/*
 *
 * 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,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
import Cocoa
import gRPC

// https://gist.github.com/rickw/cc198001f5f3aa59ae9f
extension NSTextView {
  func appendText(line: String) {
    if let textStorage = self.textStorage {
      textStorage.append(
        NSAttributedString(string:line+"\n",
                           attributes:[NSFontAttributeName:NSFont.systemFont(ofSize:12.0)]))
    }
    if let contents = self.string {
      self.scrollRangeToVisible(
        NSRange(location:contents.lengthOfBytes(using:String.Encoding.utf8),length: 0))
    }
  }
}

// http://stackoverflow.com/a/28976644/35844
func sync(lock: AnyObject, closure: () -> Void) {
  objc_sync_enter(lock)
  closure()
  objc_sync_exit(lock)
}

class Document: NSDocument {

  @IBOutlet weak var hostField: NSTextField!
  @IBOutlet weak var portField: NSTextField!
  @IBOutlet weak var connectionSelector: NSSegmentedControl!
  @IBOutlet weak var startButton: NSButton!
  @IBOutlet var textView: NSTextView!
  // http://stackoverflow.com/questions/24062437/cannot-form-weak-reference-to-instance-of-class-nstextview

  var channel : Channel!
  var server : Server!
  var running: Bool // all accesses to this should be synchronized

  override init() {
    running = false
    super.init()
  }

  override func close() {
    self.textView = nil // prevents logging to the textView
    stop()
    super.close()
  }

  override var windowNibName: String? {
    return "Document"
  }

  func log(_ line:String) {
    DispatchQueue.main.async {
      if let view = self.textView {
        view.appendText(line:line)
      }
    }
  }

  @IBAction func startButtonPressed(sender: NSButton){
    if sender.title == "Start" {
      updateInterfaceBeforeStarting()
      let address = hostField.stringValue + ":" + portField.stringValue
      if (connectionSelector.selectedSegment == 0) {
        runClient(address:address)
      } else {
        runServer(address:address)
      }
    } else {
      stop()
    }
  }

  func updateInterfaceBeforeStarting() {
    startButton.title = "Stop"
    hostField.isEnabled = false
    portField.isEnabled = false
    connectionSelector.isEnabled = false
    if let textStorage = self.textView.textStorage {
      textStorage.setAttributedString(NSAttributedString(string:"", attributes: [:]))
    }
  }

  func updateInterfaceAfterStopping() {
    DispatchQueue.main.async {
      if self.startButton != nil {
        self.startButton.title = "Start"
        self.hostField.isEnabled = true
        self.portField.isEnabled = true
        self.connectionSelector.isEnabled = true
      }
    }
  }

  func setIsRunning(_ value:Bool) {
    sync(lock:self) {
      self.running = value
    }
  }

  func isRunning() -> Bool {
    var result:Bool = false
    sync(lock:self) {
      result = self.running
    }
    return result
  }

  func stop() {
    if (self.channel != nil) {
      setIsRunning(false) // stops client
    }
    if (self.server != nil) {
      self.server.stop() // stops server
    }
  }

  func runClient(address:String) {
    DispatchQueue.global().async {
      self.log("Client Starting")
      self.log("GRPC version " + gRPC.version())

      self.channel = gRPC.Channel(address:address)
      self.channel.host = "foo.test.google.fr"
      let messageData = "hello, server!".data(using: .utf8)

      let steps = 10
      self.setIsRunning(true)
      for i in 1...steps {
        if !self.isRunning() {
          break
        }
        let method = (i < steps) ? "/hello" : "/quit"
        let call = self.channel.makeCall(method)

        let metadata = Metadata([["x": "xylophone"],
                                 ["y": "yu"],
                                 ["z": "zither"]])

        do {
          try call.perform(message: messageData!,
                           metadata: metadata)
          {(callResult) in

            if let initialMetadata = callResult.initialMetadata {
              for j in 0..<initialMetadata.count() {
                self.log("\(i): Received initial metadata -> " + initialMetadata.key(index:j)
                  + " : " + initialMetadata.value(index:j))
              }
            }

            self.log("\(i): Received status: \(callResult.statusCode) \(callResult.statusMessage)")
            if callResult.statusCode != 0 {
              self.setIsRunning(false)
            }
            if let messageData = callResult.resultData {
              let messageString = String(data: messageData as Data, encoding: .utf8)
              self.log("\(i): Received message: " + messageString!)
            }

            if let trailingMetadata = callResult.trailingMetadata {
              for j in 0..<trailingMetadata.count() {
                self.log("\(i): Received trailing metadata -> " + trailingMetadata.key(index:j)
                  + " : " + trailingMetadata.value(index:j))
              }
            }
          }
        } catch (let callError) {
          Swift.print("call error \(callError)")
        }
        self.log("------------------------------")
        sleep(1)
      }
      self.log("Client Stopped")
      self.updateInterfaceAfterStopping()
    }
  }

  func runServer(address:String) {
    self.log("Server Starting")
    self.log("GRPC version " + gRPC.version())
    self.setIsRunning(true)

    self.server = gRPC.Server(address:address)
    var requestCount = 0

    self.server.run() {(requestHandler) in

      do {
        requestCount += 1

        self.log("\(requestCount): Received request " + requestHandler.host
          + " " + requestHandler.method
          + " from " + requestHandler.caller)

        let initialMetadata = requestHandler.requestMetadata
        for i in 0..<initialMetadata.count() {
          self.log("\(requestCount): Received initial metadata -> " + initialMetadata.key(index:i)
            + ":" + initialMetadata.value(index:i))
        }

        let initialMetadataToSend = Metadata([["a": "Apple"],
                                              ["b": "Banana"],
                                              ["c": "Cherry"]])
        try requestHandler.receiveMessage(initialMetadata:initialMetadataToSend)
        {(messageData) in
          let messageString = String(data: messageData!, encoding: .utf8)
          self.log("\(requestCount): Received message: " + messageString!)
        }

        if requestHandler.method == "/quit" {
          self.stop()
        }

        let replyMessage = "hello, client!"
        let trailingMetadataToSend = Metadata([["0": "zero"],
                                               ["1": "one"],
                                               ["2": "two"]])
        try requestHandler.sendResponse(message:replyMessage.data(using: .utf8)!,
                                        statusCode:0,
                                        statusMessage:"OK",
                                        trailingMetadata:trailingMetadataToSend)

        self.log("------------------------------")
      } catch (let callError) {
        Swift.print("call error \(callError)")
      }
    }
    
    self.server.onCompletion() {
      self.log("Server Stopped")
      self.updateInterfaceAfterStopping()
    }
  }
}