import { useState, useEffect } from 'react';
import type { ProjectData } from '@/types/project';
import { DEMO_PROJECTS } from '@/lib/demoData';

const STORAGE_KEY = 'projectDashboardData';
const TIMESTAMP_KEY = 'projectDashboardLastUpdated';

/**
 * Custom hook for managing project data persistence in localStorage
 * Provides auto-save, auto-load, and clear functionality
 */
export function usePersistence() {
  const [projects, setProjects] = useState<ProjectData[]>([]);
  const [lastUpdated, setLastUpdated] = useState<string | null>(null);
  const [isLoaded, setIsLoaded] = useState(false);

  // Auto-load data on mount
  useEffect(() => {
    loadData();
  }, []);

  /**
   * Load data from localStorage
   * If no data exists, automatically load demo data
   */
  const loadData = () => {
    try {
      const savedData = localStorage.getItem(STORAGE_KEY);
      const savedTimestamp = localStorage.getItem(TIMESTAMP_KEY);
      
      if (savedData) {
        const parsedData = JSON.parse(savedData) as ProjectData[];
        setProjects(parsedData);
        setLastUpdated(savedTimestamp);
      } else {
        // Auto-load demo data for first-time visitors
        setProjects(DEMO_PROJECTS);
        setLastUpdated(null);
      }
    } catch (error) {
      console.error('Failed to load data from localStorage:', error);
      // Fallback to demo data on error
      setProjects(DEMO_PROJECTS);
      setLastUpdated(null);
    } finally {
      setIsLoaded(true);
    }
  };

  /**
   * Save data to localStorage with timestamp
   */
  const saveData = (data: ProjectData[]) => {
    try {
      const timestamp = new Date().toISOString();
      localStorage.setItem(STORAGE_KEY, JSON.stringify(data));
      localStorage.setItem(TIMESTAMP_KEY, timestamp);
      
      setProjects(data);
      setLastUpdated(timestamp);
    } catch (error) {
      console.error('Failed to save data to localStorage:', error);
      throw error;
    }
  };

  /**
   * Clear all data from localStorage
   */
  const clearData = () => {
    try {
      localStorage.removeItem(STORAGE_KEY);
      localStorage.removeItem(TIMESTAMP_KEY);
      
      setProjects([]);
      setLastUpdated(null);
    } catch (error) {
      console.error('Failed to clear data from localStorage:', error);
      throw error;
    }
  };

  /**
   * Get formatted last updated time
   */
  const getLastUpdatedFormatted = (): string => {
    if (!lastUpdated) return '暂无数据';
    
    try {
      const date = new Date(lastUpdated);
      const year = date.getFullYear();
      const month = String(date.getMonth() + 1).padStart(2, '0');
      const day = String(date.getDate()).padStart(2, '0');
      const hours = String(date.getHours()).padStart(2, '0');
      const minutes = String(date.getMinutes()).padStart(2, '0');
      
      return `${year}-${month}-${day} ${hours}:${minutes}`;
    } catch {
      return '暂无数据';
    }
  };

  return {
    projects,
    lastUpdated,
    isLoaded,
    hasData: projects.length > 0,
    saveData,
    clearData,
    getLastUpdatedFormatted,
  };
}