/**
 * Statistics.js
 *
 * @author realor
 */

import { Panel } from './Panel.js'

class Statistics extends Panel {
    constructor(application) {
        super(application)
        this.id = 'statistics'
        this.title = 'Statistics'
        this.position = 'right'
        this.preferredHeight = 80

        this.bodyElem.style.cssText = 'opacity:0.9;z-index:10000;overflow:hidden;'

        var fpsPanel = new Statistics.Panel('FPS', '#0ff', '#002')
        this.bodyElem.appendChild(fpsPanel.dom)

        var msPanel = new Statistics.Panel('MS', '#0f0', '#020')
        this.bodyElem.appendChild(msPanel.dom)

        var beginTime = (performance || Date).now()
        var prevTime = beginTime
        var frames = 0

        this.animate = function() {
            frames++

            var time = (performance || Date).now()

            msPanel.update(time - beginTime, 200)

            if (time >= prevTime + 1000) {
                fpsPanel.update((frames * 1000) / (time - prevTime), 100)

                prevTime = time
                frames = 0
            }
            beginTime = time
        }
    }

    onShow() {
        const application = this.application
        application.addEventListener('animation', this.animate)
    }

    onHide() {
        const application = this.application
        application.removeEventListener('animation', this.animate)
    }
}

Statistics.Panel = function(name, fg, bg) {
    var min = Infinity,
        max = 0,
        round = Math.round
    var PR = round(window.devicePixelRatio || 1)

    var CANVAS_WIDTH = 116,
        CANVAS_HEIGHT = 48,
        WIDTH = CANVAS_WIDTH * PR,
        HEIGHT = CANVAS_HEIGHT * PR,
        TEXT_X = 3 * PR,
        TEXT_Y = 2 * PR,
        GRAPH_X = 3 * PR,
        GRAPH_Y = 15 * PR,
        GRAPH_WIDTH = (CANVAS_WIDTH - 6) * PR,
        GRAPH_HEIGHT = (CANVAS_HEIGHT - 18) * PR

    var canvas = document.createElement('canvas')
    canvas.width = WIDTH
    canvas.height = HEIGHT
    canvas.style.cssText = 'width:' + CANVAS_WIDTH + 'px;height:' + CANVAS_HEIGHT + 'px;margin:2px 2px 0 2px'

    var context = canvas.getContext('2d')
    context.font = 'bold ' + 9 * PR + 'px Helvetica,Arial,sans-serif'
    context.textBaseline = 'top'

    context.fillStyle = bg
    context.fillRect(0, 0, WIDTH, HEIGHT)

    context.fillStyle = fg
    context.fillText(name, TEXT_X, TEXT_Y)
    context.fillRect(GRAPH_X, GRAPH_Y, GRAPH_WIDTH, GRAPH_HEIGHT)

    context.fillStyle = bg
    context.globalAlpha = 0.9
    context.fillRect(GRAPH_X, GRAPH_Y, GRAPH_WIDTH, GRAPH_HEIGHT)

    return {
        dom: canvas,

        update: function(value, maxValue) {
            min = Math.min(min, value)
            max = Math.max(max, value)

            context.fillStyle = bg
            context.globalAlpha = 1
            context.fillRect(0, 0, WIDTH, GRAPH_Y)
            context.fillStyle = fg
            context.fillText(round(value) + ' ' + name + ' (' + round(min) + '-' + round(max) + ')', TEXT_X, TEXT_Y)

            context.drawImage(canvas, GRAPH_X + PR, GRAPH_Y, GRAPH_WIDTH - PR, GRAPH_HEIGHT, GRAPH_X, GRAPH_Y, GRAPH_WIDTH - PR, GRAPH_HEIGHT)

            context.fillRect(GRAPH_X + GRAPH_WIDTH - PR, GRAPH_Y, PR, GRAPH_HEIGHT)

            context.fillStyle = bg
            context.globalAlpha = 0.9
            context.fillRect(GRAPH_X + GRAPH_WIDTH - PR, GRAPH_Y, PR, round((1 - value / maxValue) * GRAPH_HEIGHT))
        }
    }
}

export { Statistics }