/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.    
 */

/**
 * Page editing functions.
 */
var page = {};

/**
 * Default positions and sizes.
 */
var palcx = 2500;
var trashcx = 2480;

/**
 * Init a page editor. Works with all browsers except IE.
 */
page.edit = function(elem, wname, wtext, wadd, wdelete, onchange, onselect) {

    // Track element dragging and selection
    page.dragging = null;
    page.selected = null;
    wname.disabled = true;
    wtext.disabled = true;
    wdelete.disabled = true;

    // Trigger widget select and page change events
    page.onpagechange = onchange;
    page.onwidgetselect = onselect;

    /**
     * Handle a mouse down event.
     */
    elem.onmousedown = function(e) {

        // Find a draggable element
        page.dragging = page.draggable(e.target, elem);
        page.selected = page.dragging;
        if (page.dragging == null) {

            // Reset current selection
            wname.value = '';
            wname.disabled = true;
            wtext.value = '';
            wtext.disabled = true;
            wdelete.disabled = true;

            // Trigger widget select event
            page.onwidgetselect('');
            return true;
        }

        // Clone element dragged from palette
        if (page.dragging.id.substring(0, 8) == 'palette:') {
            page.dragging = page.clone(page.dragging);
            page.selected = page.dragging;

            // Move into the editing area and hide the palette
            page.selected.style.left = ui.pixpos(ui.numpos(page.selected.style.left) + palcx);
            elem.style.left = ui.pixpos(palcx * -1);
        
            // Bring it to the top
            page.bringtotop(page.dragging);

            // Trigger page change event
            page.onpagechange(true);

        } else {

            // Bring it to the top
            page.bringtotop(page.dragging);
        }

        // Remember mouse position
        var pos = typeof e.touches != "undefined" ? e.touches[0] : e;
        page.dragX = pos.screenX;
        page.dragY = pos.screenY;

        // Update the widget name and text fields
        wname.value = page.selected.id;
        wname.disabled = false;
        wtext.value = page.text(page.selected);
        wtext.disabled = !page.hastext(page.selected);
        wdelete.disabled = false;

        // Trigger widget select event
        page.onwidgetselect(page.selected.id);

        if (e.preventDefault)
            e.preventDefault();
        else
            e.returnValue = false;
        return true;
    };

    // Support touch devices
    elem.ontouchstart = elem.onmousedown;

    /**
     * Handle a mouse up event.
     */
    elem.onmouseup = function(e) {
        if (page.dragging == null)
            return true;

        // Snap to grid
        var newX = page.gridsnap(ui.numpos(page.dragging.style.left));
        var newY = page.gridsnap(ui.numpos(page.dragging.style.top));
        page.dragging.style.left = ui.pixpos(newX);
        page.dragging.style.top = ui.pixpos(newY);
        page.dragging.cover.style.left = ui.pixpos(newX);
        page.dragging.cover.style.top = ui.pixpos(newY);

        // Fixup widget style
        page.fixupwidget(page.dragging);

        // Discard element dragged out of page area
        if (ui.numpos(page.dragging.style.left) < palcx && page.dragging.id.substring(0, 8) != 'palette:') {
            if (ui.numpos(page.dragging.style.left) >= trashcx) {

                // Unless it's close enough to page area, then move it there
                page.dragging.style.left = ui.pixpos(palcx);
                page.dragging.cover.style.left = ui.pixpos(palcx);
            } else {
                page.dragging.parentNode.removeChild(page.dragging);

                // Reset current selection
                page.selected = null;
                wname.value = '';
                wname.disabled = true;
                wtext.value = '';
                wtext.disabled = true;
                wdelete.disabled = true;

                // Trigger widget select event
                page.onwidgetselect('');
            }
        }

        // Forget dragged element
        page.dragging = null;

        // Trigger page change event
        page.onpagechange(false);
        return true;
    };

    // Support touch devices
    elem.ontouchend = elem.onmouseup;

    /**
     * Handle a mouse move event.
     */
    window.onmousemove = function(e) {
        if (page.dragging == null)
            return true;

        // Compute position of dragged element
        var curX = ui.numpos(page.dragging.style.left);
        var curY = ui.numpos(page.dragging.style.top);
        var pos = typeof e.touches != "undefined" ? e.touches[0] : e;
        var newX = curX + (pos.screenX - page.dragX);
        var newY = curY + (pos.screenY - page.dragY);
        if (newX >= 0)
            page.dragX = pos.screenX;
        else
            newX = 0;
        if (newY >= 0)
            page.dragY = pos.screenY;
        else
            newY = 0;

        // Move the dragged element
        page.dragging.style.left = ui.pixpos(newX);
        page.dragging.style.top = ui.pixpos(newY);
        page.dragging.cover.style.left = ui.pixpos(newX);
        page.dragging.cover.style.top = ui.pixpos(newY);
        return true;
    };

    // Support touch devices
    elem.ontouchmove = window.onmousemove;

    /**
     * Handle a mouse click event.
     */
    elem.onclick = function(e) {
        if (page.dragging == null) {

            // Dismiss the palette
            if (ui.numpos(elem.style.left) != (palcx * -1))
                elem.style.left = ui.pixpos(palcx * -1);
        }
        return true;
    };

    /**
     * Handle field on change events.
     */
    wname.onchange = wname.onblur = function() {
        if (page.selected == null)
            return false;
        page.selected.id = wname.value;

        // Trigger page change event
        page.onpagechange(true);
        return false;
    };

    wtext.onchange = wtext.onblur = function() {
        if (page.selected == null)
            return false;
        page.settext(page.selected, wtext.value);

        // Trigger page change event
        page.onpagechange(true);
        return false;
    };

    // Handle add widget event.
    wadd.onclick = function() {

        // Show the palette
        elem.style.left = ui.pixpos(0);
        return false;
    };

    // Handle delete event.
    wdelete.onclick = function() {
        if (page.selected == null)
            return false;

        // Remove selected widget
        page.selected.parentNode.removeChild(page.selected);

        // Reset current selection
        page.selected = null;
        wname.value = '';
        wname.disabled = true;
        wtext.value = '';
        wtext.disabled = true;
        wdelete.disabled = true;

        // Trigger widget select event
        page.onwidgetselect('');

        // Trigger page change event
        page.onpagechange(true);
        return false;
    };

    // Cover child elements with span elements to prevent
    // any input events to reach them
    map(page.cover, nodeList(elem.childNodes));

    return elem;
};

/**
 * Return the text of a widget.
 */
page.text = function(e) {
    if (e.className == 'h1' || e.className == 'h2' || e.className == 'text' || e.className == 'section')
        return car(childElements(e)).innerHTML;
    if (e.className == 'button' || e.className == 'checkbox')
        return car(childElements(e)).value;
    if (e.className == 'entry' || e.className == 'password')
        return car(childElements(e)).defaultValue;
    if (e.className == 'select')
        return car(childElements(car(childElements(e)))).value;
    if (e.className == 'link') {
        var hr = car(childElements(e)).href;
        var t = car(childElements(car(childElements(e)))).innerHTML;
        return hr == t? hr : hr + ',' + t;
    }
    if (e.className == 'img') {
        var src = car(childElements(e)).src;
        return src == window.location.href? '' : src;
    }
    if (e.className == 'iframe')
        return car(childElements(e)).href;
    if (e.className == 'list')
        return '';
    if (e.className == 'table')
        return '';
    return '';
};

/**
 * Return true if a widget has editable text.
 */
page.hastext = function(e) {
    if (e.className == 'h1' || e.className == 'h2' || e.className == 'text' || e.className == 'section')
        return true;
    if (e.className == 'button' || e.className == 'checkbox')
        return true;
    if (e.className == 'entry' || e.className == 'password')
        return true;
    if (e.className == 'select')
        return false;
    if (e.className == 'link')
        return true;
    if (e.className == 'img')
        return true;
    if (e.className == 'iframe')
        return true;
    if (e.className == 'list')
        return false;
    if (e.className == 'table')
        return false;
    return false;
};

/**
 * Set the text of a widget.
 */
page.settext = function(e, t) {
    if (e.className == 'h1' || e.className == 'h2' || e.className == 'text' || e.className == 'section') {
        car(childElements(e)).innerHTML = t;
        return t;
    }
    if (e.className == 'button' || e.className == 'entry' || e.className == 'password') {
        car(childElements(e)).defaultValue = t;
        return t;
    }
    if (e.className == 'checkbox') {
        car(childElements(e)).value = t;
        map(function(n) { if (n.nodeName == "SPAN") n.innerHTML = t; return n; }, nodeList(e.childNodes));
        return t;
    }
    if (e.className == 'select') {
        var ce = car(childElements(car(childElements(e))));
        ce.value = t;
        ce.innerHTML = t;
        return t;
    }
    if (e.className == 'list') {
        return '';
    }
    if (e.className == 'table') {
        return '';
    }
    if (e.className == 'link') {
        var l = t.split(',');
        var ce = car(childElements(e));
        ce.href = car(l);
        car(childElements(ce)).innerHTML = isNil(cdr(l))? car(l) : cadr(l);
        return t;
    }
    if (e.className == 'img') {
        car(childElements(e)).src = t;
        return t;
    }
    if (e.className == 'iframe') {
        car(childElements(e)).href = t;
        return t;
    }
    return '';
};

/**
 * Initial fixup of a widget.
 */
page.fixupwidget = function(e) {
    if (e.className == 'iframe') {
        var f = car(childElements(e));
        //e.innerHTML = '<iframe src="' + f.href + '" frameborder="no" scrolling="no"></iframe>';
        return e;
    }
    if (e.className == 'section') {
        e.style.width = '100%';
        return e;
    }
    if (e.className == 'list') {
        car(childElements(e)).style.width = '100%';
        return e;
    }
    if (e.className == 'table') {
        car(childElements(e)).style.width = '100%';
        return e;
    }
    return e;
}

/**
 * Find a draggable element in a hierarchy of elements.
 */
page.draggable = function(n, e) {
    if (n == e)
        return null;
    if (n.id != '')
        return n;
    if (n.covered)
        return n.covered;
    return page.draggable(n.parentNode, e);
}

/**
 * Align a pos along a 9pixel grid.
 */
page.gridsnap = function(x) {
    return Math.round(x / 9) * 9;
}

/**
 * Bring an element and its parent to the top.
 */
page.bringtotop = function(n) {
    n.parentNode.appendChild(n);
    n.cover.parentNode.appendChild(n.cover);
}

/**
 * Cover a page element with a <span> element to prevent
 * any input events to reach it.
 */
page.cover = function(e) {
    if (e.id == '' || isNil(e.style))
        return e;
    var cover = document.createElement('span');
    cover.style.position = 'absolute';
    cover.style.left = ui.pixpos(ui.numpos(e.style.left) - 5);
    cover.style.top = ui.pixpos(ui.numpos(e.style.top) - 5);
    cover.style.width = e.clientWidth + 10;
    cover.style.height = e.clientHeight + 10;
    cover.style.visibility = 'visible';
    cover.covered = e;
    e.cover = cover;
    e.parentNode.appendChild(cover);
    return e;
}

/**
 * Clone a palette element.
 */
page.clone = function(e) {

    /**
     * Clone an element's HTML.
     */
    function mkclone(e) {
        var ne = document.createElement('span');

        // Skip the palette: prefix
        ne.id = e.id.substr(8);

        // Copy the class and HTML content
        ne.className = e.className;
        ne.innerHTML = e.innerHTML;
        return ne;
    }

    /**
     * Clone an element's position.
     */
    function posclone(ne, e) {
        ne.style.position = 'absolute';
        ne.style.left = ui.pixpos(ui.numpos(e.style.left));
        ne.style.top = ui.pixpos(ui.numpos(e.style.top));
        e.parentNode.appendChild(ne);
        page.cover(ne);
        return ne;
    }

    return posclone(mkclone(e), e);
};