString];
    }
    else
    {
        jsString = @"null";
    }

    NSString *js = [NSString stringWithFormat:kJavascriptSendResponseToPostMessageAPI,
                    requestId,
                    jsString];

    [webView evaluateJavaScript:js completionHandler:nil];
}

- (void)sendError:(NSString*)message toRequest:(NSString*)requestId
{
    NSLog(@"[WidgetVC] sendError: Action %@ failed with message: %@", requestId, message);

    // TODO: JS has an additional optional parameter: nestedError
    [self sendNSObjectResponse:@{
                                 @"error": @{
                                         @"message": message
                                         }
                                 }
                       toRequest:requestId];
}

- (void)sendLocalisedError:(NSString*)errorKey toRequest:(NSString*)requestId
{
    [self sendError:NSLocalizedStringFromTable(errorKey, @"Vector", nil) toRequest:requestId];
}


#pragma mark - Private methods

- (NSString *)stringByReplacingScalarTokenInString:(NSString*)string byScalarToken:(NSString*)scalarToken
{
    if (!string)
    {
        return nil;
    }

    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"scalar_token=\\w*"
                                                                           options:NSRegularExpressionCaseInsensitive error:nil];
    return [regex stringByReplacingMatchesInString:string
                                           options:0
                                             range:NSMakeRange(0, string.length)
                                      withTemplate:[NSString stringWithFormat:@"scalar_token=%@", scalarToken]];
}

/**
 Reset the scalar token used in the webview URL.
 */
- (void)fixScalarToken
{
    NSLog(@"[WidgetVC] fixScalarToken");

    self->webView.hidden = YES;

    // Get a fresh new scalar token
    [WidgetManager.sharedManager deleteDataForUser:widget.mxSession.myUser.userId];

    MXWeakify(self);
    [WidgetManager.sharedManager getScalarTokenForMXSession:widget.mxSession validate:NO success:^(NSString *scalarToken) {
        MXStrongifyAndReturnIfNil(self);

        NSLog(@"[WidgetVC] fixScalarToken: DONE");
        [self loadDataWithScalarToken:scalarToken];

    } failure:^(NSError *error) {
        NSLog(@"[WidgetVC] fixScalarToken: Error: %@", error);

        if ([error.domain isEqualToString:WidgetManagerErrorDomain]
            && error.code == WidgetManagerErrorCodeTermsNotSigned)
        {
            [self presentTerms];
        }
        else
        {
            [self showErrorAsAlert:error];
        }
    }];
}

- (void)loadDataWithScalarToken:(NSString*)scalarToken
{
    self.URL = [self stringByReplacingScalarTokenInString:self.URL byScalarToken:scalarToken];

    self->webView.hidden = NO;
}



#pragma mark - Service terms

- (void)presentTerms
{
    if (self.serviceTermsModalCoordinatorBridgePresenter)
    {
        return;
    }
    
    WidgetManagerConfig *config =  [[WidgetManager sharedManager] configForUser:widget.mxSession.myUser.userId];

    NSLog(@"[WidgetVC] presentTerms for %@", config.baseUrl);

    ServiceTermsModalCoordinatorBridgePresenter *serviceTermsModalCoordinatorBridgePresenter = [[ServiceTermsModalCoordinatorBridgePresenter alloc] initWithSession:widget.mxSession baseUrl:config.baseUrl
                                                                                                                                                       serviceType:MXServiceTypeIntegrationManager
                                                                                                                                                       outOfContext:NO
                                                                                                                                                        accessToken:config.scalarToken];
    serviceTermsModalCoordinatorBridgePresenter.delegate = self;

    [serviceTermsModalCoordinatorBridgePresenter presentFrom:self animated:YES];
    self.serviceTermsModalCoordinatorBridgePresenter = serviceTermsModalCoordinatorBridgePresenter;
}

- (void)serviceTermsModalCoordinatorBridgePresenterDelegateDidAccept:(ServiceTermsModalCoordinatorBridgePresenter * _Nonnull)coordinatorBridgePresenter
{
    MXWeakify(self);
    [coordinatorBridgePresenter dismissWithAnimated:YES completion:^{
        MXStrongifyAndReturnIfNil(self);

        WidgetManagerConfig *config = [[WidgetManager sharedManager] configForUser:self->widget.mxSession.myUser.userId];
        [self loadDataWithScalarToken:config.scalarToken];
    }];
    self.serviceTermsModalCoordinatorBridgePresenter = nil;
}

- (void)serviceTermsModalCoordinatorBridgePresenterDelegateDidCancel:(ServiceTermsModalCoordinatorBridgePresenter * _Nonnull)coordinatorBridgePresenter
{
    [coordinatorBridgePresenter dismissWithAnimated:YES completion:^{
        [self withdrawViewControllerAnimated:YES completion:nil];
    }];
    self.serviceTermsModalCoordinatorBridgePresenter = nil;
}

@end