/**
 * TridentSelection.js
 *
 * Copyright 2009, Moxiecode Systems AB
 * Released under LGPL License.
 *
 * License: http://tinymce.moxiecode.com/license
 * Contributing: http://tinymce.moxiecode.com/contributing
 */

(function() {
	function Selection(selection) {
		var self = this, dom = selection.dom, TRUE = true, FALSE = false;

		function getPosition(rng, start) {
			var checkRng, startIndex = 0, endIndex, inside,
				children, child, offset, index, position = -1, parent;

			// Setup test range, collapse it and get the parent
			checkRng = rng.duplicate();
			checkRng.collapse(start);
			parent = checkRng.parentElement();

			// Check if the selection is within the right document
			if (parent.ownerDocument !== selection.dom.doc)
				return;

			// IE will report non editable elements as it's parent so look for an editable one
			while (parent.contentEditable === "false") {
				parent = parent.parentNode;
			}

			// If parent doesn't have any children then return that we are inside the element
			if (!parent.hasChildNodes()) {
				return {node : parent, inside : 1};
			}

			// Setup node list and endIndex
			children = parent.children;
			endIndex = children.length - 1;

			// Perform a binary search for the position
			while (startIndex <= endIndex) {
				index = Math.floor((startIndex + endIndex) / 2);

				// Move selection to node and compare the ranges
				child = children[index];
				checkRng.moveToElementText(child);
				position = checkRng.compareEndPoints(start ? 'StartToStart' : 'EndToEnd', rng);

				// Before/after or an exact match
				if (position > 0) {
					endIndex = index - 1;
				} else if (position < 0) {
					startIndex = index + 1;
				} else {
					return {node : child};
				}
			}

			// Check if child position is before or we didn't find a position
			if (position < 0) {
				// No element child was found use the parent element and the offset inside that
				if (!child) {
					checkRng.moveToElementText(parent);
					checkRng.collapse(true);
					child = parent;
					inside = true;
				} else
					checkRng.collapse(false);

				// Walk character by character in text node until we hit the selected range endpoint, hit the end of document or parent isn't the right one
				// We need to walk char by char since rng.text or rng.htmlText will trim line endings
				offset = 0;
				while (checkRng.compareEndPoints(start ? 'StartToStart' : 'StartToEnd', rng) !== 0) {
					if (checkRng.move('character', 1) == 0 || parent != checkRng.parentElement()) {
						break;
					}

					offset++;
				}
			} else {
				// Child position is after the selection endpoint
				checkRng.collapse(true);

				// Walk character by character in text node until we hit the selected range endpoint, hit the end of document or parent isn't the right one
				offset = 0;
				while (checkRng.compareEndPoints(start ? 'StartToStart' : 'StartToEnd', rng) !== 0) {
					if (checkRng.move('character', -1) == 0 || parent != checkRng.parentElement()) {
						break;
					}

					offset++;
				}
			}

			return {node : child, position : position, offset : offset, inside : inside};
		};

		// Returns a W3C DOM compatible range object by using the IE Range API
		function getRange() {
			var ieRange = selection.getRng(), domRange = dom.createRng(), element, collapsed, tmpRange, element2, bookmark, fail;

			// If selection is outside the current document just return an empty range
			element = ieRange.item ? ieRange.item(0) : ieRange.parentElement();
			if (element.ownerDocument != dom.doc)
				return domRange;

			collapsed = selection.isCollapsed();

			// Handle control selection
			if (ieRange.item) {
				domRange.setStart(element.parentNode, dom.nodeIndex(element));
				domRange.setEnd(domRange.startContainer, domRange.startOffset + 1);

				return domRange;
			}

			function findEndPoint(start) {
				var endPoint = getPosition(ieRange, start), container, offset, textNodeOffset = 0, sibling, undef, nodeValue;

				container = endPoint.node;
				offset = endPoint.offset;

				if (endPoint.inside && !container.hasChildNodes()) {
					domRange[start ? 'setStart' : 'setEnd'](container, 0);
					return;
				}

				if (offset === undef) {
					domRange[start ? 'setStartBefore' : 'setEndAfter'](container);
					return;
				}

				if (endPoint.position < 0) {
					sibling = endPoint.inside ? container.firstChild : container.nextSibling;

					if (!sibling) {
						domRange[start ? 'setStartAfter' : 'setEndAfter'](container);
						return;
					}

					if (!offset) {
						if (sibling.nodeType == 3)
							domRange[start ? 'setStart' : 'setEnd'](sibling, 0);
						else
							domRange[start ? 'setStartBefore' : 'setEndBefore'](sibling);

						return;
					}

					// Find the text node and offset
					while (sibling) {
						nodeValue = sibling.nodeValue;
						textNodeOffset += nodeValue.length;

						// We are at or passed the position we where looking for
						if (textNodeOffset >= offset) {
							container = sibling;
							textNodeOffset -= offset;
							textNodeOffset = nodeValue.length - textNodeOffset;
							break;
						}

						sibling = sibling.nextSibling;
					}
				} else {
					// Find the text node and offset
					sibling = container.previousSibling;

					if (!sibling)
						return domRange[start ? 'setStartBefore' : 'setEndBefore'](container);

					// If there isn't any text to loop then use the first position
					if (!offset) {
						if (container.nodeType == 3)
							domRange[start ? 'setStart' : 'setEnd'](sibling, container.nodeValue.length);
						else
							domRange[start ? 'setStartAfter' : 'setEndAfter'](sibling);

						return;
					}

					while (sibling) {
						textNodeOffset += sibling.nodeValue.length;

						// We are at or passed the position we where looking for
						if (textNodeOffset >= offset) {
							container = sibling;
							textNodeOffset -= offset;
							break;
						}

						sibling = sibling.previousSibling;
					}
				}

				domRange[start ? 'setStart' : 'setEnd'](container, textNodeOffset);
			};

			try {
				// Find start point
				findEndPoint(true);

				// Find end point if needed
				if (!collapsed)
					findEndPoint();
			} catch (ex) {
				// IE has a nasty bug where text nodes might throw "invalid argument" when you
				// access the nodeValue or other properties of text nodes. This seems to happend when
				// text nodes are split into two nodes by a delete/backspace call. So lets detect it and try to fix it.
				if (ex.number == -2147024809) {
					// Get the current selection
					bookmark = self.getBookmark(2);

					// Get start element
					tmpRange = ieRange.duplicate();
					tmpRange.collapse(true);
					element = tmpRange.parentElement();

					// Get end element
					if (!collapsed) {
						tmpRange = ieRange.duplicate();
						tmpRange.collapse(false);
						element2 = tmpRange.parentElement();
						element2.innerHTML = element2.innerHTML;
					}

					// Remove the broken elements
					element.innerHTML = element.innerHTML;

					// Restore the selection
					self.moveToBookmark(bookmark);

					// Since the range has moved we need to re-get it
					ieRange = selection.getRng();

					// Find start point
					findEndPoint(true);

					// Find end point if needed
					if (!collapsed)
						findEndPoint();
				} else
					throw ex; // Throw other errors
			}

			return domRange;
		};

		this.getBookmark = function(type) {
			var rng = selection.getRng(), start, end, bookmark = {};

			function getIndexes(node) {
				var node, parent, root, children, i, indexes = [];

				parent = node.parentNode;
				root = dom.getRoot().parentNode;

				while (parent != root && parent.nodeType !== 9) {
					children = parent.children;

					i = children.length;
					while (i--) {
						if (node === children[i]) {
							indexes.push(i);
							break;
						}
					}

					node = parent;
					parent = parent.parentNode;
				}

				return indexes;
			};

			function getBookmarkEndPoint(start) {
				var position;

				position = getPosition(rng, start);
				if (position) {
					return {
						position : position.position,
						offset : position.offset,
						indexes : getIndexes(position.node),
						inside : position.inside
					};
				}
			};

			// Non ubstructive bookmark
			if (type === 2) {
				// Handle text selection
				if (!rng.item) {
					bookmark.start = getBookmarkEndPoint(true);

					if (!selection.isCollapsed())
						bookmark.end = getBookmarkEndPoint();
				} else
					bookmark.start = {ctrl : true, indexes : getIndexes(rng.item(0))};
			}

			return bookmark;
		};

		this.moveToBookmark = function(bookmark) {
			var rng, body = dom.doc.body;

			function resolveIndexes(indexes) {
				var node, i, idx, children;

				node = dom.getRoot();
				for (i = indexes.length - 1; i >= 0; i--) {
					children = node.children;
					idx = indexes[i];

					if (idx <= children.length - 1) {
						node = children[idx];
					}
				}

				return node;
			};
			
			function setBookmarkEndPoint(start) {
				var endPoint = bookmark[start ? 'start' : 'end'], moveLeft, moveRng, undef;

				if (endPoint) {
					moveLeft = endPoint.position > 0;

					moveRng = body.createTextRange();
					moveRng.moveToElementText(resolveIndexes(endPoint.indexes));

					offset = endPoint.offset;
					if (offset !== undef) {
						moveRng.collapse(endPoint.inside || moveLeft);
						moveRng.moveStart('character', moveLeft ? -offset : offset);
					} else
						moveRng.collapse(start);

					rng.setEndPoint(start ? 'StartToStart' : 'EndToStart', moveRng);

					if (start)
						rng.collapse(true);
				}
			};

			if (bookmark.start) {
				if (bookmark.start.ctrl) {
					rng = body.createControlRange();
					rng.addElement(resolveIndexes(bookmark.start.indexes));
					rng.select();
				} else {
					rng = body.createTextRange();
					setBookmarkEndPoint(true);
					setBookmarkEndPoint();
					rng.select();
				}
			}
		};

		this.addRange = function(rng) {
			var ieRng, ctrlRng, startContainer, startOffset, endContainer, endOffset, doc = selection.dom.doc, body = doc.body;

			function setEndPoint(start) {
				var container, offset, marker, tmpRng, nodes;

				marker = dom.create('a');
				container = start ? startContainer : endContainer;
				offset = start ? startOffset : endOffset;
				tmpRng = ieRng.duplicate();

				if (container == doc || container == doc.documentElement) {
					container = body;
					offset = 0;
				}

				if (container.nodeType == 3) {
					container.parentNode.insertBefore(marker, container);
					tmpRng.moveToElementText(marker);
					tmpRng.moveStart('character', offset);
					dom.remove(marker);
					ieRng.setEndPoint(start ? 'StartToStart' : 'EndToEnd', tmpRng);
				} else {
					nodes = container.childNodes;

					if (nodes.length) {
						if (offset >= nodes.length) {
							dom.insertAfter(marker, nodes[nodes.length - 1]);
						} else {
							container.insertBefore(marker, nodes[offset]);
						}

						tmpRng.moveToElementText(marker);
					} else if (container.canHaveHTML) {
						// Empty node selection for example <div>|</div>
						// Setting innerHTML with a span marker then remove that marker seems to keep empty block elements open
						container.innerHTML = '<span>\uFEFF</span>';
						marker = container.firstChild;
						tmpRng.moveToElementText(marker);
						tmpRng.collapse(FALSE); // Collapse false works better than true for some odd reason
					}

					ieRng.setEndPoint(start ? 'StartToStart' : 'EndToEnd', tmpRng);
					dom.remove(marker);
				}
			}

			// Setup some shorter versions
			startContainer = rng.startContainer;
			startOffset = rng.startOffset;
			endContainer = rng.endContainer;
			endOffset = rng.endOffset;
			ieRng = body.createTextRange();

			// If single element selection then try making a control selection out of it
			if (startContainer == endContainer && startContainer.nodeType == 1) {
				// Trick to place the caret inside an empty block element like <p></p>
				if (!startContainer.hasChildNodes()) {
					startContainer.innerHTML = '<span>\uFEFF</span><span>\uFEFF</span>';
					ieRng.moveToElementText(startContainer.lastChild);
					ieRng.select();
					dom.doc.selection.clear();
					startContainer.innerHTML = '';
					return;
				}

				if (startOffset == endOffset - 1) {
					try {
						ctrlRng = body.createControlRange();
						ctrlRng.addElement(startContainer.childNodes[startOffset]);
						ctrlRng.select();
						return;
					} catch (ex) {
						// Ignore
					}
				}
			}

			// Set start/end point of selection
			setEndPoint(true);
			setEndPoint();

			// Select the new range and scroll it into view
			ieRng.select();
		};

		// Expose range method
		this.getRangeAt = getRange;
	};

	// Expose the selection object
	tinymce.dom.TridentSelection = Selection;
})();
