/*
 * Copyright 2018, gRPC Authors All rights reserved.
 *
 * 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.
 */

import Dispatch
import Foundation
import SwiftProtobuf

public protocol ServerSessionClientStreaming: ServerSession {}

open class ServerSessionClientStreamingBase<InputType: Message, OutputType: Message>: ServerSessionBase, ServerSessionClientStreaming {
  public typealias ProviderBlock = (ServerSessionClientStreamingBase) throws -> Void
  private var providerBlock: ProviderBlock

  public init(handler: Handler, providerBlock: @escaping ProviderBlock) {
    self.providerBlock = providerBlock
    super.init(handler: handler)
  }

  public func receive() throws -> InputType {
    let sem = DispatchSemaphore(value: 0)
    var requestMessage: InputType?
    try handler.receiveMessage { requestData in
      if let requestData = requestData {
        requestMessage = try? InputType(serializedData: requestData)
      }
      sem.signal()
    }
    _ = sem.wait()
    if requestMessage == nil {
      throw ServerError.endOfStream
    }
    return requestMessage!
  }

  public func sendAndClose(_ response: OutputType) throws {
    try handler.sendResponse(message: response.serializedData(),
                             statusCode: statusCode,
                             statusMessage: statusMessage,
                             trailingMetadata: trailingMetadata)
  }

  public func run(queue: DispatchQueue) throws {
    try handler.sendMetadata(initialMetadata: initialMetadata) { _ in
      queue.async {
        do {
          try self.providerBlock(self)
        } catch (let error) {
          print("error \(error)")
        }
      }
    }
  }
}

/// Simple fake implementation of ServerSessionClientStreaming that returns a previously-defined result
/// and stores sent values for later verification.
open class ServerSessionClientStreamingTestStub<InputType: Message, OutputType: Message>: ServerSessionTestStub, ServerSessionClientStreaming {
  open var inputs: [InputType] = []
  open var output: OutputType?

  open func receive() throws -> InputType {
    if let input = inputs.first {
      inputs.removeFirst()
      return input
    } else {
      throw ServerError.endOfStream
    }
  }

  open func sendAndClose(_ response: OutputType) throws {
    output = response
  }

  open func close() throws {}
}