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 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 "use strict";

 // **********

 // Title: utils.js

 this.EXPORTED_SYMBOLS = ["Point", "Rect", "Range", "Subscribable", "Utils", "MRUList"];

 // #########

 const Ci = Components.interfaces;

 const Cu = Components.utils;

 Cu.import("resource://gre/modules/Services.jsm");

 // ##########

 // Class: Point

 // A simple point.

 //

 // Constructor: Point

 // If a is a Point, creates a copy of it. Otherwise, expects a to be x,

 // and creates a Point with it along with y. If either a or y are omitted,

 // 0 is used in their place.

 this.Point = function Point(a, y) {

   if (Utils.isPoint(a)) {

     this.x = a.x;

     this.y = a.y;

   } else {

     this.x = (Utils.isNumber(a) ? a : 0);

     this.y = (Utils.isNumber(y) ? y : 0);

   }

 };

 Point.prototype = {

   // ----------

   // Function: toString

   // Prints [Point (x,y)] for debug use

   toString: function Point_toString() {

     return "[Point (" + this.x + "," + this.y + ")]";

   },

   // ----------

   // Function: distance

   // Returns the distance from this point to the given <Point>.

   distance: function Point_distance(point) {

     var ax = this.x - point.x;

     var ay = this.y - point.y;

     return Math.sqrt((ax * ax) + (ay * ay));

   }

 };

 // ##########

 // Class: Rect

 // A simple rectangle. Note that in addition to the left and width, it also has

 // a right property; changing one affects the others appropriately. Same for the

 // vertical properties.

 //

 // Constructor: Rect

 // If a is a Rect, creates a copy of it. Otherwise, expects a to be left,

 // and creates a Rect with it along with top, width, and height.

 this.Rect = function Rect(a, top, width, height) {

   // Note: perhaps 'a' should really be called 'rectOrLeft'

   if (Utils.isRect(a)) {

     this.left = a.left;

     this.top = a.top;

     this.width = a.width;

     this.height = a.height;

   } else {

     this.left = a;

     this.top = top;

     this.width = width;

     this.height = height;

   }

 };

 Rect.prototype = {

   // ----------

   // Function: toString

   // Prints [Rect (left,top,width,height)] for debug use

   toString: function Rect_toString() {

     return "[Rect (" + this.left + "," + this.top + "," +

             this.width + "," + this.height + ")]";

   },

   get right() this.left + this.width,

   set right(value) {

     this.width = value - this.left;

   },

   get bottom() this.top + this.height,

   set bottom(value) {

     this.height = value - this.top;

   },

   // ----------

   // Variable: xRange

   // Gives you a new <Range> for the horizontal dimension.

   get xRange() new Range(this.left, this.right),

   // ----------

   // Variable: yRange

   // Gives you a new <Range> for the vertical dimension.

   get yRange() new Range(this.top, this.bottom),

   // ----------

   // Function: intersects

   // Returns true if this rectangle intersects the given <Rect>.

   intersects: function Rect_intersects(rect) {

     return (rect.right > this.left &&

             rect.left < this.right &&

             rect.bottom > this.top &&

             rect.top < this.bottom);

   },

   // ----------

   // Function: intersection

   // Returns a new <Rect> with the intersection of this rectangle and the give <Rect>,

   // or null if they don't intersect.

   intersection: function Rect_intersection(rect) {

     var box = new Rect(Math.max(rect.left, this.left), Math.max(rect.top, this.top), 0, 0);

     box.right = Math.min(rect.right, this.right);

     box.bottom = Math.min(rect.bottom, this.bottom);

     if (box.width > 0 && box.height > 0)

       return box;

     return null;

   },

   // ----------

   // Function: contains

   // Returns a boolean denoting if the <Rect> or <Point> is contained inside

   // this rectangle.

   //

   // Parameters

   //  - A <Rect> or a <Point>

   contains: function Rect_contains(a) {

     if (Utils.isPoint(a))

       return (a.x > this.left &&

               a.x < this.right &&

               a.y > this.top &&

               a.y < this.bottom);

     return (a.left >= this.left &&

             a.right <= this.right &&

             a.top >= this.top &&

             a.bottom <= this.bottom);

   },

   // ----------

   // Function: center

   // Returns a new <Point> with the center location of this rectangle.

   center: function Rect_center() {

     return new Point(this.left + (this.width / 2), this.top + (this.height / 2));

   },

   // ----------

   // Function: size

   // Returns a new <Point> with the dimensions of this rectangle.

   size: function Rect_size() {

     return new Point(this.width, this.height);

   },

   // ----------

   // Function: position

   // Returns a new <Point> with the top left of this rectangle.

   position: function Rect_position() {

     return new Point(this.left, this.top);

   },

   // ----------

   // Function: area

   // Returns the area of this rectangle.

   area: function Rect_area() {

     return this.width * this.height;

   },

   // ----------

   // Function: inset

   // Makes the rect smaller (if the arguments are positive) as if a margin is added all around

   // the initial rect, with the margin widths (symmetric) being specified by the arguments.

   //

   // Paramaters

   //  - A <Point> or two arguments: x and y

   inset: function Rect_inset(a, b) {

     if (Utils.isPoint(a)) {

       b = a.y;

       a = a.x;

     }

     this.left += a;

     this.width -= a * 2;

     this.top += b;

     this.height -= b * 2;

   },

   // ----------

   // Function: offset

   // Moves (translates) the rect by the given vector.

   //

   // Paramaters

   //  - A <Point> or two arguments: x and y

   offset: function Rect_offset(a, b) {

     if (Utils.isPoint(a)) {

       this.left += a.x;

       this.top += a.y;

     } else {

       this.left += a;

       this.top += b;

     }

   },

   // ----------

   // Function: equals

   // Returns true if this rectangle is identical to the given <Rect>.

   equals: function Rect_equals(rect) {

     return (rect.left == this.left &&

             rect.top == this.top &&

             rect.width == this.width &&

             rect.height == this.height);

   },

   // ----------

   // Function: union

   // Returns a new <Rect> with the union of this rectangle and the given <Rect>.

   union: function Rect_union(a) {

     var newLeft = Math.min(a.left, this.left);

     var newTop = Math.min(a.top, this.top);

     var newWidth = Math.max(a.right, this.right) - newLeft;

     var newHeight = Math.max(a.bottom, this.bottom) - newTop;

     var newRect = new Rect(newLeft, newTop, newWidth, newHeight);

     return newRect;

   },

   // ----------

   // Function: copy

   // Copies the values of the given <Rect> into this rectangle.

   copy: function Rect_copy(a) {

     this.left = a.left;

     this.top = a.top;

     this.width = a.width;

     this.height = a.height;

   }

 };

 // ##########

 // Class: Range

 // A physical interval, with a min and max.

 //

 // Constructor: Range

 // Creates a Range with the given min and max

 this.Range = function Range(min, max) {

   if (Utils.isRange(min) && !max) { // if the one variable given is a range, copy it.

     this.min = min.min;

     this.max = min.max;

   } else {

     this.min = min || 0;

     this.max = max || 0;

   }

 };

 Range.prototype = {

   // ----------

   // Function: toString

   // Prints [Range (min,max)] for debug use

   toString: function Range_toString() {

     return "[Range (" + this.min + "," + this.max + ")]";

   },

   // Variable: extent

   // Equivalent to max-min

   get extent() {

     return (this.max - this.min);

   },

   set extent(extent) {

     this.max = extent - this.min;

   },

   // ----------

   // Function: contains

   // Whether the <Range> contains the given <Range> or value or not.

   //

   // Parameters

   //  - a number or <Range>

   contains: function Range_contains(value) {

     if (Utils.isNumber(value))

       return value >= this.min && value <= this.max;

     if (Utils.isRange(value))

       return value.min >= this.min && value.max <= this.max;

     return false;

   },

   // ----------

   // Function: overlaps

   // Whether the <Range> overlaps with the given <Range> value or not.

   //

   // Parameters

   //  - a number or <Range>

   overlaps: function Range_overlaps(value) {

     if (Utils.isNumber(value))

       return this.contains(value);

     if (Utils.isRange(value))

       return !(value.max < this.min || this.max < value.min);

     return false;

   },

   // ----------

   // Function: proportion

   // Maps the given value to the range [0,1], so that it returns 0 if the value is <= the min,

   // returns 1 if the value >= the max, and returns an interpolated "proportion" in (min, max).

   //

   // Parameters

   //  - a number

   //  - (bool) smooth? If true, a smooth tanh-based function will be used instead of the linear.

   proportion: function Range_proportion(value, smooth) {

     if (value <= this.min)

       return 0;

     if (this.max <= value)

       return 1;

     var proportion = (value - this.min) / this.extent;

     if (smooth) {

       // The ease function ".5+.5*Math.tanh(4*x-2)" is a pretty

       // little graph. It goes from near 0 at x=0 to near 1 at x=1

       // smoothly and beautifully.

       // http://www.wolframalpha.com/input/?i=.5+%2B+.5+*+tanh%28%284+*+x%29+-+2%29

       let tanh = function tanh(x) {

         var e = Math.exp(x);

         return (e - 1/e) / (e + 1/e);

       };

       return .5 - .5 * tanh(2 - 4 * proportion);

     }

     return proportion;

   },

   // ----------

   // Function: scale

   // Takes the given value in [0,1] and maps it to the associated value on the Range.

   //

   // Parameters

   //  - a number in [0,1]

   scale: function Range_scale(value) {

     if (value > 1)

       value = 1;

     if (value < 0)

       value = 0;

     return this.min + this.extent * value;

   }

 };

 // ##########

 // Class: Subscribable

 // A mix-in for allowing objects to collect subscribers for custom events.

 this.Subscribable = function Subscribable() {

   this.subscribers = null;

 };

 Subscribable.prototype = {

   // ----------

   // Function: addSubscriber

   // The given callback will be called when the Subscribable fires the given event.

   addSubscriber: function Subscribable_addSubscriber(eventName, callback) {

     try {

       Utils.assertThrow(typeof callback == "function", "callback must be a function");

       Utils.assertThrow(eventName && typeof eventName == "string",

           "eventName must be a non-empty string");

     } catch(e) {

       Utils.log(e);

       return;

     }

     if (!this.subscribers)

       this.subscribers = {};

     if (!this.subscribers[eventName])

       this.subscribers[eventName] = [];

     let subscribers = this.subscribers[eventName];

     if (subscribers.indexOf(callback) == -1)

       subscribers.push(callback);

   },

   // ----------

   // Function: removeSubscriber

   // Removes the subscriber associated with the event for the given callback.

   removeSubscriber: function Subscribable_removeSubscriber(eventName, callback) {

     try {

       Utils.assertThrow(typeof callback == "function", "callback must be a function");

       Utils.assertThrow(eventName && typeof eventName == "string",

           "eventName must be a non-empty string");

     } catch(e) {

       Utils.log(e);

       return;

     }

     if (!this.subscribers || !this.subscribers[eventName])

       return;

     let subscribers = this.subscribers[eventName];

     let index = subscribers.indexOf(callback);

     if (index > -1)

       subscribers.splice(index, 1);

   },

   // ----------

   // Function: _sendToSubscribers

   // Internal routine. Used by the Subscribable to fire events.

   _sendToSubscribers: function Subscribable__sendToSubscribers(eventName, eventInfo) {

     try {

       Utils.assertThrow(eventName && typeof eventName == "string",

           "eventName must be a non-empty string");

     } catch(e) {

       Utils.log(e);

       return;

     }

     if (!this.subscribers || !this.subscribers[eventName])

       return;

     let subsCopy = this.subscribers[eventName].concat();

     subsCopy.forEach(function (callback) {

       try {

         callback(this, eventInfo);

       } catch(e) {

         Utils.log(e);

       }

     }, this);

   }

 };

 // ##########

 // Class: Utils

 // Singelton with common utility functions.

 this.Utils = {

   // ----------

   // Function: toString

   // Prints [Utils] for debug use

   toString: function Utils_toString() {

     return "[Utils]";

   },

   // ___ Logging

   useConsole: true, // as opposed to dump

   showTime: false,

   // ----------

   // Function: log

   // Prints the given arguments to the JavaScript error console as a message.

   // Pass as many arguments as you want, it'll print them all.

   log: function Utils_log() {

     var text = this.expandArgumentsForLog(arguments);

     var prefix = this.showTime ? Date.now() + ': ' : '';

     if (this.useConsole)    

       Services.console.logStringMessage(prefix + text);

     else

       dump(prefix + text + '\n');

   },

   // ----------

   // Function: error

   // Prints the given arguments to the JavaScript error console as an error.

   // Pass as many arguments as you want, it'll print them all.

   error: function Utils_error() {

     var text = this.expandArgumentsForLog(arguments);

     var prefix = this.showTime ? Date.now() + ': ' : '';

     if (this.useConsole)    

       Cu.reportError(prefix + "tabview error: " + text);

     else

       dump(prefix + "TABVIEW ERROR: " + text + '\n');

   },

   // ----------

   // Function: trace

   // Prints the given arguments to the JavaScript error console as a message,

   // along with a full stack trace.

   // Pass as many arguments as you want, it'll print them all.

   trace: function Utils_trace() {

     var text = this.expandArgumentsForLog(arguments);

     // cut off the first line of the stack trace, because that's just this function.

     let stack = Error().stack.split("\n").slice(1);

     // if the caller was assert, cut out the line for the assert function as well.

     if (stack[0].indexOf("Utils_assert(") == 0)

       stack.splice(0, 1);

     this.log('trace: ' + text + '\n' + stack.join("\n"));

   },

   // ----------

   // Function: assert

   // Prints a stack trace along with label (as a console message) if condition is false.

   assert: function Utils_assert(condition, label) {

     if (!condition) {

       let text;

       if (typeof label != 'string')

         text = 'badly formed assert';

       else

         text = "tabview assert: " + label;

       this.trace(text);

     }

   },

   // ----------

   // Function: assertThrow

   // Throws label as an exception if condition is false.

   assertThrow: function Utils_assertThrow(condition, label) {

     if (!condition) {

       let text;

       if (typeof label != 'string')

         text = 'badly formed assert';

       else

         text = "tabview assert: " + label;

       // cut off the first line of the stack trace, because that's just this function.

       let stack = Error().stack.split("\n").slice(1);

       throw text + "\n" + stack.join("\n");

     }

   },

   // ----------

   // Function: expandObject

   // Prints the given object to a string, including all of its properties.

   expandObject: function Utils_expandObject(obj) {

     var s = obj + ' = {';

     for (let prop in obj) {

       let value;

       try {

         value = obj[prop];

       } catch(e) {

         value = '[!!error retrieving property]';

       }

       s += prop + ': ';

       if (typeof value == 'string')

         s += '\'' + value + '\'';

       else if (typeof value == 'function')

         s += 'function';

       else

         s += value;

       s += ', ';

     }

     return s + '}';

   },

   // ----------

   // Function: expandArgumentsForLog

   // Expands all of the given args (an array) into a single string.

   expandArgumentsForLog: function Utils_expandArgumentsForLog(args) {

     var that = this;

     return Array.map(args, function(arg) {

       return typeof arg == 'object' ? that.expandObject(arg) : arg;

     }).join('; ');

   },

   // ___ Misc

   // ----------

   // Function: isLeftClick

   // Given a DOM mouse event, returns true if it was for the left mouse button.

   isLeftClick: function Utils_isLeftClick(event) {

     return event.button == 0;

   },

   // ----------

   // Function: isMiddleClick

   // Given a DOM mouse event, returns true if it was for the middle mouse button.

   isMiddleClick: function Utils_isMiddleClick(event) {

     return event.button == 1;

   },

   // ----------

   // Function: isRightClick

   // Given a DOM mouse event, returns true if it was for the right mouse button.

   isRightClick: function Utils_isRightClick(event) {

     return event.button == 2;

   },

   // ----------

   // Function: isDOMElement

   // Returns true if the given object is a DOM element.

   isDOMElement: function Utils_isDOMElement(object) {

     return object instanceof Ci.nsIDOMElement;

   },

   // ----------

   // Function: isValidXULTab

   // A xulTab is valid if it has not been closed,

   // and it has not been removed from the DOM

   // Returns true if the tab is valid.

   isValidXULTab: function Utils_isValidXULTab(xulTab) {

     return !xulTab.closing && xulTab.parentNode;

   },

   // ----------

   // Function: isNumber

   // Returns true if the argument is a valid number.

   isNumber: function Utils_isNumber(n) {

     return typeof n == 'number' && !isNaN(n);

   },

   // ----------

   // Function: isRect

   // Returns true if the given object (r) looks like a <Rect>.

   isRect: function Utils_isRect(r) {

     return (r &&

             this.isNumber(r.left) &&

             this.isNumber(r.top) &&

             this.isNumber(r.width) &&

             this.isNumber(r.height));

   },

   // ----------

   // Function: isRange

   // Returns true if the given object (r) looks like a <Range>.

   isRange: function Utils_isRange(r) {

     return (r &&

             this.isNumber(r.min) &&

             this.isNumber(r.max));

   },

   // ----------

   // Function: isPoint

   // Returns true if the given object (p) looks like a <Point>.

   isPoint: function Utils_isPoint(p) {

     return (p && this.isNumber(p.x) && this.isNumber(p.y));

   },

   // ----------

   // Function: isPlainObject

   // Check to see if an object is a plain object (created using "{}" or "new Object").

   isPlainObject: function Utils_isPlainObject(obj) {

     // Must be an Object.

     // Make sure that DOM nodes and window objects don't pass through, as well

     if (!obj || Object.prototype.toString.call(obj) !== "[object Object]" ||

        obj.nodeType || obj.setInterval) {

       return false;

     }

     // Not own constructor property must be Object

     const hasOwnProperty = Object.prototype.hasOwnProperty;

     if (obj.constructor &&

        !hasOwnProperty.call(obj, "constructor") &&

        !hasOwnProperty.call(obj.constructor.prototype, "isPrototypeOf")) {

       return false;

     }

     // Own properties are enumerated firstly, so to speed up,

     // if last one is own, then all properties are own.

     var key;

     for (key in obj) {}

     return key === undefined || hasOwnProperty.call(obj, key);

   },

   // ----------

   // Function: isEmptyObject

   // Returns true if the given object has no members.

   isEmptyObject: function Utils_isEmptyObject(obj) {

     for (let name in obj)

       return false;

     return true;

   },

   // ----------

   // Function: copy

   // Returns a copy of the argument. Note that this is a shallow copy; if the argument

   // has properties that are themselves objects, those properties will be copied by reference.

   copy: function Utils_copy(value) {

     if (value && typeof value == 'object') {

       if (Array.isArray(value))

         return this.extend([], value);

       return this.extend({}, value);

     }

     return value;

   },

   // ----------

   // Function: merge

   // Merge two array-like objects into the first and return it.

   merge: function Utils_merge(first, second) {

     Array.forEach(second, function(el) Array.push(first, el));

     return first;

   },

   // ----------

   // Function: extend

   // Pass several objects in and it will combine them all into the first object and return it.

   extend: function Utils_extend() {

     // copy reference to target object

     let target = arguments[0] || {};

     // Deep copy is not supported

     if (typeof target === "boolean") {

       this.assert(false, "The first argument of extend cannot be a boolean." +

           "Deep copy is not supported.");

       return target;

     }

     // Back when this was in iQ + iQ.fn, so you could extend iQ objects with it.

     // This is no longer supported.

     let length = arguments.length;

     if (length === 1) {

       this.assert(false, "Extending the iQ prototype using extend is not supported.");

       return target;

     }

     // Handle case when target is a string or something

     if (typeof target != "object" && typeof target != "function") {

       target = {};

     }

     for (let i = 1; i < length; i++) {

       // Only deal with non-null/undefined values

       let options = arguments[i];

       if (options != null) {

         // Extend the base object

         for (let name in options) {

           let copy = options[name];

           // Prevent never-ending loop

           if (target === copy)

             continue;

           if (copy !== undefined)

             target[name] = copy;

         }

       }

     }

     // Return the modified object

     return target;

   },

   // ----------

   // Function: attempt

   // Tries to execute a number of functions. Returns immediately the return

   // value of the first non-failed function without executing successive

   // functions, or null.

   attempt: function Utils_attempt() {

     let args = arguments;

     for (let i = 0; i < args.length; i++) {

       try {

         return args[i]();

       } catch (e) {}

     }

     return null;

   }

 };

 // ##########

 // Class: MRUList

 // A most recently used list.

 //

 // Constructor: MRUList

 // If a is an array of entries, creates a copy of it.

 this.MRUList = function MRUList(a) {

   if (Array.isArray(a))

     this._list = a.concat();

   else

     this._list = [];

 };

 MRUList.prototype = {

   // ----------

   // Function: toString

   // Prints [List (entry1, entry2, ...)] for debug use

   toString: function MRUList_toString() {

     return "[List (" + this._list.join(", ") + ")]";

   },

   // ----------

   // Function: update

   // Updates/inserts the given entry as the most recently used one in the list.

   update: function MRUList_update(entry) {

     this.remove(entry);

     this._list.unshift(entry);

   },

   // ----------

   // Function: remove

   // Removes the given entry from the list.

   remove: function MRUList_remove(entry) {

     let index = this._list.indexOf(entry);

     if (index > -1)

       this._list.splice(index, 1);

   },

   // ----------

   // Function: peek

   // Returns the most recently used entry.  If a filter exists, gets the most 

   // recently used entry which matches the filter.

   peek: function MRUList_peek(filter) {

     let match = null;

     if (filter && typeof filter == "function")

       this._list.some(function MRUList_peek_getEntry(entry) {

         if (filter(entry)) {

           match = entry

           return true;

         }

         return false;

       });

     else 

       match = this._list.length > 0 ? this._list[0] : null;

     return match;

   },

 };