import { Writable } from "stream"

import { StringEncoding } from "./StringEncoding"

export class StringWriter extends Writable {

protected byteLength = 0

protected bufs: Buffer<ArrayBuffer>[] = []

constructor(protected maxByteLength: number = 1 * 1024 * 1024) {

super()

}

_write(chunk: Buffer | string | any, _: string, callback: (error: Error | null) => void) {

if (!(chunk instanceof Buffer)) {

callback(new Error("StringWriter: expects chunks of type 'Buffer'."))

return

}

if (this.byteLength + chunk.byteLength > this.maxByteLength) {

callback(new Error(`StringWriter: Maximum bytes exceeded, maxByteLength=${this.maxByteLength}.`))

return

}

this.byteLength += chunk.byteLength

this.bufs.push(chunk)

callback(null)

}

getText(encoding: StringEncoding) {

return Buffer.concat(this.bufs).toString(encoding);

}

}