import 'package:appflowy/generated/locale_keys.g.dart';
import 'package:appflowy/plugins/ai_chat/application/chat_bloc.dart';
import 'package:appflowy/plugins/ai_chat/application/chat_entity.dart';
import 'package:appflowy/plugins/ai_chat/application/ai_prompt_input_bloc.dart';
import 'package:appflowy/plugins/ai_chat/application/chat_message_stream.dart';
import 'package:appflowy/plugins/ai_chat/presentation/chat_related_question.dart';
import 'package:appflowy/plugins/ai_chat/presentation/message/user_message_bubble.dart';
import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
import 'package:appflowy_backend/protobuf/flowy-user/protobuf.dart';
import 'package:desktop_drop/desktop_drop.dart';
import 'package:easy_localization/easy_localization.dart';
import 'package:flowy_infra_ui/flowy_infra_ui.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:flutter_chat_core/flutter_chat_core.dart';
import 'package:flutter_chat_ui/flutter_chat_ui.dart'
    hide ChatAnimatedListReversed;
import 'package:styled_widget/styled_widget.dart';
import 'package:universal_platform/universal_platform.dart';

import 'application/chat_member_bloc.dart';
import 'application/chat_side_panel_bloc.dart';
import 'presentation/animated_chat_list.dart';
import 'presentation/chat_input/desktop_ai_prompt_input.dart';
import 'presentation/chat_input/mobile_ai_prompt_input.dart';
import 'presentation/chat_side_panel.dart';
import 'presentation/chat_user_invalid_message.dart';
import 'presentation/chat_welcome_page.dart';
import 'presentation/layout_define.dart';
import 'presentation/message/ai_text_message.dart';
import 'presentation/message/user_text_message.dart';
import 'presentation/scroll_to_bottom.dart';

class AIChatPage extends StatelessWidget {
  const AIChatPage({
    super.key,
    required this.view,
    required this.onDeleted,
    required this.userProfile,
  });

  final ViewPB view;
  final VoidCallback onDeleted;
  final UserProfilePB userProfile;

  @override
  Widget build(BuildContext context) {
    if (userProfile.authenticator != AuthenticatorPB.AppFlowyCloud) {
      return Center(
        child: FlowyText(
          LocaleKeys.chat_unsupportedCloudPrompt.tr(),
          fontSize: 20,
        ),
      );
    }

    return MultiBlocProvider(
      providers: [
        /// [ChatBloc] is used to handle chat messages including send/receive message
        BlocProvider(
          create: (_) => ChatBloc(
            chatId: view.id,
            userId: userProfile.id.toString(),
          ),
        ),

        /// [AIPromptInputBloc] is used to handle the user prompt
        BlocProvider(create: (_) => AIPromptInputBloc()),
        BlocProvider(create: (_) => ChatSidePanelBloc(chatId: view.id)),
        BlocProvider(create: (_) => ChatMemberBloc()),
      ],
      child: DropTarget(
        onDragDone: (DropDoneDetails detail) async {
          if (context.read<AIPromptInputBloc>().state.supportChatWithFile) {
            for (final file in detail.files) {
              context
                  .read<AIPromptInputBloc>()
                  .add(AIPromptInputEvent.newFile(file.path, file.name));
            }
          }
        },
        child: _ChatContentPage(
          view: view,
          userProfile: userProfile,
        ),
      ),
    );
  }
}

class _ChatContentPage extends StatelessWidget {
  const _ChatContentPage({
    required this.view,
    required this.userProfile,
  });

  final UserProfilePB userProfile;
  final ViewPB view;

  @override
  Widget build(BuildContext context) {
    if (UniversalPlatform.isDesktop) {
      return BlocSelector<ChatSidePanelBloc, ChatSidePanelState, bool>(
        selector: (state) => state.isShowPanel,
        builder: (context, isShowPanel) {
          return LayoutBuilder(
            builder: (BuildContext context, BoxConstraints constraints) {
              final sidePanelRatio = isShowPanel ? 0.33 : 0.0;
              final chatWidth = constraints.maxWidth * (1 - sidePanelRatio);
              final sidePanelWidth =
                  constraints.maxWidth * sidePanelRatio - 1.0;

              return Row(
                children: [
                  Center(
                    child: buildChatWidget(context)
                        .constrained(
                          maxWidth: 784,
                        )
                        .padding(horizontal: 32)
                        .animate(
                          const Duration(milliseconds: 200),
                          Curves.easeOut,
                        ),
                  ).constrained(width: chatWidth),
                  if (isShowPanel) ...[
                    const VerticalDivider(
                      width: 1.0,
                      thickness: 1.0,
                    ),
                    buildChatSidePanel()
                        .constrained(width: sidePanelWidth)
                        .animate(
                          const Duration(milliseconds: 200),
                          Curves.easeOut,
                        ),
                  ],
                ],
              );
            },
          );
        },
      );
    } else {
      return Row(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Flexible(
            child: ConstrainedBox(
              constraints: const BoxConstraints(maxWidth: 784),
              child: buildChatWidget(context),
            ),
          ),
        ],
      );
    }
  }

  Widget buildChatSidePanel() {
    return BlocBuilder<ChatSidePanelBloc, ChatSidePanelState>(
      builder: (context, state) {
        if (state.metadata == null) {
          return const SizedBox.shrink();
        }
        return const ChatSidePanel();
      },
    );
  }

  Widget buildChatWidget(BuildContext context) {
    return ScrollConfiguration(
      behavior: ScrollConfiguration.of(context).copyWith(scrollbars: false),
      child: BlocBuilder<ChatBloc, ChatState>(
        builder: (context, state) {
          return state.loadingState.when(
            loading: () {
              return const Center(
                child: CircularProgressIndicator.adaptive(),
              );
            },
            finish: (_) {
              final chatController = context.read<ChatBloc>().chatController;
              return Column(
                children: [
                  Expanded(
                    child: Chat(
                      chatController: chatController,
                      user: User(id: userProfile.id.toString()),
                      darkTheme: ChatTheme.fromThemeData(Theme.of(context)),
                      theme: ChatTheme.fromThemeData(Theme.of(context)),
                      builders: Builders(
                        inputBuilder: (_) => const SizedBox.shrink(),
                        textMessageBuilder: _buildTextMessage,
                        chatMessageBuilder: _buildChatMessage,
                        scrollToBottomBuilder: _buildScrollToBottom,
                        chatAnimatedListBuilder: _buildChatAnimatedList,
                      ),
                    ),
                  ),
                  _buildInput(context),
                ],
              );
            },
          );
        },
      ),
    );
  }

  Widget _buildTextMessage(
    BuildContext context,
    TextMessage message,
  ) {
    final messageType = onetimeMessageTypeFromMeta(
      message.metadata,
    );

    if (messageType == OnetimeShotType.invalidSendMesssage) {
      return ChatInvalidUserMessage(
        message: message,
      );
    }

    if (messageType == OnetimeShotType.relatedQuestion) {
      return RelatedQuestionList(
        relatedQuestions: message.metadata!['questions'],
        onQuestionSelected: (question) {
          context
              .read<ChatBloc>()
              .add(ChatEvent.sendMessage(message: question));
        },
      );
    }

    if (message.author.id == userProfile.id.toString()) {
      final stream = message.metadata?["$QuestionStream"];
      return ChatUserMessageBubble(
        key: ValueKey(message.id),
        message: message,
        child: ChatUserMessageWidget(
          user: message.author,
          message: stream is QuestionStream ? stream : message.text,
        ),
      );
    }

    if (isOtherUserMessage(message)) {
      final stream = message.metadata?["$QuestionStream"];
      return ChatUserMessageBubble(
        key: ValueKey(message.id),
        message: message,
        isCurrentUser: false,
        child: ChatUserMessageWidget(
          user: message.author,
          message: stream is QuestionStream ? stream : message.text,
        ),
      );
    }

    final stream = message.metadata?["$AnswerStream"];
    final questionId = message.metadata?[messageQuestionIdKey];
    final refSourceJsonString =
        message.metadata?[messageRefSourceJsonStringKey] as String?;

    return BlocSelector<ChatBloc, ChatState, bool>(
      key: ValueKey(message.id),
      selector: (state) {
        final chatController = context.read<ChatBloc>().chatController;
        final messages = chatController.messages.where((e) {
          final oneTimeMessageType = onetimeMessageTypeFromMeta(e.metadata);
          if (oneTimeMessageType == null) {
            return true;
          }
          if (oneTimeMessageType
              case OnetimeShotType.relatedQuestion ||
                  OnetimeShotType.sendingMessage ||
                  OnetimeShotType.invalidSendMesssage) {
            return false;
          }
          return true;
        });
        return messages.isEmpty ? false : messages.last.id == message.id;
      },
      builder: (context, isLastMessage) {
        return ChatAIMessageWidget(
          user: message.author,
          messageUserId: message.id,
          message: message,
          stream: stream is AnswerStream ? stream : null,
          questionId: questionId,
          chatId: view.id,
          refSourceJsonString: refSourceJsonString,
          isLastMessage: isLastMessage,
          onSelectedMetadata: (metadata) {
            context
                .read<ChatSidePanelBloc>()
                .add(ChatSidePanelEvent.selectedMetadata(metadata));
          },
        );
      },
    );
  }

  Widget _buildChatMessage(
    BuildContext context,
    Message message,
    Animation<double> animation,
    Widget child,
  ) {
    return ChatMessage(
      message: message,
      animation: animation,
      padding: const EdgeInsets.symmetric(vertical: 8.0),
      child: child,
    );
  }

  Widget _buildScrollToBottom(
    BuildContext context,
    Animation<double> animation,
    VoidCallback onPressed,
  ) {
    return CustomScrollToBottom(
      animation: animation,
      onPressed: onPressed,
    );
  }

  Widget _buildChatAnimatedList(
    BuildContext context,
    ScrollController scrollController,
    ChatItem itemBuilder,
  ) {
    final bloc = context.read<ChatBloc>();

    if (bloc.chatController.messages.isEmpty) {
      return ChatWelcomePage(
        userProfile: userProfile,
        onSelectedQuestion: (question) {
          bloc.add(ChatEvent.sendMessage(message: question));
        },
      );
    }

    return ChatAnimatedListReversed(
      scrollController: scrollController,
      itemBuilder: itemBuilder,
      onLoadPreviousMessages: () {
        bloc.add(const ChatEvent.loadPreviousMessages());
      },
    );
  }

  Widget _buildInput(BuildContext context) {
    return Padding(
      padding: AIChatUILayout.safeAreaInsets(context),
      child: BlocSelector<ChatBloc, ChatState, bool>(
        selector: (state) {
          return state.promptResponseState == PromptResponseState.ready;
        },
        builder: (context, canSendMessage) {
          return UniversalPlatform.isDesktop
              ? DesktopAIPromptInput(
                  chatId: view.id,
                  indicateFocus: true,
                  onSubmitted: (text, metadata) {
                    context.read<ChatBloc>().add(
                          ChatEvent.sendMessage(
                            message: text,
                            metadata: metadata,
                          ),
                        );
                  },
                  isStreaming: !canSendMessage,
                  onStopStreaming: () {
                    context.read<ChatBloc>().add(const ChatEvent.stopStream());
                  },
                )
              : MobileAIPromptInput(
                  chatId: view.id,
                  onSubmitted: (text, metadata) {
                    context.read<ChatBloc>().add(
                          ChatEvent.sendMessage(
                            message: text,
                            metadata: metadata,
                          ),
                        );
                  },
                  isStreaming: !canSendMessage,
                  onStopStreaming: () {
                    context.read<ChatBloc>().add(const ChatEvent.stopStream());
                  },
                );
        },
      ),
    );
  }
}