Verite Timeline JSON controller for JSON API WordPress Plugi

<?php

/*

    JSON Controller for JSON API WordPress Plugin to return posts in Timeline format for Verite Timeline WordPress Plugin

    Usage:
    http://example.com/api/timeline/category_posts/?category_id=123&post_type=timeline&amount=10&main_post_id=456

    Default values:
    category_id = null
    post_type = 'post'
    amount = -1 (all posts)
    main_post_id = first post from query, ordered by date in ascending order (the main post should be an introduction to the timeline being viewed)

    Content values can be changed to support custom post meta for enhanced usage.

*/

class JSON_API_Timeline_Controller {

    public function category_posts() {
        global $json_api;
        $json = array();

        // get attributes
        $category_id = $json_api->query->category_id;
        $post_type = $json_api->query->post_type;
        $amount = $json_api->query->amount;
        $main_post_id = $json_api->query->main_post_id;

        if(!$post_type) $post_type = 'post';
        if(!$amount) $amount = -1;

        $posts = get_posts(array('post_type' => $post_type, 'numberposts' => $amount, 'category' => $category_id, 'orderby' => 'post_date', 'order' => 'DESC'));

        if($main_post_id) $main_post = get_post($main_post_id);
        else  {
            $main_post = $posts[0];
            unset($posts[0]);
        }

        if($main_post) {

            // setting first (main) post

            $json['timeline'] = array();

            $json['timeline']['headline'] = $main_post->post_title;
            $json['timeline']['type'] = 'default';
            $json['timeline']['startDate'] = date('Y,m,d', strtotime($main_post->post_date));
            $json['timeline']['text'] = $main_post->post_excerpt;

            // example of media asset using the post thumbnail
            if(has_post_thumbnail($main_post->ID)) {

                $thumbnail_id = get_post_thumbnail_id($main_post->ID);
                $thumbnail_src = wp_get_attachment_image_src($thumbnail_id, 'medium');
                $json['timeline']['asset']['media'] = $thumbnail_src[0];

            }

            if($posts) {
                $json['timeline']['date'] = array();
                $i = 0;
                foreach($posts as $post) {

                    $json['timeline']['date'][$i]['startDate'] = date('Y,m,d', strtotime($post->post_date));
                    $json['timeline']['date'][$i]['endDate'] = date('Y,m,d', strtotime($post->post_date));
                    $json['timeline']['date'][$i]['headline'] = $post->post_title;
                    $json['timeline']['date'][$i]['text'] = $post->post_excerpt;

                    // example of media asset using the post thumbnail
                    if(has_post_thumbnail($post->ID)) {

                        $thumbnail_id = get_post_thumbnail_id($post->ID);
                        $thumbnail_src = wp_get_attachment_image_src($thumbnail_id, 'medium');

                        $json['timeline']['date'][$i]['asset']['media'] = $thumbnail_src[0];

                    }

                    $i++;

                }

                return $json;

            } else return 'Posts not found';

        } else return 'Main post not found';

    }

}

?>