package com.leos.droidify.utility

import java.io.InputStream

fun InputStream.getProgress(callback: (Long) -> Unit): InputStream =
    ProgressInputStream(this, callback)

private class ProgressInputStream(
    private val inputStream: InputStream,
    private val callback: (Long) -> Unit
) : InputStream() {
    private var count = 0L

    private inline fun <reified T : Number> notify(one: Boolean, read: () -> T): T {
        val result = read()
        count += if (one) 1L else result.toLong()
        callback(count)
        return result
    }

    override fun read(): Int = notify(true) { inputStream.read() }
    override fun read(b: ByteArray): Int = notify(false) { inputStream.read(b) }
    override fun read(b: ByteArray, off: Int, len: Int): Int =
        notify(false) { inputStream.read(b, off, len) }

    override fun skip(n: Long): Long = notify(false) { inputStream.skip(n) }

    override fun available(): Int {
        return inputStream.available()
    }

    override fun close() {
        inputStream.close()
        super.close()
    }
}