/*
 Copyright 2017 Vector Creations 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 "WidgetManager.h"

#import <MatrixKit/MatrixKit.h>

#pragma mark - Contants

NSString *const kWidgetMatrixEventTypeString  = @"m.widget";
NSString *const kWidgetModularEventTypeString = @"im.vector.modular.widgets";
NSString *const kWidgetTypeJitsi = @"jitsi";

NSString *const kWidgetManagerDidUpdateWidgetNotification = @"kWidgetManagerDidUpdateWidgetNotification";

NSString *const WidgetManagerErrorDomain = @"WidgetManagerErrorDomain";

@interface WidgetManager ()
{
    // MXSession kind of hash -> Listener for matrix events for widgets.
    // There is one per matrix session
    NSMutableDictionary<NSString*, id> *widgetEventListener;

    // Success blocks of widgets being created
    // MXSession kind of hash -> (Widget id -> `createWidget:` success block).
    NSMutableDictionary<NSString*,
        NSMutableDictionary<NSString*, void (^)(Widget *widget)>*> *successBlockForWidgetCreation;

    // Failure blocks of widgets being created
    // MXSession kind of hash -> (Widget id -> `createWidget:` failure block).
    NSMutableDictionary<NSString*,
        NSMutableDictionary<NSString*, void (^)(NSError *error)>*> *failureBlockForWidgetCreation;

    // User id -> scalar token
    NSMutableDictionary<NSString*, NSString*> *scalarTokens;
}

@end

@implementation WidgetManager

+ (instancetype)sharedManager
{
    static WidgetManager *sharedManager = nil;
    static dispatch_once_t onceToken;

    dispatch_once(&onceToken, ^{
        sharedManager = [[WidgetManager alloc] init];
    });

    return sharedManager;
}

- (instancetype)init
{
    self = [super init];
    if (self)
    {
        widgetEventListener = [NSMutableDictionary dictionary];
        successBlockForWidgetCreation = [NSMutableDictionary dictionary];
        failureBlockForWidgetCreation = [NSMutableDictionary dictionary];

        [self load];

        if (!scalarTokens)
        {
            scalarTokens = [NSMutableDictionary dictionary];
        }
    }
    return self;
}

- (NSArray<Widget *> *)widgetsInRoom:(MXRoom *)room
{
    return [self widgetsOfTypes:nil inRoom:room];
}

- (NSArray<Widget*> *)widgetsOfTypes:(NSArray<NSString*>*)widgetTypes inRoom:(MXRoom*)room;
{
    return [self widgetsOfTypes:widgetTypes butNotTypesOf:nil inRoom:room];
}

- (NSArray<Widget*> *)widgetsNotOfTypes:(NSArray<NSString*>*)notWidgetTypes inRoom:(MXRoom*)room
{
    return [self widgetsOfTypes:nil butNotTypesOf:notWidgetTypes inRoom:room];
}

- (NSArray<Widget*> *)widgetsOfTypes:(NSArray<NSString*>*)widgetTypes butNotTypesOf:(NSArray<NSString*>*)notWidgetTypes inRoom:(MXRoom*)room;
{
    // Widget id -> widget
    NSMutableDictionary <NSString*, Widget *> *widgets = [NSMutableDictionary dictionary];

    // Get all widgets state events in the room
    NSMutableArray<MXEvent*> *widgetEvents = [NSMutableArray arrayWithArray:[room.state stateEventsWithType:kWidgetMatrixEventTypeString]];
    [widgetEvents addObjectsFromArray:[room.state stateEventsWithType:kWidgetModularEventTypeString]];

    // There can be several widgets state events for a same widget but
    // only the last one must be considered.

    // Order widgetEvents with the last event first
    [widgetEvents sortUsingComparator:^NSComparisonResult(MXEvent *event1, MXEvent *event2) {

         NSComparisonResult result = NSOrderedAscending;
         if (event2.originServerTs > event1.originServerTs)
         {
             result = NSOrderedDescending;
         }
         else if (event2.originServerTs == event1.originServerTs)
         {
             result = NSOrderedSame;
         }

         return result;
     }];

    // Create each widget from its lastest widgets state event
    for (MXEvent *widgetEvent in widgetEvents)
    {
        // Filter widget types if required
        if (widgetTypes || notWidgetTypes)
        {
            NSString *widgetType;
            MXJSONModelSetString(widgetType, widgetEvent.content[@"type"]);

            if (widgetType)
            {
                if (widgetTypes && NSNotFound == [widgetTypes indexOfObject:widgetType])
                {
                    continue;
                }
                if (notWidgetTypes && NSNotFound != [notWidgetTypes indexOfObject:widgetType])
                {
                     continue;
                }
            }
        }

        // widgetEvent.stateKey = widget id
        if (!widgets[widgetEvent.stateKey])
        {
            Widget *widget = [[Widget alloc] initWithWidgetEvent:widgetEvent inMatrixSession:room.mxSession];
            if (widget)
            {
                widgets[widget.widgetId] = widget;
            }
        }
    }

    // Return active widgets only
    NSMutableArray<Widget *> *activeWidgets = [NSMutableArray array];
    for (Widget *widget in widgets.allValues)
    {
        if (widget.isActive)
        {
            [activeWidgets addObject:widget];
        }
    }

    return activeWidgets;
}

- (NSArray<Widget*> *)userWidgets:(MXSession*)mxSession
{
    // Get all widgets in the user account data
    NSMutableArray<Widget *> *userWidgets = [NSMutableArray array];
    for (NSDictionary *widgetEventContent in [mxSession.accountData accountDataForEventType:@"m.widgets"].allValues)
    {
        // Patch: Modular uses a malformed key: "stateKey" instead of "state_key"
        // TODO: To remove once fixed server side
        NSDictionary *widgetEventContentFixed = widgetEventContent;
        if (!widgetEventContent[@"state_key"] && widgetEventContent[@"stateKey"])
        {
            NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithDictionary:widgetEventContent];
            dict[@"state_key"] = widgetEventContent[@"stateKey"];
            widgetEventContentFixed = dict;
        }

        MXEvent *widgetEvent = [MXEvent modelFromJSON:widgetEventContentFixed];
        if (widgetEvent)
        {
            Widget *widget = [[Widget alloc] initWithWidgetEvent:widgetEvent inMatrixSession:mxSession];
            if (widget)
            {
                [userWidgets addObject:widget];
            }
        }
    }

    return userWidgets;
}

- (MXHTTPOperation *)createWidget:(NSString*)widgetId
                      withContent:(NSDictionary<NSString*, NSObject*>*)widgetContent
                           inRoom:(MXRoom*)room
                          success:(void (^)(Widget *widget))success
                          failure:(void (^)(NSError *error))failure
{
    NSError *permissionError = [self checkWidgetPermissionInRoom:room];
    if (permissionError)
    {
        if (failure)
        {
            failure(permissionError);
        }
        return nil;
    }

    NSString *hash = [NSString stringWithFormat:@"%p", room.mxSession];
    successBlockForWidgetCreation[hash][widgetId] = success;
    failureBlockForWidgetCreation[hash][widgetId] = failure;

    // Send a state event with the widget data
    // TODO: This API will be shortly replaced by a pure modular API
    // TODO: Move to kWidgetMatrixEventTypeString ("m.widget") type but when?
    return [room sendStateEventOfType:kWidgetModularEventTypeString
                              content:widgetContent
                             stateKey:widgetId
                              success:nil failure:failure];
}


- (MXHTTPOperation *)createJitsiWidgetInRoom:(MXRoom*)room
                                   withVideo:(BOOL)video
                                     success:(void (^)(Widget *jitsiWidget))success
                                     failure:(void (^)(NSError *error))failure
{
    // Build data for a jitsi widget
    NSString *widgetId = [NSString stringWithFormat:@"%@_%@_%@", kWidgetTypeJitsi, room.mxSession.myUser.userId, @((uint64_t)([[NSDate date] timeIntervalSince1970] * 1000))];

    // Create a random enough jitsi conference id
    // Note: the jitsi server automatically creates conference when the conference
    // id does not exist yet
    NSString *widgetSessionId = [[[[NSProcessInfo processInfo] globallyUniqueString] substringToIndex:7] lowercaseString];
    NSString *confId = [room.roomId substringWithRange:NSMakeRange(1, [room.roomId rangeOfString:@":"].location - 1)];
    confId = [confId stringByAppendingString:widgetSessionId];

    // TODO: This url should come from modular API
    // Note: this url can be used as is inside a web container (like iframe for Riot-web)
    // Riot-iOS does not directly use it but extracts params from it (see `[JitsiViewController openWidget:withVideo:]`)
    NSString *modularRestUrl = [[NSUserDefaults standardUserDefaults] objectForKey:@"integrationsRestUrl"];
    NSString *url = [NSString stringWithFormat:@"%@/widgets/jitsi.html?confId=%@&isAudioConf=%@&displayName=$matrix_display_name&avatarUrl=$matrix_avatar_url&email=$matrix_user_id@", modularRestUrl, confId, video ? @"false" : @"true"];

    return [self createWidget:widgetId
                  withContent:@{
                                @"url": url,
                                @"type": kWidgetTypeJitsi,
                                @"data": @{
                                        @"widgetSessionId": widgetSessionId
                                        }
                                }
                       inRoom:room
                      success:success
                      failure:failure];
}

- (MXHTTPOperation *)closeWidget:(NSString *)widgetId inRoom:(MXRoom *)room success:(void (^)())success failure:(void (^)(NSError *))failure
{
    NSError *permissionError = [self checkWidgetPermissionInRoom:room];
    if (permissionError)
    {
        if (failure)
        {
            failure(permissionError);
        }
        return nil;
    }

    // Send a state event with an empty content to disable the widget
    // TODO: This API will be shortly replaced by a pure modular API
    // TODO: Move to kWidgetMatrixEventTypeString ("m.widget") type but when?
    return [room sendStateEventOfType:kWidgetModularEventTypeString
                              content:@{}
                             stateKey:widgetId
                              success:^(NSString *eventId)
            {
                if (success)
                {
                    success();
                }
            } failure:failure];
}

/**
 Check user's power for widgets management in a room.
 
 @param room the room to check.
 @return an NSError if the user cannot act on widgets in this room. Else, nil.
 */
- (NSError *)checkWidgetPermissionInRoom:(MXRoom *)room
{
    NSError *error;

    // Check user's power in the room
    MXRoomPowerLevels *powerLevels = room.state.powerLevels;
    NSInteger oneSelfPowerLevel = [powerLevels powerLevelOfUserWithUserID:room.mxSession.myUser.userId];

    // The user must be able to send state events to manage widgets
    if (oneSelfPowerLevel < powerLevels.stateDefault)
    {
        error = [NSError errorWithDomain:WidgetManagerErrorDomain
                                             code:WidgetManagerErrorCodeNotEnoughPower
                                         userInfo:@{
                                                    NSLocalizedDescriptionKey: NSLocalizedStringFromTable(@"widget_no_power_to_manage", @"Vector", nil)
                                                    }];
    }

    return error;
}

- (void)addMatrixSession:(MXSession *)mxSession
{
     __weak __typeof__(self) weakSelf = self;

    NSString *hash = [NSString stringWithFormat:@"%p", mxSession];

    id listener = [mxSession listenToEventsOfTypes:@[kWidgetMatrixEventTypeString, kWidgetModularEventTypeString] onEvent:^(MXEvent *event, MXTimelineDirection direction, id customObject) {

        typeof(self) self = weakSelf;

        if (self && direction == MXTimelineDirectionForwards)
        {
            // stateKey = widgetId
            NSString *widgetId = event.stateKey;

            NSLog(@"[WidgetManager] New widget detected: %@ in %@", widgetId, event.roomId);

            Widget *widget = [[Widget alloc] initWithWidgetEvent:event inMatrixSession:mxSession];
            if (widget)
            {
                // If it is a widget we have just created, indicate its creation is complete
                if (self->successBlockForWidgetCreation[hash][widgetId])
                {
                    self->successBlockForWidgetCreation[hash][widgetId](widget);
                }

                // Broadcast the generic notification
                [[NSNotificationCenter defaultCenter] postNotificationName:kWidgetManagerDidUpdateWidgetNotification object:widget];
            }
            else
            {
                NSLog(@"[WidgetManager] Cannot decode new widget - event: %@", event);

                if (self->failureBlockForWidgetCreation[hash][widgetId])
                {
                    // If it is a widget we have just created, indicate its creation has failed somehow
                    NSError *error = [NSError errorWithDomain:WidgetManagerErrorDomain
                                                         code:WidgetManagerErrorCodeCreationFailed
                                                     userInfo:@{
                                                                NSLocalizedDescriptionKey: NSLocalizedStringFromTable(@"widget_creation_failure", @"Vector", nil)
                                                                }];

                    self->failureBlockForWidgetCreation[hash][widgetId](error);
                }
            }

            [self->successBlockForWidgetCreation[hash] removeObjectForKey:widgetId];
            [self->failureBlockForWidgetCreation[hash] removeObjectForKey:widgetId];
        }
    }];

    widgetEventListener[hash] = listener;
    successBlockForWidgetCreation[hash] = [NSMutableDictionary dictionary];
    failureBlockForWidgetCreation[hash] = [NSMutableDictionary dictionary];
}

- (void)removeMatrixSession:(MXSession *)mxSession
{
    // mxSession.myUser.userId and mxSession.matrixRestClient.credentials.userId may be nil here
    // So, use a kind of hash value instead
    NSString *hash = [NSString stringWithFormat:@"%p", mxSession];
    id listener = widgetEventListener[hash];

    [mxSession removeListener:listener];

    [widgetEventListener removeObjectForKey:hash];
    [successBlockForWidgetCreation removeObjectForKey:hash];
    [failureBlockForWidgetCreation removeObjectForKey:hash];
}

- (void)deleteDataForUser:(NSString *)userId
{
    [scalarTokens removeObjectForKey:userId];
    [self save];
}

#pragma mark - Modular interface

- (MXHTTPOperation *)getScalarTokenForMXSession:(MXSession*)mxSession
                                        success:(void (^)(NSString *scalarToken))success
                                        failure:(void (^)(NSError *error))failure;
{
    MXHTTPOperation *operation;

    __block NSString *scalarToken = [self scalarTokenForMXSession:mxSession];
    if (scalarToken)
    {
        success(scalarToken);
    }
    else
    {
        NSLog(@"[WidgetManager] getScalarTokenForMXSession: Need to register to get a token");

        __weak __typeof__(self) weakSelf = self;
        operation = [mxSession.matrixRestClient openIdToken:^(MXOpenIdToken *tokenObject) {

            typeof(self) self = weakSelf;

            if (self)
            {
                // Exchange the token for a scalar token
                NSString *modularRestUrl = [[NSUserDefaults standardUserDefaults] objectForKey:@"integrationsRestUrl"];

                MXHTTPClient *httpClient = [[MXHTTPClient alloc] initWithBaseURL:modularRestUrl andOnUnrecognizedCertificateBlock:nil];

                MXHTTPOperation *operation2 = [httpClient requestWithMethod:@"POST"
                                                                       path:@"register"
                                                                 parameters:tokenObject.JSONDictionary
                                                                    success:^(NSDictionary *JSONResponse) {

                                                                        MXJSONModelSetString(scalarToken, JSONResponse[@"scalar_token"])
                                                                        self->scalarTokens[mxSession.myUser.userId] = scalarToken;

                                                                        [self save];

                                                                        if (success)
                                                                        {
                                                                            success(scalarToken);
                                                                        }

                                                                    } failure:^(NSError *error) {
                                                                        NSLog(@"[WidgetManager] getScalarTokenForMXSession. Error in modular/register request");

                                                                        if (failure)
                                                                        {
                                                                            failure(error);
                                                                        }
                                                                    }];

                [operation mutateTo:operation2];

            }

        } failure:^(NSError *error) {
            NSLog(@"[WidgetManager] getScalarTokenForMXSession. Error in openIdToken request");

            if (failure)
            {
                failure(error);
            }
        }];
    }

    return operation;
}

#pragma mark - Private methods

- (NSString *)scalarTokenForMXSession:(MXSession *)mxSession
{
    return scalarTokens[mxSession.myUser.userId];
}

- (void)load
{
    NSUserDefaults *userDefaults = [MXKAppSettings standardAppSettings].sharedUserDefaults;
    scalarTokens = [NSMutableDictionary dictionaryWithDictionary:[userDefaults objectForKey:@"scalarTokens"]];
}

- (void)save
{
    NSUserDefaults *userDefaults = [MXKAppSettings standardAppSettings].sharedUserDefaults;

    [userDefaults setObject:scalarTokens forKey:@"scalarTokens"];
    [userDefaults synchronize];
}

@end