import { Point } from "./vector"
export interface IDrawable2D {
    draw(context: CanvasRenderingContext2D)
}

export interface ISprite {
    next(delta: number): boolean
    reset()
}


export abstract class DrawableObject implements IDrawable2D {
    position: Point = {
        x: 0,
        y: 0
    }
    abstract draw(context: CanvasRenderingContext2D)
}

export class Group extends DrawableObject {
    draw(context) {
        for (let child of this.children) {
            context.save()
            context.translate(this.position.x, this.position.y)
            child.draw(context)
            context.restore()
        }
    }
    children: IDrawable2D[] = []
}

export abstract class FrameSprite extends DrawableObject implements ISprite {
    // fps = 20
    frameInterval = 50
    abstract generateFrames(): ImageSlice[]
    frames: ImageSlice[]
    frameIndex = 0
    time = 0
    next(delta) {
        if (!this.frames) {
            this.frames = this.generateFrames()
        }
        this.time += delta
        let offset = Math.floor(this.time / this.frameInterval) % this.frames.length
        let currentFrame = this.frames[offset]
        return true
    }
    reset() {
        this.frameIndex = 0
        this.time = 0
    }
}

export interface ImageSlice {
    image: HTMLImageElement
    offsetX: number
    offsetY: number
}