import { toDrawable } from "./toDrawable"

/**
 * 图片改变尺寸，返回 Blob
 * @param imageSrc
 * @param w
 * @param h
 * @param options
 * @returns
 */
export async function imageResize(
    imageSrc: ImageData | Blob,
    w: number,
    h: number,
    options?: {
        format?: string
        quality?: number
        srcCanvas?: HTMLCanvasElement
        outCanvas?: HTMLCanvasElement
        sx?: number
        sy?: number
        sw?: number
        sh?: number
        method?: "pixelated" | "low" | "medium" | "high"
        // 返回 Canvas
        returnCanvas?: boolean
    }
): Promise<Blob> {
    let outCanvas = options?.outCanvas || document.createElement("canvas")
    let outCtx = <CanvasRenderingContext2D>outCanvas.getContext("2d")

    outCanvas.width = w
    outCanvas.height = h

    if (options?.method === "pixelated") {
        outCtx.imageSmoothingEnabled = false
    } else {
        outCtx.imageSmoothingEnabled = true
        outCtx.imageSmoothingQuality = options?.method ?? "high"
    }

    let drawable = await toDrawable(imageSrc)
    outCtx.drawImage(
        drawable,
        options?.sx ?? 0,
        options?.sy ?? 0,
        options?.sw ?? drawable.width,
        options?.sh ?? drawable.height,
        0,
        0,
        w,
        h
    )

    if (options?.returnCanvas) return <any>outCanvas

    return new Promise<Blob>((resolve) => {
        outCanvas.toBlob((blob) => resolve(<any>blob), options?.format || "image/png", options?.quality)
    })
}