TimelineHTMLController.m

//
//  TimelineHTMLController.m
//  HelTweetica
//
//  Created by Lucius Kwok on 5/22/10.

/*
 Copyright (c) 2010, Felt Tip Inc. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:  
 1.  Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 2.  Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
 3.  Neither the name of the copyright holder(s) nor the names of any contributors may be used to endorse or promote products derived from this software without specific prior written permission.
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#import "TimelineHTMLController.h"

#import "TwitterFavoriteAction.h"
#import "TwitterDeleteAction.h"

#import "TwitterLoadDirectMessagesAction.h"
#import "TwitterLoadTimelineAction.h"
#import "TwitterLoadListsAction.h"
#import "TwitterLoadSavedSearchesAction.h"

#import "TwitterDirectMessageConversation.h"



// Constants
#ifdef TARGET_PROJECT_MAC
const int kDefaultMaxTweetsShown = 400;
#else
const int kDefaultMaxTweetsShown = 160;
#endif
const int kRewriteHTMLTimerInterval = 60;
static NSString *kTimelineIdentifier = @"Timeline";
static NSString *kMentionsIdentifier = @"Mentions";
static NSString *kDirectMessagesIdentifier = @"Direct";
static NSString *kFavoritesIdentifier = @"Favorites";



@implementation TimelineHTMLController
@synthesize webView, twitter, account, timeline, messages;
@synthesize maxTweetsShown, webViewHasValidHTML, isLoading, noInternetConnection, suppressNetworkErrorAlerts;
@synthesize customPageTitle, customTabName;
@synthesize useRewriteHTMLTimer;
@synthesize delegate;


- (id)init {
	self = [super init];
	if (self) {
		
		// Load the HTML templates.
		directMessageRowTemplate = [[self loadHTMLTemplate:@"dm-row-template"] retain];
		directMessageRowSectionOpenTemplate = [[self loadHTMLTemplate:@"dm-row-section-open"] retain];
		directMessageRowSectionCloseHTML = [[self loadHTMLTemplate:@"dm-row-section-close"] retain];
		tweetRowTemplate = [[self loadHTMLTemplate:@"tweet-row-template"] retain];
		tweetGapRowTemplate = [[self loadHTMLTemplate:@"load-gap-template"] retain];
		
		// Loading template
		loadingHTML = [@"<div class='status'><img class='status_spinner_image' src='spinner.gif'> Loading...</div>" retain];

		// Misc
		isLoading = YES;
		maxTweetsShown = kDefaultMaxTweetsShown; 
		
		// Timeline update notifications
		NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
		[nc addObserver:self selector:@selector(timelineDidFinishLoading:) name:TwitterTimelineDidFinishLoadingNotification object:nil];
		[nc addObserver:self selector:@selector(showTwitterError:) name:TwitterErrorNotification object:nil];
		
	}
	return self;
}

- (void)dealloc {
	[[NSNotificationCenter defaultCenter] removeObserver:self];
	
	[webView release];
	
	[twitter release];
	[account release];
	[timeline release];
	[messages release];
	
	[directMessageRowTemplate release];
	[directMessageRowSectionOpenTemplate release];
	[directMessageRowSectionCloseHTML release];
	
	[tweetRowTemplate release];
	[tweetGapRowTemplate release];
	[loadingHTML release];
	
	[customPageTitle release];
	[customTabName release];
	
	[rewriteHTMLTimer invalidate];
	rewriteHTMLTimer = nil;
	
	[super dealloc];
}

#pragma mark Timeline selection

- (void)updateForNewTimeline {
	// Call this after selecting a different timeline.
	suppressNetworkErrorAlerts = NO;
	self.messages = [timeline messagesWithLimit:maxTweetsShown];
	[self rewriteTweetArea];
	
	// Notify delegate that a different timeline was selected.
	if ([delegate respondsToSelector:@selector(didSelectTimeline:)])
		[delegate didSelectTimeline:timeline];
}

- (void)selectHomeTimeline {
	self.customTabName = kTimelineIdentifier;
	self.timeline = account.homeTimeline;
	[self updateForNewTimeline];
}

- (void)selectMentionsTimeline {
	self.customTabName = kMentionsIdentifier;
	self.timeline = account.mentions;
	[self updateForNewTimeline];
}

- (void)selectDirectMessageTimeline {
	self.customTabName = kDirectMessagesIdentifier;
	self.timeline = account.directMessages;
	[self updateForNewTimeline];
}

- (void)selectFavoritesTimeline {
	self.customTabName = kFavoritesIdentifier;
	self.timeline = account.favorites;
	[self updateForNewTimeline];
	[self refresh];
}


#pragma mark Twitter status line

- (void)showTwitterStatusWithString:(NSString *)string {
	[webView setDocumentElement:@"twitter_status" innerHTML:string];
	[webView setDocumentElement:@"twitter_status" visibility:YES];
	//[webView setDocumentElement:@"twitter_status" height:24];
}

- (void)showLoadingStatus {
	[self showTwitterStatusWithString:@"<img src='fave-spinner.gif'> Loading..."];
}

- (void)hideTwitterStatus {
	[webView setDocumentElement:@"twitter_status" visibility:NO];
	//[webView setDocumentElement:@"twitter_status" innerHTML:@""];
	//[webView setDocumentElement:@"twitter_status" height:0];
}


#pragma mark Loading

- (void)refresh {
	isLoading = YES;
	[self showLoadingStatus];
	//[self setLoadingSpinnerVisibility:YES];
	if (timeline == account.homeTimeline || timeline == account.mentions || timeline == account.directMessages) {
		self.messages = [timeline messagesWithLimit: maxTweetsShown];
		[self rewriteTweetArea];
		[twitter refreshNow];
	} else {
		if (timeline == account.favorites) {
			// Reload messages ignoring what's already local in case there are gaps in our version of the timeline.
			[timeline reloadAll];
		} else {
			[timeline reloadNewer];
		}
	}
	[webView scrollToTop];
}

- (void)loadTimeline:(TwitterTimeline*)aTimeline {
	self.timeline = aTimeline;
	self.messages = [timeline messagesWithLimit:maxTweetsShown];

	if (noInternetConnection == NO) {
		isLoading = YES;
		[self showLoadingStatus];
		if (timeline == account.favorites) {
			// Reload messages ignoring what's already local in case there are gaps in our version of the timeline.
			[timeline reloadAll];
		} else {
			[timeline reloadNewer];
		}
	}
}

- (void)loadOlderWithMaxIdentifier:(NSNumber*)maxIdentifier {
	// Replace link to load the gap or load older with a Loading spinner
	if (maxIdentifier) { 
		// Load gap
		NSString *element = [NSString stringWithFormat:@"gap-%@", [maxIdentifier stringValue]];
		[self.webView setDocumentElement:element innerHTML:loadingHTML];
	} else {
		[self.webView setDocumentElement:@"footer" innerHTML:loadingHTML];
	}
	isLoading = YES;
	[timeline loadOlderWithMaxIdentifier:maxIdentifier];
}

- (BOOL)array:(NSArray *)arrayA containsObjectsNotInArray:(NSArray *)arrayB {
	for (id item in arrayA) {
		if ([arrayB containsObject:item] == NO) 
			return YES;
	}
	return NO;
}

- (void)loadList:(TwitterList*)list {
	TwitterTimeline *listTimeline = list.statuses;
	
	// Style the page title
	NSString *pageTitle = list.fullName;
	NSArray *nameParts = [list.fullName componentsSeparatedByString:@"/"];
	if (nameParts.count == 2) {
		pageTitle = [NSString stringWithFormat:@"%@/<b>%@</b>", [nameParts objectAtIndex:0], [nameParts objectAtIndex:1]];
	}
	self.customPageTitle = pageTitle;
	self.customTabName = NSLocalizedString (@"List", @"tab");
	
	// Create Twitter action to load list statuses into the timeline.
	NSString *method = [NSString stringWithFormat:@"%@/lists/%@/statuses", list.username, list.identifier];
	listTimeline.loadAction = [[[TwitterLoadTimelineAction alloc] initWithTwitterMethod:method] autorelease];
	listTimeline.loadAction.countKey = @"per_page";
	suppressNetworkErrorAlerts = NO;
	
	// Set the Twitter cache connection.
	[list setTwitter:twitter account:account];
	
	// Load timeline
	[self loadTimeline: listTimeline];
	
	// Rewrite and scroll web view
	[self rewriteTweetArea];	
	[self.webView scrollToTop];

	// Notify delegate that a different timeline was selected.
	if ([delegate respondsToSelector:@selector(didSelectTimeline:)])
		[delegate didSelectTimeline:timeline];
}

#pragma mark Favorite status update

- (void) fave: (NSNumber*) messageIdentifier {
	noInternetConnection = NO;
	
	TwitterStatusUpdate *message = [twitter statusUpdateWithIdentifier: messageIdentifier];
	if (message == nil) {
		NSLog (@"Cannot find the message to fave (or unfave). id == %@", messageIdentifier);
		return;
	}
	
	BOOL isFave = [account messageIsFavorite:messageIdentifier];
	
	TwitterFavoriteAction *action = [[[TwitterFavoriteAction alloc] initWithMessage:message destroy:isFave] autorelease];
	action.completionTarget= self;
	action.completionAction = @selector(didFave:);
	[twitter startTwitterAction:action withAccount:account];
	
	// Change the star to a spinner.
	NSString *element = [NSString stringWithFormat:@"star-%@", [message.identifier stringValue]];
	NSString *html = @"<img src='fave-spinner.gif'>";
	[self.webView setDocumentElement:element innerHTML:html];
	
}

- (void)didFave:(TwitterFavoriteAction *)action {
	TwitterStatusUpdate *message = [action message];
	if (action.success == NO) return;
	BOOL isFave = !action.destroy;
	
	// Change the display of the star next to tweet in root view
	NSString *element = [NSString stringWithFormat:@"star-%@", [message.identifier stringValue]];
	NSString *html = isFave ? @"<img src='action-star-on.png'>" : @"<img src='action-star.png'>";
	[self.webView setDocumentElement:element innerHTML:html];
	
	// Remove from favorites timeline
	if (isFave) {
		[account addFavorites:[NSArray arrayWithObject:message]];
	} else {
		[account removeFavorite:message.identifier];
	}
}

#pragma mark Delete status update

- (void)deleteStatusUpdate:(NSNumber *)identifier {
	// Change the trash can to a spinner.
	NSString *element = [NSString stringWithFormat:@"trash-%@", [identifier stringValue]];
	NSString *html = @"<img src='fave-spinner.gif'>";
	[self.webView setDocumentElement:element innerHTML:html];

	TwitterDeleteAction *action = [[[TwitterDeleteAction alloc] initWithMessageIdentifier:identifier] autorelease];
	action.completionTarget= self;
	action.completionAction = @selector(didDeleteStatusUpdate:);
	[twitter startTwitterAction:action withAccount:account];
}

- (void)didDeleteStatusUpdate:(TwitterDeleteAction *)action {
	[twitter deleteStatusUpdate:action.identifier];
	self.messages = [timeline messagesWithLimit:maxTweetsShown];
	[self rewriteTweetArea];
}

#pragma mark Web view updating

- (void)loadWebView {
	// Load template and replace special tags with data
	NSString *template = [self webPageTemplate];
	if (template == nil) return;
	NSMutableString *html = [NSMutableString stringWithString:template];
	
	// Use the timeline HTML controller to create the HTML content.
	NSString *tweetAreaHTML = @"<div class='login'><a href='action:login'>Please log in.</a></div>";
	NSString *currentAccountHTML = @"";
	NSString *tabAreaHTML = @"";
	
	if (account.screenName != nil) {
		tweetAreaHTML = [self tweetAreaHTML];
		currentAccountHTML = [self currentAccountHTML];
		tabAreaHTML = [self tabAreaHTML];
	}
	
	// Replace custom tags with HTML
	[html replaceOccurrencesOfString:@"<tweetAreaHTML/>" withString:tweetAreaHTML options:0 range:NSMakeRange(0, html.length)];
	[html replaceOccurrencesOfString:@"<currentAccountHTML/>" withString:currentAccountHTML options:0 range:NSMakeRange(0, html.length)];
	[html replaceOccurrencesOfString:@"<tabAreaHTML/>" withString:tabAreaHTML options:0 range:NSMakeRange(0, html.length)];
	
	[self.webView loadHTMLString:html];

	if (useRewriteHTMLTimer) {
		[self scheduleRewriteHTMLTimer];
	}
}

- (void)setLoadingSpinnerVisibility:(BOOL)isVisible {
	if (webViewHasValidHTML)
		[self.webView setDocumentElement:@"spinner" visibility:isVisible];
}

- (void)rewriteTweetArea {
	if (webViewHasValidHTML) {
		// Replace tab area HTML with current tab
		if (customTabName != nil) {
			[self.webView setDocumentElement:@"tab_area" innerHTML:[self tabAreaHTML]];
		}
	
		// Replace tweet area HTML with new tweets
		NSString *result = [self.webView setDocumentElement:@"tweet_area" innerHTML:[self tweetAreaHTML]];
		if ([result length] == 0) { // If the result of the JavaScript call is empty, there was an error.
			NSLog (@"JavaScript error in refreshing tweet area. Reloading entire web view.");
			[self loadWebView];
		}
	} else {
		// This isn't really a bug or exception to call this method when the web view isn't ready, so it isn't logged. 
		//NSLog (@"rewriteTweetArea called when webViewHasValidHTML == NO.");
	}

	if (useRewriteHTMLTimer) {
		[self scheduleRewriteHTMLTimer];
	}
}

- (void)scheduleRewriteHTMLTimer {
	if (useRewriteHTMLTimer) {
		[rewriteHTMLTimer invalidate];
		rewriteHTMLTimer = [NSTimer scheduledTimerWithTimeInterval:kRewriteHTMLTimerInterval target:self selector:@selector(fireRewriteHTMLTimer:) userInfo:nil repeats:NO];
	}
}

- (void)fireRewriteHTMLTimer:(NSTimer *)timer {
	if (useRewriteHTMLTimer) {
		[self rewriteTweetArea];
	}
}

#pragma mark Web actions

- (BOOL)handleWebAction:(NSString*)action {
	BOOL handled = YES;
	NSNumber *messageIdentifier = [self number64WithString:[action lastPathComponent]];
	
	// Select a timeline
	if ([action isEqualToString:kTimelineIdentifier]) { // Home Timeline
		self.customPageTitle = nil; // Reset the custom page title.
		[self selectHomeTimeline];
	} else if ([action isEqualToString:kMentionsIdentifier]) { // Mentions
		self.customPageTitle = nil; // Reset the custom page title.
		[self selectMentionsTimeline];
	} else if ([action isEqualToString:kDirectMessagesIdentifier]) { // Mentions
		self.customPageTitle = nil; // Reset the custom page title.
		[self selectDirectMessageTimeline];
	} else if ([action isEqualToString:kFavoritesIdentifier]) { // Favorites
		self.customPageTitle = nil; // Reset the custom page title.
		[self selectFavoritesTimeline];
	}
	
	// Other actions
	else if ([action hasPrefix:@"fave"]) { // Add message to favorites or remove from favorites
		[self fave:messageIdentifier];
	} else if ([action hasPrefix:@"loadOlder"]) { // Load older
		[self loadOlderWithMaxIdentifier:nil];
	} else if ([action hasPrefix:@"loadGap"]) { // Load gap
		[self loadOlderWithMaxIdentifier:messageIdentifier];
	} else {
		handled = NO;
	}
	return handled;
}

- (NSNumber*)number64WithString:(NSString*)string {
	if (string == nil) return nil;
	
	NSScanner *scanner = [NSScanner scannerWithString:string];
	SInt64 identifierInt64;
	if ([scanner scanLongLong: &identifierInt64])
		return [NSNumber numberWithLongLong: identifierInt64];
	return nil;
}


#pragma mark HTML

- (NSString *)htmlWithTemplate:(NSString *)template substitutions:(NSDictionary *)substitutions {
	if (template == nil) return nil;
	
	// Use scanner to replace curly-bracketed variables with values
	NSScanner *scanner = [NSScanner scannerWithString:template];
	NSMutableString *tweetRowHTML = [[[NSMutableString alloc] init] autorelease];
	NSString *scannedString, *key, *value;
	BOOL displayBlock = YES;
	
	// Set scanner to include whitespace
	[scanner setCharactersToBeSkipped:nil];
	
	while ([scanner isAtEnd] == NO) {
		// Scan characters up to opening of variable curly brace
		if ([scanner scanUpToString:@"{" intoString:&scannedString] && displayBlock) {
			[tweetRowHTML appendString:scannedString];
		}
		
		// Scan name of variable or block
		if ([scanner scanUpToString:@"}" intoString:&scannedString]) {
			if ([scannedString hasPrefix:@"{Block:"]) {
				// Block
				if ([scannedString length] > 7) {
					key = [scannedString substringFromIndex:7];
					value = [substitutions objectForKey:key];
					displayBlock = (value != nil);
				}
			} else if ([scannedString hasPrefix:@"{/Block"]) {
				// End Block
				displayBlock = YES;
			} else {
				// Variable
				if (displayBlock && [scannedString length] > 1) {
					key = [scannedString substringFromIndex:1];
					value = [substitutions objectForKey:key];
					if (value) 
						[tweetRowHTML appendString:value];
				}
			}
		}
		
		// Scan past closing curly brace
		[scanner scanString:@"}" intoString:nil];
	}
	
	return tweetRowHTML;
}

- (NSString *)htmlWithStatusUpdate:(TwitterStatusUpdate *)statusUpdate rowIndex:(int)rowIndex {
	// Skip rows with invalid identifiers.
	if ([statusUpdate.identifier longLongValue] < 1000) return @"";
	
	BOOL lastRow = (rowIndex >= maxTweetsShown - 1 || rowIndex >= messages.count - 1);
	NSMutableDictionary *substitutions = [NSMutableDictionary dictionary];
	NSMutableString *gapRowHTML = nil;
	
	// Append "Load gap" row if needed
	BOOL gap = [timeline hasGapAfter:statusUpdate.identifier];
	NSString *messageIdentifier = [statusUpdate.identifier stringValue];
	if ((gap == YES) && (lastRow == NO)) {
		gapRowHTML = [NSMutableString stringWithString:tweetGapRowTemplate];
		[gapRowHTML replaceOccurrencesOfString:@"{gapIdentifier}" withString:messageIdentifier options:0 range:NSMakeRange(0, gapRowHTML.length)];
	}
	
	// Special handling for new-style retweets.
	if ([statusUpdate.retweetedStatusIdentifier longLongValue] != 0) {
		[substitutions setObject:@"<img src='retweet.png'>" forKey:@"retweetIcon"];
		if (statusUpdate.userScreenName) 
			[substitutions setObject:statusUpdate.userScreenName forKey:@"retweetedBy"];
		statusUpdate = [twitter statusUpdateWithIdentifier:statusUpdate.retweetedStatusIdentifier];
	}

	// Row style
	NSString *rowStyle = [self styleForStatusUpdate:statusUpdate rowIndex:rowIndex];
	if (rowStyle != nil) 
		[substitutions setObject:rowStyle forKey:@"tweetRowStyle"];
						  
	// Favorites
	if ([account messageIsFavorite:statusUpdate.identifier]) 
		[substitutions setObject:@"-on" forKey:@"faveImageSuffix"];
	
	// Own tweets.
	if ([statusUpdate.userIdentifier isEqualToNumber:account.identifier]) {
		// Show delete action but hide reply, dm, and retweet buttons.
		[substitutions setObject:@"YES" forKey:@"ownActions"];
	} else {
		// Always show action buttons on right side of page.
		[substitutions setObject:@"YES" forKey:@"actions"];
	}
	
	// Add values from status update.
	[substitutions addEntriesFromDictionary:[statusUpdate htmlSubstitutions]];
	
	// Load template and apply substitutions.
	NSString *html = [self htmlWithTemplate:tweetRowTemplate substitutions:substitutions];
	if (gapRowHTML != nil) 
		html = [html stringByAppendingString:gapRowHTML];
	
	return html;
}

- (NSString *)styleForStatusUpdate:(TwitterStatusUpdate *)statusUpdate rowIndex:(int)rowIndex {
	NSString *style = nil;
	
	// Mentions
	NSRange found = [statusUpdate.text rangeOfString:[NSString stringWithFormat:@"@%@", account.screenName] options:NSCaseInsensitiveSearch];
	if (found.location != NSNotFound)
		style = @"mention_tweet_row";
	
	// Own tweets
	if ([statusUpdate.userIdentifier isEqualToNumber:account.identifier] || [statusUpdate.userScreenName isEqualToString:account.screenName])
		style = @"self_tweet_row";

	return style;
}

- (NSString *)htmlWithDirectMessageConversation:(TwitterDirectMessageConversation *)conversation rowIndex:(int)rowIndex {
	// Each row in the messages array corresponds to one conversation with one user. Each conversation has a subarray of direct messages, sorted by date, newest first. 

	NSMutableString *html = [NSMutableString string];
	
	// Open the row and substitute the user screenName and profileImageURL in the template.
	NSMutableDictionary *substitutions = [NSMutableDictionary dictionary];
	TwitterUser *user = [twitter userWithIdentifier:conversation.userIdentifier];
	[substitutions setObject:user.screenName forKey:@"screenName"];
	[substitutions setObject:user.profileImageURL forKey:@"profileImageURL"];
	[html appendString:[self htmlWithTemplate:directMessageRowSectionOpenTemplate substitutions:substitutions]];
	
	// Loop through each message
	for (TwitterDirectMessage *message in conversation.messages) {
		[html appendString:[self htmlWithTemplate:directMessageRowTemplate substitutions:[message htmlSubstitutions]]];
	}
	
	// Close the row.
	[html appendString:directMessageRowSectionCloseHTML];
	
	return html;
}

- (NSString *)loadHTMLTemplate:(NSString *)templateName {
	// Load main template
	NSError *error = nil;
	NSString *filePath = [[NSBundle mainBundle] pathForResource:templateName ofType:@"html"];
	NSString *html = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:&error];
	if (error != nil)
		NSLog (@"Error loading %@.html: %@", templateName, [error localizedDescription]);
	return html;
}

- (NSString *)webPageTemplate {
	return [self loadHTMLTemplate:@"main-template"];
}

- (NSString *)currentAccountHTML {
	return [NSString stringWithFormat:@"<a href='action:user/%@'>%@</a>", account.screenName, account.screenName];
}

- (NSString *)tabAreaHTML {
	NSMutableString *html = [[[NSMutableString alloc] init] autorelease];
	
	int selectedTab = 0;
	NSString *tabName = self.customTabName;
	if ([tabName isEqualToString: kTimelineIdentifier] || (tabName == nil)) {
		selectedTab = 1;
	} else if ([tabName isEqualToString: kMentionsIdentifier]) {
		selectedTab = 2;
	} else if ([tabName isEqualToString: kDirectMessagesIdentifier]) {
		selectedTab = 3;
	} else if ([tabName isEqualToString: kFavoritesIdentifier]) {
		selectedTab = 4;
	} else {
		selectedTab = 5;
	}
	
	[html appendFormat:@"<div class='tab %@selected' onclick=\"location.href='action:Timeline';\">Timeline</div>", (selectedTab == 1)? @"" : @"de"];
	[html appendFormat:@"<div class='tab %@selected' onclick=\"location.href='action:Mentions';\">Mentions</div>", (selectedTab == 2)? @"" : @"de"];
	[html appendFormat:@"<div class='tab %@selected' onclick=\"location.href='action:Direct';\">Direct</div>", (selectedTab == 3)? @"" : @"de"];
	[html appendFormat:@"<div class='tab %@selected' onclick=\"location.href='action:Favorites';\">Favorites</div>", (selectedTab == 4)? @"" : @"de"];
	if (selectedTab == 5)
		[html appendFormat:@"<div class='tab selected'>%@</div>", tabName];
	
	return html;
}

- (NSString*) tweetAreaHTML {
	NSMutableString *html = [[[NSMutableString alloc] init] autorelease];

	// Page Title for Lists and Search
	if (customPageTitle) {
		// Put the title inside a regular tweet table row.
		[html appendString:@"<div class='tweet_table'><div class='tweet_row'><div class='tweet_avatar'></div><div class='tweet_content'>"];
		[html appendFormat:@"<div class='page_title'>%@</div>", customPageTitle];
		[html appendString:@"</div></div></div>"];
	}
	
	[html appendString:@"<div class='tweet_table'> "];

	// Rows of status updates or direct messages.
	id rowItem;
	for (int index=0; index<messages.count; index++) {
		rowItem = [messages objectAtIndex:index];
		if ([rowItem isKindOfClass:[TwitterStatusUpdate class]]) {
			[html appendString:[self htmlWithStatusUpdate:rowItem rowIndex:index]];
		} else if ([rowItem isKindOfClass:[TwitterDirectMessageConversation class]]) {
			[html appendString:[self htmlWithDirectMessageConversation:rowItem rowIndex:index]];
		}
	}
	
	[html appendString:@"</div> "]; // Close tweet_table
	
	// Footer
	[html appendString:@"<div id='footer'>"];
	[html appendString:[self tweetAreaFooterHTML]];
	[html appendString:@"</div> "]; // Close footer
	
	return html;
}

- (NSString*) tweetAreaFooterHTML {
	NSString *result = @"";
	
	if (noInternetConnection) {
		result = @"<div class='status'>No Internet connection.</div>";
	} else if (account.xAuthToken == nil) {
		result = @"<div class='status'><a href='action:login'>Please log in.</a></div>";
	} else if (isLoading) { // (actions.count > 0 || !webViewHasValidHTML)
		result = loadingHTML;
	} else if (messages.count == 0) {
		result = @"<div class='status'>No messages.</div>";
	} else if (timeline.noOlderMessages) {
		result = @"";
	} else if (messages.count < maxTweetsShown) {
		// Action to Load older messages 
		result = @"<div class='load_older'><a href='action:loadOlder'>Load older messages</a></div> ";
	}
	
	return result;
}


- (void) replaceBlock:(NSString*)blockName display:(BOOL)display inTemplate:(NSMutableString*)template {
	// Find beginning and end of block tags
	NSString *openTag = [NSString stringWithFormat:@"{Block:%@}", blockName];
	NSString *closeTag = [NSString stringWithFormat:@"{/Block:%@}", blockName];
	
	if (display) {
		// Just remove the tags if we're displaying the block
		[template replaceOccurrencesOfString:openTag withString:@"" options:0 range:NSMakeRange(0, template.length)];
		[template replaceOccurrencesOfString:closeTag withString:@"" options:0 range:NSMakeRange(0, template.length)];
	} else {
		// Remove the entire block if we're not displaying it
		NSRange openRange = [template rangeOfString:openTag];
		NSRange closeRange = [template rangeOfString:closeTag];
		if (openRange.location == NSNotFound || closeRange.location == NSNotFound) return; // Can't find both tags
		NSRange replaceRange = NSMakeRange(openRange.location, closeRange.location + closeRange.length - openRange.location);
		[template replaceCharactersInRange:replaceRange withString:@""];
	}
}

#pragma mark Notifications

- (void)timelineDidFinishLoading:(NSNotification *)notification {
	TwitterTimeline *aTimeline = [notification object];
	if (aTimeline == self.timeline) {
		isLoading = NO;
		[self hideTwitterStatus];
		self.messages = [timeline messagesWithLimit: maxTweetsShown];
		[self rewriteTweetArea];
	}
}

- (void)showTwitterError:(NSNotification *)notification {
	NSError *error = [notification object];
	NSString *message = [error localizedDescription];
	//int statusCode = [error code];
	
	[self showTwitterStatusWithString:message];
}


@end