Polling 30012026

polling.kts

// Task:
// Implement polling with a timeout

suspend fun makeNetworkRequest(): Result<String> {
    delay(100)
    return if (Random.nextBoolean()) {
        Result.success("hello")
    } else {
        Result.failure(RuntimeException("Bad luck"))
    }
}

// Rewrite the method:
suspend fun pollNetworkCall(): Result<String> {
    return makeNetworkRequest()
}

// Solution:

suspend fun pollNetworkCall(
    timeoutMillis: Long,
    initialDelay: Long = 500L,
    maxDelay: Long = 4000L
): Result<String> {
    var currentDelay = initialDelay
    var result: Result<String>? = null

    withTimeout(timeoutMillis) {
        while (true) {
            val localResult = makeNetworkRequest()
            if (localResult.isSuccess) {
                result = localResult
                return@withTimeout
            } else {
                delay(currentDelay)
                currentDelay = (currentDelay * 2).coerceAtMost(maxDelay)
            }
        }
    }
    return result ?: Result.failure(
        TimeoutException("Timed out after $timeoutMillis ms")
    )
}