/*
 * Copyright (C) 2014 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/** Essential APIs for working with Okio. */
@file:JvmMultifileClass
@file:JvmName("Okio")

package okio

import org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement
import java.io.File
import java.io.FileNotFoundException
import java.io.FileOutputStream
import java.io.IOException
import java.io.InputStream
import java.io.OutputStream
import java.net.Socket
import java.net.SocketTimeoutException
import java.nio.file.Files
import java.nio.file.OpenOption
import java.nio.file.Path
import java.security.MessageDigest
import java.util.logging.Level
import java.util.logging.Logger
import javax.crypto.Cipher
import javax.crypto.Mac

/** Returns a sink that writes to `out`. */
fun OutputStream.sink(): Sink = OutputStreamSink(this, Timeout())

private class OutputStreamSink(
  private val out: OutputStream,
  private val timeout: Timeout
) : Sink {

  override fun write(source: Buffer, byteCount: Long) {
    checkOffsetAndCount(source.size, 0, byteCount)
    var remaining = byteCount
    while (remaining > 0) {
      timeout.throwIfReached()
      val head = source.head!!
      val toCopy = minOf(remaining, head.limit - head.pos).toInt()
      out.write(head.data, head.pos, toCopy)

      head.pos += toCopy
      remaining -= toCopy
      source.size -= toCopy

      if (head.pos == head.limit) {
        source.head = head.pop()
        SegmentPool.recycle(head)
      }
    }
  }

  override fun flush() = out.flush()

  override fun close() = out.close()

  override fun timeout() = timeout

  override fun toString() = "sink($out)"
}

/** Returns a source that reads from `in`. */
fun InputStream.source(): Source = InputStreamSource(this, Timeout())

private class InputStreamSource(
  private val input: InputStream,
  private val timeout: Timeout
) : Source {

  override fun read(sink: Buffer, byteCount: Long): Long {
    if (byteCount == 0L) return 0L
    require(byteCount >= 0L) { "byteCount < 0: $byteCount" }
    try {
      timeout.throwIfReached()
      val tail = sink.writableSegment(1)
      val maxToCopy = minOf(byteCount, Segment.SIZE - tail.limit).toInt()
      val bytesRead = input.read(tail.data, tail.limit, maxToCopy)
      if (bytesRead == -1) {
        if (tail.pos == tail.limit) {
          // We allocated a tail segment, but didn't end up needing it. Recycle!
          sink.head = tail.pop()
          SegmentPool.recycle(tail)
        }
        return -1
      }
      tail.limit += bytesRead
      sink.size += bytesRead
      return bytesRead.toLong()
    } catch (e: AssertionError) {
      if (e.isAndroidGetsocknameError) throw IOException(e)
      throw e
    }
  }

  override fun close() = input.close()

  override fun timeout() = timeout

  override fun toString() = "source($input)"
}

/**
 * Returns a sink that writes to `socket`. Prefer this over [sink]
 * because this method honors timeouts. When the socket
 * write times out, the socket is asynchronously closed by a watchdog thread.
 */
@Throws(IOException::class)
fun Socket.sink(): Sink {
  val timeout = SocketAsyncTimeout(this)
  val sink = OutputStreamSink(getOutputStream(), timeout)
  return timeout.sink(sink)
}

/**
 * Returns a source that reads from `socket`. Prefer this over [source]
 * because this method honors timeouts. When the socket
 * read times out, the socket is asynchronously closed by a watchdog thread.
 */
@Throws(IOException::class)
fun Socket.source(): Source {
  val timeout = SocketAsyncTimeout(this)
  val source = InputStreamSource(getInputStream(), timeout)
  return timeout.source(source)
}

private val logger = Logger.getLogger("okio.Okio")

private class SocketAsyncTimeout(private val socket: Socket) : AsyncTimeout() {
  override fun newTimeoutException(cause: IOException?): IOException {
    val ioe = SocketTimeoutException("timeout")
    if (cause != null) {
      ioe.initCause(cause)
    }
    return ioe
  }

  override fun timedOut() {
    try {
      socket.close()
    } catch (e: Exception) {
      logger.log(Level.WARNING, "Failed to close timed out socket $socket", e)
    } catch (e: AssertionError) {
      if (e.isAndroidGetsocknameError) {
        // Catch this exception due to a Firmware issue up to android 4.2.2
        // https://code.google.com/p/android/issues/detail?id=54072
        logger.log(Level.WARNING, "Failed to close timed out socket $socket", e)
      } else {
        throw e
      }
    }
  }
}

/** Returns a sink that writes to `file`. */
@JvmOverloads
@Throws(FileNotFoundException::class)
fun File.sink(append: Boolean = false): Sink = FileOutputStream(this, append).sink()

/** Returns a sink that writes to `file`. */
@Throws(FileNotFoundException::class)
fun File.appendingSink(): Sink = FileOutputStream(this, true).sink()

/** Returns a source that reads from `file`. */
@Throws(FileNotFoundException::class)
fun File.source(): Source = inputStream().source()

/** Returns a source that reads from `path`. */
@Throws(IOException::class)
@IgnoreJRERequirement // Can only be invoked on Java 7+.
fun Path.sink(vararg options: OpenOption): Sink =
  Files.newOutputStream(this, *options).sink()

/** Returns a sink that writes to `path`. */
@Throws(IOException::class)
@IgnoreJRERequirement // Can only be invoked on Java 7+.
fun Path.source(vararg options: OpenOption): Source =
  Files.newInputStream(this, *options).source()

/**
 * Returns a sink that uses [cipher] to encrypt or decrypt [this].
 *
 * @throws IllegalArgumentException if [cipher] isn't a block cipher.
 */
fun Sink.cipherSink(cipher: Cipher): CipherSink = CipherSink(this.buffer(), cipher)

/**
 * Returns a source that uses [cipher] to encrypt or decrypt [this].
 *
 * @throws IllegalArgumentException if [cipher] isn't a block cipher.
 */
fun Source.cipherSource(cipher: Cipher): CipherSource = CipherSource(this.buffer(), cipher)

/**
 * Returns a sink that uses [mac] to hash [this].
 */
fun Sink.hashingSink(mac: Mac): HashingSink = HashingSink(this, mac)

/**
 * Returns a source that uses [mac] to hash [this].
 */
fun Source.hashingSource(mac: Mac): HashingSource = HashingSource(this, mac)

/**
 * Returns a sink that uses [digest] to hash [this].
 */
fun Sink.hashingSink(digest: MessageDigest): HashingSink = HashingSink(this, digest)

/**
 * Returns a source that uses [digest] to hash [this].
 */
fun Source.hashingSource(digest: MessageDigest): HashingSource = HashingSource(this, digest)

/**
 * Returns true if this error is due to a firmware bug fixed after Android 4.2.2.
 * https://code.google.com/p/android/issues/detail?id=54072
 */
internal val AssertionError.isAndroidGetsocknameError: Boolean get() {
  return cause != null && message?.contains("getsockname failed") ?: false
}