/*
Copyright 2024 New Vector Ltd.
Copyright 2015 OpenMarket Ltd

SPDX-License-Identifier: AGPL-3.0-only
Please see LICENSE in the repository root for full details.
 */

#import "MXKRoomMemberListDataSource.h"

@import MatrixSDK.MXCallManager;

#import "MXKRoomMemberCellData.h"


#pragma mark - Constant definitions
NSString *const kMXKRoomMemberCellIdentifier = @"kMXKRoomMemberCellIdentifier";


@interface MXKRoomMemberListDataSource ()
{
    /**
     The room in which members are listed.
     */
    MXRoom *mxRoom;

    /**
     Cache for loaded room state.
     */
    MXRoomState *mxRoomState;
    
    /**
     The members events listener.
     */
    id membersListener;
    
    /**
     The typing notification listener in the room.
     */
    id typingNotifListener;
}

@end

@implementation MXKRoomMemberListDataSource

- (instancetype)initWithRoomId:(NSString*)roomId andMatrixSession:(MXSession*)mxSession
{
    self = [super initWithMatrixSession:mxSession];
    if (self)
    {
        _roomId = roomId;
        
        cellDataArray = [NSMutableArray array];
        filteredCellDataArray = nil;
        
        // Consider the shared app settings by default
        _settings = [MXKAppSettings standardAppSettings];
        
        // Set default data class
        [self registerCellDataClass:MXKRoomMemberCellData.class forCellIdentifier:kMXKRoomMemberCellIdentifier];
    }
    return self;
}

- (void)destroy
{
    cellDataArray = nil;
    filteredCellDataArray = nil;
    
    if (membersListener)
    {
        [self.mxSession removeListener:membersListener];
        membersListener = nil;
    }
    
    if (typingNotifListener)
    {
        MXWeakify(self);
        [mxRoom liveTimeline:^(id<MXEventTimeline> liveTimeline) {
            MXStrongifyAndReturnIfNil(self);

            [liveTimeline removeListener:self->typingNotifListener];
            self->typingNotifListener = nil;
        }];
    }
    
    [super destroy];
}

- (void)didMXSessionStateChange
{
    if (MXSessionStateStoreDataReady <= self.mxSession.state)
    {
        // Check whether the room is not already set
        if (!mxRoom)
        {
            mxRoom = [self.mxSession roomWithRoomId:_roomId];
            if (mxRoom)
            {
                MXWeakify(self);
                [mxRoom state:^(MXRoomState *roomState) {
                    MXStrongifyAndReturnIfNil(self);

                    self->mxRoomState = roomState;

                    [self loadData];

                    // Register on typing notif
                    [self listenTypingNotifications];

                    // Register on members events
                    [self listenMembersEvents];

                    // Update here data source state
                    self->state = MXKDataSourceStateReady;

                    // Notify delegate
                    if (self.delegate)
                    {
                        if ([self.delegate respondsToSelector:@selector(dataSource:didStateChange:)])
                        {
                            [self.delegate dataSource:self didStateChange:self->state];
                        }
                        [self.delegate dataSource:self didCellChange:nil];
                    }
                }];
            }
            else
            {
                MXLogDebug(@"[MXKRoomMemberDataSource] The user does not know the room %@", _roomId);
                
                // Update here data source state
                state = MXKDataSourceStateFailed;
                
                // Notify delegate
                if (self.delegate && [self.delegate respondsToSelector:@selector(dataSource:didStateChange:)])
                {
                    [self.delegate dataSource:self didStateChange:state];
                }
            }
        }
    }
}

- (void)searchWithPatterns:(NSArray*)patternsList
{
    if (patternsList.count)
    {
        if (filteredCellDataArray)
        {
            [filteredCellDataArray removeAllObjects];
        }
        else
        {
            filteredCellDataArray = [NSMutableArray arrayWithCapacity:cellDataArray.count];
        }
        
        for (id<MXKRoomMemberCellDataStoring> cellData in cellDataArray)
        {
            for (NSString* pattern in patternsList)
            {
                if ([[cellData memberDisplayName] rangeOfString:pattern options:NSCaseInsensitiveSearch].location != NSNotFound)
                {
                    [filteredCellDataArray addObject:cellData];
                    break;
                }
            }
        }
    }
    else
    {
        filteredCellDataArray = nil;
    }
    
    if (self.delegate)
    {
        [self.delegate dataSource:self didCellChange:nil];
    }
}

- (id<MXKRoomMemberCellDataStoring>)cellDataAtIndex:(NSInteger)index
{
    if (filteredCellDataArray)
    {
        return filteredCellDataArray[index];
    }
    return cellDataArray[index];
}

- (CGFloat)cellHeightAtIndex:(NSInteger)index
{
    if (self.delegate)
    {
        id<MXKRoomMemberCellDataStoring> cellData = [self cellDataAtIndex:index];
        
        Class<MXKCellRendering> class = [self.delegate cellViewClassForCellData:cellData];
        return [class heightForCellData:cellData withMaximumWidth:0];
    }
    return 0;
}

#pragma mark - Members processing

- (void)loadData
{
    NSArray* membersList = [mxRoomState.members membersWithoutConferenceUser];
    
    if (!_settings.showLeftMembersInRoomMemberList)
    {
        NSMutableArray* filteredMembers = [[NSMutableArray alloc] init];
        
        for (MXRoomMember* member in membersList)
        {
            // Filter out left users
            if (member.membership != MXMembershipLeave)
            {
                [filteredMembers addObject:member];
            }
        }
        
        membersList = filteredMembers;
    }
    
    [cellDataArray removeAllObjects];
    
    // Retrieve the MXKCellData class to manage the data
    Class class = [self cellDataClassForCellIdentifier:kMXKRoomMemberCellIdentifier];
    NSAssert([class conformsToProtocol:@protocol(MXKRoomMemberCellDataStoring)], @"MXKRoomMemberListDataSource only manages MXKCellData that conforms to MXKRoomMemberCellDataStoring protocol");
    
    for (MXRoomMember *member in membersList)
    {
        
        id<MXKRoomMemberCellDataStoring> cellData = [[class alloc] initWithRoomMember:member roomState:mxRoomState andRoomMemberListDataSource:self];
        if (cellData)
        {
            [cellDataArray addObject:cellData];
        }
    }
    
    [self sortMembers];
}

- (void)sortMembers
{
    NSArray *sortedMembers = [cellDataArray sortedArrayUsingComparator:^NSComparisonResult(id<MXKRoomMemberCellDataStoring> member1, id<MXKRoomMemberCellDataStoring> member2)
    {
        
        // Move banned and left members at the end of the list
        if (member1.roomMember.membership == MXMembershipLeave || member1.roomMember.membership == MXMembershipBan)
        {
            if (member2.roomMember.membership != MXMembershipLeave && member2.roomMember.membership != MXMembershipBan)
            {
                return NSOrderedDescending;
            }
        }
        else if (member2.roomMember.membership == MXMembershipLeave || member2.roomMember.membership == MXMembershipBan)
        {
            return NSOrderedAscending;
        }
        
        // Move invited members just before left and banned members
        if (member1.roomMember.membership == MXMembershipInvite)
        {
            if (member2.roomMember.membership != MXMembershipInvite)
            {
                return NSOrderedDescending;
            }
        }
        else if (member2.roomMember.membership == MXMembershipInvite)
        {
            return NSOrderedAscending;
        }
        
        if (self->_settings.sortRoomMembersUsingLastSeenTime)
        {
            // Get the users that correspond to these members
            MXUser *user1 = [self.mxSession userWithUserId:member1.roomMember.userId];
            MXUser *user2 = [self.mxSession userWithUserId:member2.roomMember.userId];
            
            // Move users who are not online or unavailable at the end (before invited users)
            if ((user1.presence == MXPresenceOnline) || (user1.presence == MXPresenceUnavailable))
            {
                if ((user2.presence != MXPresenceOnline) && (user2.presence != MXPresenceUnavailable))
                {
                    return NSOrderedAscending;
                }
            }
            else if ((user2.presence == MXPresenceOnline) || (user2.presence == MXPresenceUnavailable))
            {
                return NSOrderedDescending;
            }
            else
            {
                // Here both users are neither online nor unavailable (the lastActive ago is useless)
                // We will sort them according to their display, by keeping in front the offline users
                if (user1.presence == MXPresenceOffline)
                {
                    if (user2.presence != MXPresenceOffline)
                    {
                        return NSOrderedAscending;
                    }
                }
                else if (user2.presence == MXPresenceOffline)
                {
                    return NSOrderedDescending;
                }
                return [[self->mxRoomState.members memberSortedName:member1.roomMember.userId] compare:[self->mxRoomState.members memberSortedName:member2.roomMember.userId] options:NSCaseInsensitiveSearch];
            }
            
            // Consider user's lastActive ago value
            if (user1.lastActiveAgo < user2.lastActiveAgo)
            {
                return NSOrderedAscending;
            }
            else if (user1.lastActiveAgo == user2.lastActiveAgo)
            {
                return [[self->mxRoomState.members memberSortedName:member1.roomMember.userId] compare:[self->mxRoomState.members memberSortedName:member2.roomMember.userId] options:NSCaseInsensitiveSearch];
            }
            return NSOrderedDescending;
        }
        else
        {
            // Move user without display name at the end (before invited users)
            if (member1.roomMember.displayname.length)
            {
                if (!member2.roomMember.displayname.length)
                {
                    return NSOrderedAscending;
                }
            }
            else if (member2.roomMember.displayname.length)
            {
                return NSOrderedDescending;
            }
            
            return [[self->mxRoomState.members memberSortedName:member1.roomMember.userId] compare:[self->mxRoomState.members memberSortedName:member2.roomMember.userId] options:NSCaseInsensitiveSearch];
        }
    }];
    
    cellDataArray = [NSMutableArray arrayWithArray:sortedMembers];
}

- (void)listenMembersEvents
{
    // Remove the previous live listener
    if (membersListener)
    {
        [self.mxSession removeListener:membersListener];
    }
    
    // Register a listener for events that concern room members
    NSArray *mxMembersEvents = @[
                                 kMXEventTypeStringRoomMember,
                                 kMXEventTypeStringRoomPowerLevels,
                                 kMXEventTypeStringPresence
                                 ];
    membersListener = [self.mxSession listenToEventsOfTypes:mxMembersEvents onEvent:^(MXEvent *event, MXTimelineDirection direction, id customObject)
    {
        // consider only live event
        if (direction == MXTimelineDirectionForwards)
        {
            // Check the room Id (if any)
            if (event.roomId && [event.roomId isEqualToString:self->mxRoom.roomId] == NO)
            {
                // This event does not concern the current room members
                return;
            }
            
            // refresh the whole members list. TODO GFO refresh only the updated members.
            [self loadData];
            
            if (self.delegate)
            {
                [self.delegate dataSource:self didCellChange:nil];
            }
        }
    }];
}

- (void)listenTypingNotifications
{
    // Remove the previous live listener
    if (self->typingNotifListener)
    {
        [mxRoom removeListener:self->typingNotifListener];
    }

    // Add typing notification listener
    self->typingNotifListener = [mxRoom listenToEventsOfTypes:@[kMXEventTypeStringTypingNotification] onEvent:^(MXEvent *event, MXTimelineDirection direction, MXRoomState *roomState) {
        // Handle only live events
        if (direction == MXTimelineDirectionForwards)
        {
            // Retrieve typing users list
            NSMutableArray *typingUsers = [NSMutableArray arrayWithArray:self->mxRoom.typingUsers];
            // Remove typing info for the current user
            NSUInteger index = [typingUsers indexOfObject:self.mxSession.myUser.userId];
            if (index != NSNotFound)
            {
                [typingUsers removeObjectAtIndex:index];
            }

            for (id<MXKRoomMemberCellDataStoring> cellData in self->cellDataArray)
            {
                if ([typingUsers indexOfObject:cellData.roomMember.userId] == NSNotFound)
                {
                    cellData.isTyping = NO;
                }
                else
                {
                    cellData.isTyping = YES;
                }
            }

            if (self.delegate)
            {
                [self.delegate dataSource:self didCellChange:nil];
            }
        }
    }];
}

#pragma mark - UITableViewDataSource

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    if (filteredCellDataArray)
    {
        return filteredCellDataArray.count;
    }
    return cellDataArray.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    id<MXKRoomMemberCellDataStoring> roomData = [self cellDataAtIndex:indexPath.row];
    
    if (roomData && self.delegate)
    {
        NSString *identifier = [self.delegate cellReuseIdentifierForCellData:roomData];
        if (identifier)
        {
            UITableViewCell<MXKCellRendering> *cell  = [tableView dequeueReusableCellWithIdentifier:identifier forIndexPath:indexPath];
            
            // Make the bubble display the data
            [cell render:roomData];
            
            return cell;
        }
    }
    
    // Return a fake cell to prevent app from crashing.
    return [[UITableViewCell alloc] init];
}

@end