import { useCallback, useState, useEffect } from 'react';
import { useEntity } from './useEntity';
import { haConnection } from '@/services/homeAssistant';
import { useSettingsStore } from '@/stores/settingsStore';

export interface TodoItem {
  uid: string;
  summary: string;
  status: 'needs_action' | 'completed';
  due?: string;
  description?: string;
}

export function useTodo() {
  const todoEntityId = useSettingsStore((state) => state.config.todoList);
  const entity = useEntity(todoEntityId || '');
  const [items, setItems] = useState<TodoItem[]>([]);
  const [isLoading, setIsLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const fetchItems = useCallback(async () => {
    if (!todoEntityId) return;

    setIsLoading(true);
    setError(null);

    try {
      const connection = haConnection.getConnection();
      if (!connection) {
        throw new Error('Not connected to Home Assistant');
      }

      // Use the todo.get_items service
      const result = await connection.sendMessagePromise<Record<string, unknown>>({
        type: 'call_service',
        domain: 'todo',
        service: 'get_items',
        target: { entity_id: todoEntityId },
        return_response: true,
      });

      // Extract items from response - handle different structures
      let entityItems: TodoItem[] = [];

      // Structure 1: { response: { "todo.entity": { items: [...] } } }
      const respWrapper = result?.response as Record<string, { items?: TodoItem[] }> | undefined;
      if (respWrapper?.[todoEntityId]?.items) {
        entityItems = respWrapper[todoEntityId].items;
      }
      // Structure 2: { "todo.entity": { items: [...] } }
      else if ((result?.[todoEntityId] as { items?: TodoItem[] })?.items) {
        entityItems = (result[todoEntityId] as { items: TodoItem[] }).items;
      }

      setItems(entityItems);
    } catch (err) {
      const message = err instanceof Error ? err.message : 'Failed to fetch todo items';
      setError(message);
      console.error('Failed to fetch todo items:', err);
    } finally {
      setIsLoading(false);
    }
  }, [todoEntityId]);

  // Fetch items when entity changes and poll every 30 seconds
  useEffect(() => {
    if (entity) {
      fetchItems();

      // Poll every 30 seconds for updates
      const interval = setInterval(fetchItems, 30000);
      return () => clearInterval(interval);
    }
  }, [entity, fetchItems]);

  const addItem = useCallback(async (summary: string) => {
    if (!todoEntityId) return;

    setIsLoading(true);
    setError(null);

    try {
      await haConnection.callService('todo', 'add_item', { item: summary }, { entity_id: todoEntityId });

      // Refresh items
      await fetchItems();
    } catch (err) {
      const message = err instanceof Error ? err.message : 'Failed to add todo item';
      setError(message);
      throw err;
    } finally {
      setIsLoading(false);
    }
  }, [todoEntityId, fetchItems]);

  const completeItem = useCallback(async (uid: string) => {
    if (!todoEntityId) return;

    setIsLoading(true);
    setError(null);

    try {
      // Find the item to get its summary
      const item = items.find((i) => i.uid === uid);
      if (!item) {
        throw new Error('Item not found');
      }

      await haConnection.callService(
        'todo',
        'update_item',
        { item: item.summary, status: 'completed' },
        { entity_id: todoEntityId }
      );

      // Refresh items
      await fetchItems();
    } catch (err) {
      const message = err instanceof Error ? err.message : 'Failed to complete todo item';
      setError(message);
      throw err;
    } finally {
      setIsLoading(false);
    }
  }, [todoEntityId, items, fetchItems]);

  const uncompleteItem = useCallback(async (uid: string) => {
    if (!todoEntityId) return;

    setIsLoading(true);
    setError(null);

    try {
      const item = items.find((i) => i.uid === uid);
      if (!item) {
        throw new Error('Item not found');
      }

      await haConnection.callService(
        'todo',
        'update_item',
        { item: item.summary, status: 'needs_action' },
        { entity_id: todoEntityId }
      );

      // Refresh items
      await fetchItems();
    } catch (err) {
      const message = err instanceof Error ? err.message : 'Failed to uncomplete todo item';
      setError(message);
      throw err;
    } finally {
      setIsLoading(false);
    }
  }, [todoEntityId, items, fetchItems]);

  const removeItem = useCallback(async (uid: string) => {
    if (!todoEntityId) return;

    setIsLoading(true);
    setError(null);

    try {
      const item = items.find((i) => i.uid === uid);
      if (!item) {
        throw new Error('Item not found');
      }

      await haConnection.callService(
        'todo',
        'remove_item',
        { item: item.summary },
        { entity_id: todoEntityId }
      );

      // Refresh items
      await fetchItems();
    } catch (err) {
      const message = err instanceof Error ? err.message : 'Failed to remove todo item';
      setError(message);
      throw err;
    } finally {
      setIsLoading(false);
    }
  }, [todoEntityId, items, fetchItems]);

  const clearError = useCallback(() => setError(null), []);

  // Computed values
  const activeItems = items.filter((item) => item.status === 'needs_action');
  const completedItems = items.filter((item) => item.status === 'completed');

  return {
    // State
    items,
    activeItems,
    completedItems,
    isLoading,
    error,

    // Actions
    fetchItems,
    addItem,
    completeItem,
    uncompleteItem,
    removeItem,
    clearError,
  };
}