/*
 * Copyright 2023, 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 Foundation
import GRPC
import GRPCReflectionService
import SwiftProtobuf
import XCTest

@testable import GRPCReflectionService

final class ReflectionServiceUnitTests: GRPCTestCase {
  /// Testing the fileDescriptorDataByFilename dictionary of the ReflectionServiceData object.
  func testFileDescriptorDataByFilename() throws {
    var protos = makeProtosWithDependencies()
    let registry = try ReflectionServiceData(fileDescriptors: protos)

    let registryFileDescriptorData = registry.fileDescriptorDataByFilename

    for (fileName, protoData) in registryFileDescriptorData {
      let serializedFiledescriptorData = protoData.serializedFileDescriptorProto
      let dependencyFileNames = protoData.dependencyFileNames

      guard let index = protos.firstIndex(where: { $0.name == fileName }) else {
        return XCTFail(
          """
          Could not find the file descriptor proto of \(fileName) \
          in the original file descriptor protos list.
          """
        )
      }

      let originalProto = protos[index]
      XCTAssertEqual(originalProto.name, fileName)
      XCTAssertEqual(try originalProto.serializedData(), serializedFiledescriptorData)
      XCTAssertEqual(originalProto.dependency, dependencyFileNames)

      protos.remove(at: index)
    }
    XCTAssert(protos.isEmpty)
  }

  /// Testing the serviceNames array of the ReflectionServiceData object.
  func testServiceNames() throws {
    let protos = makeProtosWithDependencies()
    let servicesNames = protos.serviceNames.sorted()
    let registry = try ReflectionServiceData(fileDescriptors: protos)
    let registryServices = registry.serviceNames.sorted()
    XCTAssertEqual(registryServices, servicesNames)
  }

  /// Testing the fileNameBySymbol array of the ReflectionServiceData object.
  func testFileNameBySymbol() throws {
    let protos = makeProtosWithDependencies()
    let registry = try ReflectionServiceData(fileDescriptors: protos)
    let registryFileNameBySymbol = registry.fileNameBySymbol

    var symbolsCount = 0

    for proto in protos {
      let qualifiedSymbolNames = proto.qualifiedSymbolNames
      symbolsCount += qualifiedSymbolNames.count
      for qualifiedSymbolName in qualifiedSymbolNames {
        XCTAssertEqual(registryFileNameBySymbol[qualifiedSymbolName], proto.name)
      }
    }

    XCTAssertEqual(symbolsCount, registryFileNameBySymbol.count)
  }

  func testFileNameBySymbolDuplicatedSymbol() throws {
    var protos = makeProtosWithDependencies()
    protos[1].messageType.append(
      Google_Protobuf_DescriptorProto.with {
        $0.name = "inputMessage"
        $0.field = [
          Google_Protobuf_FieldDescriptorProto.with {
            $0.name = "inputField"
            $0.type = .bool
          }
        ]
      }
    )

    XCTAssertThrowsError(
      try ReflectionServiceData(fileDescriptors: protos)
    ) { error in
      XCTAssertEqual(
        error as? GRPCStatus,
        GRPCStatus(
          code: .alreadyExists,
          message:
            """
            The packagebar2.inputMessage symbol from bar2.proto \
            already exists in bar2.proto.
            """
        )
      )
    }
  }

  // Testing the nameOfFileContainingSymbol method for different types of symbols.

  func testNameOfFileContainingSymbolEnum() throws {
    let protos = makeProtosWithDependencies()
    let registry = try ReflectionServiceData(fileDescriptors: protos)
    let fileName = registry.nameOfFileContainingSymbol(named: "packagebar2.enumType2")
    XCTAssertEqual(fileName, "bar2.proto")
  }

  func testNameOfFileContainingSymbolMessage() throws {
    let protos = makeProtosWithDependencies()
    let registry = try ReflectionServiceData(fileDescriptors: protos)
    let fileName = registry.nameOfFileContainingSymbol(named: "packagebar1.inputMessage")
    XCTAssertEqual(fileName, "bar1.proto")
  }

  func testNameOfFileContainingSymbolService() throws {
    let protos = makeProtosWithDependencies()
    let registry = try ReflectionServiceData(fileDescriptors: protos)
    let fileName = registry.nameOfFileContainingSymbol(named: "packagebar3.service3")
    XCTAssertEqual(fileName, "bar3.proto")
  }

  func testNameOfFileContainingSymbolMethod() throws {
    let protos = makeProtosWithDependencies()
    let registry = try ReflectionServiceData(fileDescriptors: protos)
    let fileName = registry.nameOfFileContainingSymbol(
      named: "packagebar4.service4.testMethod4"
    )
    XCTAssertEqual(fileName, "bar4.proto")
  }

  func testNameOfFileContainingSymbolNonExistentSymbol() throws {
    let protos = makeProtosWithDependencies()
    let registry = try ReflectionServiceData(fileDescriptors: protos)
    let fileName = registry.nameOfFileContainingSymbol(named: "packagebar2.enumType3")
    XCTAssertEqual(fileName, nil)
  }

  // Testing the serializedFileDescriptorProto method in different cases.

  func testSerialisedFileDescriptorProtosForDependenciesOfFile() throws {
    var protos = makeProtosWithDependencies()
    let registry = try ReflectionServiceData(fileDescriptors: protos)
    let serializedFileDescriptorProtos =
      try registry
      .serialisedFileDescriptorProtosForDependenciesOfFile(named: "bar1.proto")
    let fileDescriptorProtos = try serializedFileDescriptorProtos.map {
      try Google_Protobuf_FileDescriptorProto(serializedData: $0)
    }
    // Tests that the functions returns all the transitive dependencies, with their services and
    // methods, together with the initial proto, as serialized data.
    XCTAssertEqual(fileDescriptorProtos.count, 4)
    for fileDescriptorProto in fileDescriptorProtos {
      guard let protoIndex = protos.firstIndex(of: fileDescriptorProto) else {
        return XCTFail(
          """
          Could not find the file descriptor proto of \(fileDescriptorProto.name) \
          in the original file descriptor protos list.
          """
        )
      }

      for service in fileDescriptorProto.service {
        guard let serviceIndex = protos[protoIndex].service.firstIndex(of: service) else {
          return XCTFail(
            """
            Could not find the \(service.name) in the service \
            list of the \(fileDescriptorProto.name) file descriptor proto.
            """
          )
        }

        let originalMethods = protos[protoIndex].service[serviceIndex].method
        for method in service.method {
          XCTAssert(originalMethods.contains(method))
        }

        for messageType in fileDescriptorProto.messageType {
          XCTAssert(protos[protoIndex].messageType.contains(messageType))
        }
      }

      protos.removeAll { $0 == fileDescriptorProto }
    }
    XCTAssert(protos.isEmpty)
  }

  func testSerialisedFileDescriptorProtosForDependenciesOfFileComplexDependencyGraph() throws {
    var protos = makeProtosWithComplexDependencies()
    let registry = try ReflectionServiceData(fileDescriptors: protos)
    let serializedFileDescriptorProtos =
      try registry
      .serialisedFileDescriptorProtosForDependenciesOfFile(named: "foo0.proto")
    let fileDescriptorProtos = try serializedFileDescriptorProtos.map {
      try Google_Protobuf_FileDescriptorProto(serializedData: $0)
    }
    // Tests that the functions returns all the tranzitive dependencies, with their services and
    // methods, together with the initial proto, as serialized data.
    XCTAssertEqual(fileDescriptorProtos.count, 21)
    for fileDescriptorProto in fileDescriptorProtos {
      guard let protoIndex = protos.firstIndex(of: fileDescriptorProto) else {
        return XCTFail(
          """
          Could not find the file descriptor proto of \(fileDescriptorProto.name) \
          in the original file descriptor protos list.
          """
        )
      }

      for service in fileDescriptorProto.service {
        guard let serviceIndex = protos[protoIndex].service.firstIndex(of: service) else {
          return XCTFail(
            """
            Could not find the \(service.name) in the service \
            list of the \(fileDescriptorProto.name) file descriptor proto.
            """
          )
        }

        let originalMethods = protos[protoIndex].service[serviceIndex].method
        for method in service.method {
          XCTAssert(originalMethods.contains(method))
        }

        for messageType in fileDescriptorProto.messageType {
          XCTAssert(protos[protoIndex].messageType.contains(messageType))
        }
      }

      protos.removeAll { $0 == fileDescriptorProto }
    }
    XCTAssert(protos.isEmpty)
  }

  func testSerialisedFileDescriptorProtosForDependenciesOfFileDependencyLoops() throws {
    var protos = makeProtosWithDependencies()
    // Making dependencies of the "bar1.proto" to depend on "bar1.proto".
    protos[1].dependency.append("bar1.proto")
    protos[2].dependency.append("bar1.proto")
    protos[3].dependency.append("bar1.proto")
    let registry = try ReflectionServiceData(fileDescriptors: protos)
    let serializedFileDescriptorProtos =
      try registry
      .serialisedFileDescriptorProtosForDependenciesOfFile(named: "bar1.proto")
    let fileDescriptorProtos = try serializedFileDescriptorProtos.map {
      try Google_Protobuf_FileDescriptorProto(serializedData: $0)
    }
    // Test that we get only 4 serialized File Descriptor Protos as response.
    XCTAssertEqual(fileDescriptorProtos.count, 4)
    for fileDescriptorProto in fileDescriptorProtos {
      guard let protoIndex = protos.firstIndex(of: fileDescriptorProto) else {
        return XCTFail(
          """
          Could not find the file descriptor proto of \(fileDescriptorProto.name) \
          in the original file descriptor protos list.
          """
        )
      }

      for service in fileDescriptorProto.service {
        guard let serviceIndex = protos[protoIndex].service.firstIndex(of: service) else {
          return XCTFail(
            """
            Could not find the \(service.name) in the service \
            list of the \(fileDescriptorProto.name) file descriptor proto.
            """
          )
        }

        let originalMethods = protos[protoIndex].service[serviceIndex].method
        for method in service.method {
          XCTAssert(originalMethods.contains(method))
        }

        for messageType in fileDescriptorProto.messageType {
          XCTAssert(protos[protoIndex].messageType.contains(messageType))
        }
      }

      protos.removeAll { $0 == fileDescriptorProto }
    }
    XCTAssert(protos.isEmpty)
  }

  func testSerialisedFileDescriptorProtosForDependenciesOfFileInvalidFile() throws {
    let protos = makeProtosWithDependencies()
    let registry = try ReflectionServiceData(fileDescriptors: protos)
    XCTAssertThrowsError(
      try registry.serialisedFileDescriptorProtosForDependenciesOfFile(named: "invalid.proto")
    ) { error in
      XCTAssertEqual(
        error as? GRPCStatus,
        GRPCStatus(
          code: .notFound,
          message: "The provided file or a dependency of the provided file could not be found."
        )
      )
    }
  }

  func testSerialisedFileDescriptorProtosForDependenciesOfFileDependencyNotProto() throws {
    var protos = makeProtosWithDependencies()
    protos[0].dependency.append("invalidDependency")
    let registry = try ReflectionServiceData(fileDescriptors: protos)
    XCTAssertThrowsError(
      try registry.serialisedFileDescriptorProtosForDependenciesOfFile(named: "bar1.proto")
    ) { error in
      XCTAssertEqual(
        error as? GRPCStatus,
        GRPCStatus(
          code: .notFound,
          message: "The provided file or a dependency of the provided file could not be found."
        )
      )
    }
  }
}