// Copyright (c) 2018, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';

import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
import 'package:analysis_server/lsp_protocol/protocol_special.dart';
import 'package:analysis_server/src/lsp/constants.dart';
import 'package:analysis_server/src/lsp/handlers/handler_code_actions.dart';
import 'package:analysis_server/src/lsp/handlers/handler_completion.dart';
import 'package:analysis_server/src/lsp/handlers/handler_definition.dart';
import 'package:analysis_server/src/lsp/handlers/handler_document_symbols.dart';
import 'package:analysis_server/src/lsp/handlers/handler_execute_command.dart';
import 'package:analysis_server/src/lsp/handlers/handler_format_on_type.dart';
import 'package:analysis_server/src/lsp/handlers/handler_formatting.dart';
import 'package:analysis_server/src/lsp/handlers/handler_hover.dart';
import 'package:analysis_server/src/lsp/handlers/handler_initialize.dart';
import 'package:analysis_server/src/lsp/handlers/handler_initialized.dart';
import 'package:analysis_server/src/lsp/handlers/handler_references.dart';
import 'package:analysis_server/src/lsp/handlers/handler_signature_help.dart';
import 'package:analysis_server/src/lsp/handlers/handler_text_document_changes.dart';
import 'package:analysis_server/src/lsp/handlers/handlers.dart';
import 'package:analysis_server/src/lsp/lsp_analysis_server.dart';

/// The server moves to this state when a critical unrecoverrable error (for
/// example, inconsistent document state between server/client) occurs and will
/// reject all messages.
class FailureStateMessageHandler extends ServerStateMessageHandler {
  FailureStateMessageHandler(LspAnalysisServer server) : super(server);

  @override
  FutureOr<ErrorOr<Object>> handleUnknownMessage(IncomingMessage message) {
    return failure(
        ErrorCodes.InternalError,
        'An unrecoverable error occurred and the server cannot process messages',
        null);
  }
}

class InitializedStateMessageHandler extends ServerStateMessageHandler {
  InitializedStateMessageHandler(LspAnalysisServer server) : super(server) {
    reject(Method.initialize, ServerErrorCodes.ServerAlreadyInitialized,
        'Server already initialized');
    reject(Method.initialized, ServerErrorCodes.ServerAlreadyInitialized,
        'Server already initialized');
    registerHandler(new TextDocumentOpenHandler(server));
    registerHandler(new TextDocumentChangeHandler(server));
    registerHandler(new TextDocumentCloseHandler(server));
    registerHandler(new HoverHandler(server));
    registerHandler(new CompletionHandler(server));
    registerHandler(new SignatureHelpHandler(server));
    registerHandler(new DefinitionHandler(server));
    registerHandler(new ReferencesHandler(server));
    registerHandler(new FormattingHandler(server));
    registerHandler(new FormatOnTypeHandler(server));
    registerHandler(new DocumentSymbolHandler(server));
    registerHandler(new CodeActionHandler(server));
    registerHandler(new ExecuteCommandHandler(server));
  }
}

class InitializingStateMessageHandler extends ServerStateMessageHandler {
  InitializingStateMessageHandler(
      LspAnalysisServer server, List<String> openWorkspacePaths)
      : super(server) {
    reject(Method.initialize, ServerErrorCodes.ServerAlreadyInitialized,
        'Server already initialized');
    registerHandler(new IntializedMessageHandler(server, openWorkspacePaths));
  }

  @override
  ErrorOr<void> handleUnknownMessage(IncomingMessage message) {
    // Silently drop non-requests.
    if (message is! RequestMessage) {
      return success();
    }
    return failure(
        ErrorCodes.ServerNotInitialized,
        'Unable to handle ${message.method} before the server is initialized '
        'and the client has sent the initialized notification');
  }
}

class UninitializedStateMessageHandler extends ServerStateMessageHandler {
  UninitializedStateMessageHandler(LspAnalysisServer server) : super(server) {
    registerHandler(new InitializeMessageHandler(server));
  }

  @override
  FutureOr<ErrorOr<Object>> handleUnknownMessage(IncomingMessage message) {
    // Silently drop non-requests.
    if (message is! RequestMessage) {
      return success();
    }
    return failure(ErrorCodes.ServerNotInitialized,
        'Unable to handle ${message.method} before client has sent initialize request');
  }
}