<?php
/**
 * Generate a simple api
 * 
 * @author Daniel Leitner
 * @version 1.2
 * @link mail@danielleitner.de
 */

class Api {
    
    /**
     * Mysql connection
     * 
     * @var resource
     * @access private
     */
    private $_db;
    
    /**
     * Store namcespaces
     * 
     * @var array
     * @access private
     */
    private $_namespaces = array();
    
    /**
     * Working namespace name
     * 
     * @var string
     * @access private
     */
    private $_current_namaspace;
    
    /**
     * Namespace which is rendered
     * 
     * @var string
     * @access private
     */
    private $_render_namepsace;
    
    /**
     * Url data
     * 
     * @var array 
     * @access private
     */
    private $_route_data;
    
    /**
     * Class options
     * 
     * @var array
     * @access private
     */
    private $_options = array(
        'output_types' => array(
            'json', 'xml', 'csv', 'yaml'
        )
    );
    
    /**
     * Rules to check the route
     * 
     * @var array
     * @access private 
     */
    private $_rules = array(
        'alpha_numeric', 'numeric'
    );
    
    /**
     * Select result for api
     * 
     * @var array 
     */
    private $_result = array();
    
    /**
     * Let the magic start ;)
     * 
     * @param resource $db 
     * @access public
     */
    public function __construct($db) {
        
        $this->_db = $db;
    }
    
    /**
     * Register new namespace
     * 
     * @param type $namespace 
     * @todo Set defaults to array
     * @access public
     * @return Api 
     */
    public function register($namespace) {
        
        if( ! isset($this->_namespaces[$namespace]) ) {
            $this->_namespaces[$namespace] = array(
                'key'           => false,
                'sort'       	=> false,
                'request'       => false,
                'limit'         => false,
                'cache'         => false,
                'conditions'    => false
            );
            
            $this->_current_namaspace = $namespace;
        } else {
            $this->_error('Namespace already exists.');
        }
        
        return $this;
    }
    
    /**
     *
     * @param string $message 
     * @access private
     * @todo output
     * @return Api 
     */
    private function _error($message) {
        header("Content-Type: application/json");
        
        die(json_encode($message));
    }
    
    /**
     * Set table name
     * 
     * @param string $table 
     * @return Api 
     */
    public function setTable($table) {
        
        if( is_string($table) ) {
            $this->_namespaces[$this->_current_namaspace]['table'] = $table;
        } else {
            $this->_error('Table name musst be a string.');
        }
        
        return $this;
    }
    
    /**
     * Set output type
     * 
     * @access public
     * @param array|string $output
     * @return Api 
     */
    public function setOutput($output) {
        
        if( is_array($output) ) {
            foreach($output as $o) {
                if( ! in_array($o, $this->_options['output_types']) ) {
                    $this->_error('Output as '.$o.' is not supported.');
                }
            }
            
            $this->_namespaces[$this->_current_namaspace]['output'] = $output;
        } else {
            
            if( ! in_array($output, $this->_options['output_types']) ) {
                $this->_error('Output as '.$output.' is not supported.');
            }
            
            $this->_namespaces[$this->_current_namaspace]['output'] = $output;
        }
        
        return $this;
    }
    
    /**
     * Set if unique key is required (false = default)
     * 
     * @access public
     * @param boolean $key
     * @return Api 
     */
    public function setKey($key) {
        
        if( is_bool($key) ) {
            $this->_namespaces[$this->_current_namaspace]['key'] = $key;
        }
        
        return $this;
    }
    
    /**
     * Set request limit per hour. (false = default)
     * 
     * @access public
     * @param integer $limit
     * @return Api 
     */
    public function setLimit($limit) {
        
        if( is_integer($limit) ) {
            $this->_namespaces[$this->_current_namaspace]['limit'] = $limit;
        }
        
        return $this;
    }
    
    // Limit output
    public function setRequest($request) {
        
        if( is_integer($request) ) {
            $this->_namespaces[$this->_current_namaspace]['request'] = $request;
        }
        
        return $this;
    }
    
    
    // Sort output
    public function setSort($sort) {
        
        if( is_string($sort) ) {
            $this->_namespaces[$this->_current_namaspace]['sort'] = $sort;
        }
        
        return $this;
    }
    
    /**
     * Activate cache
     * 
     * @param integer $time
     * @param string $folder
     * @return Api 
     */
    public function setCache($time, $folder) {
        
        if( ! is_dir($folder) ) {
            $this->_error('Cache folder musst be a folder.');
        }
        
        if( ! is_integer($time) ) {
            $this->_error('Cache time musst be integer.');
        }
        
        $this->_namespaces[$this->_current_namaspace]['cache'] = array(
            'folder' => $folder,
            'time'   => $time
        );
        
        return $this;
    }
    
    /**
     * Set columns which should be displayed
     * 
     * @param array $columns
     * @return Api 
     */
    public function setColumns($columns) {
        
        if( is_array($columns) ) {
            $this->_namespaces[$this->_current_namaspace]['columns'] = $columns;
        } else {
            $this->_error('Columns musst be given as array.');
        }
        
        return $this;
    }
    
    /**
     * Set conditions for data
     * 
     * @param array $conditions
     * @return Api 
     */
    public function setWhere($conditions) {
        
        if( is_array($conditions) ) {
            $this->_namespaces[$this->_current_namaspace]['conditions'] = $conditions;
        } else {
            $this->_error('Where conditions musst be given as array.');
        }
        
        return $this;
    }
    
    /**
     * Output data
     * 
     * @access public
     * @param arra $route 
     */
    public function render($route) {
        if( ! isset($route['namespace']) || ! isset($this->_namespaces[$route['namespace']]) || strlen($route['namespace']) == 0 ) {
            $this->_error('No namespace found.');
        }
        
        $this->_render_namepsace = $route['namespace'];
        
        // secure input
        foreach($route as $key => $value) {
            $route[strip_tags($key)] = strip_tags($value);
        }
        
        $this->_route_data = $route;
        
        // check if connection is working
        if( ! mysql_ping($this->_db) ) {
            $this->_error('Database connection is not working.');
        }
        
        // check if request limit is reached
        if( ! $this->_check_key() ) {
            $this->_error('Soory, but your api key is not valid.');
        }
        
        // check if request limit is reached
        if( ! $this->_check_request() ) {
            $this->_error('Soory, you reached the maximum request limit per hour ('.$this->_namespaces[$this->_render_namepsace]['limit'].').');
        }
        
        // get data from mysql table
        if( ! $this->_create() ) {
            $this->_error('Soory, but the system was not able to generate data.');
        }
    }
    
    /**
     * Check if the user key is valid
     * 
     * @access private
     * @return boolean 
     */
    private function _check_key() {
        if( $this->_namespaces[$this->_render_namepsace]['key'] == true ) {
            $result = mysql_query('SELECT id FROM api_keys WHERE hash = "'.mysql_real_escape_string($this->_route_data['key']).'"', $this->_db) or die(mysql_error());
                    
            if( mysql_num_rows($result) == false ) {
                return false;
            } else {
                return true;
            }
        } else {
            return true;
        }
    }
    
    /**
     * Check if request limit is reached
     * 
     * @access prviate
     * @return boolean 
     */
    private function _check_request() {
        
        if( $this->_namespaces[$this->_render_namepsace]['limit'] != false ) {
            // check request limit
            
            // delete old requests
            if( $this->_namespaces[$this->_render_namepsace]['key'] == true ) {
                // request limit with key
                
                // delete old requests
                mysql_query('DELETE FROM api_requests WHERE hash = "'.mysql_real_escape_string($this->_route_data['key']).'" AND ((UNIX_TIMESTAMP() - time) > 3600) AND namespace = "'.$this->_render_namepsace.'"', $this->_db) or die(mysql_error());
            
                // count stored requests
                $result = mysql_query('SELECT COUNT(time) AS requests FROM api_requests WHERE hash = "'.mysql_real_escape_string($this->_route_data['key']).'" AND ((UNIX_TIMESTAMP() - time) < 3600) AND namespace = "'.$this->_render_namepsace.'"', $this->_db) or die(mysql_error());
                
                $total_requests = mysql_fetch_array($result);
                
                if( $total_requests['requests'] >= $this->_namespaces[$this->_render_namepsace]['limit'] )  {
                    // request limit reached
                    return false;
                } else {
                    
                    // insert new request
                    mysql_query('INSERT INTO api_requests (namespace, hash, ip, time) VALUES("'.$this->_render_namepsace.'", "'.mysql_real_escape_string($this->_route_data['key']).'", "'.$_SERVER['REMOTE_ADDR'].'", "'.time().'")', $this->_db) or die(mysql_error());
                    
                    return true;
                }
                
            } else {
                // request limit without key
                
                // delete old requests
                mysql_query('DELETE FROM api_requests WHERE ((UNIX_TIMESTAMP() - time) > 3600) AND namespace = "'.$this->_render_namepsace.'"', $this->_db) or die(mysql_error());
            
                // count stored requests
                $result = mysql_query('SELECT COUNT(time) AS requests FROM api_requests WHERE ((UNIX_TIMESTAMP() - time) < 3600) AND namespace = "'.$this->_render_namepsace.'"', $this->_db) or die(mysql_error());
                
                $total_requests = mysql_fetch_array($result);
                
                if( $total_requests['requests'] >= $this->_namespaces[$this->_render_namepsace]['limit'] )  {
                    // request limit reached
                    return false;
                } else {
                    
                    // insert new request
                    mysql_query('INSERT INTO api_requests (namespace, ip, time) VALUES("'.$this->_render_namepsace.'", "'.$_SERVER['REMOTE_ADDR'].'", "'.time().'")', $this->_db) or die(mysql_error());
                    
                    return true;
                }
            }
        } else {
            // no limit is set
            return true;
        }
    }
    
    /**
     * Array to json
     *
     * @access private
     * @return json
     */
    private function _write_json() {
        
        header("Content-Type: application/json");
        
        return json_encode($this->_result);
    }
    
    /**
     * Array to xml
     * 
     * @access private
     * @return string
     */
    private function _write_xml() {
        
        header("Content-Type: application/xml");
        
        $xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
        
        $xml .= "<root>";
        
        foreach($this->_result as $key => $value) {
            $xml .= "<{$this->_render_namepsace}>\n";
                
                foreach($value as $k => $d) {
                    $xml .= "<{$k}>{$d}</{$k}>\n";
                }
            
            $xml .= "</{$this->_render_namepsace}>\n";
        }
        
        $xml .= "</root>";
        
        return $xml;
    }
    
    /**
     * Array to csv 
     * 
     * @access private
     * @return string 
     */
    private function _write_csv() {        
        $lines = array();
        
        foreach ($this->_result as $key => $value) {
            
            $lines[] = implode(';', array_filter($value, function($var) {
                return $var; 
            }));
            
	}
        
        return implode("\n", $lines);
    }
    
    /**
     * Array to yaml
     * 
     * @access private
     * @return string 
     */
    private function _write_yaml() {
        $yaml = "---\n";
        
        $yaml .= "{$this->_render_namepsace}: \n";
        
        foreach($this->_result as $key => $value) {
            $yaml .= "-";
            $count = 0;
            
            foreach($value as $k => $d) {
                if( $count != 0 ) {
                    $yaml .= " ";
                }
                
                $yaml .= " {$k}: {$d} \n";
                $count++;
            }
        }
        
        return $yaml;
    }    
    
    /**
     * Gets data from database
     * 
     * @access private
     */
    private function _get() {
        
        foreach($this->_namespaces[$this->_render_namepsace]['columns'] as $c) {
            $columns .= $c.', ';
        }
        
        $sql = 'SELECT '.substr($columns, 0, -2).' FROM ' .
               $this->_namespaces[$this->_render_namepsace]['table'];
        
        if( $this->_namespaces[$this->_render_namepsace]['conditions'] != false ) {
            $sql .= ' WHERE ';
            
            foreach($this->_namespaces[$this->_render_namepsace]['conditions'] as $where => $data) {
                
                if( ! isset($this->_route_data[$data['route']]) ) {
                    $this->_error('Route '.$data['route'].' is required.');
                }
                
                // validate
                if( isset($data['rule']) ) {
                    if( ! in_array($data['rule'], $this->_rules) ) {
                        $this->_error('Rule '.$data['rule'].' is not avaiable.');
                    }

                    $rule = '_'.$data['rule'];

                    if( ! $this->$rule($this->_route_data[$data['route']]) ) {
                        $this->_error('Wrong route format.');
                    }                    
                }
                
                $sql .= $where.' = "'.mysql_real_escape_string($this->_route_data[$data['route']]).'"';
                
                if( isset($data['connect']) ) {
                    $sql .= ' '.$data['connect'];
                }
            } 
        }
        
        if( $this->_namespaces[$this->_render_namepsace]['sort'] != false ) {
        	$sql .= ' ORDER BY ' . $this->_namespaces[$this->_render_namepsace]['sort'];
        }
        
        if( $this->_namespaces[$this->_render_namepsace]['request'] != false ) {
        	$sql .= ' LIMIT ' . $this->_namespaces[$this->_render_namepsace]['request'];
        }
                
        $result = mysql_query($sql, $this->_db) or die(mysql_error());
        
        if( mysql_num_rows($result) == false ) {
            $this->_error('No results found.');
        }
                
        // write data to a nice array
        for($i = 0; $i < mysql_num_rows($result); $i++)
        {
            $dump[$i] = mysql_fetch_array($result, MYSQL_ASSOC);
        }
        
        $this->_result = $dump;
    }
    
    private function _alpha_numeric($validate) {
        if( ctype_alnum($validate) ) {
            return true;
        } else {
            return false;
        }
    }
    
    private function _numeric($validate) {
        if( ctype_digit($validate) ) {
            return true;
        } else {
            return false;
        }
    }
    
    
    private function _create() {
        
            
        if( $this->_namespaces[$this->_render_namepsace]['cache'] == false ) {
            
            $this->_get();
            
        } else {
            // cache is turned on
            if( $this->_namespaces[$this->_render_namepsace]['key'] == false ) {
                // key musst truned off
                
                $file = $this->_namespaces[$this->_render_namepsace]['cache']['folder'].sha1($this->_render_namepsace).'.txt';
                
                if( ! file_exists($file) || (time() - filemtime($file) > $this->_namespaces[$this->_render_namepsace]['cache']['time']) ) {

                    // write to cache and delete old file
                    @unlink($file);
                    
                    $f = fopen($file, 'w');
            
                    $this->_get();
                    
                    $cache = new stdClass;
                    $cache->result = $this->_result;
                    
                    fwrite($f, serialize($cache));
                    
                    fclose($f);
                }
                
                // read from cache
                $data = unserialize(file_get_contents($file));
                
                $this->_result = $data->result;
                
                
            } else {
                $this->_namespaces[$this->_render_namepsace]['cache'] = false;
                
                $this->_create();
            }
        }
            
        $type_function = '_write_';

        if( is_array($this->_namespaces[$this->_render_namepsace]['output']) ) {
            if( isset($this->_route_data['output']) ) {
                $type_function .= $this->_route_data['output'];
            } else {
                $type_function .= $this->_namespaces[$this->_render_namepsace]['output'][0];
            }
        } else {
            $type_function .= $this->_namespaces[$this->_render_namepsace]['output'];
        }


        die($this->$type_function());
        
    }
}
?>