/*
 *
 * Copyright 2016, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
#if SWIFT_PACKAGE
  import CgRPC
#endif

/// A gRPC Client
public class Client {

  /// Pointer to underlying C representation
  var c: UnsafeMutableRawPointer!

  /// Completion queue for client call operations
  var completionQueue: CompletionQueue

  /// Initializes a gRPC client
  ///
  /// - Parameter address: the address of the server to be called
  public init(address: String) {
    c = cgrpc_client_create(address)
    completionQueue = CompletionQueue(cq:cgrpc_client_completion_queue(c))
  }

  deinit {
    cgrpc_client_destroy(c)
  }

  /// Constructs a Call object to make a gRPC API call
  ///
  /// - Parameter host: the gRPC host name for the call
  /// - Parameter method: the gRPC method name for the call
  /// - Parameter timeout: a timeout value in seconds
  /// - Returns: a Call object that can be used to make the request
  func createCall(host:String, method:String, timeout:Double) -> Call {
    let call = cgrpc_client_create_call(c, method, host, timeout)!
    return Call(call:call, owned:true)
  }

  /// Performs a nonstreaming gRPC API call
  ///
  /// - Parameter host: the gRPC host name for the call
  /// - Parameter method: the gRPC method name for the call
  /// - Parameter message: a ByteBuffer containing the message to send
  /// - Parameter metadata: metadata to send with the call
  /// - Returns: a CallResponse object containing results of the call
  public func performRequest(host: String,
                             method: String,
                             message: ByteBuffer,
                             metadata: Metadata) -> CallResponse  {

    let operation_sendInitialMetadata = Operation_SendInitialMetadata(metadata:metadata);
    let operation_sendMessage = Operation_SendMessage(message:message)
    let operation_sendCloseFromClient = Operation_SendCloseFromClient()
    let operation_receiveInitialMetadata = Operation_ReceiveInitialMetadata()
    let operation_receiveStatusOnClient = Operation_ReceiveStatusOnClient()
    let operation_receiveMessage = Operation_ReceiveMessage()

    let operations: [Operation] = [
      operation_sendInitialMetadata,
      operation_sendMessage,
      operation_sendCloseFromClient,
      operation_receiveInitialMetadata,
      operation_receiveStatusOnClient,
      operation_receiveMessage
    ]

    let call = createCall(host:host, method:method, timeout:5.0)
    let call_error = call.performOperations(operations:operations, tag:111)
    if call_error != GRPC_CALL_OK {
      return CallResponse(error: call_error)
    }

    let call_status = completionQueue.waitForCompletion(timeout:5.0)
    if (call_status == GRPC_OP_COMPLETE) {
      let response = CallResponse(status:operation_receiveStatusOnClient.status(),
                                  statusDetails:operation_receiveStatusOnClient.statusDetails(),
                                  message:operation_receiveMessage.message(),
                                  initialMetadata:operation_receiveInitialMetadata.metadata(),
                                  trailingMetadata:operation_receiveStatusOnClient.metadata())
      return response
    } else {
      return CallResponse(completion: call_status)
    }
  }
}