// Functions for interacting with `io.Reader` & `io.Writer` objects.
module util

import io
import os

// reader_to_writer tries to consume the entire reader & write it to the writer.
pub fn reader_to_writer(mut reader io.Reader, mut writer io.Writer) ! {
	mut buf := []u8{len: 8192}

	for {
		bytes_read := reader.read(mut buf) or { break }
		mut bytes_written := 0

		for bytes_written < bytes_read {
			c := writer.write(buf[bytes_written..bytes_read]) or { break }

			bytes_written += c
		}
	}
}

// reader_to_file writes the contents of a BufferedReader to a file
pub fn reader_to_file(mut reader io.BufferedReader, length int, path string) ! {
	mut file := os.create(path)!
	defer {
		file.close()
	}

	mut buf := []u8{len: 8192}
	mut bytes_left := length

	// Repeat as long as the stream still has data
	for bytes_left > 0 {
		// TODO check if just breaking here is safe
		bytes_read := reader.read(mut buf) or { break }
		bytes_left -= bytes_read

		mut to_write := bytes_read

		for to_write > 0 {
			// TODO don't just loop infinitely here
			bytes_written := file.write(buf[bytes_read - to_write..bytes_read]) or { continue }
			// file.flush()

			to_write = to_write - bytes_written
		}
	}
}