/* Copyright (c) 2015 William Toohey <will@mon.im>
 * Portions Copyright (c) 2015 Calvin Walton <calvin.walton@kepstin.ca>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

(function(window, document) {
"use strict";

/*  Takes root element to attach to, and an audio context element for
    getting the current time with reasonable accuracy */
function HuesCanvas(root, audioContext, core) {
    this.audio = audioContext;
    core.addEventListener("newimage", this.setImage.bind(this));
    core.addEventListener("newcolour", this.setColour.bind(this));
    core.addEventListener("beat", this.beat.bind(this));
    core.addEventListener("invert", this.setInvert.bind(this));
    core.addEventListener("settingsupdated", this.settingsUpdated.bind(this));
    this.core = core;

    this.needsRedraw = false;
    this.colour = 0xFFFFFF;
    this.image = null;
    this.smartAlign = true; // avoid string comparisons every frame

    this.animTimeout = null;
    this.animFrame = null;
    this.lastBeat = 0;

    // set later
    this.blurDecay = null;
    this.blurAmount = null;
    this.blurIterations = null;
    this.blurDelta = null;
    this.blurAlpha = null;
    // dynamic
    this.blurStart = 0;
    this.blurDistance = 0;
    this.xBlur = false;
    this.yBlur = false;
    
    // trippy mode
    this.trippyStart = [0, 0]; // x, y
    this.trippyRadii = [0, 0]; // x, y
    // force trippy mode
    this.trippyOn = false;
    this.trippyRadius = 0;

    this.blackout = false;
    this.blackoutColour = "#000"; // for the whiteout case we must store this
    this.blackoutTimeout = null;
    
    this.invert = false;

    this.colourFade = false;
    this.colourFadeStart=0;
    this.colourFadeLength=0;
    this.oldColour=0xFFFFFF;
    this.newColour=0xFFFFFF;

    this.blendMode = "hard-light";
    // Chosen because they look decent
    this.setBlurAmount("medium");
    this.setBlurQuality("high");
    this.setBlurDecay("fast");
    
    this.canvas = document.createElement('canvas');
    this.context = this.canvas.getContext("2d");
    this.canvas.width = 1280;
    this.canvas.height = 720;
    this.canvas.className = "hues-canvas";
    root.appendChild(this.canvas);
    
    this.offCanvas = document.createElement('canvas');
    this.offContext = this.offCanvas.getContext('2d');
    
    window.addEventListener('resize', this.resize.bind(this));
    this.resize();

    this.animating = true;
    requestAnimationFrame(this.animationLoop.bind(this));
}

HuesCanvas.prototype.setInvert = function(invert) {
    this.invert = invert;
    this.needsRedraw = true;
};

HuesCanvas.prototype.settingsUpdated = function() {
    this.setSmartAlign(localStorage["smartAlign"]);
    this.setBlurAmount(localStorage["blurAmount"]);
    this.setBlurDecay(localStorage["blurDecay"]);
    this.setBlurQuality(localStorage["blurQuality"]);
    this.trippyOn = localStorage["trippyMode"] == "on";
};

HuesCanvas.prototype.resize = function() {
    // height is max 720px, we expand width to suit
    let height = this.core.root.clientHeight;
    let ratio = this.core.root.clientWidth / height;
    this.canvas.height = Math.min(height, 720);
    this.canvas.width = Math.ceil(this.canvas.height * ratio);
    this.offCanvas.height = this.canvas.height;
    this.offCanvas.width = this.canvas.width;
    this.trippyRadius = Math.max(this.canvas.width, this.canvas.height) / 2;
    this.needsRedraw = true;
};

HuesCanvas.prototype.redraw = function() {
    let offset; // for centering/right/left align
    let bOpacity;
    let width = this.canvas.width;
    let height = this.canvas.height;

    let cTime = this.audio.currentTime;
    // white BG for the hard light filter
    this.context.globalAlpha = 1;
    this.context.globalCompositeOperation = "source-over";
    if(this.blackout) {
        // original is 3 frames at 30fps, this is close
        bOpacity = (cTime - this.blackoutStart)*10;
        if(bOpacity > 1) { // optimise the draw
            this.context.fillStyle = this.blackoutColour;
            this.context.fillRect(0,0,width,height);
            this.needsRedraw = false;
            this.drawInvert();
            return;
        }
    } else {
        this.context.fillStyle = "#FFF";
        this.context.fillRect(0,0,width,height);
    }

    if(this.image && (this.image.bitmap || this.image.bitmaps)) {
        let bitmap = this.image.animated ?
            this.image.bitmaps[this.animFrame] : this.image.bitmap;
        let drawHeight = bitmap.height * (height / bitmap.height);
        let drawWidth = (bitmap.width / bitmap.height) * drawHeight;
        if(this.smartAlign) {
            switch(this.image.align) {
                case "left":
                    offset = 0;
                    break;
                case "right":
                    offset = width - drawWidth;
                    break;
                default:
                    offset = width/2 - drawWidth/2;
                    break;
            }
        } else {
            offset = width/2 - drawWidth/2;
        }
        if(this.xBlur || this.yBlur) {
            this.context.globalAlpha = this.blurAlpha;
        }
        if(this.xBlur) {
            if(this.blurIterations < 0) {
                this.context.globalAlpha = 1;
                this.context.drawImage(bitmap, Math.floor(offset - this.blurDistance/2), 0,
                    drawWidth + this.blurDistance, drawHeight);
            } else {
                for(let i=-1; i<=1; i+= this.blurDelta) {
                    this.context.drawImage(bitmap, Math.floor(this.blurDistance * i) + offset, 0, drawWidth, drawHeight);
                }
            }
        } else if(this.yBlur) {
            if(this.blurIterations < 0) {
                this.context.globalAlpha = 1;
                this.context.drawImage(bitmap, offset, Math.floor(-this.blurDistance/2),
                    drawWidth, drawHeight + this.blurDistance);
            } else {
                for(let i=-1; i<=1; i+= this.blurDelta) {
                    this.context.drawImage(bitmap, offset, Math.floor(this.blurDistance * i), drawWidth, drawHeight);
                }
            }
        } else {
            this.context.globalAlpha = 1;
            this.context.drawImage(bitmap, offset, 0, drawWidth, drawHeight);
        }
    }
    
    if(this.trippyStart[0] || this.trippyStart[1]) {
        // x blur moves inwards from the corners, y comes out
        // So the base colour is inverted for y, normal for x
        // Thus if the y start is more recent, we invert
        let baseInvert = this.trippyStart[1] > this.trippyStart[0];
        let invertC = this.intToHex(0xFFFFFF ^ this.colour);
        let normalC = this.intToHex(this.colour);
        this.offContext.fillStyle = baseInvert ? invertC : normalC;
        this.offContext.fillRect(0,0,width,height);
        
        // sort high to low
        this.trippyRadii.sort(function(a,b) {
            return b - a;
        });
        
        let invert = !baseInvert;
        for(let i = 0; i < 2; i++) {
            if(this.trippyRadii[i] === 0) {
                continue;
            }
            // Invert for each subsequent draw
            this.offContext.beginPath();
            this.offContext.fillStyle = this.intToHex(invert ? invertC : normalC);
            this.offContext.arc(width/2, height/2, this.trippyRadii[i], 0, 2 * Math.PI, false);
            this.offContext.fill();
            this.offContext.closePath();
            invert = !invert;
        }
    } else {
        this.offContext.fillStyle = this.intToHex(this.colour);
        this.offContext.fillRect(0,0,width,height);
    }
    this.context.globalAlpha = 0.7;
    this.context.globalCompositeOperation = this.blendMode;
    this.context.drawImage(this.offCanvas, 0, 0);
    if(this.blackout) {
        this.context.globalAlpha = bOpacity;
        this.context.fillStyle = this.blackoutColour;
        this.context.fillRect(0,0,width,height);
        this.needsRedraw = true;
    } else {
        this.needsRedraw = false;
    }
    this.drawInvert();
};

HuesCanvas.prototype.drawInvert = function() {
    if(this.invert) {
        this.context.globalAlpha = 1;
        this.context.globalCompositeOperation = "difference";
        this.context.fillStyle = "#FFF";
        this.context.fillRect(0,0,this.canvas.width,this.canvas.height);
    }
};

/* Second fastest method from
 http://stackoverflow.com/questions/10073699/pad-a-number-with-leading-zeros-in-javascript
 It stil does millions of ops per second, and isn't ugly like the integer if/else */
HuesCanvas.prototype.intToHex = function(num) {
    return '#' + ("00000"+num.toString(16)).slice(-6);
};

HuesCanvas.prototype.animationLoop = function() {
    if (this.colourFade) {
        let delta = this.audio.currentTime - this.colourFadeStart;
        let fadeVal = delta / this.colourFadeLength;
        if (fadeVal >= 1) {
            this.stopFade();
            this.colour = this.newColour;
        } else {
            this.mixColours(fadeVal);
        }
        this.needsRedraw = true;
    }
    if(this.blackoutTimeout && this.audio.currentTime > this.blackoutTimeout) {
        this.clearBlackout();
    }
    if(this.image && this.image.animated){
        if(this.image.beatsPerAnim && this.core.currentSong && this.core.currentSong.charsPerBeat) {
            let a = this.animFrame;
            this.syncAnim();
            if(this.animFrame != a) {
                this.needsRedraw = true;
                // If you change to a non-synced song, this needs to be reset
                this.animTimeout = this.audio.currentTime;
            }
        } else if(this.animTimeout < this.audio.currentTime) {
            this.animFrame++;
            this.animFrame %= this.image.frameDurations.length;
            // Don't rebase to current time otherwise we may lag
            this.animTimeout += this.image.frameDurations[this.animFrame]/1000;
            this.needsRedraw = true;
        }
    }
    if(this.blurStart) {
        // flash offsets blur gen by a frame
        let delta = this.audio.currentTime - this.blurStart + (1/30);
        this.blurDistance = this.blurAmount * Math.exp(-this.blurDecay * delta);
        
        // Update UI
        let dist = this.blurDistance / this.blurAmount;
        if(this.xBlur)
            this.core.blurUpdated(dist, 0);
        else
            this.core.blurUpdated(0, dist);
    }
    if(this.trippyStart[0] || this.trippyStart[1]) {
        for(let i = 0; i < 2; i++) {
            this.trippyRadii[i] = Math.floor((this.audio.currentTime - this.trippyStart[i]) * this.trippyRadius) * 2;
            if(this.trippyRadii[i] > this.trippyRadius) {
                this.trippyStart[i] = 0;
                this.trippyRadii[i] = 0;
                continue;
            }
            // x comes from outside the window
            if(i % 2 === 0) {
                this.trippyRadii[i] = this.trippyRadius - this.trippyRadii[i];
            }
        }
        this.needsRedraw = true;
    }
    
    if(this.blurStart && this.blurDistance < 1) {
        this.core.blurUpdated(0, 0);
        this.blurDistance = 0;
        this.blurStart = 0;
        this.xBlur = this.yBlur = false;
        this.redraw();
    } else if(this.blurStart) {
        this.redraw();
    } else if(this.needsRedraw){
        this.redraw();
    }
    if(this.animating) {
        requestAnimationFrame(this.animationLoop.bind(this));
    }
};

HuesCanvas.prototype.setImage = function(image) {
    if(this.image == image) {
        return;
    }
    this.needsRedraw = true;
    this.image = image;
    // Null images don't need anything interesting done to them
    if(!image || (!image.bitmap && !image.bitmaps)) {
        return;
    }
    if(image.animated) {
        this.animBeat = null;
        this.animFrame = 0;
        this.animTimeout = this.audio.currentTime + image.frameDurations[0]/1000;
        if(image.beatsPerAnim && this.core.currentSong && this.core.currentSong.charsPerBeat) {
            this.syncAnim();
        }
    }
};

HuesCanvas.prototype.beat = function() {
    this.lastBeat = this.audio.currentTime;
};

HuesCanvas.prototype.syncAnim = function() {
    let song = this.core.currentSong;
    if(!song) { // fallback to default
       return;
    }
    let index = this.core.beatIndex;
    // When animation has more frames than song has beats, or part thereof
    if(this.lastBeat && this.core.getBeatLength()) {
        let interp = (this.audio.currentTime - this.lastBeat) / this.core.getBeatLength();
        index += Math.min(interp, 1);
    }
    // This loops A-OK because the core's beatIndex never rolls over for a new loop
    let beatLoc = (index / song.charsPerBeat) % this.image.beatsPerAnim;

    let aLen = this.image.bitmaps.length;
    this.animFrame = Math.floor(aLen * (beatLoc / this.image.beatsPerAnim));
    if(this.image.syncOffset) {
        this.animFrame += this.image.syncOffset;
    }
    // Because negative mods are different in JS
    this.animFrame = ((this.animFrame % aLen) + aLen) % aLen;
};

HuesCanvas.prototype.setColour = function(colour, isFade) {
    if(colour.c == this.colour) {
        return;
    }
    if(isFade) {
        this.newColour = colour.c;
    } else {
        this.stopFade();
        this.colour = colour.c;
    }
    this.needsRedraw = true;
};

HuesCanvas.prototype.doBlackout = function(whiteout) {
    if (typeof(whiteout)==='undefined') whiteout = false;
    if(whiteout) {
        this.blackoutColour = "#FFF";
    } else {
        this.blackoutColour = "#000";
    }
    this.blackoutTimeout = 0; // indefinite
    // Don't restart the blackout animation if we're already blacked out
    if(!this.blackout) {
        this.blackoutStart = this.audio.currentTime;
    }
    this.blackout = true;
    this.needsRedraw = true;
    if(localStorage["blackoutUI"] == "on") {
        this.core.userInterface.hide();
    }
};

// for song changes
HuesCanvas.prototype.clearBlackout = function() {
    this.blackout = false;
    this.blackoutTimeout = 0;
    this.needsRedraw = true;
    if(localStorage["blackoutUI"] == "on") {
        this.core.userInterface.show();
    }
};

HuesCanvas.prototype.doShortBlackout = function(beatTime) {
    this.doBlackout();
    this.blackoutTimeout = this.audio.currentTime + beatTime / 1.7;
    // looks better if we go right to black
    this.blackoutStart = 0;
};

HuesCanvas.prototype.doColourFade = function(length) {
    this.colourFade = true;
    this.colourFadeLength = length;
    this.colourFadeStart = this.audio.currentTime;
    this.oldColour = this.colour;
};

HuesCanvas.prototype.stopFade = function() {
    this.colourFade = false;
    this.colourFadeStart = 0;
    this.colourFadeLength = 0;
};

HuesCanvas.prototype.mixColours = function(percent) {
    percent = Math.min(1, percent);
    let oldR = this.oldColour >> 16 & 0xFF;
    let oldG = this.oldColour >> 8  & 0xFF;
    let oldB = this.oldColour       & 0xFF;
    let newR = this.newColour >> 16 & 0xFF;
    let newG = this.newColour >> 8  & 0xFF;
    let newB = this.newColour       & 0xFF;
    let mixR = oldR * (1 - percent) + newR * percent;
    let mixG = oldG * (1 - percent) + newG * percent;
    let mixB = oldB * (1 - percent) + newB * percent;
    this.colour = mixR << 16 | mixG << 8 | mixB;
};

HuesCanvas.prototype.doXBlur = function() {
    this.blurStart = this.audio.currentTime;
    if(this.trippyOn)
        this.trippyStart[0] = this.blurStart;
    this.blurDistance = this.blurAmount;
    this.xBlur = true;
    this.yBlur = false;
    this.needsRedraw = true;
};

HuesCanvas.prototype.doYBlur = function() {
    this.blurStart = this.audio.currentTime;
    if(this.trippyOn)
        this.trippyStart[1] = this.blurStart;
    this.blurDistance = this.blurAmount;
    this.xBlur = false;
    this.yBlur = true;
    this.needsRedraw = true;
};

HuesCanvas.prototype.doTrippyX = function() {
    let saveTrippy = this.trippyOn;
    // force trippy
    this.trippyOn = true;
    this.doXBlur();
    this.trippyOn = saveTrippy;
};

HuesCanvas.prototype.doTrippyY = function() {
    let saveTrippy = this.trippyOn;
    // force trippy
    this.trippyOn = true;
    this.doYBlur();
    this.trippyOn = saveTrippy;
};

HuesCanvas.prototype.setBlurDecay = function(decay) {
    this.blurDecay = {"slow" : 7.8, "medium" : 14.1, "fast" : 20.8, "faster!" : 28.7}[decay];
};

HuesCanvas.prototype.setBlurQuality = function(quality) {
    this.blurIterations = {"low" : -1, "medium" : 11, "high" : 19, "extreme" : 35}[quality];
    this.blurDelta = 1 / (this.blurIterations/2);
    this.blurAlpha = 1 / (this.blurIterations/2);
};

HuesCanvas.prototype.setBlurAmount = function(amount) {
    this.blurAmount = {"low" : 48, "medium" : 96, "high" : 384}[amount];
};

HuesCanvas.prototype.setSmartAlign = function(align) {
    this.smartAlign = align == "on";
};

HuesCanvas.prototype.setAnimating = function(anim) {
    if(!this.animating && anim) {
        requestAnimationFrame(this.animationLoop);
    }
    this.animating = anim;
};

window.HuesCanvas = HuesCanvas;

})(window, document);