<?php

/**
 * Retrieve a backup row from the database using it's ID.
 * 
 * Returns the following data as an array:
 * 
 * [ BUName, Dir_Src, Dir_Dest, Files_Ex, Bu_Type, BuRunning, BuError, LastRunDt ]
 * 
 */
function get_bu_item( $id ){

	$db = new SQLite3( __DIR__.'/../bin/data.db', SQLITE3_OPEN_READONLY );

	$html_rows='';
	$results = $db->query("SELECT * FROM BULIST where BUID=$id");
	$row = $results->fetchArray();
	
	if($row){
		return array( $row['BUName'], $row['Dir_Src'], $row['Dir_Dest'], $row['Files_Ex'], $row['BuType'], $row['BuRunning'], $row['BuError'], $row['LastRunDt'] );
	}
	
}

/**
 * Set (unset) the running datbase flag. Return true on success. The flag is
 * unaltered if running in test mode.
 */
function set_bu_running( $id, bool $setit, bool $bu_test ){
	
	if($bu_test) return true;

	$db = new SQLite3( __DIR__.'/../bin/data.db' );
	
	$setit_int = $setit?1:0;
	return $db->exec("update BULIST set BuRunning=$setit_int where BUID=$id");	
}

/**
 * Set the error string in the database.
 */
function set_bu_error( $buid, $str_errs ){	
	$db = new SQLite3( __DIR__.'/../bin/data.db' );
	if($str_errs==''){
		return $db->exec("update BULIST set BuError = NULL where BUID=$buid");	
	}
	$p = $db->prepare("update BULIST set BuError=:str_errs where BUID=:buid");	
	$p->bindValue(':str_errs', $str_errs );
	$p->bindValue(':buid', $buid );
	$p->execute();
		
	if( $db->lastErrorCode()!==0){
		return $db->lastErrorCode();
	}
}

/**
 * 
 */
function set_last_run_date( $buid, $str_dt ){
	$db = new SQLite3( __DIR__.'/../bin/data.db' );
	$p = $db->prepare("update BULIST set LastRunDt=:str_dt where BUID=:buid");	
	$p->bindValue(':str_dt', $str_dt );
	$p->bindValue(':buid', $buid );
	$p->execute();
		
	if( $db->lastErrorCode()!==0){
		return $db->lastErrorCode();
	}
}


/**
 * Run the backup process for the given backup ID.
 * 
 * Returns an error string on failure.
 */
function run_backup_block( $buid, $bu_test=true ){
	
	$row = get_bu_item( $buid );
		
	if( !$bu_test && $row[5]==1){
		return "Backup for item($buid) is already running\n";		
	}

	$bu_name = $row[0];
	$bu_src = $row[1];
	$bu_dest = $row[2];
	$exFiles = $row[3];
	$bu_type = $row[4];
	$bu_rnng = $row[5];

	// NOTE:
	// using pcntl_fork() was a waste of time because the parent always waited for the child to finish.
	// so we rely on bash &
	
	if($bu_type==1 ){
		return run_backup_DB( $bu_test, $buid, $bu_src, $bu_dest );	
	}	

	return run_backup_F( $bu_test, $buid, $bu_src, $bu_dest, $exFiles );
}

function run_backup_F( $bu_test, $buid, $bu_src, $bu_dest, $exFiles ){
	
	if(!set_bu_running( $buid, true, $bu_test )){
		return "Could not set the DB flag";		
	}

	if($bu_test){
		$flags = '-anv';	// n is the dry run indicator
	}else{
		$flags = '-av';
		set_bu_error( $buid, '' );	//clear any previous error
		set_last_run_date( $buid, gmdate("Y-m-d H:i:s") );
	}

	$fn_o = getFilename_out( $buid, $bu_test, false );
	$fn_e = getFilename_out( $buid, $bu_test, true );

	// create the output files with the ID in the first line
	exec("echo 'ID: $buid' > bin/$fn_o");
	exec("echo 'ID: $buid' > bin/$fn_e");		
	
	$str_exPaths = '';
	if(trim( $exFiles )!=''){
		$fn_x = getFilename_tmp( $buid, 'x' );
		file_put_contents( "bin/$fn_x", $exFiles );
		$str_exPaths = "--exclude-from=bin/$fn_x";
	}

	// bash command
	//rsync -a --exclude-from=to-exclude.txt $PATH_SRC $BKUP_DEST
	//rsync -anv --exclude-from=to-exclude.txt $PATH_SRC $BKUP_DEST	<-- for testing
	$command = "rsync $flags $str_exPaths $bu_src $bu_dest 2>> bin/$fn_e 1>> bin/$fn_o";

	$output = array();
	$result_code = null;
	if( exec( $command, $output, $result_code )===FALSE){		
		set_bu_running( $buid, false, $bu_test );
		return "rsync failed";
	}	
	set_bu_running( $buid, false, $bu_test );

	// can we find any error strings in the error file?
	$str_errs = file_get_contents( "bin/$fn_e" );
	$pos = strpos($str_errs, 'error' );
	if($pos===FALSE){
		$pos = strpos($str_errs, 'failed' );
	}
	if($pos===FALSE) return;

	//place it in the database
	set_bu_error( $buid, $str_errs );
	
}


/**
 * Very similar to the file version. The common code is running the bach script.
 */
function run_backup_DB( $bu_test, $buid, $bu_src, $bu_dest ){

	if(!set_bu_running( $buid, true, $bu_test )){
		return "Could not set the DB flag";		
	}
	
	if(!is_dir($bu_dest) ){
		return "Destination ($bu_dest) is not a directory";
	}

	if($bu_test){
		$fn_o = getFilename_out( $buid, $bu_test, false );		
		$bu_dest = "bin";
	}else{
		$fn_o = "$bu_src.sql";		
		set_bu_error( $buid, '' );	//clear any previous error
		set_last_run_date( $buid, gmdate("Y-m-d H:i:s") );
	}

	// create the error files with the ID in the first line
	$fn_e = getFilename_out( $buid, $bu_test, true );
	exec("echo 'ID: $buid' > bin/$fn_e");

	// bash command
	//mysqldump johntest > /home/johnp/tmp/dbs/johntest.sql
		
	$command = "mysqldump $bu_src 2>> bin/$fn_e 1>> $bu_dest/$fn_o";

	$output = array();
	$result_code = null;
	if( exec( $command, $output, $result_code )===FALSE){		
		set_bu_running( $buid, false, $bu_test );
		return "mysqldump failed";
	}	
	set_bu_running( $buid, false, $bu_test );

	// can we find any error strings in the error file?
	$str_errs = file_get_contents( "bin/$fn_e" );
	$pos = strpos($str_errs, 'error' );
	if($pos===FALSE){
		$pos = strpos($str_errs, 'failed' );
	}
	if($pos===FALSE) return;

	//place it in the database
	set_bu_error( $buid, $str_errs );

}

function getFilename_out( $buid, bool $bu_test, bool $isErr=false ){	
	return getFilename_tmp( $buid, $bu_test?'t':'n', $isErr? 'err': 'op' );	
}

/**
 * Create an output file for the backup (forked) process to use. These are essentually
 * temporary files which may be deleted after the back process completes.
 * 
 * buid:	backup record id
 * 
 * fn_type:
 * 	t:	for test files
 * 	n: for non-test files
 * 	x: for file exclusion list
 * 
 * fn_stream:
 * 	op: output stream
 * 	err: error stream
 */
function getFilename_tmp( $buid, $fn_type='t', $fn_stream='op' ){	
	return "bu-$fn_type-$fn_stream-$buid.txt";	
}

?>