<?php
/**
 * Abstract request parsing class.
 *
 * @author     Time.ly Network Inc.
 * @since      2.0
 *
 * @package    AI1EC
 * @subpackage AI1EC.Http.Request
 */
abstract class Ai1ec_Abstract_Query extends Ai1ec_Base implements arrayaccess {
    /**
     * @var array Request array to parse
     */
    protected $_request = null;

    /**
     * @var array Parsing rules map
     */
    protected $_rules    = null;

    /**
     * @var array Parsed values
     */
    protected $_parsed    = null;

    /**
     * @var array Indicator - whereas parsing was finished
     */
    protected $_ready    = false;

    /**
     * Return prefix that shall be used to access values
     */
    abstract protected function _get_prefix( );

    /**
     * Constructor
     *
     * Store locally copy of arguments array
     *
     * @param array $argv Arguments to be parsed [optional=null]
     *
     * @return void Constructor does not return
     */
    public function __construct( Ai1ec_Registry_Object $registry, array $argv = NULL ) {
        parent::__construct( $registry );
        if ( NULL === $argv ) {
            $request_uri = '';
            if ( isset( $_SERVER['REQUEST_URI'] ) ) {
                $request_uri = explode( '?', $_SERVER['REQUEST_URI'] );
                $request_uri = urldecode( $request_uri[0] );
            }
            $argv = trim( $request_uri, '/' );
            if ( ( $arg_start = strpos( $argv, '/' ) ) > 0 ) {
                $argv = substr( $argv, $arg_start + 1 );
            }
            $arg_list = explode( '/', $argv );
            $argv     = array();
            foreach ( $arg_list as $arg ) {
                if ( ( $colon = strpos( $arg, Ai1ec_Uri::DIRECTION_SEPARATOR ) ) > 0 ) {
                    $argv[substr( $arg, 0, $colon )] = substr( $arg, $colon + 1 );
                }
            }
        }
        $this->_rules   = array( );
        $this->_request = $argv;
    }

    /**
     * parse method
     *
     * Parse request values given rules array
     *
     * @return bool Success
     */
    public function parse() {
        if ( ! isset( $this->_request['ai1ec'] ) ) {
            $this->_request['ai1ec'] = array();
        }
        foreach ( $this->_rules as $field => $options ) {
            $value = $options['default'];
            if ( ( $ext_var = $this->_get_var( $field ) ) ) {
                $value = $this->_sane_value(
                    $ext_var,
                    $options
                );
            } elseif ( $options['mandatory'] ) {
                $this->_parsed = array( );
                return false;
            }
            if ( $options['is_list'] ) {
                $value = (array)$value;
            }
            $this->_parsed[$field] = $value;
            if ( ! isset( $this->_request['ai1ec'][$field] ) ) {
                $this->_request['ai1ec'][$field] = $value;
            }
        }
        $this->_ready = true;
        return true;
    }

    /**
     * Get parsed values map.
     *
     * @param array $name_list List of values to pull
     * If associative value is encountered - *key* is used to pull
     * request entity, and *value* to store it in returned map.
     *
     * @return array Parsed values map
     */
    public function get_dict( array $name_list ) {
        $dictionary = array( );
        foreach ( $name_list as $alias => $name ) {
            if ( is_int( $alias ) ) {
                $alias = $name;
            }
            $value = $this->get( $name );
            if ( empty( $value ) ) {
                $value = $this->get( $alias );
            }
            $dictionary[$alias] = $value;
        }
        return $dictionary;
    }

    /**
     * Get parsed value
     *
     * @param array $name Name of value to pull
     *
     * @return array Parsed value
     */
    public function get( $name ) {
        if ( ! $this->_ready ) {
            return false;
        }
        if ( ! isset( $this->_parsed[$name] ) ) {
            return false;
        }
        return $this->_parsed[$name];
    }

    /**
     * Check if the request is empry ( that means we are accessing the calendare page without parameters )
     *
     * @return boolean
     */
    public function is_empty_request() {
        return empty( $this->_request );
    }

    protected function _get_var( $name, $prefix = '' ) {
        $name     = $this->_name_without_prefix( $name );
        $use_name = $prefix . $name;
        if ( isset( $this->_request[$use_name] ) ) {
            return $this->_request[$use_name];
        }
        $result = $this->_registry->get( 'http.request.wordpress-adapter' )
            ->variable( $use_name );
        if ( null === $result || false === $result ) {
            $defined_prefix = $this->_get_prefix( );
            if ( '' === $prefix && $defined_prefix !== $prefix ) {
                return $this->_get_var( $name, $defined_prefix );
            }
        }
        return $result;
    }

    protected function _name_without_prefix( $name ) {
        $prefix = $this->_get_prefix( );
        $length = strlen( $prefix );
        if ( 0 === strncmp( $name, $prefix, $length ) ) {
            return substr( $name, $length );
        }
        return $name;
    }

    /**
     * Get scalar value representation
     *
     * @param array $name Name of value to pull
     *
     * @return array Parsed value converted to scalar
     */
    public function get_scalar( $name ) {
        $value = $this->get( $name );
        if ( ! is_scalar( $value ) ) {
            $value = implode( $this->_rules[$name]['list_sep'], $value );
        }
        return $value;
    }

    /**
     * @overload ArrayAccess::offsetExists()
     */
    public function offsetExists( $offset ) {
        if ( false === $this->get( $offset ) ) {
            return false;
        }
        return true;
    }

    /**
     * @overload ArrayAccess::offsetGet()
     */
    public function offsetGet( $offset ) {
        return $this->get_scalar( $offset );
    }

    /**
     * @overload ArrayAccess::offsetSet()
     */
    public function offsetSet( $offset, $value ) {
        // not implemented and will not be
    }

    /**
     * @overload ArrayAccess::offsetUnset()
     */
    public function offsetUnset( $offset ) {
        // not implemented and will not be
    }

    /**
     * Add argument parsing rule
     *
     * @param string      $field     Name of field to parse
     * @param bool        $mandatory Set to true for mandatory fields
     * @param string      $type      Type of field
     * @param mixed       $default   Default value to use if one is not present
     * @param string|bool $list_sep  Set to list separator (i.e. ',') if it is a
     *                               list or false if value is not a list value.
     *                               For 'enum' set to array of values.
     *
     * @return bool Success
     */
    public function add_rule(
        $field,
        $mandatory = true,
        $type      = 'int',
        $default   = null,
        $list_sep  = false
    ) {
        if ( ! is_scalar( $field ) || is_bool( $field ) ) {
            return false;
        }
        if ( false === $this->_valid_type( $type ) ) {
            return false;
        }
        $mandatory = (bool)$mandatory;
        $is_list   = false !== $list_sep && is_scalar( $list_sep );
        $field     = $this->_name_without_prefix( $field );
        $prefix    = $this->_get_prefix( );
        $record    = compact(
            'field',
            'mandatory',
            'type',
            'default',
            'is_list',
            'list_sep'
        );
        // ? => emit notice, if field is already defined
        $this->_rules[$field]           = $record;
        $this->_rules[$prefix . $field] = $record;
        $this->_ready                   = false;
        return true;
    }

    /**
     * _sane_value method
     *
     * Check if given type definition is valid.
     * Return sanitizer function name (if applicable) for valid type.
     *
     * @param string $name Type name to use
     *
     * @return string|bool Name of sanitization function or false
     */
    protected function _valid_type( $name ) {
        static $map = array(
            'int'     => 'intval',
            'integer' => 'intval',
            'float'   => 'floatval',
            'double'  => 'floatval',
            'real'    => 'floatval',
            'string'  => 'strval',
            'enum'    => null,
        );
        if ( !isset( $map[$name] ) ) {
            return false;
        }
        return $map[$name];
    }

    /**
     * _sane_value method
     *
     * Parse single input value according to processing rules.
     * Relies on {@see self::_type_cast()} for value conversion.
     *
     * @param mixed $input   Original request value
     * @param array $options Type definition options
     *
     * @return mixed Sanitized value
     */
    protected function _sane_value( $input, array $options ) {
        $sane_value = null;
        if ( $options['is_list'] ) {
            $value      = explode( $options['list_sep'], $input );
            $sane_value = array( );
            foreach ( $value as $element ) {
                $cast_element = $this->_type_cast( $element, $options );
                if ( ! empty( $cast_element ) ) {
                    $sane_value[] = $cast_element;
                }
            }
        } else {
            $sane_value = $this->_type_cast( $input, $options );
        }
        return $sane_value;
    }

    /**
     * _type_cast method
     *
     * Cast value to given type.
     * Non-PHP type 'enum' is accepted
     *
     * @param mixed $value   Value to cast
     * @param array $options Type definition options
     *
     * @return mixed Casted value
     */
    protected function _type_cast( $value, array $options ) {
        if ( 'enum' === $options['type'] ) {
            if ( in_array( $value, $options['list_sep'] ) ) {
                return $value;
            }
            return null;
        }
        $cast  = $this->_valid_type( $options['type'] );
        $value = $cast( $value );
        return $value;
    }
}