/**
* Apple-Style Flip Counter
* Version 0.5.3 - May 7, 2011 
*
* Copyright (c) 2010 Chris Nanney
* http://cnanney.com/journal/code/apple-style-counter-revisited/
*
* Licensed under MIT
* http://www.opensource.org/licenses/mit-license.php
*/

var flipCounter = function (d, options) {

    // Default values
    var defaults = {
        value: 0,
        inc: 1,
        pace: 1000,
        auto: true
    };

    var o = options || {},
	doc = window.document;

    for (var opt in defaults) o[opt] = (opt in o) ? o[opt] : defaults[opt];

    var inc = o.inc;

    var digitsOld = [], digitsNew = [], digitsAnimate = [], x, y, nextCount = null,
		best = {
		    q: null,
		    pace: 0,
		    inc: 0
		};

    /**
    * Sets the value of the counter and animates the digits to new value.
    * 
    * Example: myCounter.setValue(500); would set the value of the counter to 500,
    * no matter what value it was previously.
    *
    * @param {int} n
    *   New counter value
    */
    this.setValue = function (n) {
        if (isNumber(n)) {
            x = o.value;
            y = n;
            o.value = n;
            digitCheck(x, y);
        }
        return this;
    };

    /**
    * Sets the increment for the counter. Does NOT animate digits.
    */
    this.setIncrement = function (n) {
        o.inc = isNumber(n) ? n : defaults.inc;
        return this;
    };

    /**
    * Sets the pace of the counter. Only affects counter when auto == true.
    *
    * @param {int} n
    *   New pace for counter in milliseconds
    */
    this.setPace = function (n) {
        o.pace = isNumber(n) ? n : defaults.pace;
        return this;
    };

    /**
    * Sets counter to auto-increment (true) or not (false).
    *
    * @param {bool} a
    *   Should counter auto-increment, true or false
    */
    this.setAuto = function (a) {
        var sa = typeof a !== "boolean" ? true : a;
        if (o.auto) {
            if (!sa) {
                if (nextCount) clearNext();
                o.auto = false;
            }
        }
        else {
            if (sa) {
                if (nextCount) clearNext();
                o.auto = true;
                doCount();
            }
        }
        return this;
    };

    /**
    * Increments counter by one animation based on set 'inc' value.
    */
    this.step = function () {
        if (!o.auto) doCount();
        return this;
    };

    /**
    * Adds a number to the counter value, not affecting the 'inc' or 'pace' of the counter.
    *
    * @param {int} n
    *   Number to add to counter value
    */
    this.add = function (n) {
        if (isNumber(n)) {
            x = o.value;
            o.value += n;
            y = o.value;
            digitCheck(x, y);
        }
        return this;
    };

    /**
    * Subtracts a number from the counter value, not affecting the 'inc' or 'pace' of the counter.
    *
    * @param {int} n
    *   Number to subtract from counter value
    */
    this.subtract = function (n) {
        if (isNumber(n)) {
            x = o.value;
            o.value -= n;
            if (o.value >= 0) {
                y = o.value;
            }
            else {
                y = "0";
                o.value = 0;
            }
            digitCheck(x, y);
        }
        return this;
    };

    /**
    * Increments counter to given value, animating by current pace and increment.
    *
    * @param {int} n
    *   Number to increment to
    * @param {int} t (optional)
    *   Time duration in seconds - makes increment a 'smart' increment
    * @param {int} p (optional)
    *   Desired pace for counter if 'smart' increment
    */
    this.incrementTo = function (n, t, p) {
        if (nextCount) clearNext();

        // Smart increment
        if (typeof t !== "undefined") {
            var time = isNumber(t) ? t * 1000 : 10000,
				pace = typeof p !== "undefined" && isNumber(p) ? p : o.pace,
				diff = typeof n !== "undefined" && isNumber(n) ? n - o.value : 0,
				cycles, inc, i = 0;
            best.q = null;

            // Initial best guess
            pace = (time / diff > pace) ? Math.round((time / diff) / 10) * 10 : pace;
            cycles = Math.floor(time / pace);
            inc = Math.floor(diff / cycles);

            var check = checkSmartValues(diff, cycles, inc, pace, time);

            if (diff > 0) {
                while (check.result === false && i < 100) {
                    pace += 10;
                    cycles = Math.floor(time / pace);
                    inc = Math.floor(diff / cycles);

                    check = checkSmartValues(diff, cycles, inc, pace, time);
                    i++;
                }

                if (i == 100) {
                    // Could not find optimal settings, use best found so far
                    o.inc = best.inc;
                    o.pace = best.pace;
                }
                else {
                    // Optimal settings found, use those
                    o.inc = inc;
                    o.pace = pace;
                }

                doIncrement(n, true, cycles);
            }

        }
        // Regular increment
        else {
            doIncrement(n);
        }

    }

    /**
    * Gets current value of counter.
    */
    this.getValue = function () {
        return o.value;
    }

    /**
    * Stops all running increments.
    */
    this.stop = function () {
        if (nextCount) clearNext();
        return this;
    }

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

    function doCount(first) {
        var first_run = typeof first === "undefined" ? false : first;
        x = Math.round(o.value);
        if (!first_run)
            o.value += inc;
        y = Math.round(o.value);
        if (this.console && typeof console.log != "undefined") {
            if (first) 
                  console.log("Initial value is " + y);            
            else
            console.log("new value is " + y);
        }
        digitCheck(x, y);
        var newPaceArr = [1000, 5000, 10000, 15000, 20000];
        var newPace = newPaceArr[Math.floor(Math.random() * newPaceArr.length)];
        if (this.console && typeof console.log != "undefined")
            console.log('Pace is ' + newPace);
        var paceChange = newPace / o.pace;
        inc = o.inc * paceChange;
        // Do first animation
        if (o.auto === true)
            nextCount = setTimeout(function () { doCount() }, newPace);
    }

    function doIncrement(n, s, c) {
        var val = o.value,
			smart = (typeof s === "undefined") ? false : s,
			cycles = (typeof c === "undefined") ? 1 : c;

        if (smart === true) cycles--;

        if (val != n) {
            x = o.value;
            o.auto = true;

            if (val + o.inc <= n && cycles != 0) val += o.inc;
            else val = n;

            o.value = val;
            y = o.value;

            digitCheck(x, y);
            nextCount = setTimeout(function () { doIncrement(n, smart, cycles) }, o.pace);
        }
        else o.auto = false;
    }

    function digitCheck(x, y) {
        digitsOld = splitToArray(x);
        digitsNew = splitToArray(y);
        var ylen = digitsNew.length;
        for (var i = 0; i < ylen; i++) {
            digitsAnimate[i] = digitsNew[i] != digitsOld[i];
        }
        draw_counter();
    }

    // Creates array of digits for easier manipulation
    function splitToArray(input) {
        return input.toString().split('').reverse();
    }

    // Sets the correct digits on load
    function draw_counter() {
        var count = digitsNew.length,
		bit = 1, i, ch = '<ul>', dNew, dOld;
        for (i = 0; i < count; i++) {
            dNew = isNumber(digitsNew[i]) ? digitsNew[i] : '';
            dOld = isNumber(digitsOld[i]) ? digitsOld[i] : '';
            ch += '<li class="digit"><div id="digit-a' + i + '" class="digit-wrap"><div class="shadow"></div>' +
			'<div class="top-new"><span>' + dNew + '</span></div>' +
			'<div class="digit-hinge"><div class="top-old"><span>' + dOld + '</span></div>' +
			'<div class="bottom-new"><span>' + dNew + '</span></div></div>' +
			'<div class="bottom-old"><span>' + dOld + '</span></div></div></li>';            
            if (bit != (count) && bit % 3 == 0) {            
                ch += '<li class="digit-separator">,</li>';
            }
            bit++;
        }
        ch += '<li class="digit"><div class="digit-wrap"><div class="shadow"></div><div class="top-new">&pound</div></div></li></ul>';
        var element = doc.getElementById("flip-counter");
        element.innerHTML = ch;

        var alen = digitsAnimate.length;
        for (i = 0; i < alen; i++) {
            if (digitsAnimate[i]) {
                var a = doc.getElementById('digit-a' + i);
                a.className = 'digit-wrap do-digit-animate';
            }
        }
    }

    // Checks values for smart increment and creates debug text
    function checkSmartValues(diff, cycles, inc, pace, time) {
        var check = { result: true }, q;
        // Test conditions, all must pass to continue:
        // 1: Unrounded inc value needs to be at least 1
        check.test1 = (diff / cycles >= 1);
        // 2: Don't want to overshoot the target number
        check.test2 = (cycles * inc <= diff);
        // 3: Want to be within 10 of the target number
        check.test3 = (Math.abs(cycles * inc - diff) <= 10);
        // 4: Total time should be within 100ms of target time.
        check.test4 = (Math.abs(cycles * pace - time) <= 100);
        // 5: Calculated time should not be over target time
        check.test5 = (cycles * pace <= time);

        // Keep track of 'good enough' values in case can't find best one within 100 loops
        q = Math.abs(diff - (cycles * inc)) + Math.abs(cycles * pace - time);
        if (best.q === null) best.q = q;
        if (q <= best.q) {
            best.q = q;
            best.pace = pace;
            best.inc = inc;
        }

        for (var test in check) {
            if (check[test] === false) check.result = false;
        }

        return check;
    }

    // http://stackoverflow.com/questions/18082/validate-numbers-in-javascript-isnumeric/1830844
    function isNumber(n) {
        return !isNaN(parseFloat(n)) && isFinite(n);
    }

    function clearNext() {
        clearTimeout(nextCount);
        nextCount = null;
    }

    // Start it up
    doCount(true);
};