package org.opendc.common.utils

import java.io.File
import java.io.InputStreamReader
import java.net.URI
import java.net.http.*
import java.net.http.HttpResponse.BodyHandlers.ofString

/**
 * Singleton class representing the real datacenter client.
 * The client is asynchronous and initiates the connection first.
 *
 * @author Mateusz Kwiatkowski
 */

public class HTTPClient private constructor() {
    public companion object {
        private var instance: HTTPClient? = null
        private var client = HttpClient.newBuilder().build()

        public fun getInstance(): HTTPClient? {
            if (instance == null) {
                instance = HTTPClient()
            }
            return instance
        }
    }

    // TODO: this class must send the experiment JSON file to the digital twin
    public fun sendExperiment(experiment: File) {
        val input =  experiment.inputStream()
        val charArray = CharArray(experiment.length().toInt())
        val isr = InputStreamReader(input)

        isr.read(charArray)

        val request = HttpRequest.newBuilder()
            .uri(URI.create("http://localhost:8080/assets"))
            .header("Content-type", "application/json")
            // TODO: this is obviously wrong, find an efficient way to send JSON over network
            .POST(HttpRequest.BodyPublishers.ofString(String(charArray)))
            .build()
        val response = client?.send(request, ofString())
        check(response?.statusCode() == 200)
    }
}