/*
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 "MXKSearchDataSource.h"

#import "MXKSearchCellData.h"

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


@interface MXKSearchDataSource ()
{
    /**
     The current search request.
     */
    MXHTTPOperation *searchRequest;

    /**
     Token that can be used to get the next batch of results in the group, if exists.
     */
    NSString *nextBatch;
}

@end

@implementation MXKSearchDataSource 

- (instancetype)initWithMatrixSession:(MXSession *)mxSession
{
    self = [super initWithMatrixSession:mxSession];
    if (self)
    {
        // Set default data and view classes
        // Cell data
        [self registerCellDataClass:MXKSearchCellData.class forCellIdentifier:kMXKSearchCellDataIdentifier];

        // Set default MXEvent -> NSString formatter
        _eventFormatter = [[MXKEventFormatter alloc] initWithMatrixSession:mxSession];
        
        _roomEventFilter = [[MXRoomEventFilter alloc] init];

        cellDataArray = [NSMutableArray array];
    }
    return self;
}

- (void)destroy
{
    cellDataArray = nil;
    _eventFormatter = nil;
    
    _roomEventFilter = nil;
    
    [super destroy];
}

- (void)searchMessages:(NSString*)textPattern force:(BOOL)force
{
    if (force || ![_searchText isEqualToString:textPattern])
    {
        // Reset data before making the new search
        if (searchRequest)
        {
            [searchRequest cancel];
            searchRequest = nil;
        }
        
        _searchText = textPattern;
        _serverCount = 0;
        _canPaginate = NO;
        nextBatch = nil;
        
        self.state = MXKDataSourceStatePreparing;
        [cellDataArray removeAllObjects];
        
        if (textPattern.length)
        {
            MXLogDebug(@"[MXKSearchDataSource] searchMessages: %@", textPattern);
            [self doSearch];
        }
        else
        {
            // Refresh table display.
            self.state = MXKDataSourceStateReady;
            [self.delegate dataSource:self didCellChange:nil];
        }
    }
}

- (void)paginateBack
{
    MXLogDebug(@"[MXKSearchDataSource] paginateBack");

    self.state = MXKDataSourceStatePreparing;
    [self doSearch];
}

- (MXKCellData*)cellDataAtIndex:(NSInteger)index
{
    MXKCellData *cellData;
    if (index < cellDataArray.count)
    {
        cellData = cellDataArray[index];
    }

    return cellData;
}

- (void)convertHomeserverResultsIntoCells:(MXSearchRoomEventResults*)roomEventResults onComplete:(dispatch_block_t)onComplete
{
    // Retrieve the MXKCellData class to manage the data
    // Note: MXKSearchDataSource only manages MXKCellData that conforms to MXKSearchCellDataStoring protocol
    // see `[registerCellDataClass:forCellIdentifier:]`
    Class class = [self cellDataClassForCellIdentifier:kMXKSearchCellDataIdentifier];

    dispatch_group_t group = dispatch_group_create();

    for (MXSearchResult *result in roomEventResults.results)
    {
        dispatch_group_enter(group);
        [class cellDataWithSearchResult:result andSearchDataSource:self onComplete:^(__autoreleasing id<MXKSearchCellDataStoring> cellData) {
            dispatch_group_leave(group);

            if (cellData)
            {
                ((id<MXKSearchCellDataStoring>)cellData).shouldShowRoomDisplayName = self.shouldShowRoomDisplayName;

                // Use profile information as data to display
                MXSearchUserProfile *userProfile = result.context.profileInfo[result.result.sender];
                cellData.senderDisplayName = userProfile.displayName;

                [self->cellDataArray insertObject:cellData atIndex:0];
            }
        }];
    }

    dispatch_group_notify(group, dispatch_get_main_queue(), ^{
        onComplete();
    });
}

#pragma mark - Private methods

// Update the MXKDataSource and notify the delegate
- (void)setState:(MXKDataSourceState)newState
{
    state = newState;

    if (self.delegate)
    {
        if ([self.delegate respondsToSelector:@selector(dataSource:didStateChange:)])
        {
            [self.delegate dataSource:self didStateChange:state];
        }
    }
}

- (void)doSearch
{
    // Handle one request at a time
    if (searchRequest)
    {
        return;
    }

    NSDate *startDate = [NSDate date];

    MXWeakify(self);
    searchRequest = [self.mxSession.matrixRestClient searchMessagesWithText:_searchText roomEventFilter:_roomEventFilter beforeLimit:0 afterLimit:0 nextBatch:nextBatch success:^(MXSearchRoomEventResults *roomEventResults) {
        MXStrongifyAndReturnIfNil(self);

        MXLogDebug(@"[MXKSearchDataSource] searchMessages: %@ (%d). Done in %.3fms - Got %tu / %tu messages", self.searchText, self.roomEventFilter.containsURL, [[NSDate date] timeIntervalSinceDate:startDate] * 1000, roomEventResults.results.count, roomEventResults.count);

        self->searchRequest = nil;
        self->_serverCount = roomEventResults.count;
        self->nextBatch = roomEventResults.nextBatch;
        self->_canPaginate = (nil != self->nextBatch);

        // Process HS response to cells data
        MXWeakify(self);
        [self convertHomeserverResultsIntoCells:roomEventResults onComplete:^{
            MXStrongifyAndReturnIfNil(self);

            self.state = MXKDataSourceStateReady;

            // Provide changes information to the delegate
            NSIndexSet *insertedIndexes;
            if (roomEventResults.results.count)
            {
                insertedIndexes = [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(0, roomEventResults.results.count)];
            }

            [self.delegate dataSource:self didCellChange:insertedIndexes];
        }];

    } failure:^(NSError *error) {
        MXStrongifyAndReturnIfNil(self);

        self->searchRequest = nil;
        self.state = MXKDataSourceStateFailed;
    }];
}

#pragma mark - Override MXKDataSource

- (void)registerCellDataClass:(Class)cellDataClass forCellIdentifier:(NSString *)identifier
{
    if ([identifier isEqualToString:kMXKSearchCellDataIdentifier])
    {
        // Sanity check
        NSAssert([cellDataClass conformsToProtocol:@protocol(MXKSearchCellDataStoring)], @"MXKSearchDataSource only manages MXKCellData that conforms to MXKSearchCellDataStoring protocol");
    }
    
    [super registerCellDataClass:cellDataClass forCellIdentifier:identifier];
}

- (void)cancelAllRequests
{
    if (searchRequest)
    {
        [searchRequest cancel];
        searchRequest = nil;
    }

    [super cancelAllRequests];
}

#pragma mark - UITableViewDataSource

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

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    MXKCellData* cellData = [self cellDataAtIndex:indexPath.row];

    NSString *cellIdentifier = [self.delegate cellReuseIdentifierForCellData:cellData];
    if (cellIdentifier)
    {
        UITableViewCell<MXKCellRendering> *cell  = [tableView dequeueReusableCellWithIdentifier:cellIdentifier forIndexPath:indexPath];

        // Make the bubble display the data
        [cell render:cellData];

        // Disable any interactions defined in the cell
        // because we want [tableView didSelectRowAtIndexPath:] to be called
        cell.contentView.userInteractionEnabled = NO;

        // Force background color change on selection
        cell.selectionStyle = UITableViewCellSelectionStyleDefault;

        return cell;
    }

    // Return a fake cell to prevent app from crashing.
    return [[UITableViewCell alloc] init];
}

@end