/*
 * Copyright 2019, 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 EchoImplementation
import EchoModel
import Foundation
@testable import GRPC
import Logging
import NIO
import NIOHTTP1
import XCTest

class GRPCServerRequestRoutingHandlerTests: GRPCTestCase {
  var channel: EmbeddedChannel!

  override func setUp() {
    super.setUp()

    let provider = EchoProvider()
    let handler = GRPCServerRequestRoutingHandler(
      servicesByName: [provider.serviceName: provider],
      encoding: .disabled,
      errorDelegate: nil,
      logger: self.logger
    )

    self.channel = EmbeddedChannel(handler: handler)
  }

  override func tearDown() {
    XCTAssertNoThrow(try self.channel.finish())
    super.tearDown()
  }

  func testInvalidGRPCContentTypeReturnsUnsupportedMediaType() throws {
    let requestHead = HTTPRequestHead(
      version: .init(major: 2, minor: 0),
      method: .POST,
      uri: "/echo.Echo/Get",
      headers: ["content-type": "not-grpc"]
    )

    XCTAssertNoThrow(try self.channel.writeInbound(HTTPServerRequestPart.head(requestHead)))

    let firstResponsePart = try self.channel.readOutbound(as: HTTPServerResponsePart.self)
    switch firstResponsePart {
    case let .some(.head(head)):
      XCTAssertEqual(head.status, .unsupportedMediaType)
    default:
      XCTFail("Unexpected response part: \(String(describing: firstResponsePart))")
    }

    let secondResponsePart = try self.channel.readOutbound(as: HTTPServerResponsePart.self)
    switch secondResponsePart {
    case .some(.end(nil)):
      ()
    default:
      XCTFail("Unexpected response part: \(String(describing: secondResponsePart))")
    }
  }

  func testUnimplementedMethodReturnsUnimplementedStatus() throws {
    let requestHead = HTTPRequestHead(
      version: .init(major: 2, minor: 0),
      method: .POST,
      uri: "/foo/Bar",
      headers: ["content-type": "application/grpc"]
    )

    XCTAssertNoThrow(try self.channel.writeInbound(HTTPServerRequestPart.head(requestHead)))

    let firstResponsePart = try self.channel.readOutbound(as: HTTPServerResponsePart.self)
    switch firstResponsePart {
    case let .some(.head(head)):
      XCTAssertEqual(head.status, .ok)
      XCTAssertEqual(
        head.headers.first(name: "grpc-status"),
        "\(GRPCStatus.Code.unimplemented.rawValue)"
      )
    default:
      XCTFail("Unexpected response part: \(String(describing: firstResponsePart))")
    }

    let secondResponsePart = try self.channel.readOutbound(as: HTTPServerResponsePart.self)
    switch secondResponsePart {
    case .some(.end(nil)):
      ()
    default:
      XCTFail("Unexpected response part: \(String(describing: secondResponsePart))")
    }
  }

  func testImplementedMethodReconfiguresPipeline() throws {
    let requestHead = HTTPRequestHead(
      version: .init(major: 2, minor: 0),
      method: .POST,
      uri: "/echo.Echo/Get",
      headers: ["content-type": "application/grpc"]
    )

    XCTAssertNoThrow(try self.channel.writeInbound(HTTPServerRequestPart.head(requestHead)))

    // The router should be removed from the pipeline.
    let router = self.channel.pipeline.handler(type: GRPCServerRequestRoutingHandler.self)
    XCTAssertThrowsError(try router.wait())

    // There should now be a unary call handler.
    let unary = self.channel.pipeline.handler(
      type: UnaryCallHandler<
        ProtobufDeserializer<Echo_EchoRequest>,
        ProtobufSerializer<Echo_EchoResponse>
      >.self
    )
    XCTAssertNoThrow(try unary.wait())
  }

  func testSplitPathNormal() {
    let path = "/server/method"
    let parsedPath = GRPCServerRequestRoutingHandler.CallPath(requestURI: path)
    let splitPath = path.split(separator: "/")

    XCTAssertEqual(splitPath[0], String.SubSequence(parsedPath!.service))
    XCTAssertEqual(splitPath[1], String.SubSequence(parsedPath!.method))
  }

  func testSplitPathTooShort() {
    let path = "/badPath"
    let parsedPath = GRPCServerRequestRoutingHandler.CallPath(requestURI: path)

    XCTAssertNil(parsedPath)
  }

  func testSplitPathTooLong() {
    let path = "/server/method/discard"
    let parsedPath = GRPCServerRequestRoutingHandler.CallPath(requestURI: path)
    let splitPath = path.split(separator: "/")

    XCTAssertEqual(splitPath[0], String.SubSequence(parsedPath!.service))
    XCTAssertEqual(splitPath[1], String.SubSequence(parsedPath!.method))
  }

  func testTrimPrefixEmpty() {
    var toSplit = "".utf8[...]
    let head = toSplit.trimPrefix(to: UInt8(ascii: "/"))
    XCTAssertNil(head)
    XCTAssertEqual(toSplit.count, 0)
  }

  func testTrimPrefixAll() {
    let source = "words"
    var toSplit = source.utf8[...]
    let head = toSplit.trimPrefix(to: UInt8(ascii: "/"))
    XCTAssertEqual(head?.count, source.utf8.count)
    XCTAssertEqual(toSplit.count, 0)
  }

  func testTrimPrefixAndRest() {
    let source = "words/moreWords"
    var toSplit = source.utf8[...]
    let head = toSplit.trimPrefix(to: UInt8(ascii: "/"))
    XCTAssertEqual(head?.count, "words".utf8.count)
    XCTAssertEqual(toSplit.count, "moreWords".utf8.count)
  }
}