// src/components/HomeFeed.jsx

import React, { useState, useEffect, useCallback } from 'react'
import { useNavigate } from 'react-router-dom'
import { ThumbsUp } from 'lucide-react'
import { fetchPosts, fetchPost } from '../api/posts_wzy'
import { searchAPI } from '../api/search_jwlll'
import { getUserInfo } from '../utils/auth'
import '../style/HomeFeed.css'

const categories = [
  '推荐','穿搭','美食','彩妆','影视',
  '职场','情感','家居','游戏','旅行','健身'
]

const recommendModes = [
  { label: '标签推荐', value: 'tag' },
  { label: '协同过滤推荐', value: 'cf' }
]

const DEFAULT_USER_ID = '3' // 确保数据库有此用户（作为回退值）
const DEFAULT_TAGS = ['美食','影视','穿搭'] // 可根据实际数据库调整

export default function HomeFeed() {
  const navigate = useNavigate()
  
  // 获取当前用户ID，如果未登录则使用默认值
  const getCurrentUserId = () => {
    const userInfo = getUserInfo()
    return userInfo?.id ? String(userInfo.id) : DEFAULT_USER_ID
  }
  const [activeCat, setActiveCat] = useState('推荐')
  const [items, setItems]         = useState([])
  const [loading, setLoading]     = useState(true)
  const [error, setError]         = useState(null)
    // JWLLL 搜索推荐相关状态
  const [search, setSearch] = useState('')
  const [recMode, setRecMode] = useState('tag')
  const [recCFNum, setRecCFNum] = useState(20)
  const [useSearchRecommend, setUseSearchRecommend] = useState(false) // 是否使用搜索推荐模式  // JWLLL 搜索推荐功能函数
  
  // JWLLL搜索推荐内容
  const fetchSearchContent = useCallback(async (keyword = '') => {
    setLoading(true)
    setError(null)
    try {
      const data = await searchAPI.search(keyword || activeCat, activeCat === '推荐' ? undefined : activeCat)
      const formattedItems = (data.results || []).map(item => ({
        id: item.id,
        title: item.title,
        author: item.author || '佚名',
        avatar: `https://i.pravatar.cc/40?img=${item.id}`,
        img: item.img || '', 
        likes: item.heat || 0,
        content: item.content
      }))
      setItems(formattedItems)
    } catch (e) {
      console.error('搜索失败:', e)
      setError('搜索失败')
      setItems([])
    }
    setLoading(false)
  }, [activeCat])
  // 标签推荐
  const fetchTagRecommend = useCallback(async (tags) => {
    setLoading(true)
    setError(null)
    try {
      const currentUserId = getCurrentUserId()
      const data = await searchAPI.recommendByTags(currentUserId, tags)
      const formattedItems = (data.recommendations || []).map(item => ({
        id: item.id,
        title: item.title,
        author: item.author || '佚名',
        avatar: `https://i.pravatar.cc/40?img=${item.id}`,
        img: item.img || '', 
        likes: item.heat || 0,
        content: item.content
      }))
      setItems(formattedItems)
    } catch (e) {
      console.error('标签推荐失败:', e)
      setError('标签推荐失败')
      setItems([])
    }
    setLoading(false)
  }, [])
  // 协同过滤推荐
  const fetchCFRecommend = useCallback(async (topN = recCFNum) => {
    setLoading(true)
    setError(null)
    try {
      const currentUserId = getCurrentUserId()
      const data = await searchAPI.userBasedRecommend(currentUserId, topN)
      const formattedItems = (data.recommendations || []).map(item => ({
        id: item.id,
        title: item.title,
        author: item.author || '佚名',
        avatar: `https://i.pravatar.cc/40?img=${item.id}`,
        img: item.img || '', 
        likes: item.heat || 0,
        content: item.content
      }))
      setItems(formattedItems)
    } catch (e) {
      console.error('协同过滤推荐失败:', e)
      setError('协同过滤推荐失败')
      setItems([])
    }
    setLoading(false)
  }, [recCFNum])
  // 获取用户兴趣标签后再推荐
  const fetchUserTagsAndRecommend = useCallback(async () => {
    setLoading(true)
    setError(null)
    let tags = []
    try {
      const currentUserId = getCurrentUserId()
      const data = await searchAPI.getUserTags(currentUserId)
      tags = Array.isArray(data.tags) && data.tags.length > 0 ? data.tags : DEFAULT_TAGS
    } catch {
      tags = DEFAULT_TAGS
    }
    if (recMode === 'tag') {
      await fetchTagRecommend(tags)
    } else {
      await fetchCFRecommend()
    }
    setLoading(false)
  }, [recMode, fetchTagRecommend, fetchCFRecommend])

  useEffect(() => {
    // 原始数据加载函数
    const loadPosts = async () => {
      try {
        const list = await fetchPosts()  // [{id, title, heat, created_at}, …]
        // 为了拿到 media_urls 和 user_id，这里再拉详情
        const detailed = await Promise.all(
          list.map(async p => {
            const d = await fetchPost(p.id)
            return {
              id:     d.id,
              title:  d.title,
              author: `作者 ${d.user_id}`,
              avatar: `https://i.pravatar.cc/40?img=${d.user_id}`,
              img:    d.media_urls?.[0] || '', // 用第一张媒体作为封面
              likes:  d.heat
            }
          })
        )
        setItems(detailed)
      } catch (e) {
        setError(e.message)
      } finally {
        setLoading(false)
      }
    }

    // 根据模式选择加载方式
    if (activeCat === '推荐' && useSearchRecommend) {
      fetchUserTagsAndRecommend()
    } else {
      loadPosts()
    }
  }, [activeCat, useSearchRecommend, fetchUserTagsAndRecommend])
  // 切换推荐模式时的额外处理
  useEffect(() => {
    if (activeCat === '推荐' && useSearchRecommend) {
      fetchUserTagsAndRecommend()
    }
    // eslint-disable-next-line
  }, [recMode, fetchUserTagsAndRecommend])

  // 根据模式选择不同的加载方式
  const handleSearch = e => {
    e.preventDefault()
    if (useSearchRecommend) {
      fetchSearchContent(search)
    } else {
      // 切换到搜索推荐模式
      setUseSearchRecommend(true)
      fetchSearchContent(search)
    }
  }

  const handlePostClick = (postId) => {
    navigate(`/post/${postId}`)
  }
  return (
    <div className="home-feed">
      {/* 数据源切换 */}
      <div style={{marginBottom:12, display:'flex', alignItems:'center', gap:16}}>
        <span>数据源：</span>
        <div style={{display:'flex', gap:8}}>
          <button
            className={!useSearchRecommend ? 'rec-btn styled active' : 'rec-btn styled'}
            onClick={() => {setUseSearchRecommend(false); setActiveCat('推荐')}}
            type="button"
            style={{
              borderRadius: 20,
              padding: '4px 18px',
              border: !useSearchRecommend ? '2px solid #e84c4a' : '1px solid #ccc',
              background: !useSearchRecommend ? '#fff0f0' : '#fff',
              color: !useSearchRecommend ? '#e84c4a' : '#333',
              fontWeight: !useSearchRecommend ? 600 : 400,
              cursor: 'pointer',
              transition: 'all 0.2s',
              outline: 'none',
            }}
          >原始数据</button>
          <button
            className={useSearchRecommend ? 'rec-btn styled active' : 'rec-btn styled'}
            onClick={() => {setUseSearchRecommend(true); setActiveCat('推荐')}}
            type="button"
            style={{
              borderRadius: 20,
              padding: '4px 18px',
              border: useSearchRecommend ? '2px solid #e84c4a' : '1px solid #ccc',
              background: useSearchRecommend ? '#fff0f0' : '#fff',
              color: useSearchRecommend ? '#e84c4a' : '#333',
              fontWeight: useSearchRecommend ? 600 : 400,
              cursor: 'pointer',
              transition: 'all 0.2s',
              outline: 'none',
            }}
          >智能推荐</button>
        </div>
      </div>

      {/* 推荐模式切换，仅在推荐页显示且使用搜索推荐时 */}
      {activeCat === '推荐' && useSearchRecommend && (
        <div style={{marginBottom:12, display:'flex', alignItems:'center', gap:16}}>
          <span style={{marginRight:8}}>推荐模式：</span>
          <div style={{display:'flex', gap:8}}>
            {recommendModes.map(m => (
              <button
                key={m.value}
                className={recMode===m.value? 'rec-btn styled active':'rec-btn styled'}
                onClick={() => setRecMode(m.value)}
                type="button"
                style={{
                  borderRadius: 20,
                  padding: '4px 18px',
                  border: recMode===m.value ? '2px solid #e84c4a' : '1px solid #ccc',
                  background: recMode===m.value ? '#fff0f0' : '#fff',
                  color: recMode===m.value ? '#e84c4a' : '#333',
                  fontWeight: recMode===m.value ? 600 : 400,
                  cursor: 'pointer',
                  transition: 'all 0.2s',
                  outline: 'none',
                }}
              >{m.label}</button>
            ))}
          </div>
          {/* 协同过滤推荐数量选择 */}
          {recMode === 'cf' && (
            <div style={{display:'flex',alignItems:'center',gap:4}}>
              <span>推荐数量：</span>
              <select value={recCFNum} onChange={e => { setRecCFNum(Number(e.target.value)); fetchCFRecommend(Number(e.target.value)) }} style={{padding:'2px 8px',borderRadius:6,border:'1px solid #ccc'}}>
                {[10, 20, 30, 50].map(n => <option key={n} value={n}>{n}</option>)}
              </select>
            </div>
          )}
        </div>
      )}

      {/* 搜索栏 */}
      <form className="feed-search" onSubmit={handleSearch} style={{marginBottom:16, display:'flex', gap:8, alignItems:'center'}}>
        <input
          type="text"
          className="search-input"
          placeholder="搜索内容/标题/标签"
          value={search}
          onChange={e => setSearch(e.target.value)}
        />
        <button type="submit" className="search-btn">搜索</button>
      </form>

      {/* 顶部分类 */}
      <nav className="feed-tabs">
        {categories.map(cat => (
          <button
            key={cat}
            className={cat === activeCat ? 'tab active' : 'tab'}
            onClick={() => { 
              setActiveCat(cat); 
              setSearch('');
              if (useSearchRecommend) {
                if (cat === '推荐') {
                  fetchUserTagsAndRecommend()
                } else {
                  fetchSearchContent()
                }
              }
            }}
          >
            {cat}
          </button>
        ))}
      </nav>      {/* 状态提示 */}
      {loading ? (
        <div className="loading">加载中…</div>
      ) : error ? (
        <div className="error">加载失败：{error}</div>
      ) : (
        /* 瀑布流卡片区 */
        <div className="feed-grid">
          {items.length === 0 ? (
            <div style={{padding:32, color:'#aaa'}}>暂无内容</div>
          ) : (
            items.map(item => (
              <div key={item.id} className="feed-card" onClick={() => handlePostClick(item.id)}>
                {item.img && <img className="card-img" src={item.img} alt={item.title} />}
                <h3 className="card-title">{item.title}</h3>
                {item.content && <div className="card-content">{item.content.slice(0, 60) || ''}</div>}
                <div className="card-footer">
                  <div className="card-author">
                    <img className="avatar" src={item.avatar} alt={item.author} />
                    <span className="username">{item.author}</span>
                  </div>
                  <div className="card-likes">
                    <ThumbsUp size={16} />
                    <span className="likes-count">{item.likes}</span>
                  </div>
                </div>
              </div>
            ))
          )}
        </div>
      )}
    </div>
  )
}