import "dart:convert";
import "dart:math" as math;
import "package:dio/dio.dart";
import "package:easy_localization/easy_localization.dart";
import "package:flutter/material.dart";
import "package:flutter_hooks/flutter_hooks.dart";
import "package:hooks_riverpod/hooks_riverpod.dart";
import "package:island/models/thought.dart";
import "package:island/pods/network.dart";
import "package:island/pods/userinfo.dart";
import "package:island/widgets/content/sheet.dart";
import "package:island/widgets/thought/thought_shared.dart";
import "package:super_sliver_list/super_sliver_list.dart";

class ThoughtSheet extends HookConsumerWidget {
  final List<Map<String, dynamic>> attachedMessages;
  final List<String> attachedPosts;

  const ThoughtSheet({
    super.key,
    this.attachedMessages = const [],
    this.attachedPosts = const [],
  });

  static Future<void> show(
    BuildContext context, {
    List<Map<String, dynamic>> attachedMessages = const [],
    List<String> attachedPosts = const [],
  }) {
    return showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      useSafeArea: true,
      builder:
          (context) => ThoughtSheet(
            attachedMessages: attachedMessages,
            attachedPosts: attachedPosts,
          ),
    );
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final sequenceId = useState<String?>(null);
    final localThoughts = useState<List<SnThinkingThought>>([]);
    final currentTopic = useState<String?>('aiThought'.tr());

    final messageController = useTextEditingController();
    final scrollController = useScrollController();
    final isStreaming = useState(false);
    final streamingParts = useState<List<SnThinkingMessagePart>>([]);
    final reasoningChunks = useState<List<String>>([]);

    final listController = useMemoized(() => ListController(), []);

    // Scroll animation notifiers
    final bottomGradientNotifier = useState(ValueNotifier<double>(0.0));

    // Scroll to bottom when thoughts change or streaming state changes
    useEffect(() {
      if (localThoughts.value.isNotEmpty || isStreaming.value) {
        WidgetsBinding.instance.addPostFrameCallback((_) {
          scrollController.animateTo(
            0,
            duration: const Duration(milliseconds: 300),
            curve: Curves.easeOut,
          );
        });
      }
      return null;
    }, [localThoughts.value.length, isStreaming.value]);

    // Add scroll listener for gradient animations
    useEffect(() {
      void onScroll() {
        // Update gradient animations
        final pixels = scrollController.position.pixels;

        // Bottom gradient: appears when not at bottom (pixels > 0)
        bottomGradientNotifier.value.value = (pixels / 500.0).clamp(0.0, 1.0);
      }

      scrollController.addListener(onScroll);
      return () => scrollController.removeListener(onScroll);
    }, [scrollController]);

    void sendMessage() async {
      if (messageController.text.trim().isEmpty) return;

      final userMessage = messageController.text.trim();

      // Add user message to local thoughts
      final userInfo = ref.read(userInfoProvider);
      final now = DateTime.now();
      final userThought = SnThinkingThought(
        id: 'user-${DateTime.now().millisecondsSinceEpoch}',
        parts: [
          SnThinkingMessagePart(
            type: ThinkingMessagePartType.text,
            text: userMessage,
          ),
        ],
        files: [],
        role: ThinkingThoughtRole.user,
        sequenceId: sequenceId.value ?? '',
        createdAt: now,
        updatedAt: now,
        sequence: SnThinkingSequence(
          id: sequenceId.value ?? '',
          accountId: userInfo.value!.id,
          createdAt: now,
          updatedAt: now,
        ),
      );
      localThoughts.value = [userThought, ...localThoughts.value];

      final request = StreamThinkingRequest(
        userMessage: userMessage,
        sequenceId: sequenceId.value,
        accpetProposals: ['post_create'],
        attachedMessages: attachedMessages,
        attachedPosts: attachedPosts,
      );

      try {
        isStreaming.value = true;
        streamingParts.value = [];
        reasoningChunks.value = [];

        final apiClient = ref.read(apiClientProvider);
        final response = await apiClient.post(
          '/insight/thought',
          data: request.toJson(),
          options: Options(
            responseType: ResponseType.stream,
            sendTimeout: Duration(minutes: 1),
            receiveTimeout: Duration(minutes: 1),
          ),
        );

        final stream = response.data.stream;
        final lineBuffer = StringBuffer();

        stream.listen(
          (data) {
            final chunk = utf8.decode(data);
            lineBuffer.write(chunk);
            final lines = lineBuffer.toString().split('\n');
            lineBuffer.clear();
            lineBuffer.write(lines.last); // keep incomplete line

            for (final line in lines.sublist(0, lines.length - 1)) {
              if (line.trim().isEmpty) continue;
              try {
                if (line.startsWith('data: ')) {
                  final jsonStr = line.substring(6);
                  final event = jsonDecode(jsonStr);
                  final type = event['type'];
                  final eventData = event['data'];
                  if (type == 'text') {
                    if (streamingParts.value.isNotEmpty &&
                        streamingParts.value.last.type ==
                            ThinkingMessagePartType.text) {
                      final last = streamingParts.value.last;
                      final newParts = [...streamingParts.value];
                      newParts[newParts.length - 1] = last.copyWith(
                        text: (last.text ?? '') + eventData,
                      );
                      streamingParts.value = newParts;
                    } else {
                      streamingParts.value = [
                        ...streamingParts.value,
                        SnThinkingMessagePart(
                          type: ThinkingMessagePartType.text,
                          text: eventData,
                        ),
                      ];
                    }
                  } else if (type == 'function_call') {
                    streamingParts.value = [
                      ...streamingParts.value,
                      SnThinkingMessagePart(
                        type: ThinkingMessagePartType.functionCall,
                        functionCall: SnFunctionCall.fromJson(eventData),
                      ),
                    ];
                  } else if (type == 'function_result') {
                    streamingParts.value = [
                      ...streamingParts.value,
                      SnThinkingMessagePart(
                        type: ThinkingMessagePartType.functionResult,
                        functionResult: SnFunctionResult.fromJson(eventData),
                      ),
                    ];
                  } else if (type == 'reasoning') {
                    reasoningChunks.value = [
                      ...reasoningChunks.value,
                      eventData,
                    ];
                  }
                } else if (line.startsWith('topic: ')) {
                  final jsonStr = line.substring(7);
                  final event = jsonDecode(jsonStr);
                  currentTopic.value = event['data'];
                } else if (line.startsWith('thought: ')) {
                  final jsonStr = line.substring(9);
                  final event = jsonDecode(jsonStr);
                  final aiThought = SnThinkingThought.fromJson(event['data']);
                  localThoughts.value = [aiThought, ...localThoughts.value];
                  if (sequenceId.value == null &&
                      aiThought.sequenceId.isNotEmpty) {
                    sequenceId.value = aiThought.sequenceId;
                  }
                  isStreaming.value = false;
                }
              } catch (e) {
                // Ignore parsing errors for individual events
              }
            }
          },
          onDone: () {
            if (isStreaming.value) {
              isStreaming.value = false;
              // Add error thought to the list for incomplete response
              final userInfo = ref.read(userInfoProvider);
              final now = DateTime.now();
              final errorThought = SnThinkingThought(
                id: 'error-${DateTime.now().millisecondsSinceEpoch}',
                parts: [
                  SnThinkingMessagePart(
                    type: ThinkingMessagePartType.text,
                    text: 'Error: ${'thoughtParseError'.tr()}',
                  ),
                ],
                files: [],
                role: ThinkingThoughtRole.assistant,
                sequenceId: sequenceId.value ?? '',
                createdAt: now,
                updatedAt: now,
                sequence: SnThinkingSequence(
                  id: sequenceId.value ?? '',
                  accountId: userInfo.value!.id,
                  createdAt: now,
                  updatedAt: now,
                ),
              );
              localThoughts.value = [errorThought, ...localThoughts.value];
            }
          },
          onError: (error) {
            isStreaming.value = false;

            // Add error thought to the list
            final userInfo = ref.read(userInfoProvider);
            final now = DateTime.now();
            final errorMessage =
                error is DioException && error.response?.data is ResponseBody
                    ? 'toughtParseError'.tr()
                    : error.toString();
            final errorThought = SnThinkingThought(
              id: 'error-${DateTime.now().millisecondsSinceEpoch}',
              parts: [
                SnThinkingMessagePart(
                  type: ThinkingMessagePartType.text,
                  text: 'Error: $errorMessage',
                ),
              ],
              files: [],
              role: ThinkingThoughtRole.assistant,
              sequenceId: sequenceId.value ?? '',
              createdAt: now,
              updatedAt: now,
              sequence: SnThinkingSequence(
                id: sequenceId.value ?? '',
                accountId: userInfo.value!.id,
                createdAt: now,
                updatedAt: now,
              ),
            );
            localThoughts.value = [errorThought, ...localThoughts.value];
          },
        );

        messageController.clear();
        FocusManager.instance.primaryFocus?.unfocus();
      } catch (error) {
        isStreaming.value = false;

        // Add error thought to the list for initial request errors
        final userInfo = ref.read(userInfoProvider);
        final now = DateTime.now();
        final errorMessage = error.toString();
        final errorThought = SnThinkingThought(
          id: 'error-${DateTime.now().millisecondsSinceEpoch}',
          parts: [
            SnThinkingMessagePart(
              type: ThinkingMessagePartType.text,
              text: 'Error: $errorMessage',
            ),
          ],
          files: [],
          role: ThinkingThoughtRole.assistant,
          sequenceId: sequenceId.value ?? '',
          createdAt: now,
          updatedAt: now,
          sequence: SnThinkingSequence(
            id: sequenceId.value ?? '',
            accountId: userInfo.value!.id,
            createdAt: now,
            updatedAt: now,
          ),
        );
        localThoughts.value = [errorThought, ...localThoughts.value];
      }
    }

    return SheetScaffold(
      titleText: currentTopic.value ?? 'aiThought'.tr(),
      child: Stack(
        children: [
          // Thoughts list
          Center(
            child: Container(
              constraints: BoxConstraints(maxWidth: 640),
              child: Column(
                children: [
                  Expanded(
                    child: SuperListView.builder(
                      listController: listController,
                      controller: scrollController,
                      padding: EdgeInsets.only(
                        top: 16,
                        bottom:
                            MediaQuery.of(context).padding.bottom +
                            80, // Leave space for thought input
                      ),
                      reverse: true,
                      itemCount:
                          localThoughts.value.length +
                          (isStreaming.value ? 1 : 0),
                      itemBuilder: (context, index) {
                        if (isStreaming.value && index == 0) {
                          final streamingText = streamingParts.value
                              .where(
                                (p) => p.type == ThinkingMessagePartType.text,
                              )
                              .map((p) => p.text ?? '')
                              .join('');
                          final streamingFunctionCalls =
                              streamingParts.value
                                  .where(
                                    (p) =>
                                        p.type ==
                                        ThinkingMessagePartType.functionCall,
                                  )
                                  .map(
                                    (p) => JsonEncoder.withIndent(
                                      '  ',
                                    ).convert(p.functionCall?.toJson() ?? {}),
                                  )
                                  .toList();
                          return ThoughtItem(
                            isStreaming: true,
                            streamingText: streamingText,
                            reasoningChunks: reasoningChunks.value,
                            streamingFunctionCalls: streamingFunctionCalls,
                          );
                        }
                        final thoughtIndex =
                            isStreaming.value ? index - 1 : index;
                        final thought = localThoughts.value[thoughtIndex];
                        return ThoughtItem(
                          thought: thought,
                          thoughtIndex: thoughtIndex,
                        );
                      },
                    ),
                  ),
                ],
              ),
            ),
          ),
          // Bottom gradient - appears when scrolling towards newer thoughts (behind thought input)
          AnimatedBuilder(
            animation: bottomGradientNotifier.value,
            builder:
                (context, child) => Positioned(
                  left: 0,
                  right: 0,
                  bottom: 0,
                  child: Opacity(
                    opacity: bottomGradientNotifier.value.value,
                    child: Container(
                      height: math.min(
                        MediaQuery.of(context).size.height * 0.1,
                        128,
                      ),
                      decoration: BoxDecoration(
                        gradient: LinearGradient(
                          begin: Alignment.bottomCenter,
                          end: Alignment.topCenter,
                          colors: [
                            Theme.of(
                              context,
                            ).colorScheme.surfaceContainer.withOpacity(0.8),
                            Theme.of(
                              context,
                            ).colorScheme.surfaceContainer.withOpacity(0.0),
                          ],
                        ),
                      ),
                    ),
                  ),
                ),
          ),
          // Thought Input positioned above gradient (higher z-index)
          Positioned(
            left: 0,
            right: 0,
            bottom: 0, // At the very bottom, above gradient
            child: Center(
              child: Container(
                constraints: BoxConstraints(maxWidth: 640),
                child: ThoughtInput(
                  messageController: messageController,
                  isStreaming: isStreaming.value,
                  onSend: sendMessage,
                  attachedMessages: attachedMessages,
                  attachedPosts: attachedPosts,
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}