'use strict';

var HTML = require('../common/html');

//Aliases var $ = HTML.TAG_NAMES,

NS = HTML.NAMESPACES;

//Element utils

//OPTIMIZATION: Integer comparisons are low-cost, so we can use very fast tag name length filters here. //It's faster than using dictionary. function isImpliedEndTagRequired(tn) {

switch (tn.length) {
    case 1:
        return tn === $.P;
    case 2:
        return tn === $.RP || tn === $.RT || tn === $.DD || tn === $.DT || tn === $.LI;
    case 6:
        return tn === $.OPTION;
    case 8:
        return tn === $.OPTGROUP;
}
return false;

}

function isScopingElement(tn, ns) {

switch (tn.length) {
    case 2:
        if (tn === $.TD || tn === $.TH)
            return ns === NS.HTML;
        else if (tn === $.MI || tn === $.MO || tn == $.MN || tn === $.MS)
            return ns === NS.MATHML;
        break;
    case 4:
        if (tn === $.HTML)
            return ns === NS.HTML;
        else if (tn === $.DESC)
            return ns === NS.SVG;
        break;
    case 5:
        if (tn === $.TABLE)
            return ns === NS.HTML;
        else if (tn === $.MTEXT)
            return ns === NS.MATHML;
        else if (tn === $.TITLE)
            return ns === NS.SVG;
        break;
    case 6:
        return (tn === $.APPLET || tn === $.OBJECT) && ns === NS.HTML;
    case 7:
        return (tn === $.CAPTION || tn === $.MARQUEE) && ns === NS.HTML;
    case 8:
        return tn === $.TEMPLATE && ns === NS.HTML;
    case 13:
        return tn === $.FOREIGN_OBJECT && ns === NS.SVG;
    case 14:
        return tn === $.ANNOTATION_XML && ns === NS.MATHML;
}
return false;

}

//Stack of open elements var OpenElementStack = module.exports = function (document, treeAdapter) {

this.stackTop = -1;
this.items = [];
this.current = document;
this.currentTagName = null;
this.currentTmplContent = null;
this.tmplCount = 0;
this.treeAdapter = treeAdapter;

};

//Index of element OpenElementStack.prototype._indexOf = function (element) {

var idx = -1;
for (var i = this.stackTop; i >= 0; i--) {
    if (this.items[i] === element) {
        idx = i;
        break;
    }
}
return idx;

};

//Update current element OpenElementStack.prototype._isInTemplate = function () {

if (this.currentTagName !== $.TEMPLATE)
    return false;
return this.treeAdapter.getNamespaceURI(this.current) === NS.HTML;

};

OpenElementStack.prototype._updateCurrentElement = function () {

this.current = this.items[this.stackTop];
this.currentTagName = this.current && this.treeAdapter.getTagName(this.current);
this.currentTmplContent = this._isInTemplate() ? this.treeAdapter.getChildNodes(this.current)[0] : null;

};

//Mutations OpenElementStack.prototype.push = function (element) {

this.items[++this.stackTop] = element;
this._updateCurrentElement();
if (this._isInTemplate())
    this.tmplCount++;

};

OpenElementStack.prototype.pop = function () {

this.stackTop--;
if (this.tmplCount > 0 && this._isInTemplate())
    this.tmplCount--;
this._updateCurrentElement();

};

OpenElementStack.prototype.replace = function (oldElement, newElement) {

var idx = this._indexOf(oldElement);
this.items[idx] = newElement;
if (idx === this.stackTop)
    this._updateCurrentElement();

};

OpenElementStack.prototype.insertAfter = function (referenceElement, newElement) {

var insertionIdx = this._indexOf(referenceElement) + 1;
this.items.splice(insertionIdx, 0, newElement);
if (insertionIdx == ++this.stackTop)
    this._updateCurrentElement();

};

OpenElementStack.prototype.popUntilTagNamePopped = function (tagName) {

while (this.stackTop > -1) {
    var tn = this.currentTagName;
    this.pop();
    if (tn === tagName)
        break;
}

};

OpenElementStack.prototype.popUntilTemplatePopped = function () {

while (this.stackTop > -1) {
    var tn = this.currentTagName,
        ns = this.treeAdapter.getNamespaceURI(this.current);
    this.pop();
    if (tn === $.TEMPLATE && ns === NS.HTML)
        break;
}

};

OpenElementStack.prototype.popUntilElementPopped = function (element) {

while (this.stackTop > -1) {
    var poppedElement = this.current;
    this.pop();
    if (poppedElement === element)
        break;
}

};

OpenElementStack.prototype.popUntilNumberedHeaderPopped = function () {

while (this.stackTop > -1) {
    var tn = this.currentTagName;
    this.pop();
    if (tn === $.H1 || tn === $.H2 || tn === $.H3 || tn === $.H4 || tn === $.H5 || tn === $.H6)
        break;
}

};

OpenElementStack.prototype.popAllUpToHtmlElement = function () {

//NOTE: here we assume that root <html> element is always first in the open element stack, so
//we perform this fast stack clean up.
this.stackTop = 0;
this._updateCurrentElement();

};

OpenElementStack.prototype.clearBackToTableContext = function () {

while (this.currentTagName !== $.TABLE && this.currentTagName !== $.TEMPLATE && this.currentTagName !== $.HTML)
    this.pop();

};

OpenElementStack.prototype.clearBackToTableBodyContext = function () {

while (this.currentTagName !== $.TBODY && this.currentTagName !== $.TFOOT &&
       this.currentTagName !== $.THEAD && this.currentTagName !== $.TEMPLATE &&
       this.currentTagName !== $.HTML) {
    this.pop();
}

};

OpenElementStack.prototype.clearBackToTableRowContext = function () {

while (this.currentTagName !== $.TR && this.currentTagName !== $.TEMPLATE && this.currentTagName !== $.HTML)
    this.pop();

};

OpenElementStack.prototype.remove = function (element) {

for (var i = this.stackTop; i >= 0; i--) {
    if (this.items[i] === element) {
        this.items.splice(i, 1);
        this.stackTop--;
        this._updateCurrentElement();
        break;
    }
}

};

//Search OpenElementStack.prototype.tryPeekProperlyNestedBodyElement = function () {

//Properly nested <body> element (should be second element in stack).
var element = this.items[1];
return element && this.treeAdapter.getTagName(element) === $.BODY ? element : null;

};

OpenElementStack.prototype.contains = function (element) {

return this._indexOf(element) > -1;

};

OpenElementStack.prototype.getCommonAncestor = function (element) {

var elementIdx = this._indexOf(element);
return --elementIdx >= 0 ? this.items[elementIdx] : null;

};

OpenElementStack.prototype.isRootHtmlElementCurrent = function () {

return this.stackTop === 0 && this.currentTagName === $.HTML;

};

//Element in scope OpenElementStack.prototype.hasInScope = function (tagName) {

for (var i = this.stackTop; i >= 0; i--) {
    var tn = this.treeAdapter.getTagName(this.items[i]);
    if (tn === tagName)
        return true;
    var ns = this.treeAdapter.getNamespaceURI(this.items[i]);
    if (isScopingElement(tn, ns))
        return false;
}
return true;

};

OpenElementStack.prototype.hasNumberedHeaderInScope = function () {

for (var i = this.stackTop; i >= 0; i--) {
    var tn = this.treeAdapter.getTagName(this.items[i]);
    if (tn === $.H1 || tn === $.H2 || tn === $.H3 || tn === $.H4 || tn === $.H5 || tn === $.H6)
        return true;
    if (isScopingElement(tn, this.treeAdapter.getNamespaceURI(this.items[i])))
        return false;
}
return true;

};

OpenElementStack.prototype.hasInListItemScope = function (tagName) {

for (var i = this.stackTop; i >= 0; i--) {
    var tn = this.treeAdapter.getTagName(this.items[i]);
    if (tn === tagName)
        return true;
    var ns = this.treeAdapter.getNamespaceURI(this.items[i]);
    if (((tn === $.UL || tn === $.OL) && ns === NS.HTML) || isScopingElement(tn, ns))
        return false;
}
return true;

};

OpenElementStack.prototype.hasInButtonScope = function (tagName) {

for (var i = this.stackTop; i >= 0; i--) {
    var tn = this.treeAdapter.getTagName(this.items[i]);
    if (tn === tagName)
        return true;
    var ns = this.treeAdapter.getNamespaceURI(this.items[i]);
    if ((tn === $.BUTTON && ns === NS.HTML) || isScopingElement(tn, ns))
        return false;
}
return true;

};

OpenElementStack.prototype.hasInTableScope = function (tagName) {

for (var i = this.stackTop; i >= 0; i--) {
    var tn = this.treeAdapter.getTagName(this.items[i]);
    if (tn === tagName)
        return true;
    var ns = this.treeAdapter.getNamespaceURI(this.items[i]);
    if ((tn === $.TABLE || tn === $.TEMPLATE || tn === $.HTML) && ns === NS.HTML)
        return false;
}
return true;

};

OpenElementStack.prototype.hasTableBodyContextInTableScope = function () {

for (var i = this.stackTop; i >= 0; i--) {
    var tn = this.treeAdapter.getTagName(this.items[i]);
    if (tn === $.TBODY || tn === $.THEAD || tn === $.TFOOT)
        return true;
    var ns = this.treeAdapter.getNamespaceURI(this.items[i]);
    if ((tn === $.TABLE || tn === $.HTML) && ns === NS.HTML)
        return false;
}
return true;

};

OpenElementStack.prototype.hasInSelectScope = function (tagName) {

for (var i = this.stackTop; i >= 0; i--) {
    var tn = this.treeAdapter.getTagName(this.items[i]);
    if (tn === tagName)
        return true;
    var ns = this.treeAdapter.getNamespaceURI(this.items[i]);
    if (tn !== $.OPTION && tn !== $.OPTGROUP && ns === NS.HTML)
        return false;
}
return true;

};

//Implied end tags OpenElementStack.prototype.generateImpliedEndTags = function () {

while (isImpliedEndTagRequired(this.currentTagName))
    this.pop();

};

OpenElementStack.prototype.generateImpliedEndTagsWithExclusion = function (exclusionTagName) {

while (isImpliedEndTagRequired(this.currentTagName) && this.currentTagName !== exclusionTagName)
    this.pop();

};