<?php  if ( ! class_exists( 'AAFormHelper' ) ):

	/*
	Copyright (c) 2009 Benedikt Forchhammer

	This program 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 2
	of the License, or (at your option) any later version.

	This program 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 this program; if not, write to the Free Software
	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
	*/

	/**
	 * This class provides a collection of functions which ease the generation of form elements.
	 */
	class AAFormHelper {

		/**
		 * Renders a set of choices/values inside a select element or a group of checkboxes/radio buttons.
		 *
		 * The $attributes parameter accepts the following values:
		 * - "multiple": If set to true the element allows the user to select multiple values (default: false)
		 * - "expanded": If set to true the choices are rendered as a set of radio buttons or checkboxes (if "multiple" is set to true). (default: false)
		 * - "wrapper_tag": A html tag which is used to wrap expanded fields into a container, the default value is "div".
		 * - "id": Set this value to override the id which by default is generated from the $name parameter.
		 * - "label": Set to display a label above the field. This is automatically wrapped into "label" tags for non-expanded fields.
		 * - "help": Set to display a (help) text underneith the field.
		 * - "inline": Set to true to display all choices "inline" without line breaks in-between. (default: false)
		 * - anything else is simply used rendered as an html attribute on the element (or wrapper span if expanded=true). You can e.g. specify "class" to add a css class name.
		 *
		 * Which combination of expanded and multiple is rendered in which field?
		 * - expanded and multiple: checkboxes (input with type checkbox)
		 * - expanded but not multiple: radio buttons (input with type radio)
		 * - not expanded but multiple: multi-select (select with multiple=true)
		 * - not expanded and not multiple: dropdown (plain normal select)
		 *
		 * @static
		 * @access public
		 *
		 * @param string $name The name of the form element.
		 * @param array $choices The array of choices. The array keys are used as form element values, the array values as labels.
		 * @param mixed $values The selected value of the element. Can be a string or an array of values.
		 * @param array $attributes Array of (html) attributes.
		 *
		 * @return string Html rendered form element.
		 */
		static function choice( $name, $choices, $values, $attributes = array() ) {
			// make sure we have an array of choices
			if ( ! is_array( $choices ) || empty( $choices ) ) {
				return __( "Sorry, no choices available." );
			}

			// make sure we have all values in an array.
			if ( ! is_array( $values ) ) {
				$values = array( $values );
			}

			// render in expanded mode?
			$expanded = isset( $attributes['expanded'] ) && $attributes['expanded'] == true;

			// multiple value selection allowed?
			$multiple = isset( $attributes['multiple'] ) && $attributes['multiple'] == true;

			// render fields inline?
			$fields_inline = isset( $attributes['inline'] ) && $attributes['inline'] == true;

			// label or help text?
			$field_label = ! empty( $attributes['label'] ) ? $attributes['label'] : false;
			$field_help  = ! empty( $attributes['help'] ) ? $attributes['help'] : false;
			$wrapper_tag = ! empty( $attributes['wrapper_tag'] ) ? $attributes['wrapper_tag'] : 'div';

			// set up variables for tags and attributes.
			$wrapper_attributes = array();
			$row_attributes     = array();

			// id = either from $attributes['id'] or safe version of $name
			$wrapper_attributes['id'] = ! empty( $attributes['id'] ) ? $attributes['id'] : $name;
			$wrapper_attributes['id'] = AAFormHelper::cleanHtmlId( $wrapper_attributes['id'] );

			if ( $multiple ) {
				$name .= '[]';
			}

			if ( $expanded ) {
				$row_attributes['name'] = $name;

				if ( $multiple || count( $choices ) == 1 ) {
					$row_attributes['type']  = 'checkbox';
					$row_attributes['class'] = empty( $row_attributes['class'] ) ? 'checkbox' : ' checkbox';
				} else {
					$row_attributes['type']  = 'radio';
					$row_attributes['class'] = empty( $row_attributes['class'] ) ? 'radio' : ' radio';
				}
			} else {
				$wrapper_attributes['name'] = $name;

				if ( $multiple ) {
					$wrapper_attributes['multiple'] = 'multiple';
					$_size                          = count( $choices );
					$wrapper_attributes['size']     = $_size <= 5 ? '5' : ( $_size > 10 ? '10' : $_size );
					unset( $_size );

					// reset height, which is set to 2em on wordpress 2.6 default admin theme.
					if ( empty( $wrapper_attributes['style'] ) ) {
						$wrapper_attributes['style'] = '';
					}
					$wrapper_attributes['style'] .= 'height: auto;';
				}
			}

			// filter out values which we set ourselves
			unset( $attributes['name'], $attributes['id'], $attributes['multiple'], $attributes['expanded'], $attributes['label'], $attributes['help'], $attributes['wrapper_tag'], $attributes['inline'] );
			// add remaining $attributes values onto $wrapper_attributes
			$wrapper_attributes = array_merge( $attributes, $wrapper_attributes );

			// return value
			$html = '';

			if ( ! $expanded && $field_label ) {
				$html .= '<label>' . $field_label;
			}
			$html .= '<' . ( $expanded ? $wrapper_tag : 'select' ) . AAFormHelper::buildHtmlAttributes( $wrapper_attributes ) . '>';
			if ( $expanded && $field_label ) {
				$html .= $field_label;
			}

			foreach ( $choices as $value => $label ) {
				$attr = AAFormHelper::buildHtmlAttributes( $row_attributes );
				$attr .= ' value="' . $value . '"';

				$row = '';
				if ( $expanded ) {
					$row = '<label><input';
					if ( in_array( $value, $values ) ) {
						$row .= ' checked="checked"';
					}
					$row .= $attr;
					$row .= '/> ';
					$row .= $label;
					$row .= '</label>';
					if ( ! $fields_inline ) {
						$row .= '<br/>';
					}
				} else {
					$row = '<option';
					$row .= $attr;
					if ( in_array( $value, $values ) ) {
						$row .= ' selected="selected"';
					}
					$row .= '>';
					$row .= $label;
					$row .= '</option>';
				}

				$html .= $row;
			}

			if ( $expanded && $field_help ) {
				$html .= $field_help;
			}

			$html .= '</' . ( $expanded ? $wrapper_tag : 'select' ) . '>';

			if ( ! $expanded && $field_label ) {
				$html .= '</label>';
			}
			if ( ! $expanded && $field_help ) {
				$html .= $field_help;
			}

			return $html;
		}

		/**
		 * Renders a form input field
		 *
		 * The attributes parameter accepts any html properties plus the following:
		 * - "label": set this value to wrap the input field into a label with the given value in front of the input field.
		 * - "help": Set to display a (help) text underneith the field.
		 *
		 * @static
		 * @access public
		 *
		 * @param string $type The type of the input field. (E.g. "text" or "hidden").
		 * @param string $name The name of the input field.
		 * @param string $value The value of the input field.
		 * @param array $attributes Array of (html) attributes.
		 *
		 * @return string Html rendered form element.
		 */
		static function input( $type, $name, $value, $attributes = array() ) {
			$valid_types = array( 'text', 'hidden', 'password', 'submit', 'reset' );
			if ( ! in_array( $type, $valid_types ) ) {
				return '[Only types "' . join( '", "', $valid_types ) . '" are allowed in FormHelper::input()]';
			}

			if ( $type == 'text' && isset( $attributes['rows'] ) && intval( $attributes['rows'] ) > 0 ) {
				$tag                = 'textarea';
				$attributes['rows'] = intval( $attributes['rows'] );
			} else {
				$tag                 = 'input';
				$attributes['type']  = $type;
				$attributes['value'] = $value;
			}

			$attributes['id']   = ! empty( $attributes['id'] ) ? $attributes['id'] : $name;
			$attributes['id']   = AAFormHelper::cleanHtmlId( $attributes['id'] );
			$attributes['name'] = $name;

			$label = '';
			if ( isset( $attributes['label'] ) ) {
				$label = $attributes['label'] . ' ';
				unset( $attributes['label'] );
			}

			$help = '';
			if ( isset( $attributes['help'] ) ) {
				$help = $attributes['help'] . ' ';
				unset( $attributes['help'] );
			}

			$attr = AAFormHelper::buildHtmlAttributes( $attributes );

			$html = '<' . $tag . $attr;
			if ( $tag == 'textarea' ) {
				$html .= '>';
				$html .= htmlspecialchars( $value );
				$html .= '</' . $tag . '>';
			} else {
				$html .= ' />';
			}
			if ( ! empty( $label ) ) {
				$html = '<label>' . $label . $html . '</label>';
			}
			if ( ! empty( $help ) ) {
				$html .= $help;
			}

			return $html;
		}

		/**
		 * Builds a string of html attributes from an associative array.
		 *
		 * Example:
		 * Array('title' => 'My title'); will be transformed into this string: [ title="My title"]
		 *
		 * All attribute values are cleaned up using the function esc_html().
		 *
		 * @static
		 * @access public
		 *
		 * @param $attributes Array of attributes
		 *
		 * @return string
		 */
		static function buildHtmlAttributes( $attributes ) {
			if ( ! is_array( $attributes ) || empty( $attributes ) ) {
				return '';
			}

			$string = '';
			foreach ( $attributes as $key => $value ) {
				$string .= ' ' . $key . '="' . esc_html( $value ) . '"';
			}

			return $string;
		}

		/**
		 * Transforms any string into a valid html id by replacing non-alphanumeric characters with dashes.
		 *
		 * @static
		 * @access public
		 *
		 * @param $id string id
		 *
		 * @return string
		 */
		static function cleanHtmlId( $id ) {
			return strtolower( trim( str_replace( '--', '-', preg_replace( '/[\W]/', '-', $id ) ), "- \t\n\r\0\x0B" ) );
		}
	}
endif;