/*
 * Copyright(c) 2011
 *     OJC Technologies
 *     all rights reserved
 * @author: Jake Smith
 */

function takeClickAction(e) {
    try {
        e.preventDefault();
        processClick(e);
    } catch (err) {
        alert(err);
    }
    return false;
}

function processClick(e) {
    var event, target;
    event = e || window.event;
    event.stopPropagation();
    target = event.target || event.srcElement;
    if (target == cursor.LEFT.element || target == cursor.RIGHT.element) { 
        return;
    } 
    cursor.remove();
    if (target.nodeName == 'BODY' || target.nodeName == 'HTML') {
        return; // for now?
    }
    placeACursor(event, target);
}

function placeACursor(event, target) {
    var clickChooser, contenderNodes, posInfo;
    clickChooser = new ClickChooser(event);
    contenderNodes = getTerminalNodesIn(target);
    posInfo = clickChooser.getPositionInfo(contenderNodes);
    cursor.placeAt(posInfo[0], posInfo[1]);
}

// standalone 'helper' function
function getTerminalNodesIn(target) {
    var i, termNodes, termCount;
    termNodes = new Array();
    termCount = 0;
    for (i = 0; i < target.childNodes.length; i++) {
        var childNode = target.childNodes[i];
        if (childNode.nodeType == Node.TEXT_NODE) {
            termNodes[termCount] = childNode;
            termCount++;
        }
    }
    return termNodes;
}

function ClickChooser(event) {
    this.x = event.pageX;
    this.y = event.pageY;
    
    this.getPositionInfo = function(terminalNodes) {
        var clickedTextNode, helper, posInfo, foundIndex;
        clickedTextNode = this.getClickedTextNode(terminalNodes);
        if (clickedTextNode != null) {
            foundIndex = this.specifyIndex(clickedTextNode);
            posInfo = new Array(clickedTextNode, foundIndex);
        } else {
            helper = new ProximityHelper(event);
            posInfo = helper.getInfoFromRelation(terminalNodes);
        }
        return posInfo;
    }
    
    this.getClickedTextNode = function(terminalNodes) {
        var i, consideredNode;
        for (i = 0; i < terminalNodes.length; i += 1) {
            consideredNode = terminalNodes[i];
            if (this.clickInBounds(consideredNode)) {
                return consideredNode;
            }
        }
        return null; // not in any of the terminal nodes
    }
    
    this.clickInBounds = function(textNode) {
        var i, rects, tempSpan, flag, parent;
        parent = textNode.parentNode;
        flag = false;
        tempSpan = makeTempSpan(textNode);
        parent.replaceChild(tempSpan, textNode);
        rects = tempSpan.getClientRects();
        for (i = 0; i < rects.length; i += 1) {
            if (rectContains(rects[i], this.x, this.y)) {
                flag = true;
            }
        }
        parent.replaceChild(textNode, tempSpan);
        return flag;
    }
    
    this.specifyIndex = function(node) {
        var textLength, index, NOT_HERE;
        NOT_HERE = -2;
        textLength = node.nodeValue.length;
        if (textLength < 1) {
            index = NOT_HERE; // definitely not here
        } else  if (textLength === 1) {
            index = (this.clickInBounds(node)) ? 0 : NOT_HERE;
        } else { // length > 1
            index = this.splitAndSearch(node, textLength);
        }
        return index;
    }
    
    this.splitAndSearch = function(node, textLength) {
        var fence, index, parent;
        parent = node.parentNode
        fence = Math.ceil(textLength / 2);
        var newNode = node.splitText(fence);
        if (this.clickInBounds(node)) {
            index = this.specifyIndex(node);
        } else if (this.clickInBounds(newNode)) {
            index = fence + this.specifyIndex(newNode);
        } else {
            throw new Error("error: specifyIndex search");
        }
        parent.normalize();
        return index;
    }
}

function ProximityHelper(event) {
    this.x = event.pageX;
    this.y = event.pageY;
    
    this.getInfoFromRelation = function(terminalNodes) {
        var properNode, index, firstNode, lastNode;
        firstNode = terminalNodes[0];
        lastNode = terminalNodes[terminalNodes.length - 1];
        if (this.clickedAbove(firstNode)
                || clickedToLeft(this.x, this.y, terminalNodes)) {
            properNode = firstNode;
            index = 0;
        } else if (this.clickedBelow(lastNode)) {
            properNode = lastNode;
            index = properNode.nodeValue.length;
        } else { 
            // to right of text
            properNode = lastNode;
            index = properNode.nodeValue.length;
        }
        return new Array(properNode, index);
    }
    
    this.getBoundingRectFor = function(textNode) {
        var span, bounds;
        span = makeTempSpan(textNode);
        textNode.parentNode.replaceChild(span, textNode);
        bounds = span.getBoundingClientRect();
        span.parentNode.replaceChild(textNode, span);
        return bounds;
    }
    
    this.clickedAbove = function(textNode) {
        var bounds, top;
        bounds = this.getBoundingRectFor(textNode);
        top = Math.round(bounds.top);
        return (this.y < top);
    }
    
    this.clickedBelow = function(textNode) {
        var bounds, bottom;
        bounds = this.getBoundingRectFor(textNode);
        bottom = Math.round(bounds.bottom);
        return (this.y > bottom);
    }
    
}

// standalone 'helper' function
function makeTempSpan(textNode) {
    var elem, copyTextNode; 
    copyTextNode = document.createTextNode(textNode.nodeValue);
    elem = getEmptyTempSpan();
    elem.appendChild(copyTextNode);
    return elem;
}

// standalone 'helper' function
function getEmptyTempSpan() {
    var elem;
    elem = document.createElement('span');
    elem.setAttribute('class', 'temporarysearchspan');
    return elem;
}

// standalone 'helper' function
function rectContains(rect, x, y) {
    var bool, l, r, t, b;
    l = rect.left + window.scrollX;
    r = rect.right + window.scrollX;
    t = Math.round(rect.top) + window.scrollY;
    b = Math.round(rect.bottom) + window.scrollY;
    // possibily rounding issues with Firefox (rect.top & bottom)
    if (x < l) {
        bool = false;
    } else if (x > r) {
        bool = false;
    } else if (y < t) {
        bool = false;
    } else if (y > b) {
        bool = false;
    } else {
        bool = true;
    }
    return bool;
}

function clickedToLeft(x, y, terminalNodes) {
    var i, j, rects, r, tempSpan, parent, currNode;
    for (i = 0; i < terminalNodes.length; i += 1) {
        currNode = terminalNodes[i];
        parent = currNode.parentNode;
        tempSpan = makeTempSpan(currNode);
        parent.replaceChild(tempSpan, currNode);
        rects = tempSpan.getClientRects();
        for (j = 0; j < rects.length; j += 1) {
            r = rects[j];
            if (inVerticalBounds(r, y)) {
                if (toLeftOf(r, x)) {
                    parent.replaceChild(currNode, tempSpan);
                    return true;
                }
            }
        }
        parent.replaceChild(currNode, tempSpan);
    }
    return false;
}

function inVerticalBounds(rect, y) {
    var top, bottom
    top = Math.round(rect.top) + window.scrollY;
    bottom = Math.round(rect.bottom) + window.scrollY;
    if (y > top && y < bottom) {
        return true;
    }
    return false;
}

function toLeftOf(rect, x) {
    var leftEdge = rect.left + window.scrollX;
    return (x < leftEdge);
}