// Constructor for CoolClock objects
window.CoolClock = function(canvasId,displayRadius,skinId,showSecondHand,gmtOffset) {
    return this.init(canvasId,displayRadius,skinId,showSecondHand,gmtOffset);
}

// Config contains some defaults, and clock skins
CoolClock.config = {
    tickDelay: 1000,
    longTickDelay: 15000,
    defaultRadius: 85,
    renderRadius: 100,
    defaultSkin: "swissRail",

    skins: {
        // There are more skins in moreskins.js
        // Try making your own skin by copy/pasting one of these and tweaking it
        swissRail: {
            outerBorder: { lineWidth: 2, radius:95, color: "white", alpha: 1 },
            smallIndicator: { lineWidth: 2, startAt: 88, endAt: 92, color: "white", alpha: 1 },
            largeIndicator: { lineWidth: 4, startAt: 79, endAt: 92, color: "white", alpha: 1 },
            hourHand: { lineWidth: 8, startAt: -15, endAt: 50, color: "white", alpha: 1 },
            minuteHand: { lineWidth: 7, startAt: -15, endAt: 75, color: "white", alpha: 1 },
            secondHand: { lineWidth: 1, startAt: -20, endAt: 85, color: "red", alpha: 1 },
            secondDecoration: { lineWidth: 1, startAt: 70, radius: 4, fillColor: "red", color: "red", alpha: 1 }
        },
        chunkySwiss: {
            outerBorder: { lineWidth: 4, radius:98, color: "black", alpha: 1 },
            smallIndicator: { lineWidth: 4, startAt: 89, endAt: 93, color: "black", alpha: 1 },
            largeIndicator: { lineWidth: 8, startAt: 80, endAt: 93, color: "black", alpha: 1 },
            hourHand: { lineWidth: 12, startAt: -15, endAt: 60, color: "black", alpha: 1 },
            minuteHand: { lineWidth: 10, startAt: -15, endAt: 85, color: "black", alpha: 1 },
            secondHand: { lineWidth: 4, startAt: -20, endAt: 85, color: "red", alpha: 1 },
            secondDecoration: { lineWidth: 2, startAt: 70, radius: 8, fillColor: "red", color: "red", alpha: 1 }
        },
        chunkySwissOnBlack: {
            outerBorder: { lineWidth: 4, radius:97, color: "white", alpha: 1 },
            smallIndicator: { lineWidth: 4, startAt: 89, endAt: 93, color: "white", alpha: 1 },
            largeIndicator: { lineWidth: 8, startAt: 80, endAt: 93, color: "white", alpha: 1 },
            hourHand: { lineWidth: 12, startAt: -15, endAt: 60, color: "white", alpha: 1 },
            minuteHand: { lineWidth: 10, startAt: -15, endAt: 85, color: "white", alpha: 1 },
            secondHand: { lineWidth: 4, startAt: -20, endAt: 85, color: "red", alpha: 1 },
            secondDecoration: { lineWidth: 2, startAt: 70, radius: 8, fillColor: "red", color: "red", alpha: 1 }
        }

    },

    // Test for IE so we can nurse excanvas in a couple of places
    isIE: !!document.all,

    // Will store (a reference to) each clock here, indexed by the id of the canvas element
    clockTracker: {},

    // For giving a unique id to coolclock canvases with no id
    noIdCount: 0
};

// Define the CoolClock object's methods
CoolClock.prototype = {

    // Initialise using the parameters parsed from the colon delimited class
    init: function(canvasId,displayRadius,skinId,showSecondHand,gmtOffset) {
        // Store the parameters
        this.canvasId = canvasId;
        this.displayRadius = displayRadius || CoolClock.config.defaultRadius;
        this.skinId = skinId || CoolClock.config.defaultSkin;
        this.showSecondHand = typeof showSecondHand == "boolean" ? showSecondHand : true;
        this.tickDelay = CoolClock.config[ this.showSecondHand ? "tickDelay" : "longTickDelay" ];
        this.gmtOffset = gmtOffset != null ? parseFloat(gmtOffset) : gmtOffset;

        // Get the canvas element
        this.canvas = document.getElementById(canvasId);

        // Make the canvas the requested size. It's always square.
        this.canvas.setAttribute("width",this.displayRadius*2);
        this.canvas.setAttribute("height",this.displayRadius*2);
        this.canvas.style.width = this.displayRadius*2 + "px";
        this.canvas.style.height = this.displayRadius*2 + "px";

        // Explain me please...?
        this.renderRadius = CoolClock.config.renderRadius;
        this.scale = this.displayRadius / this.renderRadius;

        // Initialise canvas context
        this.ctx = this.canvas.getContext("2d");
        this.ctx.scale(this.scale,this.scale);

        // Keep track of this object
        CoolClock.config.clockTracker[canvasId] = this;

        // Start the clock going
        this.tick();

        return this;
    },

    // Draw a circle at point x,y with params as defined in skin
    fullCircleAt: function(x,y,skin) {
        with (this.ctx) {
            save();
            globalAlpha = skin.alpha;
            lineWidth = skin.lineWidth;

            if (!CoolClock.config.isIE) {
                beginPath();
            }

            if (CoolClock.config.isIE) {
                // excanvas doesn't scale line width so we will do it here
                lineWidth = lineWidth * this.scale;
            }

            arc(x, y, skin.radius, 0, 2*Math.PI, false);

            if (CoolClock.config.isIE) {
                // excanvas doesn't close the circle so let's fill in the tiny gap
                arc(x, y, skin.radius, -0.1, 0.1, false);
            }

            if (skin.fillColor) {
                fillStyle = skin.fillColor
                fill();
            }
            else {
                // XXX why not stroke and fill
                strokeStyle = skin.color;
                stroke();
            }
            restore();
        }
    },

    // Draw a radial line by rotating then drawing a straight line
    radialLineAtAngle: function(angleFraction,skin) {
        with (this.ctx) {
            save();
            translate(this.renderRadius,this.renderRadius);
            rotate(Math.PI * (2 * angleFraction - 0.5));
            globalAlpha = skin.alpha;
            strokeStyle = skin.color;
            lineWidth = skin.lineWidth;

            if (CoolClock.config.isIE)
            // excanvas doesn't scale line width so we will do it here
                lineWidth = lineWidth * this.scale;

            if (skin.radius) {
                this.fullCircleAt(skin.startAt,0,skin)
            }
            else {
                beginPath();
                moveTo(skin.startAt,0)
                lineTo(skin.endAt,0);
                stroke();
            }
            restore();
        }
    },

    render: function(hour,min,sec) {
        // Get the skin
        var skin = CoolClock.config.skins[this.skinId];
        if (!skin) skin = CoolClock.config.skins[CoolClock.config.defaultSkin];

        // Clear
        this.ctx.clearRect(0,0,this.renderRadius*2,this.renderRadius*2);

        // Draw the outer edge of the clock
        if (skin.outerBorder)
            this.fullCircleAt(this.renderRadius,this.renderRadius,skin.outerBorder);

        // Draw the tick marks. Every 5th one is a big one
        for (var i=0;i<60;i++) {
            (i%5) && skin.smallIndicator && this.radialLineAtAngle(i/60,skin.smallIndicator);
                !(i%5) && skin.largeIndicator && this.radialLineAtAngle(i/60,skin.largeIndicator);
        }

        // Draw the hands
        if (skin.hourHand)
            this.radialLineAtAngle((hour+min/60)/12,skin.hourHand);

        if (skin.minuteHand)
            this.radialLineAtAngle((min+sec/60)/60,skin.minuteHand);

        if (this.showSecondHand && skin.secondHand)
            this.radialLineAtAngle(sec/60,skin.secondHand);

        // Second hand decoration doesn't render right in IE so lets turn it off
        if (!CoolClock.config.isIE && this.showSecondHand && skin.secondDecoration)
            this.radialLineAtAngle(sec/60,skin.secondDecoration);
    },

    // Check the time and display the clock
    refreshDisplay: function() {
        var now = new Date();
        if (this.gmtOffset != null) {
            // Use GMT + gmtOffset
            var offsetNow = new Date(now.valueOf() + (this.gmtOffset * 1000 * 60 * 60));
            this.render(offsetNow.getUTCHours(),offsetNow.getUTCMinutes(),offsetNow.getUTCSeconds());
        }
        else {
            // Use local time
            this.render(now.getHours(),now.getMinutes(),now.getSeconds());
        }
    },

    // Set timeout to trigger a tick in the future
    nextTick: function() {
        setTimeout("CoolClock.config.clockTracker['"+this.canvasId+"'].tick()",this.tickDelay);
    },

    // Check the canvas element hasn't been removed
    stillHere: function() {
        return document.getElementById(this.canvasId) != null;
    },

    // Main tick handler. Refresh the clock then setup the next tick
    tick: function() {
        if (this.stillHere()) {
            this.refreshDisplay()
            this.nextTick();
        }
    }
};

// Find all canvas elements that have the CoolClock class and turns them into clocks
CoolClock.findAndCreateClocks = function() {
    // (Let's not use a jQuery selector here so it's easier to use frameworks other than jQuery)
    var canvases = $("canvas");
    
    for (var i=0;i<canvases.length;i++) {

        // Pull out the fields from the class. Example "CoolClock:chunkySwissOnBlack:1000"
        var fields = canvases[i].className.split(" ")[0].split(":");
        if (fields[0] == "CoolClock") {
            if (!canvases[i].id) {
                // If there's no id on this canvas element then give it one
                canvases[i].id = '_coolclock_auto_id_' + CoolClock.config.noIdCount++;
            }
            // Create a clock object for this element
            new CoolClock(canvases[i].id,fields[2],fields[1],fields[3]!="noSeconds",fields[4]);
        }
    }
};

// If you don't have jQuery then you need a body onload like this: <body onload="CoolClock.findAndCreateClocks()">
// If you do have jQuery and it's loaded already then we can do it right now
//if (window.jQuery) jQuery(document).ready(CoolClock.findAndCreateClocks);