<?php

$debug_level = 0;
const DEBUG_LOW = 0;
const DEBUG_MED = DEBUG_LOW+1;
const DEBUG_HIGH = DEBUG_MED+1;
const DEBUG_VHIGH = DEBUG_HIGH+1;

$log_print_file = __DIR__."/../data/rpc_op.log";

function log_print( $msg ){
	global $log_print_file;
	if($log_print_file==''){
		print($msg);
		return;
	}
	file_put_contents( $log_print_file, $msg, FILE_APPEND);
}

function debug_print( $msg, $dl=0 ){
	global $debug_level;
	if($dl>$debug_level) return;
	log_print( $msg );
}

function debug_println( $msg, $dl=0 ){
	global $debug_level;
	if($dl>$debug_level) return;
	debug_print( date_format( date_create("now", new DateTimeZone("UTC")), 'Y-m-d H:i:s') . " $msg\n", $dl );
}

//$argv[0] is always the name that was used to run the script. 
if(count($argv)>1){

	//do not output to service log file
	$log_print_file=null;
	
	include __DIR__."/main-svc.php";
	
	if($argv[1]==='stop'){
		debug_println( "stopping" );
		$rtn = run_main_command( 'f:cli-stop' );
		print_r( $rtn );
		exit(0);
	}
	
	if($argv[1]==='reload'){
		debug_println( "reloading" );
		$rtn = run_main_command( 'f:cli-reload' );
		print_r( $rtn );
		exit(0);
	}
	
	if($argv[1]==='debug_inc'){
		debug_println( "debug_inc" );
		run_main_command( 'f:debug_inc' );
		exit(0);
	}

	if($argv[1]==='debug_dec'){
		debug_println( "debug_dec" );
		run_main_command( 'f:debug_dec' );
		exit(0);
	}

	$rtn = run_main_command( $argv[1] );
	print_r( $rtn );
	exit(0);

}

$g_shutdown = false;

/*
 * This is the backup process CLI application.
 * 
 * Rather than use 2 threads, I've decided to poll. This is because the threading in PHP is no longer supported.
 * Instead we should use parallel:
 * 	https://www.php.net/manual/en/parallel.run.php
 * which I don't like. Basically, it doesn't look like you can share code (by way of a reference)?!!
 * 
 * So we are polling the RPC layer every 0.1secs. In practice, this will be plenty for the backup app.
 * 
 */
include __DIR__."/../lib/sysVcom.php";


debug_println("started");

//create the comms file
touch('BU-commander');

//remove all queues at startup
clear_IPC( '../svc/BU-commander' );

rpc_setGlobals( 'procName', 'BU-commander' );
rpc_setGlobals( 'max_chan', 8182 );
rpc_setGlobals( 'main_pid', getmypid() );

print("rpc using ". __DIR__ . "/$g_procName\n" );

// problem is that the paths are not correct wrt this location, so we need to adjust them
include __DIR__."/../inc/paths.php";
$g_database_path = '../' . $g_database_path;

$g_data_dir = realpath( __DIR__."/../data" );

include "db-reads.php";
include "db-writes.php";
include "file-line-reader.php";
include "table-cache.php";

$g_bu_states = null;


// maximum number of forks allowed
$g_fork_max = 4;
// currently running fork count
$g_fork_cnt=0;
//a queue of backup IDs waiting to commence
$g_bu_queue = array();

function isQueued( $buid ){
	global $g_bu_queue;
	foreach( $g_bu_queue as $q ){
		if($q==$buid) return true;
	}
	return false;
}

while(true){

	if($g_shutdown){
		print("CLI request to shutdown: googbye!\n");
		exit(0);
	}

	$bDidWork = false;
		
	$bDidWork |= check_rpc_clients();
	$bDidWork |= check_bu_sched();
	$bDidWork |= check_bu_queue();
	
	
	if(!$bDidWork){
		time_nanosleep( 0, 100000000);
	}
		
}

/**
 * Return true if the backup was kicked off
 */
function check_bu_sched(){
	
	global $g_bu_table;
	global $g_bu_colIdxs;
	
	//get the first non null entry which is not running
	$idfound = 0;
	$row = null;
	for( $i=0; $i<count($g_bu_table); $i++){
		$row = $g_bu_table[$i];
		if( $row[ $g_bu_colIdxs['BU_DATE'] ] == '' ) continue;		//skip anything without a date
		if( $row[ $g_bu_colIdxs['BuRunning'] ] == 1 ) continue;		//skip any already running
		if( $row[ $g_bu_colIdxs['BuError'] ] != null ) continue;	//skip entries with problems
		if( isQueued( $row[ $g_bu_colIdxs['BUID'] ] ) ) continue;	//skip entries already queued
		$idfound = $row[ $g_bu_colIdxs['BUID'] ];
		break;
	}
	
	if($idfound==0) return;
	
	// is it time...?
	$str_bu_dt = $row[ $g_bu_colIdxs['BU_DATE']] . ' ' . $row[ $g_bu_colIdxs['BU_TIME']] . ':00';
	$schedTime = new DateTime( $str_bu_dt, new DateTimeZone("UTC") );
	
	if( $schedTime > new DateTime('now', new DateTimeZone("UTC") ) ){
		//...no it's not
		return;
	}
	
	[ $res, $state ] = queue_backup( $idfound );

	return $state!=='queued';	//return true if something some work was started
}

function check_bu_queue(){
	$res = dequeue_backup();
	if($res==null) return false;
	if($res[1]=='queued') return false;
	return true;
}

/**
 * Adds a backup ID to the queue. It is kicked off immediately if a slot is available.
 */
function queue_backup( $buid, $scheduled = true, $bu_test = false ){
	
	global $g_bu_queue;

	debug_println("(queue_backup) queue backup($buid)", DEBUG_MED );	

	array_push( $g_bu_queue, array($buid, $scheduled, $bu_test) );
	$res = dequeue_backup( );
	if($res!=null){
		return $res;	//either running or error.
	}
	debug_println("(queue_backup) backup($buid) in queue", DEBUG_MED );	
	return array("ok:", "queued" );	//will be run later
}

/**
 * Removes the next back up item from the front of the queue and kicks it off if there are enough
 * free forks. Returns the result of the kick-off or null if nothing to do.
 */
function dequeue_backup( ){

	global $g_bu_queue;
	global $g_fork_cnt;
	global $g_fork_max;

	if( count($g_bu_queue)==0){
		return null;	//nothing to do
	}
	
	if($g_fork_cnt>=$g_fork_max){
		//There are no available forks
		return null;
	}
	$bu_item = array_shift( $g_bu_queue );
	debug_println("(dequeue_backup) dequeued backup($buid)", DEBUG_MED );	
	return kickoff_backup( $bu_item );
}

/**
 * Kicks off a back up. Returns immediately. Deligates the work to a client fork.
 * 
 * $scheduled:
 * 	true if it is run according to the $schedule info in the db
 * 	false if it has been manually initiated
 */
function kickoff_backup( $bu_item ){
	
	[$buid, $scheduled, $bu_test] = $bu_item;
	
	debug_println("(kickoff_backup) backup($buid) to run now", DEBUG_MED );	
	
	global $g_bu_table;
	global $g_bu_colIdxs;
	global $g_fork_cnt;

	$row = &find_rec_by_id( $buid );
	
	$isRunning = $row[ $g_bu_colIdxs['BuRunning'] ];
	if( !$bu_test && $isRunning==1) return array("e:Error", "Backup already running" );
	
	$i=0;
	$bu_row[$i++] = $row[ $g_bu_colIdxs['BUName'] ];
	$bu_row[$i++] = $row[ $g_bu_colIdxs['Dir_Src'] ];
	$bu_row[$i++] = $row[ $g_bu_colIdxs['Dir_Dest'] ];
	$bu_row[$i++] = $row[ $g_bu_colIdxs['Files_Ex'] ];
	$bu_row[$i++] = $row[ $g_bu_colIdxs['BuType'] ];
	$bu_row[$i++] = $isRunning;
	
	// we should be able to use pcntl_fork()
	$pid = pcntl_fork();
	if ( $pid == -1 ) {   
		debug_println("fork failed");
		return array("e:Error", "fork failed" );
	}

	if ( $pid ) {
		// parent process
		debug_println( "(kickoff_backup) bu($buid) running, parent(". getmypid().")", DEBUG_MED );
		set_bu_running_db( $buid, true );
		
		$row[ $g_bu_colIdxs['BuRunning'] ] = 1;
		return array("ok:", "running" );
		 
	} else {
		
		// child process
		$g_fork_cnt++;

		$g_bu_table = array();	//for safety
		$pid = getmypid();
		debug_println( "child($pid) running backup($buid)" );

		include_once __DIR__."/backup.php";
		$bu_result = '';
		global $g_data_dir;
		$g_data_dir = __DIR__."/../data";
		
		$bu_result = run_backup_block( $buid, $bu_row, $bu_test );
	
		debug_println( "child($pid) finished bu($buid)" );
		$obj = rpc( 'm:fork-complete', $pid, "backup-complete", $buid, $scheduled );	//we use our rpc mechanism to notify parent
		//print_r( $obj );
		//print( "\n" );
		exit(0);
	}
	
}



$msgArr = null;

/**
 * Return true if a request was found and handled
 */
function check_rpc_clients(){
	
	global $msgArr;
	global $g_fork_cnt;

	$caller_id = 0;
	
	$obj_in = rpc_listen( $caller_id, $msgArr, false );
	$obj_out = null;

	if($caller_id==0) return false; //nothing to do
	
	try{
		if( !is_array($obj_in[0])) {
			debug_println("req {$obj_in[0]}", DEBUG_MED );		
		}
		$obj_out = handle_rpc_req( $obj_in );
		if($obj_out==null) $obj_out = array('ok:');	//generic return value
		
	}catch( Exception $e ){
		debug_println( "Exception: " . $e->getMessage() );
		$obj_out = array( 'e:Exception', $e );
	}
		
	if( !is_array($obj_out[0])) {
		debug_println("reply {$obj_out[0]}", DEBUG_MED );		
	}
		
	//send msg back
	rpc_reply( $caller_id, $obj_out );

	if( $obj_in[0] === 'm:fork-complete' ){
		//clean up child process
				
		debug_println("wait for child({$obj_in[1]})", DEBUG_MED );		
		$status;
		pcntl_waitpid( $obj_in[1], $status );

		$g_fork_cnt--;
		debug_println("child({$obj_in[1]}) complete.", DEBUG_MED );	

		//finish any requirements for specific child processes (db updates etc)
		if( count($obj_in)>2 && $obj_in[2]="backup-complete"){
			backupComplete( $obj_in[3], $obj_in[4] );			
		}
	}
	
	return true;
	
}


/**
 * Called by the parent after a client notified that a backup completed.
 */
function backupComplete( $buid, $scheduled ){
	
	global $g_bu_colIdxs;
				
	//reload the table data (in case child modified error field)
	$row = reload_cached_rec( $buid );

	if($scheduled){
		//if DB error, do nothing
		$err = $row[ $g_bu_colIdxs['BuError'] ];
		if($err==''){
			//update date and time according to the repeat field.
			$date = date_create( $row[ $g_bu_colIdxs['BU_DATE'] ] );
			$dt_new = null;
			
			switch( $row[ $g_bu_colIdxs['BU_REPEAT'] ] ){
			case 'M':
				//monthly
				date_add( $date, new DateInterval('P1M') );
				$dt_new = date_format( $date, "Y-m-d");
				break;
				
			case 'W':
				//weekly
				date_add( $date, new DateInterval('P1W') );
				$dt_new = date_format( $date, "Y-m-d");
				break;
				
			case 'D':
				//daily
				date_add( $date, new DateInterval('P1D') );
				$dt_new = date_format( $date, "Y-m-d");
				break;
				
			}			
			$row[ $g_bu_colIdxs['BU_DATE'] ] = $dt_new;

			set_sched_date_db( $buid, $dt_new );
			
		}
		
		set_bu_running_db( $buid, false );

	}//if manually kicked off - nothing to do

	$row = reload_cached_rec( $buid );

	debug_println("(backupComplete) bu($buid) done", DEBUG_MED );

}


/**
 * Carries out the task requested from any RPC client.
 * That client may be from the webserver or from a forked child or any other process.
 */
function handle_rpc_req( $obj ){
	
	// The idea will be that the indicator before the colon will be handled generically in cases
	// where it is a simple function call, i.e. 'f:' (provided it is a trusted source and/or has been previously checked)
	
	global $g_data_dir;
	global $g_shutdown;
	global $debug_level;
	
		
	if( 'f:getbu_list_state' !== $obj[0] ){		
		//print_r( $obj );
	}
	
	switch( $obj[0] ){
		
	case 'f:bu-test-file-lines':
		$buid = $obj[1];
		$lineNum = $obj[2];
		$lineData = '';
		$objFile = getObject_outputFile( $g_data_dir, $buid );
		$cnt = getLinesFrom( $objFile, $lineNum, $lineData );
		if($cnt==0){
			closeFile( $buid );
			return array( 'r:bu-test-file-lines', 0 );
		}
		return array( 'r:bu-test-file-lines', $cnt, $lineData );
			
	case 'm:fork-complete':
		//send the same message back to the caller
		return $obj;
		
	case 'f:getbu_list_all':
		//($table, $colIdxs) = rpc( 'f:getbu_list_all', "order by BUID" );
		$table = array();
		$colIdxs = array();
		getbu_list_all( $table, $colIdxs, $obj[1] );		
		return array( $table, $colIdxs );
		
	case 'f:getbu_list_state':
		global $g_bu_states;
		if($g_bu_states==null){
			//print("getbu_list_state (refresh\n");
			$g_bu_states = getbu_list_state();
		}
		return $g_bu_states;
		
	case 'f:save_bu_schedule':
		$buid = $obj[1]['id'];
		$err = save_bu_schedule( $obj[1] );
		reload_cached_rec( $buid );
		return array($err);
		
	case 'f:save_bu_item':
		$buid = $obj[2];
		//[$err] = rpc( 'f:save_bu_item', $postVars, $bu_id );
		$err = save_bu_item( $obj[1], $buid );
		reload_cached_rec( $buid );
		return array($err);
		
	case 'f:set_bu_error':
		$buid = $obj[1];
		$err = set_bu_error_db( $obj[1], $obj[2] );
		reload_cached_rec( $buid );
		return array($err);
			
	case 'f:set_bu_running':
		$buid = $obj[1];
		$err = set_bu_running_db( $obj[1], $obj[2] );
		reload_cached_rec( $buid );
		return array($err);	
				
	case 'f:kickoff-backup':
		$buid = $obj[1];
		$isTest = $obj[2];
		$res = queue_backup( $buid, false, $isTest );
		if($res[1]==='queued') return array('ok:','running'); //ToDo: return queued and client to handle
		return $res;

	case 'f:set_last_run_date':
		//[$err] = rpc( 'f:set_last_run_date', $buid, $str_dt );
		$buid = $obj[1];
		$err = set_last_run_date_db( $buid, $obj[2] );
		reload_cached_rec( $buid );
		return array($err);		

	case 'f:cli-reload':
		clear_cached_data();
		ensure_cached_table();
		return array('ok:reload');

	case 'f:cache-show':
		foreach( format_cache() as $line){
			log_print( "$line\n" );
		}
		return array('ok:cache-show');

	case 'f:cli-stop':
		$g_shutdown = true;
		return array('ok:shutdown');

	case 'f:delete_bu_item':
		$buid = $obj[1];
		$err = delete_bu_item_db( $buid );
		delete_cached_rec( $buid );
		return array($err);	

	case 'f:debug_inc':	//increment the debug level
		$debug_level++;
		debug_println( "debug level $debug_level" );
		return array('ok:');
		
	case 'f:debug_dec':	//decrement the debug level
		$debug_level--;
		if($debug_level<0) $debug_level=0;
		debug_println( "debug level $debug_level" );
		return array('ok:');

	}
		
	array_unshift( $obj, "Unknown Command" );
	print_r( $obj );
	return $obj;
	
}

?>