<?php
/*
Plugin Name: Presentations
Plugin URI: http://automattic.com/wordpress-plugins/
Description: Presentations plugin based on the work done by <a href="http://darylkoop.com/">Daryl Koopersmith</a>. Powered by jmpress.js
Version: 0.2
Author: Automattic
Author URI: http://automattic.com/wordpress-plugins/

	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 St, Fifth Floor, Boston, MA  02110-1301  USA
*/


/**
 * Known issues:
 *
 * - IE 7/8 are not supported by jmpress and presentations will not work
 * - IE 9 will not animate transitions at all, though it's possible to at least
 *   switch between slides.
 * - Infinite Scroll themes will not load presentations properly unless the post
 *   happens to be on the first loaded page. The permalink page will function
 *   properly, however.
 * - Exiting fullscreen mode will not properly reset the scroll locations in Safari
 */


/*
HOW TO: How the plugin settings are organized and which features are supported.

The entire presentation should be wrapped with a [presentation] shortcode, and every
individual slide should be wrapped with a [slide] shortcode. Any settings supported
by [slide] can be set into [presentation], which will apply that setting for the entire
presentation unless overridden by individual slides.

- [presentation] only settings:
   - duration: transition durations, default is one second.
   - height:   content height, default is 400px
   - width:    content width, default is 550px
   - autoplay: delay between transitions in seconds, default 3s
			   when set the presentation will automatically transition between slides
			   as long as the presentation remains in focus

- [slide] settings:
	- transition: specifies where the next slide will be placed relative
				  to the last one before it. Supported values are "up", "down"
				  "left", "right", or "none". Default value is "down".

	- scale:      scales the content relative to other slides, default value is one

	- rotate:     rotates the content by the specified degrees, default is zero

	- fade:       slides will fade in and out during transition. Values of "on" or
				  "true" will enable fading, while values of "no" or "false" will
				  disable it. Default value is "on"

	- bgcolor:    specifies a background color for the slides. Any CSS valid value
				  is permitted. Default color is transparent.

	- bgimg:	  specifies an image url which will fill the background. Image is
				  set to fill the background 100% width and height

	- fadebullets: any html <li> tags will start out with an opacity of 0 and any
				   subsequent slide transitions will show the bullets one by one
*/

if ( ! class_exists( 'Presentations' ) ) :
	class Presentations {

		private $presentation_settings;
		private $presentation_initialized;
		private $scripts_and_style_included;

		/**
		 * Constructor
		 */
		function __construct() {
			$this->presentation_initialized   = false;
			$this->scripts_and_style_included = false;

			// Registers shortcodes
			add_action( 'wp_head', array( &$this, 'add_scripts' ), 1 );

			add_shortcode( 'presentation', array( &$this, 'presentation_shortcode' ) );
			add_shortcode( 'slide', array( &$this, 'slide_shortcode' ) );
		}

		function add_scripts() {
			$this->scripts_and_style_included = false;

			if ( empty( $GLOBALS['posts'] ) || ! is_array( $GLOBALS['posts'] ) ) {
				return;
			}

			foreach ( $GLOBALS['posts'] as $p ) {
				if ( has_shortcode( $p->post_content, 'presentation' ) ) {
					$this->scripts_and_style_included = true;
					break;
				}
			}

			if ( ! $this->scripts_and_style_included ) {
				return;
			}

			$plugin = plugin_dir_url( __FILE__ );
			// Add CSS
			wp_enqueue_style( 'presentations', $plugin . 'css/style.css' );
			// Add JavaScript
			wp_enqueue_script( 'jquery' );
			wp_enqueue_script(
				'jmpress',
				Jetpack::get_file_url_for_environment( '_inc/build/shortcodes/js/jmpress.min.js', 'modules/shortcodes/js/jmpress.js' ),
				array( 'jquery' ),
				'0.4.5',
				true
			);
			wp_enqueue_script(
				'presentations',
				Jetpack::get_file_url_for_environment( '_inc/build/shortcodes/js/main.min.js', 'modules/shortcodes/js/main.js' ),
				array( 'jquery', 'jmpress' ),
				false,
				true
			);
		}

		function presentation_shortcode( $atts, $content = '' ) {
			// Mark that we've found a valid [presentation] shortcode
			$this->presentation_initialized = true;

			$atts = shortcode_atts(
				array(
					'duration'    => '',
					'height'      => '',
					'width'       => '',
					'bgcolor'     => '',
					'bgimg'       => '',
					'autoplay'    => '',

					// Settings
					'transition'  => '',
					'scale'       => '',
					'rotate'      => '',
					'fade'        => '',
					'fadebullets' => '',
				),
				$atts,
				'presentation'
			);

			$this->presentation_settings = array(
				'transition'  => 'down',
				'scale'       => 1,
				'rotate'      => 0,
				'fade'        => 'on',
				'fadebullets' => 0,
				'last'        => array(
					'x'      => 0,
					'y'      => 0,
					'scale'  => 1,
					'rotate' => 0,
				),
			);

			// Set the presentation-wide settings
			if ( '' != trim( $atts['transition'] ) ) {
				$this->presentation_settings['transition'] = $atts['transition'];
			}

			if ( '' != trim( $atts['scale'] ) ) {
				$this->presentation_settings['scale'] = floatval( $atts['scale'] );
			}

			if ( '' != trim( $atts['rotate'] ) ) {
				$this->presentation_settings['rotate'] = floatval( $atts['rotate'] );
			}

			if ( '' != trim( $atts['fade'] ) ) {
				$this->presentation_settings['fade'] = $atts['fade'];
			}

			if ( '' != trim( $atts['fadebullets'] ) ) {
				$this->presentation_settings['fadebullets'] = $atts['fadebullets'];
			}

			// Set any settings the slides don't care about
			if ( '' != trim( $atts['duration'] ) ) {
				$duration = floatval( $atts['duration'] ) . 's';
			} else {
				$duration = '1s';
			}

			// Autoplay durations are set in milliseconds
			if ( '' != trim( $atts['autoplay'] ) ) {
				$autoplay = floatval( $atts['autoplay'] ) * 1000;
			} else {
				$autoplay = 0;
			} // No autoplay

			// Set the presentation size as specified or with some nicely sized dimensions
			if ( '' != trim( $atts['width'] ) ) {
				$this->presentation_settings['width'] = intval( $atts['width'] );
			} else {
				$this->presentation_settings['width'] = 480;
			}

			if ( '' != trim( $atts['height'] ) ) {
				$this->presentation_settings['height'] = intval( $atts['height'] );
			} else {
				$this->presentation_settings['height'] = 370;
			}

			// Hide the content by default in case the scripts fail
			$style = 'display: none; width: ' . $this->presentation_settings['width'] . 'px; height: ' . $this->presentation_settings['height'] . 'px;';

			// Check for background color XOR background image
			// Use a white background if nothing specified
			if ( preg_match( '/https?\:\/\/[^\'"\s]*/', $atts['bgimg'], $matches ) ) {
				$style .= ' background-image: url("' . esc_url( $matches[0] ) . '");';
			} elseif ( '' != trim( $atts['bgcolor'] ) ) {
				$style .= ' background-color: ' . esc_attr( $atts['bgcolor'] ) . ';';
			} else {
				$style .= ' background-color: #fff;';
			}

			// Not supported message style is inlined incase the style sheet doesn't get included
			$out  = "<section class='presentation-wrapper'>";
			$out .= "<p class='not-supported-msg' style='display: inherit; padding: 25%; text-align: center;'>";
			$out .= __( 'This slideshow could not be started. Try refreshing the page or viewing it in another browser.', 'jetpack' ) . '</p>';

			// Bail out unless the scripts were added
			if ( $this->scripts_and_style_included ) {
				$out .= sprintf(
					'<div class="presentation" duration="%s" data-autoplay="%s" style="%s">',
					esc_attr( $duration ),
					esc_attr( $autoplay ),
					esc_attr( $style )
				);
				$out .= "<div class='nav-arrow-left'></div>";
				$out .= "<div class='nav-arrow-right'></div>";
				$out .= "<div class='nav-fullscreen-button'></div>";

				if ( $autoplay ) {
					$out .= '<div class="autoplay-overlay" style="display: none;"><p class="overlay-msg">';
					$out .= __( 'Click to autoplay the presentation!', 'jetpack' );
					$out .= '</p></div>';
				}

				$out .= do_shortcode( $content );
			}

			$out .= '</section>';

			$this->presentation_initialized = false;

			return $out;
		}

		function slide_shortcode( $atts, $content = '' ) {
			// Bail out unless wrapped by a [presentation] shortcode
			if ( ! $this->presentation_initialized ) {
				return $content;
			}

			$atts = shortcode_atts(
				array(
					'transition'  => '',
					'scale'       => '',
					'rotate'      => '',
					'fade'        => '',
					'fadebullets' => '',
					'bgcolor'     => '',
					'bgimg'       => '',
				),
				$atts,
				'slide'
			);

			// Determine positioning based on transition
			if ( '' == trim( $atts['transition'] ) ) {
				$atts['transition'] = $this->presentation_settings['transition'];
			}

			// Setting the content scale
			if ( '' == trim( $atts['scale'] ) ) {
				$atts['scale'] = $this->presentation_settings['scale'];
			}

			if ( '' == trim( $atts['scale'] ) ) {
				$scale = 1;
			} else {
				$scale = floatval( $atts['scale'] );
			}

			if ( $scale < 0 ) {
				$scale *= -1;
			}

			// Setting the content rotation
			if ( '' == trim( $atts['rotate'] ) ) {
				$atts['rotate'] = $this->presentation_settings['rotate'];
			}

			if ( '' == trim( $atts['rotate'] ) ) {
				$rotate = 0;
			} else {
				$rotate = floatval( $atts['rotate'] );
			}

			// Setting if the content should fade
			if ( '' == trim( $atts['fade'] ) ) {
				$atts['fade'] = $this->presentation_settings['fade'];
			}

			if ( 'on' == $atts['fade'] || 'true' == $atts['fade'] ) {
				$fade = 'fade';
			} else {
				$fade = '';
			}

			// Setting if bullets should fade on step changes
			if ( '' == trim( $atts['fadebullets'] ) ) {
				$atts['fadebullets'] = $this->presentation_settings['fadebullets'];
			}

			if ( 'on' == $atts['fadebullets'] || 'true' == $atts['fadebullets'] ) {
				$fadebullets = 'fadebullets';
			} else {
				$fadebullets = '';
			}

			$coords = $this->get_coords(
				array(
					'transition' => $atts['transition'],
					'scale'      => $scale,
					'rotate'     => $rotate,
				)
			);

			$x = $coords['x'];
			$y = $coords['y'];

			// Check for background color XOR background image
			// Use a white background if nothing specified
			if ( preg_match( '/https?\:\/\/[^\'"\s]*/', $atts['bgimg'], $matches ) ) {
				$style = 'background-image: url("' . esc_url( $matches[0] ) . '");';
			} elseif ( '' != trim( $atts['bgcolor'] ) ) {
				$style = 'background-color: ' . esc_attr( $atts['bgcolor'] ) . ';';
			} else {
				$style = '';
			}

			// Put everything together and let jmpress do the magic!
			$out = sprintf(
				'<div class="step %s %s" data-x="%s" data-y="%s" data-scale="%s" data-rotate="%s" style="%s">',
				esc_attr( $fade ),
				esc_attr( $fadebullets ),
				esc_attr( $x ),
				esc_attr( $y ),
				esc_attr( $scale ),
				esc_attr( $rotate ),
				esc_attr( $style )
			);

			$out .= '<div class="slide-content">';
			$out .= do_shortcode( $content );
			$out .= '</div></div>';

			return $out;
		}

		/**
		 * Determines the position of the next slide based on the position and scaling of the previous slide.
		 *
		 * @param array $args : an array with the following key-value pairs
		 *                    string $transition: the transition name, "up", "down", "left", or "right"
		 *                    float $scale: the scale of the next slide (used to determine the position of the slide after that)
		 *
		 * @return array with the 'x' and 'y' coordinates of the slide
		 */
		function get_coords( $args ) {
			if ( 0 == $args['scale'] ) {
				$args['scale'] = 1;
			}

			$width  = $this->presentation_settings['width'];
			$height = $this->presentation_settings['height'];
			$last   = $this->presentation_settings['last'];
			$scale  = $last['scale'];

			$next = array(
				'x'      => $last['x'],
				'y'      => $last['y'],
				'scale'  => $args['scale'],
				'rotate' => $args['rotate'],
			);

			// All angles are measured from the vertical axis, so everything is backwards!
			$diagAngle = atan2( $width, $height );
			$diagonal  = sqrt( pow( $width, 2 ) + pow( $height, 2 ) );

			// We offset the angles by the angle formed by the diagonal so that
			// we can multiply the sines directly against the diagonal length
			$theta = deg2rad( $last['rotate'] ) - $diagAngle;
			$phi   = deg2rad( $next['rotate'] ) - $diagAngle;

			// We start by displacing by the slide dimensions
			$totalHorizDisp = $width * $scale;
			$totalVertDisp  = $height * $scale;

			// If the previous slide was rotated, we add the incremental offset from the rotation
			// Namely the difference between the regular dimension (no rotation) and the component
			// of the diagonal for that angle
			$totalHorizDisp += ( ( ( abs( sin( $theta ) ) * $diagonal ) - $width ) / 2 ) * $scale;
			$totalVertDisp  += ( ( ( abs( cos( $theta ) ) * $diagonal ) - $height ) / 2 ) * $scale;

			// Similarly, we check if the current slide has been rotated and add whatever additional
			// offset has been added. This is so that two rotated corners don't clash with each other.
			// Note: we are checking the raw angle relative to the vertical axis, NOT the diagonal angle.
			if ( 0 !== $next['rotate'] % 180 ) {
				$totalHorizDisp += ( abs( ( sin( $phi ) * $diagonal ) - $width ) / 2 ) * $next['scale'];
				$totalVertDisp  += ( abs( ( cos( $phi ) * $diagonal ) - $height ) / 2 ) * $next['scale'];
			}

			switch ( trim( $args['transition'] ) ) {
				case 'none':
					break;

				case 'left':
					$next['x'] -= $totalHorizDisp;
					break;

				case 'right':
					$next['x'] += $totalHorizDisp;
					break;

				case 'up':
					$next['y'] -= $totalVertDisp;
					break;

				case 'down':
				default:
					$next['y'] += $totalVertDisp;
					break;
			}

			$this->presentation_settings['last'] = $next;

			return $next;
		}
	}

	$GLOBALS['presentations'] = new Presentations();
endif;
