function random(min = 0, max = 1) {
    return Math.floor(Math.random() * (max - min + 1) + min)
}
function colorToText(r, g, b, a = 1) {
    return `rgba(${r},${g},${b},${a})`
}
class Entity {
    static showAll(list) {
        for (let i = 0; i < list.length; i++) {
            if (!list[i].show()) {
                list.splice(i, 1)
            }
        }
    }
    constructor(x, y, ctx) {
        this.pos = { x, y }
        this.ctx = ctx
    }
    show() {
        if (this.update()) {
            this.draw()
            return true
        } else {
            return false
        }
    }
}
class Strand extends Entity {
    constructor(x, canvas, ctx, charList, color) {
        super(x, Char.height, ctx)
        this.canvas = canvas
        this.charList = charList
        this.color = color
        this.chars = []
    }
    update() {
        if (this.chars.length < 1 || this.chars[this.chars.length - 1].pos.y < this.canvas.height * 2) {
            this.chars.push(new Char(this.pos.x, this.pos.y, this.ctx, this.charList, this.color))
            this.pos.y += Char.height
            return true
        } else {
            return false
        }
    }
    draw() {
        Entity.showAll(this.chars)
    }
}
class Char extends Entity {
    static size = 20
    static width = 12
    static height = 14
    constructor(x, y, ctx, charList, color) {
        super(x, y, ctx)
        this.charList = charList
        this.color = color
        this.head = true
        this.alpha = 1
        this.randomizeCharVal()
    }
    randomizeCharVal() {
        this.val = this.charList[random(0, this.charList.length - 1)]
    }
    update() {
        if (random(0, 100) < 5) {
            this.randomizeCharVal()
        }
        this.alpha *= 0.95
        return this.alpha >= 0.01 ? true : false
    }
    draw() {
        this.ctx.font = Char.size + 'px Monospace'
        if (!this.head) {
            this.ctx.fillStyle = colorToText(this.color.red, this.color.green, this.color.blue, this.alpha)
        } else {
            this.ctx.fillStyle = colorToText(255, 255, 255, 1)
            this.head = false
        }
        this.ctx.fillText(this.val, this.pos.x, this.pos.y)
    }
}
class MatrixRain {
    constructor(element, width, height, charList, red, green, blue, randomColors, flowRate, fps) {
        this.canvas = element
        this.setCanvasDimensions(width, height)
        this.charList = charList
        this.color = { red, green, blue }
        this.randomColors = randomColors
        this.flowRate = flowRate
        this.ctx = this.canvas.getContext('2d')
        this.ctx.translate(this.canvas.width, 0)
        this.ctx.scale(-1, 1)
        this.columns = Math.ceil(this.canvas.width / Char.width)
        this.strands = []
        setInterval(() => {
            this.run()
        }, 1000 / fps)
    }
    setCanvasDimensions(width, height) {
        this.canvas.width = width
        this.canvas.height = height
        this.columns = Math.ceil(this.canvas.width / Char.width)
    }
    run() {
        this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height)
        this.ctx.fillStyle = colorToText(0, 0, 0, 1)
        this.ctx.fillRect(0, 0, this.canvas.width, this.canvas.height)
        let column, available
        for (let i = 0; i < this.flowRate; i++) {
            column = random(0, this.columns)
            available = true
            for (let i = 0; i < this.strands.length; i++) {
                if (this.strands[i].pos.x == column * Char.width && this.strands[i].pos.y <= this.canvas.height) {
                    available = false
                }
            }
            if (available) {
                this.strands.push(
                    new Strand(
                        column * Char.width,
                        this.canvas,
                        this.ctx,
                        this.charList,
                        this.randomColors
                            ? {
                                  red: random(0, 255),
                                  green: random(0, 255),
                                  blue: random(0, 255),
                              }
                            : this.color
                    )
                )
            }
        }
        Entity.showAll(this.strands)
    }
}