<?php

/*

	Copyright (c) 2009-2019 F3::Factory/Bong Cosca, All rights reserved.

	This file is part of the Fat-Free Framework (http://fatfreeframework.com).

	This is free software: you can redistribute it and/or modify it under the
	terms of the GNU General Public License as published by the Free Software
	Foundation, either version 3 of the License, or later.

	Fat-Free Framework is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	General Public License for more details.

	You should have received a copy of the GNU General Public License along
	with Fat-Free Framework.  If not, see <http://www.gnu.org/licenses/>.

*/

namespace DB\Jig;

//! Flat-file DB mapper
class Mapper extends \DB\Cursor {

	protected
		//! Flat-file DB wrapper
		$db,
		//! Data file
		$file,
		//! Document identifier
		$id,
		//! Document contents
		$document=[],
		//! field map-reduce handlers
		$_reduce;

	/**
	*	Return database type
	*	@return string
	**/
	function dbtype() {
		return 'Jig';
	}

	/**
	*	Return TRUE if field is defined
	*	@return bool
	*	@param $key string
	**/
	function exists($key) {
		return array_key_exists($key,$this->document);
	}

	/**
	*	Assign value to field
	*	@return scalar|FALSE
	*	@param $key string
	*	@param $val scalar
	**/
	function set($key,$val) {
		return ($key=='_id')?FALSE:($this->document[$key]=$val);
	}

	/**
	*	Retrieve value of field
	*	@return scalar|FALSE
	*	@param $key string
	**/
	function &get($key) {
		if ($key=='_id')
			return $this->id;
		if (array_key_exists($key,$this->document))
			return $this->document[$key];
        throw new \Exception(sprintf(self::E_Field,$key));
	}

	/**
	*	Delete field
	*	@return NULL
	*	@param $key string
	**/
	function clear($key) {
		if ($key!='_id')
			unset($this->document[$key]);
	}

	/**
	*	Convert array to mapper object
	*	@return object
	*	@param $id string
	*	@param $row array
	**/
	function factory($id,$row) {
		$mapper=clone($this);
		$mapper->reset();
		$mapper->id=$id;
		foreach ($row as $field=>$val)
			$mapper->document[$field]=$val;
		$mapper->query=[clone($mapper)];
		if (isset($mapper->trigger['load']))
			\Base::instance()->call($mapper->trigger['load'],$mapper);
		return $mapper;
	}

	/**
	*	Return fields of mapper object as an associative array
	*	@return array
	*	@param $obj object
	**/
	function cast($obj=NULL) {
		if (!$obj)
			$obj=$this;
		return $obj->document+['_id'=>$this->id];
	}

	/**
	*	Convert tokens in string expression to variable names
	*	@return string
	*	@param $str string
	**/
	function token($str) {
		$str=preg_replace_callback(
			'/(?<!\w)@(\w(?:[\w\.\[\]])*)/',
			function($token) {
				// Convert from JS dot notation to PHP array notation
				return '$'.preg_replace_callback(
					'/(\.\w+)|\[((?:[^\[\]]*|(?R))*)\]/',
					function($expr) {
						$fw=\Base::instance();
						return
							'['.
							($expr[1]?
								$fw->stringify(substr($expr[1],1)):
								(preg_match('/^\w+/',
									$mix=$this->token($expr[2]))?
									$fw->stringify($mix):
									$mix)).
							']';
					},
					$token[1]
				);
			},
			$str
		);
		return trim($str);
	}

	/**
	*	Return records that match criteria
	*	@return static[]|FALSE
	*	@param $filter array
	*	@param $options array
	*	@param $ttl int|array
	*	@param $log bool
	**/
	function find($filter=NULL,?array $options=NULL,$ttl=0,$log=TRUE) {
		if (!$options)
			$options=[];
		$options+=[
			'order'=>NULL,
			'limit'=>0,
			'offset'=>0,
			'group'=>NULL,
		];
		$fw=\Base::instance();
		$cache=\Cache::instance();
		$db=$this->db;
		$now=microtime(TRUE);
		$data=[];
		$tag='';
		if (is_array($ttl))
			list($ttl,$tag)=$ttl;
		if (!$fw->CACHE || !$ttl || !($cached=$cache->exists(
			$hash=$fw->hash($this->db->dir().
				$fw->stringify([$filter,$options])).($tag?'.'.$tag:'').'.jig',$data)) ||
			$cached[0]+$ttl<microtime(TRUE)) {
			$data=$db->read($this->file);
			if (is_null($data))
				return FALSE;
			foreach ($data as $id=>&$doc) {
				$doc['_id']=$id;
				unset($doc);
			}
			if ($filter) {
				if (!is_array($filter))
					return FALSE;
				// Normalize equality operator
				$expr=preg_replace('/(?<=[^<>!=])=(?!=)/','==',$filter[0]);
				// Prepare query arguments
				$args=isset($filter[1]) && is_array($filter[1])?
					$filter[1]:
					array_slice($filter,1,NULL,TRUE);
				$args=is_array($args)?$args:[1=>$args];
				$keys=$vals=[];
				$tokens=array_slice(
					token_get_all('<?php '.$this->token($expr)),1);
				$data=array_filter($data,
					function($_row) use($fw,$args,$tokens) {
						$_expr='';
						$ctr=0;
						$named=FALSE;
						foreach ($tokens as $token) {
							if (is_string($token))
								if ($token=='?') {
									// Positional
									++$ctr;
									$key=$ctr;
								}
								else {
									if ($token==':')
										$named=TRUE;
									else
										$_expr.=$token;
									continue;
								}
							elseif ($named &&
								token_name($token[0])=='T_STRING') {
								$key=':'.$token[1];
								$named=FALSE;
							}
							else {
								$_expr.=$token[1];
								continue;
							}
							$_expr.=$fw->stringify(
								is_string($args[$key])?
									addcslashes($args[$key],'\''):
									$args[$key]);
						}
						// Avoid conflict with user code
						unset($fw,$tokens,$args,$ctr,$token,$key,$named);
						extract($_row);
						// Evaluate pseudo-SQL expression
						return eval('return '.$_expr.';');
					}
				);
			}
			if (isset($options['group'])) {
				$cols=array_reverse($fw->split($options['group']));
				// sort into groups
				$data=$this->sort($data,$options['group']);
				foreach($data as $i=>&$row) {
					if (!isset($prev)) {
						$prev=$row;
						$prev_i=$i;
					}
					$drop=false;
					foreach ($cols as $col)
						if ($prev_i!=$i && array_key_exists($col,$row) &&
							array_key_exists($col,$prev) && $row[$col]==$prev[$col])
							// reduce/modify
							$drop=!isset($this->_reduce[$col]) || call_user_func_array(
								$this->_reduce[$col][0],[&$prev,&$row])!==FALSE;
						elseif (isset($this->_reduce[$col])) {
							$null=null;
							// initial
							call_user_func_array($this->_reduce[$col][0],[&$row,&$null]);
						}
					if ($drop)
						unset($data[$i]);
					else {
						$prev=&$row;
						$prev_i=$i;
					}
					unset($row);
				}
				// finalize
				if ($this->_reduce[$col][1])
					foreach($data as $i=>&$row) {
						$row=call_user_func($this->_reduce[$col][1],$row);
						if (!$row)
							unset($data[$i]);
						unset($row);
					}
			}
			if (isset($options['order']))
				$data=$this->sort($data,$options['order']);
			$data=array_slice($data,
				$options['offset'],$options['limit']?:NULL,TRUE);
			if ($fw->CACHE && $ttl)
				// Save to cache backend
				$cache->set($hash,$data,$ttl);
		}
		$out=[];
		foreach ($data as $id=>&$doc) {
			unset($doc['_id']);
			$out[]=$this->factory($id,$doc);
			unset($doc);
		}
		if ($log && isset($args)) {
			if ($filter)
				foreach ($args as $key=>$val) {
					$vals[]=$fw->stringify(is_array($val)?$val[0]:$val);
					$keys[]='/'.(is_numeric($key)?'\?':preg_quote($key)).'/';
				}
			$db->jot('('.sprintf('%.1f',1e3*(microtime(TRUE)-$now)).'ms) '.
				$this->file.' [find] '.
				($filter?preg_replace($keys,$vals,$filter[0],1):''));
		}
		return $out;
	}

	/**
	*	Sort a collection
	*	@param $data
	*	@param $cond
	*	@return mixed
	*/
	protected function sort($data,$cond) {
		$cols=\Base::instance()->split($cond);
		uasort(
			$data,
			function($val1,$val2) use($cols) {
				foreach ($cols as $col) {
					$parts=explode(' ',$col,2);
					$order=empty($parts[1])?
						SORT_ASC:
						constant($parts[1]);
					$col=$parts[0];
					if (!array_key_exists($col,$val1))
						$val1[$col]=NULL;
					if (!array_key_exists($col,$val2))
						$val2[$col]=NULL;
					list($v1,$v2)=[$val1[$col],$val2[$col]];
					if ($out=strnatcmp($v1?:'',$v2?:'')*
						(($order==SORT_ASC)*2-1))
						return $out;
				}
				return 0;
			}
		);
		return $data;
	}

	/**
	*	Add reduce handler for grouped fields
	*	@param $key string
	*	@param $handler callback
	*	@param $finalize callback
	*/
	function reduce($key,$handler,$finalize=null){
		$this->_reduce[$key]=[$handler,$finalize];
	}

	/**
	*	Count records that match criteria
	*	@return int
	*	@param $filter array
	*	@param $options array
	*	@param $ttl int|array
	**/
	function count($filter=NULL,?array $options=NULL,$ttl=0) {
		$now=microtime(TRUE);
		$out=count($this->find($filter,$options,$ttl,FALSE));
		$this->db->jot('('.sprintf('%.1f',1e3*(microtime(TRUE)-$now)).'ms) '.
			$this->file.' [count] '.($filter?json_encode($filter):''));
		return $out;
	}

	/**
	*	Return record at specified offset using criteria of previous
	*	load() call and make it active
	*	@return array
	*	@param $ofs int
	**/
	function skip($ofs=1) {
		$this->document=($out=parent::skip($ofs))?$out->document:[];
		$this->id=$out?$out->id:NULL;
		if ($this->document && isset($this->trigger['load']))
			\Base::instance()->call($this->trigger['load'],$this);
		return $out;
	}

	/**
	*	Insert new record
	*	@return array
	**/
	function insert() {
		if ($this->id)
			return $this->update();
		$db=$this->db;
		$now=microtime(TRUE);
		while (($id=uniqid('',TRUE)) &&
			($data=&$db->read($this->file)) && isset($data[$id]) &&
			!connection_aborted())
			usleep(mt_rand(0,100));
		$this->id=$id;
		$pkey=['_id'=>$this->id];
		if (isset($this->trigger['beforeinsert']) &&
			\Base::instance()->call($this->trigger['beforeinsert'],
				[$this,$pkey])===FALSE)
			return $this->document;
		$data[$id]=$this->document;
		$db->write($this->file,$data);
		$db->jot('('.sprintf('%.1f',1e3*(microtime(TRUE)-$now)).'ms) '.
			$this->file.' [insert] '.json_encode($this->document));
		if (isset($this->trigger['afterinsert']))
			\Base::instance()->call($this->trigger['afterinsert'],
				[$this,$pkey]);
		$this->load(['@_id=?',$this->id]);
		return $this->document;
	}

	/**
	*	Update current record
	*	@return array
	**/
	function update() {
		$db=$this->db;
		$now=microtime(TRUE);
		$data=&$db->read($this->file);
		if (isset($this->trigger['beforeupdate']) &&
			\Base::instance()->call($this->trigger['beforeupdate'],
				[$this,['_id'=>$this->id]])===FALSE)
			return $this->document;
		$data[$this->id]=$this->document;
		$db->write($this->file,$data);
		$db->jot('('.sprintf('%.1f',1e3*(microtime(TRUE)-$now)).'ms) '.
			$this->file.' [update] '.json_encode($this->document));
		if (isset($this->trigger['afterupdate']))
			\Base::instance()->call($this->trigger['afterupdate'],
				[$this,['_id'=>$this->id]]);
		return $this->document;
	}

	/**
	*	Delete current record
	*	@return bool
	*	@param $filter array
	*	@param $quick bool
	**/
	function erase($filter=NULL,$quick=FALSE) {
		$db=$this->db;
		$now=microtime(TRUE);
		$data=&$db->read($this->file);
		$pkey=['_id'=>$this->id];
		if ($filter) {
			foreach ($this->find($filter,NULL,FALSE) as $mapper)
				if (!$mapper->erase(null,$quick))
					return FALSE;
			return TRUE;
		}
		elseif (isset($this->id)) {
			unset($data[$this->id]);
			parent::erase();
		}
		else
			return FALSE;
		if (!$quick && isset($this->trigger['beforeerase']) &&
			\Base::instance()->call($this->trigger['beforeerase'],
				[$this,$pkey])===FALSE)
			return FALSE;
		$db->write($this->file,$data);
		if ($filter) {
			$args=isset($filter[1]) && is_array($filter[1])?
				$filter[1]:
				array_slice($filter,1,NULL,TRUE);
			$args=is_array($args)?$args:[1=>$args];
			foreach ($args as $key=>$val) {
				$vals[]=\Base::instance()->
					stringify(is_array($val)?$val[0]:$val);
				$keys[]='/'.(is_numeric($key)?'\?':preg_quote($key)).'/';
			}
		}
		$db->jot('('.sprintf('%.1f',1e3*(microtime(TRUE)-$now)).'ms) '.
			$this->file.' [erase] '.
			($filter?preg_replace($keys,$vals,$filter[0],1):''));
		if (!$quick && isset($this->trigger['aftererase']))
			\Base::instance()->call($this->trigger['aftererase'],
				[$this,$pkey]);
		return TRUE;
	}

	/**
	*	Reset cursor
	*	@return NULL
	**/
	function reset() {
		$this->id=NULL;
		$this->document=[];
		parent::reset();
	}

	/**
	*	Hydrate mapper object using hive array variable
	*	@return NULL
	*	@param $var array|string
	*	@param $func callback
	**/
	function copyfrom($var,$func=NULL) {
		if (is_string($var))
			$var=\Base::instance()->$var;
		if ($func)
			$var=call_user_func($func,$var);
		foreach ($var as $key=>$val)
			$this->set($key,$val);
	}

	/**
	*	Populate hive array variable with mapper fields
	*	@return NULL
	*	@param $key string
	**/
	function copyto($key) {
		$var=&\Base::instance()->ref($key);
		foreach ($this->document as $key=>$field)
			$var[$key]=$field;
	}

	/**
	*	Return field names
	*	@return array
	**/
	function fields() {
		return array_keys($this->document);
	}

	/**
	*	Retrieve external iterator for fields
	*	@return object
	**/
	function getiterator() {
		return new \ArrayIterator($this->cast());
	}

	/**
	*	Instantiate class
	*	@return void
	*	@param $db object
	*	@param $file string
	**/
	function __construct(\DB\Jig $db,$file) {
		$this->db=$db;
		$this->file=$file;
		$this->reset();
	}

}
