#!/usr/bin/php

<?php

	require_once __DIR__.'/../../include/php/const';

	$f_auth;
	$f_accesslog;
	$f_states;
	$f_actions;

	$state = [];

	$actions  = [];
	$states   = [];

	$last_user = null;
	$timeout   = 1;







	/* RETURNS THE PERMISSIONS FOR A SPECIFIC CODE AND AN ACTION
	*
	* @code<string>							Some RFID code
	*
	* @return user<array>						User info if found ; else NULL
	*
	*/
	function auth($code){

		global $f_auth;


		/* (1) Goto first line */
		$f_auth->seek(0);

		/* (2) Parse each line */
		while( $f_auth->eof() ){
			
			/* (3) Try to parse line */
			$parsed = json_decode($f_auth->fgets(), true);

			/* (3) Ignore if parse error */
			if( is_null($parsed) )
				continue;

			/* (4) If wrong code -> go to next */
			if( $parsed[0] != $code )
				continue;
		
			/* (5) return user info */
			return [
				'id'  => $parsed[1],
				'can' => $parsed[2]
			];

		}

		/* (6) Return FALSE if not found */
		return null;

	}
















	function mfrc522_setup(){

		/* [0] Initialize global variables
		=========================================================*/
		/* (1) File descriptiors */
		global $f_auth, $f_accesslog;

		/* (2) Caches */
		global $actions, $states, $state;



		/* [1] Open file descriptors on useful files
		=========================================================*/
		/* (1) Read accesses */
		$f_auth      = new SplFileObject(AUTH_LIST, 'r');
		$f_states    = new SplFileObject(STATES_CONF, 'r');
		$f_actions   = new SplFileObject(ACTIONS_CONF, 'r');
		$f_gstate    = @file_get_contents(STATE_CONF);

		/* (2) Append accesses (logs) */
		$f_accesslog = new SplFileObject(ACCESS_LOG, 'a');



		/* [2] Parse ACTIONS and cache them
		=========================================================*/
		/* (1) Parse each line */
		while( $f_actions->eof() ){
			
			/* (2) Try to parse line */
			$parsed = json_decode($f_actions->fgets(), true);

			/* (2) Ignore if parse error */
			if( is_null($parsed) )
				continue;

			/* (3) Add key (timeout) to cache */
			if( !isset($actions[$parsed[0]] )
				$actions[$parsed[0]] = [];

			/* (4) Add entry to cache */
			$actions[$parsed[0]][] = [
				'id'   => $parsed[1],
				'prev' => $parsed[2],
				'next' => $parsed[3],
			];

		}

		/* (5) Free file descriptor */
		$f_actions = null;



		/* [3] Parse STATES and cache them
		=========================================================*/
		/* (1) Parse each line */
		while( $f_states->eof() ){
			
			/* (2) Try to parse line */
			$parsed = json_decode($f_states->fgets(), true);

			/* (2) Ignore if parse error */
			if( is_null($parsed) )
				continue;

			/* (3) Add entry to cache */
			$states[] = $parsed;

		}

		/* (4) Free file descriptor */
		$f_states = null;



		/* [4] Cache global state
		=========================================================*/
		/* (1) Check file */
		if( $f_gstate === false )
			return;

		/* (2) Remove external spaces */
		$f_gstate = preg_replace('@^\s+@', '', $f_gstate);
		$f_gstate = preg_replace('@\s+$@', '', $f_gstate);

		/* (3) For each character create an entry */
		for( $c = 0 ; $c < strlen($f_gstate) ; $c++ )
			$state[] = $c;
	

	}





	function mfrc522_loop(){

		/* [1] Load global variables
		=========================================================*/
		global $last_user;
		global $timeout;

		/* [1] Wait for rfid card
		=========================================================*/
		while( ($code=syscall(SOURCE_DIR.'/lib/mfrc522/read')) === false );

		$code = strtoupper($code);

		slog("card '$code' read", 'mfrc522:read');

		$start_ts = microtime(true);

		
		/* [2] Check for user in auth list
		=========================================================*/
		/* (0) CHECK FOR USER INFO IN AUTH LIST
		---------------------------------------------------------*/
		$user = auth($code);


		/* (1) UNKNOWN USER -> reset count
		---------------------------------------------------------*/
		if( is_null($user) ){
			
			$last_user = null;
			$timeout   = 1;


		/* (2) KNOWN USER -> Manage timeout
		---------------------------------------------------------*/
		}else{

			/* (1) If same as last -> increment @timeout */
			if( $last_user == $user['id'] )
				$timeout++;



		}
		



		/* [n] Wait for 0.5 s before reading again 
		=========================================================*/
		while( microtime(true)-$start_ts < 0.5 );
	}






	slog('daemon started (loop)', 'mfrc522:loop');

	while( true )
		mfrc522_loop();
?>