// This file is part of Moodle - http://moodle.org/
//
// Moodle 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 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Javascript helper function for IMS Content Package module.
 *
 * @package   mod-scorm
 * @copyright 2009 Petr Skoda (http://skodak.org)
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

mod_scorm_next = null;
mod_scorm_prev = null;
mod_scorm_activate_item = null;

M.mod_scorm = {};

M.mod_scorm.init = function(Y, hide_nav, hide_toc, toc_title, window_name, launch_sco) {

    if (hide_nav == 0) {
        scorm_hide_nav = false;
    }
    else {
        scorm_hide_nav = true;
    }
    if (hide_toc == 0) {
        scorm_hide_toc = false;
    }
    else {
        scorm_hide_toc = true;
    }

    var scorm_layout_widget;
    var scorm_current_node;
    var scorm_buttons = [];
    var scorm_bloody_labelclick = false;
    var scorm_nav_panel;


    Y.use('yui2-resize', 'yui2-dragdrop', 'yui2-container', 'yui2-button', 'yui2-layout', 'yui2-treeview', 'yui2-json', 'yui2-event', function(Y) {


        var scorm_activate_item = function(node) {
            if (!node) {
                return;
            }
            scorm_current_node = node;
            scorm_current_node.highlight();

            // remove any reference to the old API
            if (window.API) {
                window.API = null;
            }
            if (window.API_1484_11) {
                window.API_1484_11 = null;
            }
            var url_prefix = M.cfg.wwwroot + '/mod/scorm/loadSCO.php?';
            var el_old_api = document.getElementById('scormapi123');
            if (el_old_api) {
                el_old_api.parentNode.removeChild(el_old_api);
            }

            if (node.title) {
            	var el_scorm_api = document.getElementById("external-scormapi");
            	el_scorm_api.parentNode.removeChild(el_scorm_api);
                el_scorm_api = document.createElement('script');
                el_scorm_api.setAttribute('id','external-scormapi');
                el_scorm_api.setAttribute('type','text/javascript');
                var pel_scorm_api = document.getElementById('scormapi-parent');
                pel_scorm_api.appendChild(el_scorm_api);
                var api_url = M.cfg.wwwroot + '/mod/scorm/api.php?' + node.title;
                document.getElementById('external-scormapi').src = api_url;
            }
         
            var content = new YAHOO.util.Element('scorm_content');
            try {
                // first try IE way - it can not set name attribute later
                // and also it has some restrictions on DOM access from object tag
                if (window_name || node.title == null) {
                    var obj = document.createElement('<iframe id="scorm_object" src="">');
                    if (window_name) {
                        var mine = window.open('','','width=1,height=1,left=0,top=0,scrollbars=no');
                        if(! mine) {
                             alert(M.str.scorm.popupsblocked);
                        }
                        mine.close()
                    }
                }
                else {
                    var obj = document.createElement('<iframe id="scorm_object" src="'+url_prefix + node.title+'">');
                } 
                // fudge IE7 to redraw the screen
                if (YAHOO.env.ua.ie > 5 && YAHOO.env.ua.ie < 8) {
                    obj.attachEvent("onload", scorm_resize_parent);
                }
            } catch (e) {
                var obj = document.createElement('object');
                obj.setAttribute('id', 'scorm_object');
                obj.setAttribute('type', 'text/html');
                if (!window_name && node.title != null) {
                    obj.setAttribute('data', url_prefix + node.title);
                }
                    if (window_name) {
                        var mine = window.open('','','width=1,height=1,left=0,top=0,scrollbars=no');
                        if(! mine) {
                             alert(M.str.scorm.popupsblocked);
                        }
                        mine.close()
                    }
            }
            var old = YAHOO.util.Dom.get('scorm_object');
            if (old) {
                content.replaceChild(obj, old);
            } else {
                content.appendChild(obj);
            }

            scorm_resize_frame();

            var left = scorm_layout_widget.getUnitByPosition('left');
            if (left.expanded) {
                scorm_current_node.focus();
            }
            if (scorm_hide_nav == false) {
                scorm_fixnav();
            }
        };

        mod_scorm_activate_item = scorm_activate_item;

        /**
         * Enables/disables navigation buttons as needed.
         * @return void
         */
        var scorm_fixnav = function() {
            scorm_buttons[0].set('disabled', (scorm_skipprev(scorm_current_node) == null));
            scorm_buttons[1].set('disabled', (scorm_prev(scorm_current_node) == null));
            scorm_buttons[2].set('disabled', (scorm_up(scorm_current_node) == null));
            scorm_buttons[3].set('disabled', (scorm_next(scorm_current_node) == null));
            scorm_buttons[4].set('disabled', (scorm_skipnext(scorm_current_node) == null));
        };

        var scorm_resize_parent = function() {
            // fudge  IE7 to redraw the screen
            parent.resizeBy(-10, -10);
            parent.resizeBy(10, 10);
            var ifr = YAHOO.util.Dom.get('scorm_object');
            if (ifr) {
                ifr.detachEvent("onload", scorm_resize_parent);
            }
        }

        var scorm_resize_layout = function(alsowidth) {
            if (window_name) {
                return;
            }

            if (alsowidth) {
                scorm_layout_widget.setStyle('width', '');
                var newwidth = scorm_get_htmlelement_size('content', 'width');
                if (newwidth > 600) {
                    scorm_layout_widget.setStyle('width', newwidth+'px');
                }
            }
            // make sure that the max width of the TOC doesn't go to far

            var left = scorm_layout_widget.getUnitByPosition('left');
            var maxwidth = parseInt(YAHOO.util.Dom.getStyle('scorm_layout', 'width'));
            left.set('maxWidth', (maxwidth - 10));
            var cwidth = left.get('width');
            if (cwidth > (maxwidth - 10)) {
                left.set('width', (maxwidth - 10));
            }

            var pageheight = scorm_get_htmlelement_size('page', 'height');
            var layoutheight = scorm_get_htmlelement_size(scorm_layout_widget, 'height');
            var newheight = layoutheight + parseInt(YAHOO.util.Dom.getViewportHeight()) - pageheight - 20;
            if (newheight > 400) {
                if (newheight > 768) {
                    scorm_layout_widget.setStyle('height', '768px');
                }
                else {
                    scorm_layout_widget.setStyle('height', newheight+'px');
                }
            }

            scorm_layout_widget.render();
            scorm_resize_frame();

            if (scorm_nav_panel) {
                scorm_nav_panel.align('bl', 'bl');
            }
        };

        var scorm_get_htmlelement_size = function(el, prop) {
            var val = YAHOO.util.Dom.getStyle(el, prop);
            if (val == 'auto') {
                if (el.get) {
                    el = el.get('element'); // get real HTMLElement from YUI element
                }
                val = YAHOO.util.Dom.getComputedStyle(YAHOO.util.Dom.get(el), prop);
            }
            return parseInt(val);
        };

        var scorm_resize_frame = function() {
            var obj = YAHOO.util.Dom.get('scorm_object');
            if (obj) {
                var content = scorm_layout_widget.getUnitByPosition('center').get('wrap');
                // basically trap IE6 and 7
                if (YAHOO.env.ua.ie > 5 && YAHOO.env.ua.ie < 8) {
                    if( obj.style.setAttribute ) {
                        obj.style.setAttribute("cssText", 'width: ' +(content.offsetWidth - 6)+'px; height: ' + (content.offsetHeight - 10)+'px;');
                    }
                    else {
                        obj.style.setAttribute('width', (content.offsetWidth - 6)+'px', 0);
                        obj.style.setAttribute('height', (content.offsetHeight - 10)+'px', 0);
                    }
                }
                else {
                    obj.style.width = (content.offsetWidth - 6)+'px';
                    obj.style.height = (content.offsetHeight - 10)+'px';
                }
            }
        };


        var scorm_up = function(node) {
            var node = scorm_tree_node.getHighlightedNode();
            if (node.depth > 0) {
                return node.parent;
            }
            return null;
        };

        var scorm_lastchild = function(node) {
            if (node.children.length) {
                return scorm_lastchild(node.children[node.children.length-1]);
            } else {
                return node;
            }
        };

        var scorm_prev = function(node) {
            if (node.previousSibling && node.previousSibling.children.length) {
                return scorm_lastchild(node.previousSibling);
            }
            return scorm_skipprev(node);
        };

        var scorm_skipprev = function(node) {
            if (node.previousSibling) {
                return node.previousSibling;
            } else if (node.depth > 0) {
                return node.parent;
            }
            return null;
        };

        var scorm_next = function(node) {
            if (node === false) {
                return scorm_tree_node.getRoot().children[0];
            }
            if (node.children.length) {
                return node.children[0];
            }
            return scorm_skipnext(node);
        };

        var scorm_skipnext = function(node) {
            if (node.nextSibling) {
                return node.nextSibling;
            } else if (node.depth > 0) {
                return scorm_skipnext(node.parent);
            }
            return null;
        };

        mod_scorm_next = scorm_next;
        mod_scorm_prev = scorm_prev;


        // layout
        YAHOO.widget.LayoutUnit.prototype.STR_COLLAPSE = M.str.moodle.hide;
        YAHOO.widget.LayoutUnit.prototype.STR_EXPAND = M.str.moodle.show;

        scorm_layout_widget = new YAHOO.widget.Layout('scorm_layout', {
            minWidth: 255,
            minHeight: 400,
            units: [
                { position: 'left', body: 'scorm_toc', header: toc_title, width: 250, resize: true, gutter: '2px 5px 5px 2px', collapse: true, minWidth:250, maxWidth: 590},
                { position: 'center', body: '<div id="scorm_content"></div>', gutter: '2px 5px 5px 2px', scroll: true}
            ]
        });
        scorm_layout_widget.render();
        var left = scorm_layout_widget.getUnitByPosition('left');
        left.on('collapse', function() {
            scorm_resize_frame();
        });
        left.on('expand', function() {
            scorm_resize_frame();
        });

        // ugly resizing hack that works around problems with resizing of iframes and objects
        left._resize.on('startResize', function() {
            var obj = YAHOO.util.Dom.get('scorm_object');
            obj.style.display = 'none';
        });
        left._resize.on('endResize', function() {
            var obj = YAHOO.util.Dom.get('scorm_object');
            obj.style.display = 'block';
            scorm_resize_frame();
        });

        // hide the TOC if that is the default
        if (scorm_hide_toc == true) {
            left.collapse();
        }

        // TOC tree
        var tree = new YAHOO.widget.TreeView('scorm_tree');
        scorm_tree_node = tree;
        tree.singleNodeHighlight = true;
        tree.subscribe('labelClick', function(node) {
            scorm_activate_item(node);
            if (node.children.length) {
                scorm_bloody_labelclick = true;
            }
        });
        tree.subscribe('collapse', function(node) {
            if (scorm_bloody_labelclick) {
                scorm_bloody_labelclick = false;
                return false;
            }
        });
        tree.subscribe('expand', function(node) {
            if (scorm_bloody_labelclick) {
                scorm_bloody_labelclick = false;
                return false;
            }
        });
        tree.expandAll();
        tree.render();

        // navigation
        if (scorm_hide_nav == false) {
            scorm_nav_panel = new YAHOO.widget.Panel('scorm_navpanel', { visible:true, draggable:true, close:false, xy: [250, 450],
                                                                    autofillheight: "body"} );
            scorm_nav_panel.setHeader(M.str.scorm.navigation);
    
            //TODO: make some better&accessible buttons
            scorm_nav_panel.setBody('<span id="scorm_nav"><button id="nav_skipprev">&lt;&lt;</button><button id="nav_prev">&lt;</button><button id="nav_up">^</button><button id="nav_next">&gt;</button><button id="nav_skipnext">&gt;&gt;</button></span>');
            scorm_nav_panel.render();
            scorm_buttons[0] = new YAHOO.widget.Button('nav_skipprev');
            scorm_buttons[1] = new YAHOO.widget.Button('nav_prev');
            scorm_buttons[2] = new YAHOO.widget.Button('nav_up');
            scorm_buttons[3] = new YAHOO.widget.Button('nav_next');
            scorm_buttons[4] = new YAHOO.widget.Button('nav_skipnext');
            scorm_buttons[0].on('click', function(ev) {
                scorm_activate_item(scorm_skipprev(scorm_tree_node.getHighlightedNode()));
            });
            scorm_buttons[1].on('click', function(ev) {
                scorm_activate_item(scorm_prev(scorm_tree_node.getHighlightedNode()));
            });
            scorm_buttons[2].on('click', function(ev) {
                scorm_activate_item(scorm_up(scorm_tree_node.getHighlightedNode()));
            });
            scorm_buttons[3].on('click', function(ev) {
                scorm_activate_item(scorm_next(scorm_tree_node.getHighlightedNode()));
            });
            scorm_buttons[4].on('click', function(ev) {
                scorm_activate_item(scorm_skipnext(scorm_tree_node.getHighlightedNode()));
            });
            scorm_nav_panel.render();
        }

        // finally activate the chosen item
        var scorm_first_url = tree.getRoot().children[0];
        var nxt = false;
        while (nxt = scorm_next(nxt)) {
            if (nxt.title) {
                expression = new RegExp('^.*?scoid=' + launch_sco + '.*?$');
                matches = nxt.title.match(expression);
                if (matches != null) {
                    scorm_first_url = nxt;
                    break;
                }
            }
        }
        scorm_activate_item(scorm_first_url);

        // resizing
        scorm_resize_layout(false);

        // fix layout if window resized
        window.onresize = function() {
            scorm_resize_layout(true);
        };
    });
};


function scorm_get_prev() {
	scorm_tree_node = YAHOO.widget.TreeView.getTree('scorm_tree');
    if (scorm_tree_node) {
        var hnode = scorm_tree_node.getHighlightedNode();
        var prev = mod_scorm_prev(hnode);
        if (prev) {
            mod_scorm_activate_item(prev);
        }
    }
}

function scorm_get_next() {
	scorm_tree_node = YAHOO.widget.TreeView.getTree('scorm_tree');
    if (scorm_tree_node) {
        var hnode = scorm_tree_node.getHighlightedNode();
        var next = mod_scorm_next(hnode);
        if (next) {
            mod_scorm_activate_item(next);
        }
    }
}