/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is utils.js.
 *
 * The Initial Developer of the Original Code is
 * Aza Raskin <aza@mozilla.com>
 * Portions created by the Initial Developer are Copyright (C) 2010
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 * Ian Gilman <ian@iangilman.com>
 * Michael Yoshitaka Erlewine <mitcho@mitcho.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

// **********
// Title: utils.js

(function(){

const Cc = Components.classes;
const Ci = Components.interfaces;
const Cu = Components.utils;
const Cr = Components.results;

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

XPCOMUtils.defineLazyGetter(this, "gWindow", function() {
  let windows = Services.wm.getEnumerator("navigator:browser");
  while (windows.hasMoreElements()) {
    let browser = windows.getNext();
    let tabCandyFrame = browser.document.getElementById("tab-candy");
    if (tabCandyFrame.contentWindow == window)
      return browser;
  }
});

XPCOMUtils.defineLazyGetter(this, "gBrowser", function() gWindow.gBrowser);

XPCOMUtils.defineLazyGetter(this, "gTabViewDeck", function() {
  return gWindow.document.getElementById("tab-candy-deck");
});

XPCOMUtils.defineLazyGetter(this, "gTabViewFrame", function() {
  return gWindow.document.getElementById("tab-candy");
});

var consoleService = Cc["@mozilla.org/consoleservice;1"]
    .getService(Components.interfaces.nsIConsoleService);

// ##########
// 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.
window.Point = function(a, y) {
  if (Utils.isPoint(a)) {
    // Variable: x
    this.x = a.x;
    // Variable: y
    this.y = a.y;
  } else {
    this.x = (Utils.isNumber(a) ? a : 0);
    this.y = (Utils.isNumber(y) ? y : 0);
  }
};
window.Point.prototype = {
  // ----------
  // Function: distance
  // Returns the distance from this point to the given <Point>.
  distance: function(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.
window.Rect = function(a, top, width, height) {
  // Note: perhaps 'a' should really be called 'rectOrLeft'
  if (Utils.isRect(a)) {
    // Variable: left
    this.left = a.left;

    // Variable: top
    this.top = a.top;

    // Variable: width
    this.width = a.width;

    // Variable: height
    this.height = a.height;
  } else {
    this.left = a;
    this.top = top;
    this.width = width;
    this.height = height;
  }
};

window.Rect.prototype = {
  // ----------
  // Variable: right
  get right() {
    return this.left + this.width;
  },

  // ----------
  set right(value) {
    this.width = value - this.left;
  },

  // ----------
  // Variable: bottom
  get bottom() {
    return 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() {
    return new Range(this.left,this.right);
  },

  // ----------
  // Variable: yRange
  // Gives you a new <Range> for the vertical dimension.
  get yRange() {
    return new Range(this.top,this.bottom);
  },

  // ----------
  // Function: intersects
  // Returns true if this rectangle intersects the given <Rect>.
  intersects: function(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) {
    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> is contained inside
  // of the bounding rect.
  //
  // Paramaters
  //  - A <Rect>
  contains: function(rect){
    return( rect.left > this.left
         && rect.right < this.right
         && rect.top > this.top
         && rect.bottom < this.bottom )
  },

  // ----------
  // Function: center
  // Returns a new <Point> with the center location of this rectangle.
  center: function() {
    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() {
    return new Point(this.width, this.height);
  },

  // ----------
  // Function: position
  // Returns a new <Point> with the top left of this rectangle.
  position: function() {
    return new Point(this.left, this.top);
  },

  // ----------
  // Function: area
  // Returns the area of this rectangle.
  area: function() {
    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(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(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) {
    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(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(a) {
    this.left = a.left;
    this.top = a.top;
    this.width = a.width;
    this.height = a.height;
  },

  // ----------
  // Function: css
  // Returns an object with the dimensions of this rectangle, suitable for passing
  // into iQ.fn.css.
  // You could of course just pass the rectangle straight in, but this is cleaner.
  css: function() {
    return {
      left: this.left,
      top: this.top,
      width: this.width,
      height: this.height
    };
  }
};

// ##########
// Class: Range
// A physical interval, with a min and max.
//
// Constructor: Range
// Creates a Range with the given min and max
window.Range = function(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;
  }
};

window.Range.prototype = {
  // 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.
  //
  // Paramaters
  //  - a number or <Range>
  contains: function(value) {
    return Utils.isNumber(value) ?
      value >= this.min && value <= this.max :
      Utils.isRange(value) ?
        ( value.min <= this.max && this.min <= value.max ) :
        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).
  //
  // Paramaters
  //  - a number
  //  - (bool) smooth? If true, a smooth tanh-based function will be used instead of the linear.
  proportion: function(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
      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.
  //
  // Paramaters
  //  - a number in [0,1]
  scale: function(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.
window.Subscribable = function() {
  this.subscribers = null;
};

window.Subscribable.prototype = {
  // ----------
  // Function: addSubscriber
  // The given callback will be called when the Subscribable fires the given event.
  // The refObject is used to facilitate removal if necessary.
  addSubscriber: function(refObject, eventName, callback) {
    try {
      Utils.assertThrow("refObject", refObject);
      Utils.assertThrow("callback must be a function", iQ.isFunction(callback));
      Utils.assertThrow("eventName must be a non-empty string",
          eventName && typeof(eventName) == "string");

      if (!this.subscribers)
        this.subscribers = {};

      if (!this.subscribers[eventName])
        this.subscribers[eventName] = [];

      var subs = this.subscribers[eventName];
      var existing = subs.filter(function(element) {
        return element.refObject == refObject;
      });

      if (existing.length) {
        Utils.assert('should only ever be one', existing.length == 1);
        existing[0].callback = callback;
      } else {
        subs.push({
          refObject: refObject,
          callback: callback
        });
      }
    } catch(e) {
      Utils.log(e);
    }
  },

  // ----------
  // Function: removeSubscriber
  // Removes the callback associated with refObject for the given event.
  removeSubscriber: function(refObject, eventName) {
    try {
      Utils.assertThrow("refObject", refObject);
      Utils.assertThrow("eventName must be a non-empty string",
          eventName && typeof(eventName) == "string");

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

      this.subscribers[eventName] = this.subscribers[eventName].filter(function(element) {
        return element.refObject != refObject;
      });
    } catch(e) {
      Utils.log(e);
    }
  },

  // ----------
  // Function: _sendToSubscribers
  // Internal routine. Used by the Subscribable to fire events.
  _sendToSubscribers: function(eventName, eventInfo) {
    try {
      Utils.assertThrow("eventName must be a non-empty string",
          eventName && typeof(eventName) == "string");

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

      var self = this;
      var subsCopy = iQ.merge([], this.subscribers[eventName]);
      subsCopy.forEach(function(object) {
        object.callback(self, eventInfo);
      });
    } catch(e) {
      Utils.log(e);
    }
  }
};

// ##########
// Class: Utils
// Singelton with common utility functions.
var Utils = {
  // ___ Logging

  // ----------
  // 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() {
    var text = this.expandArgumentsForLog(arguments);
    consoleService.logStringMessage(text);
  },

  // ----------
  // 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.
  // TODO: Does this still work?
  error: function() {
    var text = this.expandArgumentsForLog(arguments);
    Cu.reportError('tabcandy error: ' + text);
  },

  // ----------
  // 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() {
    var text = this.expandArgumentsForLog(arguments);
    try { // coerce an error
      throw new Error("error");
    } catch (e) {
      // cut off the first two lines of the stack trace, because they're just this function.
      var stack = e.stack.replace(/^.*?\n.*?\n/,'');
      // if the caller was assert, cut out the line for the assert function as well.
      if (this.trace.caller.name == 'Utils_assert')
        stack = stack.replace(/^.*?\n/,'');
      this.log('trace: ' + text + '\n' + stack);
    }
  },

  // ----------
  // Function: assert
  // Prints a stack trace along with label (as a console message) if condition is false.
  assert: function Utils_assert(label, condition) {
    if (!condition) {
      var text;
      if (typeof(label) == 'undefined')
        text = 'badly formed assert';
      else
        text = 'tabcandy assert: ' + label;

      this.trace(text);
    }
  },

  // ----------
  // Function: assertThrow
  // Throws label as an exception if condition is false.
  assertThrow: function(label, condition) {
    if (!condition) {
      var text;
      if (typeof(label) == 'undefined')
        text = 'badly formed assert';
      else
        text = 'tabcandy assert: ' + label;

      try { // coerce an error
        throw new Error("error");
      } catch (e) {
        // cut off the first two lines of the stack trace, because they're just this function.
        text += e.stack.replace(/^.*?\n.*?\n/,'');
      }

      throw text;
    }
  },

  // ----------
  // Function: expandObject
  // Prints the given object to a string, including all of its properties.
  expandObject: function(obj) {
      var s = obj + ' = {';
      for (prop in obj) {
        var 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(args) {
    var s = '';
    var count = args.length;
    var a;
    for (a = 0; a < count; a++) {
      var arg = args[a];
      if (typeof(arg) == 'object')
        arg = this.expandObject(arg);

      s += arg;
      if (a < count - 1)
        s += '; ';
    }

    return s;
  },

  // ___ Misc

  // ----------
  // Function: isRightClick
  // Given a DOM mouse event, returns true if it was for the right mouse button.
  isRightClick: function(event) {
    if (event.which)
      return (event.which == 3);
    if (event.button)
      return (event.button == 2);
    return false;
  },

  // ----------
  // Function: isDOMElement
  // Returns true if the given object is a DOM element.
  isDOMElement: function(object) {
    return (object && typeof(object.nodeType) != 'undefined' ? true : false);
  },

  // ----------
  // Function: isNumber
  // Returns true if the argument is a valid number.
  isNumber: function(n) {
    return (typeof(n) == 'number' && !isNaN(n));
  },

  // ----------
  // Function: isRect
  // Returns true if the given object (r) looks like a <Rect>.
  isRect: function(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(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(p) {
    return (p && this.isNumber(p.x) && this.isNumber(p.y));
  },

  // ----------
  // 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(value) {
    if (value && typeof(value) == 'object') {
      if (iQ.isArray(value))
        return iQ.extend([], value);

      return iQ.extend({}, value);
    }

    return value;
  }
};

window.Utils = Utils;

})();