// Concrete Model Editor
//
// Copyright (c) 2010 Martin Thiede
//
// Concrete is freely distributable under the terms of an MIT-style license.

Concrete.Selector = Class.create({

  // Options:
  //   cursorEdgeOnly: if set to true snap cursor to element edges, default: true
  //	
	initialize: function(options) {
    options = options || {};
		this.cursor = {x: 0, y: 0};
		this._inlineFirst = true;
		this._cursorEdgeOnly = options.cursorEdgeOnly == undefined ? true : options.cursorEdgeOnly;
		this.selected = undefined;
		this.multiSelected = [];
	},

  setOnChangeFunction: function(f) {
    this.changeActionFunc = f;
  },
	
	selectDirect: function(s, multi) {
		var selectable = this.surroundingSelectable(s);
		if (selectable) {
			var last = this.selected;
			this._setSelected(selectable, multi);
			this.changeActionFunc && this.changeActionFunc(last, selectable);
		}
	},
	
	surroundingSelectable: function(s) {
		return s.findAncestorOrSelf(Concrete.Selector.SelectableClasses);
	},
	
	selectTab: function(dir) {
		var inner = this._findTabSelectables(this.selected)
		if (inner.size() > 0) {
			this.selectDirect(inner.first());
		}
		else {
			var parent = this.selected.findAncestor(Concrete.Selector.SelectableClasses); 
			var sameLevel = parent ? this._findTabSelectables(parent) : [];
			var idx = sameLevel.indexOf(this.selected);
			if (idx >= 0) {
				if (dir == "next") idx++;
				if (dir == "prev") idx--;
				if (idx >= sameLevel.size()) idx = 0;
				if (idx < 0) idx = sameLevel.size()-1;
				this.selectDirect(sameLevel[idx]);
			}
		}
	},
	
	selectCursor: function(dir, multi) {
		// multi select only works on elements
		if (multi && !this.selected.hasClassName("ct_element")) this._setSelected(this.selected.up(".ct_element"));
		
		var inner = this._findCursorSelectables(this.selected);
		var parent = this.selected.findAncestor(Concrete.Selector.SelectableClasses); 
		var outer = this._findCursorSelectables(parent ? parent : this.selected.up()).without(this.selected);
		
		var candidates = [];
		if (!multi && this._shouldGoInside(dir) && inner.size() > 0) {
			if (this._inlineFirst) {
				var inline = inner.select(function(s){ return this._isCursorInline(dir, s)}, this);
			}
			else {
				var inline = [];
			}
			candidates = (inline.size() > 0 ? inline : inner);
		}
		else if (outer.size() > 0) {
			if (this._inlineFirst) {
				var inline = outer.select(function(s){	return this._isSelectedElementInline(dir, s)}, this).select(function(s){ return this._isOuterInDirection(dir, s)}, this);
			}
			else {
				var inline = [];
			}
			candidates = (inline.size() > 0 ? inline : outer.select(function(s){ return this._isOuterInDirection(dir, s)}, this));
		}
		
		function sortNextInDirection(dir, s) {
			if (dir == "left") {
				return -s.right();
			}
			else if (dir == "right") {
				return s.left();
			}
			else if (dir == "up") {
				return -s.bottom();
			}
			else if (dir == "down") {
				return s.top();
			}
		}		
		
		var next = undefined;
		if (candidates.size() > 0) {
			next = candidates.sortBy(function(s) { return sortNextInDirection(dir, s) }, this).first();				
			var last = this.selected;
			this._setSelected(next, multi);
			this._adjustCursorNext(dir, next);
			this.changeActionFunc && this.changeActionFunc(last, this.selected);
		}
		else if (parent) {
			next = parent;
			var last = this.selected;
			this._setSelected(next, multi);
			this._adjustCursorParent(dir, next);
			this.changeActionFunc && this.changeActionFunc(last, this.selected);
		}
	},
	
	getCursorPosition: function() {
		if (this.cursor.element) {
			return {
				x: this.cursor.element.left()+this.cursor.x*Element.getWidth(this.cursor.element),
				y: this.cursor.element.top()+this.cursor.y*Element.getHeight(this.cursor.element) };
		}
		else {
			return {x: 0, y: 0};
		}
	},
	
	// Private
	
	_findTabSelectables: function(root) {
		return root.findFirstDescendants(Concrete.Selector.TabSelectableClasses, Concrete.Selector.SelectableClasses).select(function(n) {
			return n.visible() && n.ancestors().all(function(a){ return a.visible()})
		})
	},
	
	_findCursorSelectables: function(root) {
		return root.findFirstDescendants(Concrete.Selector.CursorSelectableClasses, []).select(function(n) {
			return n.visible() && n.ancestors().all(function(a){ return a.visible()})
		})
	},
		
	// returns true if s is inline with the cursor in the give direction
	_isCursorInline: function(dir, s) {
		var result = false;
		var cursor = this.getCursorPosition();
		if (dir == "left" || dir == "right") {
			result = (s.top() <= cursor.y && s.bottom() >= cursor.y);
		}	
		else if (dir == "up" || dir == "down") {
			result = (s.left() <= cursor.x && s.right() >= cursor.x);
		}	
		return result;
	},
	
	// returns true if s is inline (i.e. overlaps) with the currently selected element in the given direction
	_isSelectedElementInline: function(dir, s) {
		var result = false;
		if (dir == "left" || dir == "right") {
			result = (s.top() <= this.selected.bottom() && s.bottom() >= this.selected.top());
		}
		else if (dir == "up" || dir == "down") {
			result = (s.left() <= this.selected.right() && s.right() >= this.selected.left());
		}
		return result;
	},
	
	// returns true if s is outside of the current element in direction dir
	_isOuterInDirection: function(dir, s) {
		if (dir == "left") {
			return s.right() <= this.selected.left();
		}
		else if (dir == "right") {
			return s.left() >= this.selected.right();
		}
		else if (dir == "up") {
			return s.bottom() <= this.selected.top();
		}
		else if (dir == "down") {
			return s.top() >= this.selected.bottom();
		}
	},
	
	// determine if next selectable should be looked for inside of the current element
	_shouldGoInside: function(dir) {
		var cursor = this.getCursorPosition();
		if (dir == "left") {
			return cursor.x == this.selected.right();
		}
		else if (dir == "right") {
			return cursor.x == this.selected.left();
		} 
		else if (dir == "up") {
			return cursor.y == this.selected.bottom();
		}
		else if (dir == "down") {
			return cursor.y == this.selected.top();
		}
	},
	
	// adjust the cursor when the next selected is next to the current element
	// this should be used after _setSelected() to override the default adjustment
	_adjustCursorNext: function(dir, s) {
		if (dir == "left") {
			this.cursor.x = 1;
		}
		else if (dir == "right") {
			this.cursor.x = 0;			
		}
		else if (dir == "up") {
			this.cursor.y = 1;
		}
		else if (dir == "down") {
			this.cursor.y = 0;
		}
	},
	
	// adjust the cursor when the next selected is a parent of the current element
	// this should be used after _setSelected() to override the default adjustment
	_adjustCursorParent: function(dir, s) {
		if (dir == "left") {
			this.cursor.x = 0;
		}
		else if (dir == "right") {
			this.cursor.x = 1;			
		}
		else if (dir == "up") {
			this.cursor.y = 0;
		}
		else if (dir == "down") {
			this.cursor.y = 1;
		}
	},
	
	// set the currently selected element to s and adjusts the cursor to be on the boundaries of s
	_setSelected: function(s, multi) {
		if (s == this.selected) return;
		this.multiSelected.each(function(e) { e.removeClassName("ct_selected"); });
		if (this.selected) this.selected.removeClassName("ct_selected");
		this.multiSelected = [];
		if (multi && this.selected) {
			this.multiSelectStart = this.multiSelectStart || this.selected;
			var last = this.multiSelectStart;
			last = last.hasClassName("ct_element") ? last : last.up(".ct_element");
			s = s.hasClassName("ct_element") ? s : s.up(".ct_element");
			var lastAncestors = [last].concat(last.ancestors());
			var newAncestors = [s].concat(s.ancestors());
			if (s == last) {
				this.selected = s;
			}
			else if (lastAncestors.include(s)) {
				this.selected = s;
			}
			else if (newAncestors.include(last)) {
				this.selected = last;
			}
			else {
				while (lastAncestors.last() == newAncestors.last()) { 
					lastAncestors.pop();
					newAncestors.pop();
				}
				last = lastAncestors.last();
				s = newAncestors.last();
				this.selected = s;
				var siblings = s.up().childElements();
				var lastIndex = siblings.indexOf(last);
				var newIndex = siblings.indexOf(s);
				this.multiSelected = (newIndex > lastIndex) ? siblings.slice(lastIndex, newIndex+1) : siblings.slice(newIndex, lastIndex+1);
			}
		}
		else {
			this.selected = s;
			this.multiSelectStart = undefined;
		}
		this.multiSelected.each(function(e) { e.addClassName("ct_selected"); });
		this.selected.addClassName("ct_selected");
		this._adjustCursor(this.selected);
	},
	
	_adjustCursor: function(s) {
		var cur = this.getCursorPosition();
    this.cursor.element = s;
		if (this._cursorEdgeOnly) {
			this.cursor.x = (cur.x < (s.left()+s.right())/2) ? 0 : 1;
			this.cursor.y = (cur.y < (s.top()+s.bottom())/2) ? 0 : 1;
		}
		else {
			var x = cur.x;
			var y = cur.y;
			if (x < s.left()) x = s.left();
			if (x > s.right()) x = s.right();
			if (y < s.top()) y = s.top();
			if (y > s.bottom()) y = s.bottom();
			this.cursor.x = (x - s.left()) / Element.getWidth(s);
			this.cursor.y = (y - s.top()) / Element.getHeight(s);
		}		
	}
	
})

Concrete.Selector.TabSelectableClasses = ['ct_value', 'ct_element'];
Concrete.Selector.CursorSelectableClasses = ['ct_value', 'ct_element'];
Concrete.Selector.SelectableClasses = ['ct_value', 'ct_element'];