Structure Of Application:

The main entry point of application is index file.

All the files place on root folder of the project are entry point of a request made from the application.

These files will access the class files placed in 'classes' folder to complete the task.

One class ma have access to function of same or other class.

Moreover, 3rd party libraries used are placed inside 'lib' folder.

Below are the details about all fodlers of the project:

	audio: Contains audio files used in application for sound of new message. 

	classes: Contains class files used in the application.

	crons: Contains cron file which you can modify as per your need and use to sync messages to any database system. 

	css: Contains css stylesheet files.

	files: Contains user related persistent information.

	h: Contains file with history of user messages.

	images: Contains image files used in the application.

	js: Contains javascript files used in the application.

	lib: Contains external (3rd party) libraries used in the application.

	pub: Contains files uploaded by the user.

	server: Contains files used to websocket support.

	tmp: Temporarily stored messages received from the user



Now lets have a detailed view for each file / folder.

Root folder:

	common: File containing common code which is included inside all other files for each request. 
		In this file first of all time zone is set using date_default_timezone_set() function.
		In the next few lines site path and site url are determined .
		After that an arrays is created to define text code for smileys.
		Now, few global variables are defined which we have used through out the application.
			debug_mode: Not used yet
			manage_tmp_files: If true user messages will be deleted from 'tmp' folder by the application, if false application won't but you will have to delete it using the cron
			port: If websocket server is started it will run on this port
			long_polling_inerval: Minimum interval for which request to server for new message will wait for server's response after which it will disconnect and make new request
			group_prefix: Prefix prepended to the group files to identify them as group files and not to consider as user files.
			name_sep: Separator used to separate names of two users when used together for association of those two users inside the application.
			group_sep Seperator used to separate group name and group unique number
		Finally, class 'FSDS' is included and its object is created. This is used throughout the application to deal with data storage. 

	index: Main entry file of the application
		You can see that common file is included in the index file. The same way it is also included in every file which serve as entry point to any request.
		Next, two variables are set from get requests if available. These are 'name' (name of user) and 'cpcode' (change password code, used in forgot password flow).
		Next, we have assigned few variable from post request and also assigned ejc (extra javascript code) variable to call login in case these variables are assigned. 
		This is to facilitate you to integrate with your application and make your application users login into this chat application using a post method redirect (* user files must exist, more detail later on).
		Next, we have defined a variable containing html code to load default smileys. Make sure this code is proper as per smileys variable in common file.
		Next, we are scanning 'images/custom/' folder to check for any other smileys available. Uncomment the line inside foreach loop starting with code '// $anims' and also the line outside foreach loop starting with code '// $emos' to enable loading of these smileys.

	chat: This file can be used to run websocket server.
		Command to execute this file is: path_to_php_executable -q /path_to_this_file/chat.php
		For e.g. /usr/bin/php -q /var/www/simple-web-chat/chat.php
		You can see the here also 'common' file is loaded first and then the required class files are loaded.
		Finally, server object is created and run method of the server object is executed which will start the websocket server.

	download: This file is the entry point to download user's uploaded files. It is not using any class file and itself contains logic to provide download to user's uploaded files. 
		Whenever a file is uploaded one empty flag file is created at 'files/tfs/' folder under a folder with username of uploading user. 
		The name of this file is appended with username of contact with which this file is shared. In case of group its group's identifier instead of username of contact.
		Also, the link stored in message contains username of uploader.  
		Hence, in this file we fetch uploader's username from 'fl' variable obtained from request.
		The 'name' variable is the username of the user from which request to download is received.
		So, if the 'name' variable is the same as that obtained from 'fl' variable of request or if a flag file exists for the user who requested to download; means the user can access / download the file.

	acceptcreq: This file is the entry point for add as contact request. It uses acceptCReq() function of 'AcceptRequest' class. 

	acceptgreq: This file is the entry point for add to group request. It uses acceptGReq() function of 'AcceptRequest' class. 
	
	biCChat: This file is the entry point for request to begin chat with any contact. It uses initCChat() function of 'InitContactChat' class. 
	
	biGChat: This file is the entry point for request to begin chat with any group. It uses initGChat() function of 'InitGroupChat' class.
	
	chkusr: This file is the entry point for request to check user login details. It uses checkIdentity() function of 'CheckUserIdentity' class.

	cp: This file is the entry point to forgot password request. It uses modifyPasscode() function of 'ModifyPass' class.

	csrch: This file is the entry point to contact search request. It uses getUserGroupsNContacts() function of 'UserContacts' class.

	filehandler: This file is the entry point to file upload request. It uses fileCopy() function of 'Reply' class.

	history: This file is the entry point to display user's history of messages. It uses getHistory() function of 'ChatHistory' class.

	logout: This file is the entry point to user logout request. It uses clearSession() function of 'ClearUserSession' class.

	managegroup: This file is the entry point to user's manage group (add / edit group) request. It uses manageUserGroups() function of 'ManageGroups' class.

	nchat: This file is the entry point to fetch user messages. It uses fetchMessages() function of 'Messages' class.

	newcontact: This file is the entry point to add new contact request. It uses addNewContact() function of 'NewContact' class.

	rejectcreq: This file is the entry point to reject contact request. It uses rejectCRequest() function of 'RejectRequest' class.

	rejectgreq: This file is the entry point to reject add to group request. It uses rejectGRequest() function of 'RejectRequest' class.

	rejectgroup: This file is the entry point to exit from a group request. It uses removeGroup() function of 'RemoveContacts' class.

	removecon: This file is the entry point of request to remove a user from contact. It uses removeContact() function of 'RemoveContacts' class.

	reply: This file is the entry point to send a message. It uses sendMessage() function of 'Reply' class.

	selcgroup: This file is the entry point of request to fetch group details. It uses groupContacts() function of 'GroupDetails' class.

	ssrch: This file is the entry point of request to search people. It uses findPeople() function of 'SearchPeople' class.

	uverify: This file is the entry point of request to verify user account. It uses verifyUser() function of 'UserVerification' class.