SATS/feature/motheure-simple/source/loop.php

#!/usr/bin/php
<?php

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

	$f_data;
	$start_ts;

	$FEATURE   = basename(dirname(__DIR__));

	$MOTOR_PIN = 19;

	$LOOP_FREQ = 100; // check frequency in ms
	$THRESHOLD = 4;   // maximum number of reads to wait for motor to be active back




	/* READ MOTOR STATE
	*
	*/
	function motheure_read(){

		/* [1] Export global caches + variables
		=========================================================*/
		/* (1) Motor pin */
		global $MOTOR_PIN;

		/* [2] Try to read motor state
		=========================================================*/
		/* (1) Get its state */
		$STATE = syscall( SOURCE_DIR."/lib/gpio/in $MOTOR_PIN" );

		/* (2) If invalid */
		if( is_bool($STATE) ){
			slog('read: 0', 'motheure-simple:loop', 'motheure');
			return false;
		}

		/* (3) If active, pass */
		if( $STATE == 0 ){
			slog('read: 1', 'motheure-simple:loop', 'motheure');
			return true;
		}

		/* (4) Return FALSE means motor inactive */
		slog('read: 0', 'motheure-simple:loop', 'motheure');
		return false;

	}


	/* MAIN LOOP
	*
	*/
	function motheure_loop(){

		/* [1] Export global caches + variables
		=========================================================*/
		/* (1) Log history file descriptor */
		global $f_data;

		/* (2) Motor pin */
		global $MOTOR_PIN;

		/* (3) Loop data */
		global $start_ts;
		global $LOOP_FREQ;
		global $THRESHOLD;



		/* [2] Try to read motor state
		=========================================================*/
		/* (1) Read motor pin */
		if( !motheure_read() ) // if not active -> continue watching
			return false;

		slog('Motor start', 'motheure-simple:loop', 'motheure');

		/* [3] Wait for machine to stop
		=========================================================*/
		/* (0) Userful variables */
		$offset = 0; // offset (number of 0 reads)
		$loop_ts = 0; // loop start time
		$stop_ts = microtime(true); // last active time for now

		while( $offset <= $THRESHOLD ){ // exit when motor active for $threshold cycles

			/* (1) Start loop timer */
			$loop_ts = microtime(true);

			/* (2) If stopped -> increment offset */
			if( !motheure_read() ){

				$offset++;
				slog("Motor offset: $offset/$THRESHOLD", 'motheure-simple:loop', 'motheure');

			/* (3) If not stopped */
			}else{
				$offset = 0;
				$stop_ts = microtime(true); // last active time for now
			}

			/* (4) Wait for loop to last @LOOP_FREQ seconds (if not already elapsed) */
			while( microtime(true) - $loop_ts < ($LOOP_FREQ/1000) );
		}



		/* [2] Main loop
		=========================================================*/
		/* (1) Log action to default log file */
		$f_data->fwrite( json_encode([
			floor( $stop_ts - $start_ts )
		]).PHP_EOL );
		slog("Motor stop", 'motheure-simple:loop', 'motheure');

		/* (2) Return status */
		return true;

	}













	function motheure_setup(){

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

		/* (3) Useful data */
		global $FEATURE;
		global $MOTOR_PIN;

		/* [1] Open file descriptors on useful files
		=========================================================*/
		/* (1) Append accesses (logs) */
		if( !file_exists(DATA_DIR."/$FEATURE") )
			file_put_contents(DATA_DIR."/$FEATURE", '');

		$f_data = new SplFileObject(DATA_DIR."/$FEATURE", 'a');


		/* [2] Set up GPIO pin
		=========================================================*/
		/* (1) Set as input */
		if( !syscall(SOURCE_DIR."/lib/gpio/in $MOTOR_PIN") ){
			slog('Cannot set up motor pin as INPUT', 'motheure-simple:setup');
			return 127;
		}



		return 0;
	}





	/* [1] Set up daemon
	=========================================================*/
	/* (1) Set up */
	$exec = motheure_setup();

	/* (2) Manage error */
	if( $exec != 0 ){
		slog('cannot set up the daemon', 'motheure-simple:loop');
		die($exec);
	}

	/* (3) Success message */
	slog('daemon started (loop)', 'motheure-simple:loop');




	/* [2] Daemon loop
	=========================================================*/
	while( true ){

		/* (1) Store time */
		$start_ts = microtime(true);

		/* (2) Execute loop code */
		motheure_loop();

	}
?>