package community.yuvomi.mobile

import android.content.ContentResolver
import android.net.Uri
import java.net.URI
import javax.net.ssl.HttpsURLConnection

object FileTransfer {
    /** Never forwards session cookies across a redirect, even to another HTTPS origin. */
    fun save(server: ServerAddress, url: String, cookie: String?, resolver: ContentResolver, destination: Uri) {
        require(server.owns(url))
        val connection = URI(url).toURL().openConnection() as HttpsURLConnection
        try {
            connection.instanceFollowRedirects = false
            connection.connectTimeout = 15_000
            connection.readTimeout = 20_000
            cookie?.let { connection.setRequestProperty("Cookie", it) }
            require(connection.responseCode == 200) { "Download refused" }
            require(connection.contentLengthLong <= 100L * 1024 * 1024) { "Download too large" }
            connection.inputStream.use { input ->
                requireNotNull(resolver.openOutputStream(destination, "w")).use { output ->
                    val buffer = ByteArray(8192)
                    var total = 0L
                    val deadline = System.nanoTime() + 120_000_000_000L
                    while (true) {
                        check(!Thread.currentThread().isInterrupted && System.nanoTime() < deadline)
                        val count = input.read(buffer)
                        if (count < 0) break
                        total += count
                        require(total <= 100L * 1024 * 1024)
                        output.write(buffer, 0, count)
                    }
                }
            }
        } finally {
            connection.disconnect()
        }
    }
}