/**
 * EnterKey.js
 *
 * Released under LGPL License.
 * Copyright (c) 1999-2015 Ephox Corp. All rights reserved
 *
 * License: http://www.tinymce.com/license
 * Contributing: http://www.tinymce.com/contributing
 */

/**
 * Contains logic for handling the enter key to split/generate block elements.
 *
 * @private
 * @class tinymce.EnterKey
 */
define("tinymce/EnterKey", [
	"tinymce/dom/TreeWalker",
	"tinymce/dom/RangeUtils",
	"tinymce/Env"
], function(TreeWalker, RangeUtils, Env) {
	var isIE = Env.ie && Env.ie < 11;

	return function(editor) {
		var dom = editor.dom, selection = editor.selection, settings = editor.settings;
		var undoManager = editor.undoManager, schema = editor.schema, nonEmptyElementsMap = schema.getNonEmptyElements(),
			moveCaretBeforeOnEnterElementsMap = schema.getMoveCaretBeforeOnEnterElements();

		function handleEnterKey(evt) {
			var rng, tmpRng, editableRoot, container, offset, parentBlock, documentMode, shiftKey,
				newBlock, fragment, containerBlock, parentBlockName, containerBlockName, newBlockName, isAfterLastNodeInContainer;

			// Returns true if the block can be split into two blocks or not
			function canSplitBlock(node) {
				return node &&
					dom.isBlock(node) &&
					!/^(TD|TH|CAPTION|FORM)$/.test(node.nodeName) &&
					!/^(fixed|absolute)/i.test(node.style.position) &&
					dom.getContentEditable(node) !== "true";
			}

			function isTableCell(node) {
				return node && /^(TD|TH|CAPTION)$/.test(node.nodeName);
			}

			// Renders empty block on IE
			function renderBlockOnIE(block) {
				var oldRng;

				if (dom.isBlock(block)) {
					oldRng = selection.getRng();
					block.appendChild(dom.create('span', null, '\u00a0'));
					selection.select(block);
					block.lastChild.outerHTML = '';
					selection.setRng(oldRng);
				}
			}

			// Remove the first empty inline element of the block so this: <p><b><em></em></b>x</p> becomes this: <p>x</p>
			function trimInlineElementsOnLeftSideOfBlock(block) {
				var node = block, firstChilds = [], i;

				if (!node) {
					return;
				}

				// Find inner most first child ex: <p><i><b>*</b></i></p>
				while ((node = node.firstChild)) {
					if (dom.isBlock(node)) {
						return;
					}

					if (node.nodeType == 1 && !nonEmptyElementsMap[node.nodeName.toLowerCase()]) {
						firstChilds.push(node);
					}
				}

				i = firstChilds.length;
				while (i--) {
					node = firstChilds[i];
					if (!node.hasChildNodes() || (node.firstChild == node.lastChild && node.firstChild.nodeValue === '')) {
						dom.remove(node);
					} else {
						// Remove <a> </a> see #5381
						if (node.nodeName == "A" && (node.innerText || node.textContent) === ' ') {
							dom.remove(node);
						}
					}
				}
			}

			// Moves the caret to a suitable position within the root for example in the first non
			// pure whitespace text node or before an image
			function moveToCaretPosition(root) {
				var walker, node, rng, lastNode = root, tempElm;
				function firstNonWhiteSpaceNodeSibling(node) {
					while (node) {
						if (node.nodeType == 1 || (node.nodeType == 3 && node.data && /[\r\n\s]/.test(node.data))) {
							return node;
						}

						node = node.nextSibling;
					}
				}

				if (!root) {
					return;
				}

				// Old IE versions doesn't properly render blocks with br elements in them
				// For example <p><br></p> wont be rendered correctly in a contentEditable area
				// until you remove the br producing <p></p>
				if (Env.ie && Env.ie < 9 && parentBlock && parentBlock.firstChild) {
					if (parentBlock.firstChild == parentBlock.lastChild && parentBlock.firstChild.tagName == 'BR') {
						dom.remove(parentBlock.firstChild);
					}
				}

				if (/^(LI|DT|DD)$/.test(root.nodeName)) {
					var firstChild = firstNonWhiteSpaceNodeSibling(root.firstChild);

					if (firstChild && /^(UL|OL|DL)$/.test(firstChild.nodeName)) {
						root.insertBefore(dom.doc.createTextNode('\u00a0'), root.firstChild);
					}
				}

				rng = dom.createRng();

				// Normalize whitespace to remove empty text nodes. Fix for: #6904
				// Gecko will be able to place the caret in empty text nodes but it won't render propery
				// Older IE versions will sometimes crash so for now ignore all IE versions
				if (!Env.ie) {
					root.normalize();
				}

				if (root.hasChildNodes()) {
					walker = new TreeWalker(root, root);

					while ((node = walker.current())) {
						if (node.nodeType == 3) {
							rng.setStart(node, 0);
							rng.setEnd(node, 0);
							break;
						}

						if (moveCaretBeforeOnEnterElementsMap[node.nodeName.toLowerCase()]) {
							rng.setStartBefore(node);
							rng.setEndBefore(node);
							break;
						}

						lastNode = node;
						node = walker.next();
					}

					if (!node) {
						rng.setStart(lastNode, 0);
						rng.setEnd(lastNode, 0);
					}
				} else {
					if (root.nodeName == 'BR') {
						if (root.nextSibling && dom.isBlock(root.nextSibling)) {
							// Trick on older IE versions to render the caret before the BR between two lists
							if (!documentMode || documentMode < 9) {
								tempElm = dom.create('br');
								root.parentNode.insertBefore(tempElm, root);
							}

							rng.setStartBefore(root);
							rng.setEndBefore(root);
						} else {
							rng.setStartAfter(root);
							rng.setEndAfter(root);
						}
					} else {
						rng.setStart(root, 0);
						rng.setEnd(root, 0);
					}
				}

				selection.setRng(rng);

				// Remove tempElm created for old IE:s
				dom.remove(tempElm);
				selection.scrollIntoView(root);
			}

			function setForcedBlockAttrs(node) {
				var forcedRootBlockName = settings.forced_root_block;

				if (forcedRootBlockName && forcedRootBlockName.toLowerCase() === node.tagName.toLowerCase()) {
					dom.setAttribs(node, settings.forced_root_block_attrs);
				}
			}

			function emptyBlock(elm) {
				// BR is needed in empty blocks on non IE browsers
				elm.innerHTML = !isIE ? '<br data-mce-bogus="1">' : '';
			}

			// Creates a new block element by cloning the current one or creating a new one if the name is specified
			// This function will also copy any text formatting from the parent block and add it to the new one
			function createNewBlock(name) {
				var node = container, block, clonedNode, caretNode, textInlineElements = schema.getTextInlineElements();

				if (name || parentBlockName == "TABLE") {
					block = dom.create(name || newBlockName);
					setForcedBlockAttrs(block);
				} else {
					block = parentBlock.cloneNode(false);
				}

				caretNode = block;

				// Clone any parent styles
				if (settings.keep_styles !== false) {
					do {
						if (textInlineElements[node.nodeName]) {
							// Never clone a caret containers
							if (node.id == '_mce_caret') {
								continue;
							}

							clonedNode = node.cloneNode(false);
							dom.setAttrib(clonedNode, 'id', ''); // Remove ID since it needs to be document unique

							if (block.hasChildNodes()) {
								clonedNode.appendChild(block.firstChild);
								block.appendChild(clonedNode);
							} else {
								caretNode = clonedNode;
								block.appendChild(clonedNode);
							}
						}
					} while ((node = node.parentNode) && node != editableRoot);
				}

				// BR is needed in empty blocks on non IE browsers
				if (!isIE) {
					caretNode.innerHTML = '<br data-mce-bogus="1">';
				}

				return block;
			}

			// Returns true/false if the caret is at the start/end of the parent block element
			function isCaretAtStartOrEndOfBlock(start) {
				var walker, node, name;

				// Caret is in the middle of a text node like "a|b"
				if (container.nodeType == 3 && (start ? offset > 0 : offset < container.nodeValue.length)) {
					return false;
				}

				// If after the last element in block node edge case for #5091
				if (container.parentNode == parentBlock && isAfterLastNodeInContainer && !start) {
					return true;
				}

				// If the caret if before the first element in parentBlock
				if (start && container.nodeType == 1 && container == parentBlock.firstChild) {
					return true;
				}

				// Caret can be before/after a table
				if (container.nodeName === "TABLE" || (container.previousSibling && container.previousSibling.nodeName == "TABLE")) {
					return (isAfterLastNodeInContainer && !start) || (!isAfterLastNodeInContainer && start);
				}

				// Walk the DOM and look for text nodes or non empty elements
				walker = new TreeWalker(container, parentBlock);

				// If caret is in beginning or end of a text block then jump to the next/previous node
				if (container.nodeType == 3) {
					if (start && offset === 0) {
						walker.prev();
					} else if (!start && offset == container.nodeValue.length) {
						walker.next();
					}
				}

				while ((node = walker.current())) {
					if (node.nodeType === 1) {
						// Ignore bogus elements
						if (!node.getAttribute('data-mce-bogus')) {
							// Keep empty elements like <img /> <input /> but not trailing br:s like <p>text|<br></p>
							name = node.nodeName.toLowerCase();
							if (nonEmptyElementsMap[name] && name !== 'br') {
								return false;
							}
						}
					} else if (node.nodeType === 3 && !/^[ \t\r\n]*$/.test(node.nodeValue)) {
						return false;
					}

					if (start) {
						walker.prev();
					} else {
						walker.next();
					}
				}

				return true;
			}

			// Wraps any text nodes or inline elements in the specified forced root block name
			function wrapSelfAndSiblingsInDefaultBlock(container, offset) {
				var newBlock, parentBlock, startNode, node, next, rootBlockName, blockName = newBlockName || 'P';

				// Not in a block element or in a table cell or caption
				parentBlock = dom.getParent(container, dom.isBlock);
				if (!parentBlock || !canSplitBlock(parentBlock)) {
					parentBlock = parentBlock || editableRoot;

					if (parentBlock == editor.getBody() || isTableCell(parentBlock)) {
						rootBlockName = parentBlock.nodeName.toLowerCase();
					} else {
						rootBlockName = parentBlock.parentNode.nodeName.toLowerCase();
					}

					if (!parentBlock.hasChildNodes()) {
						newBlock = dom.create(blockName);
						setForcedBlockAttrs(newBlock);
						parentBlock.appendChild(newBlock);
						rng.setStart(newBlock, 0);
						rng.setEnd(newBlock, 0);
						return newBlock;
					}

					// Find parent that is the first child of parentBlock
					node = container;
					while (node.parentNode != parentBlock) {
						node = node.parentNode;
					}

					// Loop left to find start node start wrapping at
					while (node && !dom.isBlock(node)) {
						startNode = node;
						node = node.previousSibling;
					}

					if (startNode && schema.isValidChild(rootBlockName, blockName.toLowerCase())) {
						newBlock = dom.create(blockName);
						setForcedBlockAttrs(newBlock);
						startNode.parentNode.insertBefore(newBlock, startNode);

						// Start wrapping until we hit a block
						node = startNode;
						while (node && !dom.isBlock(node)) {
							next = node.nextSibling;
							newBlock.appendChild(node);
							node = next;
						}

						// Restore range to it's past location
						rng.setStart(container, offset);
						rng.setEnd(container, offset);
					}
				}

				return container;
			}

			// Inserts a block or br before/after or in the middle of a split list of the LI is empty
			function handleEmptyListItem() {
				function isFirstOrLastLi(first) {
					var node = containerBlock[first ? 'firstChild' : 'lastChild'];

					// Find first/last element since there might be whitespace there
					while (node) {
						if (node.nodeType == 1) {
							break;
						}

						node = node[first ? 'nextSibling' : 'previousSibling'];
					}

					return node === parentBlock;
				}

				function getContainerBlock() {
					var containerBlockParent = containerBlock.parentNode;

					if (/^(LI|DT|DD)$/.test(containerBlockParent.nodeName)) {
						return containerBlockParent;
					}

					return containerBlock;
				}

				if (containerBlock == editor.getBody()) {
					return;
				}

				// Check if we are in an nested list
				var containerBlockParentName = containerBlock.parentNode.nodeName;
				if (/^(OL|UL|LI)$/.test(containerBlockParentName)) {
					newBlockName = 'LI';
				}

				newBlock = newBlockName ? createNewBlock(newBlockName) : dom.create('BR');

				if (isFirstOrLastLi(true) && isFirstOrLastLi()) {
					if (containerBlockParentName == 'LI') {
						// Nested list is inside a LI
						dom.insertAfter(newBlock, getContainerBlock());
					} else {
						// Is first and last list item then replace the OL/UL with a text block
						dom.replace(newBlock, containerBlock);
					}
				} else if (isFirstOrLastLi(true)) {
					if (containerBlockParentName == 'LI') {
						// List nested in an LI then move the list to a new sibling LI
						dom.insertAfter(newBlock, getContainerBlock());
						newBlock.appendChild(dom.doc.createTextNode(' ')); // Needed for IE so the caret can be placed
						newBlock.appendChild(containerBlock);
					} else {
						// First LI in list then remove LI and add text block before list
						containerBlock.parentNode.insertBefore(newBlock, containerBlock);
					}
				} else if (isFirstOrLastLi()) {
					// Last LI in list then remove LI and add text block after list
					dom.insertAfter(newBlock, getContainerBlock());
					renderBlockOnIE(newBlock);
				} else {
					// Middle LI in list the split the list and insert a text block in the middle
					// Extract after fragment and insert it after the current block
					containerBlock = getContainerBlock();
					tmpRng = rng.cloneRange();
					tmpRng.setStartAfter(parentBlock);
					tmpRng.setEndAfter(containerBlock);
					fragment = tmpRng.extractContents();

					if (newBlockName == 'LI' && fragment.firstChild.nodeName == 'LI') {
						newBlock = fragment.firstChild;
						dom.insertAfter(fragment, containerBlock);
					} else {
						dom.insertAfter(fragment, containerBlock);
						dom.insertAfter(newBlock, containerBlock);
					}
				}

				dom.remove(parentBlock);
				moveToCaretPosition(newBlock);
				undoManager.add();
			}

			// Inserts a BR element if the forced_root_block option is set to false or empty string
			function insertBr() {
				editor.execCommand("InsertLineBreak", false, evt);
			}

			// Trims any linebreaks at the beginning of node user for example when pressing enter in a PRE element
			function trimLeadingLineBreaks(node) {
				do {
					if (node.nodeType === 3) {
						node.nodeValue = node.nodeValue.replace(/^[\r\n]+/, '');
					}

					node = node.firstChild;
				} while (node);
			}

			function getEditableRoot(node) {
				var root = dom.getRoot(), parent, editableRoot;

				// Get all parents until we hit a non editable parent or the root
				parent = node;
				while (parent !== root && dom.getContentEditable(parent) !== "false") {
					if (dom.getContentEditable(parent) === "true") {
						editableRoot = parent;
					}

					parent = parent.parentNode;
				}

				return parent !== root ? editableRoot : root;
			}

			// Adds a BR at the end of blocks that only contains an IMG or INPUT since
			// these might be floated and then they won't expand the block
			function addBrToBlockIfNeeded(block) {
				var lastChild;

				// IE will render the blocks correctly other browsers needs a BR
				if (!isIE) {
					block.normalize(); // Remove empty text nodes that got left behind by the extract

					// Check if the block is empty or contains a floated last child
					lastChild = block.lastChild;
					if (!lastChild || (/^(left|right)$/gi.test(dom.getStyle(lastChild, 'float', true)))) {
						dom.add(block, 'br');
					}
				}
			}

			function insertNewBlockAfter() {
				// If the caret is at the end of a header we produce a P tag after it similar to Word unless we are in a hgroup
				if (/^(H[1-6]|PRE|FIGURE)$/.test(parentBlockName) && containerBlockName != 'HGROUP') {
					newBlock = createNewBlock(newBlockName);
				} else {
					newBlock = createNewBlock();
				}

				// Split the current container block element if enter is pressed inside an empty inner block element
				if (settings.end_container_on_empty_block && canSplitBlock(containerBlock) && dom.isEmpty(parentBlock)) {
					// Split container block for example a BLOCKQUOTE at the current blockParent location for example a P
					newBlock = dom.split(containerBlock, parentBlock);
				} else {
					dom.insertAfter(newBlock, parentBlock);
				}

				moveToCaretPosition(newBlock);
			}

			rng = selection.getRng(true);

			// Event is blocked by some other handler for example the lists plugin
			if (evt.isDefaultPrevented()) {
				return;
			}

			// Delete any selected contents
			if (!rng.collapsed) {
				editor.execCommand('Delete');
				return;
			}

			// Setup range items and newBlockName
			new RangeUtils(dom).normalize(rng);
			container = rng.startContainer;
			offset = rng.startOffset;
			newBlockName = (settings.force_p_newlines ? 'p' : '') || settings.forced_root_block;
			newBlockName = newBlockName ? newBlockName.toUpperCase() : '';
			documentMode = dom.doc.documentMode;
			shiftKey = evt.shiftKey;

			// Resolve node index
			if (container.nodeType == 1 && container.hasChildNodes()) {
				isAfterLastNodeInContainer = offset > container.childNodes.length - 1;

				container = container.childNodes[Math.min(offset, container.childNodes.length - 1)] || container;
				if (isAfterLastNodeInContainer && container.nodeType == 3) {
					offset = container.nodeValue.length;
				} else {
					offset = 0;
				}
			}

			// Get editable root node, normally the body element but sometimes a div or span
			editableRoot = getEditableRoot(container);

			// If there is no editable root then enter is done inside a contentEditable false element
			if (!editableRoot) {
				return;
			}

			undoManager.beforeChange();

			// If editable root isn't block nor the root of the editor
			if (!dom.isBlock(editableRoot) && editableRoot != dom.getRoot()) {
				if (!newBlockName || shiftKey) {
					insertBr();
				}

				return;
			}

			// Wrap the current node and it's sibling in a default block if it's needed.
			// for example this <td>text|<b>text2</b></td> will become this <td><p>text|<b>text2</p></b></td>
			// This won't happen if root blocks are disabled or the shiftKey is pressed
			if ((newBlockName && !shiftKey) || (!newBlockName && shiftKey)) {
				container = wrapSelfAndSiblingsInDefaultBlock(container, offset);
			}

			// Find parent block and setup empty block paddings
			parentBlock = dom.getParent(container, dom.isBlock);
			containerBlock = parentBlock ? dom.getParent(parentBlock.parentNode, dom.isBlock) : null;

			// Setup block names
			parentBlockName = parentBlock ? parentBlock.nodeName.toUpperCase() : ''; // IE < 9 & HTML5
			containerBlockName = containerBlock ? containerBlock.nodeName.toUpperCase() : ''; // IE < 9 & HTML5

			// Enter inside block contained within a LI then split or insert before/after LI
			if (containerBlockName == 'LI' && !evt.ctrlKey) {
				parentBlock = containerBlock;
				parentBlockName = containerBlockName;
			}

			// Handle enter in list item
			if (/^(LI|DT|DD)$/.test(parentBlockName)) {
				if (!newBlockName && shiftKey) {
					insertBr();
					return;
				}

				// Handle enter inside an empty list item
				if (dom.isEmpty(parentBlock)) {
					handleEmptyListItem();
					return;
				}
			}

			// Don't split PRE tags but insert a BR instead easier when writing code samples etc
			if (parentBlockName == 'PRE' && settings.br_in_pre !== false) {
				if (!shiftKey) {
					insertBr();
					return;
				}
			} else {
				// If no root block is configured then insert a BR by default or if the shiftKey is pressed
				if ((!newBlockName && !shiftKey && parentBlockName != 'LI') || (newBlockName && shiftKey)) {
					insertBr();
					return;
				}
			}

			// If parent block is root then never insert new blocks
			if (newBlockName && parentBlock === editor.getBody()) {
				return;
			}

			// Default block name if it's not configured
			newBlockName = newBlockName || 'P';

			// Insert new block before/after the parent block depending on caret location
			if (isCaretAtStartOrEndOfBlock()) {
				insertNewBlockAfter();
			} else if (isCaretAtStartOrEndOfBlock(true)) {
				// Insert new block before
				newBlock = parentBlock.parentNode.insertBefore(createNewBlock(), parentBlock);
				renderBlockOnIE(newBlock);
				moveToCaretPosition(parentBlock);
			} else {
				// Extract after fragment and insert it after the current block
				tmpRng = rng.cloneRange();
				tmpRng.setEndAfter(parentBlock);
				fragment = tmpRng.extractContents();
				trimLeadingLineBreaks(fragment);
				newBlock = fragment.firstChild;
				dom.insertAfter(fragment, parentBlock);
				trimInlineElementsOnLeftSideOfBlock(newBlock);
				addBrToBlockIfNeeded(parentBlock);

				if (dom.isEmpty(parentBlock)) {
					emptyBlock(parentBlock);
				}

				newBlock.normalize();

				// New block might become empty if it's <p><b>a |</b></p>
				if (dom.isEmpty(newBlock)) {
					dom.remove(newBlock);
					insertNewBlockAfter();
				} else {
					moveToCaretPosition(newBlock);
				}
			}

			dom.setAttrib(newBlock, 'id', ''); // Remove ID since it needs to be document unique

			// Allow custom handling of new blocks
			editor.fire('NewBlock', {newBlock: newBlock});

			undoManager.add();
		}

		editor.on('keydown', function(evt) {
			if (evt.keyCode == 13) {
				if (handleEnterKey(evt) !== false) {
					evt.preventDefault();
				}
			}
		});
	};
});