import React, { useState, useEffect } from 'react';
import { Link } from 'wouter';
import axios from 'axios';
import logo from '../../assets/logo.png';
import Recommend from './Recommend/Recommend';
import './SeedList.css';

const API_BASE = process.env.REACT_APP_API_BASE;

const SeedList = () => {
    const [seeds, setSeeds] = useState([]);
    const [filteredSeeds, setFilteredSeeds] = useState([]);
    const [loading, setLoading] = useState(true);
    const [searchTerm, setSearchTerm] = useState('');
    const [sortOption, setSortOption] = useState('最新');
    const [activeTab, setActiveTab] = useState('种子列表');
    const [filters, setFilters] = useState({});
    const [selectedFilters, setSelectedFilters] = useState({});
    const [tagMode, setTagMode] = useState('all');
    const [errorMsg, setErrorMsg] = useState('');

    const TAGS = ['猜你喜欢', '电影', '电视剧', '动漫', '音乐', '游戏', '综艺', '软件', '体育', '学习', '纪录片', '其他'];

    const CATEGORY_MAP = {
        '电影': 'movie',
        '电视剧': 'tv',
        '动漫': 'anime',
        '音乐': 'music',
        '游戏': 'game',
        '综艺': 'variety',
        '软件': 'software',
        '体育': 'sports',
        '学习': 'education',
        '纪录片': 'documentary',
        '其他': 'other'
    };

    const buildQueryParams = () => {
        const category = CATEGORY_MAP[activeTab];
        const params = {
            category,
            sort_by: sortOption === '最新' ? 'newest' : sortOption === '最热' ? 'downloads' : undefined,
            page: 1,
            limit: 20,
            include_fields: 'seed_id,title,category,tags,size,upload_time,downloads,image_url',
        };

        if (searchTerm.trim()) params.search = searchTerm.trim();

        const tags = Object.entries(selectedFilters)
            .filter(([_, value]) => value !== '不限')
            .map(([_, value]) => value);

        if (tags.length > 0) {
            params.tags = tags.join(',');
            params.tag_mode = tagMode;
        }

        return params;
    };

    const fetchSeeds = async () => {
        setLoading(true);
        setErrorMsg('');
        try {
            const params = buildQueryParams();
            const queryString = new URLSearchParams(params).toString();
            const response = await fetch(`${API_BASE}/echo/seeds?${queryString}`);
            const data = await response.json();

            if (data.status !== 'success') throw new Error(data.message || '获取失败');
            const seeds = data.seeds || [];
            setSeeds(seeds);
            setFilteredSeeds(seeds);
        } catch (error) {
            console.error('获取种子列表失败:', error);
            setErrorMsg(error.message || '获取失败，请稍后再试。');
            setSeeds([]);
            setFilteredSeeds([]);
        } finally {
            setLoading(false);
        }
    };

    const fetchFilterOptions = async () => {
        if (activeTab === '猜你喜欢') return;
        const category = CATEGORY_MAP[activeTab];
        try {
            const res = await axios.get(`${API_BASE}/echo/seed-filters?category=${category}`);
            const filterData = res.data || {};
            setFilters(filterData);

            const defaultSelections = {};
            for (const key in filterData) {
                defaultSelections[key] = '不限';
            }
            setSelectedFilters(defaultSelections);
        } catch (err) {
            console.error('获取筛选项失败:', err);
            setFilters({});
            setSelectedFilters({});
        }
    };

    useEffect(() => {
        if (activeTab !== '猜你喜欢') {
            fetchFilterOptions();
        }
    }, [activeTab]);

    useEffect(() => {
        if (activeTab !== '猜你喜欢') {
            fetchSeeds();
        }
    }, [activeTab, sortOption, selectedFilters, tagMode, searchTerm]);

    const handleDownload = async (seedId) => {
        const peer_id = 'echo-' + Math.random().toString(36).substring(2, 10);
        const ip = '127.0.0.1';
        const port = 6881;
        const uploaded = 0;
        const downloaded = 0;
        const left = 0;

        try {
            const response = await axios.get(`${API_BASE}/echo/seeds/${seedId}/download`, {
                params: { peer_id, ip, port, uploaded, downloaded, left },
                responseType: 'blob'
            });

            const blob = new Blob([response.data], { type: 'application/x-bittorrent' });
            const downloadUrl = URL.createObjectURL(blob);
            const a = document.createElement('a');
            a.href = downloadUrl;
            a.download = `${seedId}.torrent`;
            a.click();
            URL.revokeObjectURL(downloadUrl);
        } catch (error) {
            console.error('下载失败:', error);
            alert('下载失败，请稍后再试。');
        }
    };

    const handleFilterChange = (key, value) => {
        setSelectedFilters((prev) => ({
            ...prev,
            [key]: value
        }));
    };

    const clearFilter = (key) => {
        setSelectedFilters((prev) => ({
            ...prev,
            [key]: '不限'
        }));
    };

    return (
        <div className="main-page">
            <header className="header">
                <div className="logo-and-name">
                    <img src={logo} alt="网站logo" className="logo" />
                    <span className="site-name">Echo</span>
                </div>
                <div className="user-and-message">
                    <img src="user-avatar.png" alt="用户头像" className="user-avatar" />
                    <span className="message-center">消息</span>
                </div>
            </header>

            <nav className="nav">
                <Link to="/friend-moments" className="nav-item">好友动态</Link>
                <Link to="/forum" className="nav-item">论坛</Link>
                <Link to="/interest-groups" className="nav-item">兴趣小组</Link>
                <Link to="/seed-list" className="nav-item active">种子列表</Link>
                <Link to="/publish-seed" className="nav-item">发布种子</Link>
            </nav>

            <div className="controls">
                <input
                    type="text"
                    placeholder="搜索种子..."
                    value={searchTerm}
                    onChange={(e) => setSearchTerm(e.target.value)}
                    className="search-input"
                />
                <select value={sortOption} onChange={(e) => setSortOption(e.target.value)} className="sort-select">
                    <option value="最新">最新</option>
                    <option value="最热">最热</option>
                </select>
                <select value={tagMode} onChange={(e) => setTagMode(e.target.value)} className="tag-mode-select">
                    <option value="any">包含任意标签</option>
                    <option value="all">包含所有标签</option>
                </select>
            </div>

            <div className="tag-filters">
                {TAGS.map((tag) => (
                    <button
                        key={tag}
                        className={`tag-button ${activeTab === tag ? 'active-tag' : ''}`}
                        onClick={() => {
                            setActiveTab(tag);
                            setFilters({});
                            setSelectedFilters({});
                        }}
                    >
                        {tag}
                    </button>
                ))}
            </div>

            {activeTab !== '猜你喜欢' && Object.keys(filters).length > 0 && (
                <div className="filter-bar">
                    {Object.entries(filters).map(([key, options]) => (
                        <div className="filter-group" key={key}>
                            <label>{key}:</label>
                            <select
                                value={selectedFilters[key]}
                                onChange={(e) => handleFilterChange(key, e.target.value)}
                            >
                                {options.map((opt) => (
                                    <option key={opt} value={opt}>{opt}</option>
                                ))}
                            </select>
                            {selectedFilters[key] !== '不限' && (
                                <button className="clear-filter-btn" onClick={() => clearFilter(key)}>✕</button>
                            )}
                        </div>
                    ))}
                </div>
            )}

            <div className="seed-list-content">
                {activeTab === '猜你喜欢' ? (
                    <Recommend />
                ) : loading ? (
                    <p>加载中...</p>
                ) : errorMsg ? (
                    <p className="error-text">{errorMsg}</p>
                ) : filteredSeeds.length === 0 ? (
                    <p>未找到符合条件的种子。</p>
                ) : (
                    <div className="seed-cards">
                        {filteredSeeds.map((seed, index) => (
                            <div key={index} className="seed-card">
                                {seed.image_url && (
                                    <img src={seed.image_url} alt={seed.title} className="seed-cover" />
                                )}
                                <div className="seed-card-header">
                                    <h3>{seed.title}</h3>
                                </div>

                                <div className="seed-card-body">
                                    <div className="seed-info">
                                        <span>{seed.size || '未知'} GB</span>
                                        <span>{seed.upload_time?.split('T')[0] || '未知'}</span>
                                        <span>{seed.downloads ?? 0} 次下载</span>
                                    </div>
                                    {seed.tags && seed.tags.length > 0 && (
                                        <div className="seed-card-tags">
                                            {seed.tags.map((tag, i) => (
                                                <span key={i} className="tag-label">{tag}</span>
                                            ))}
                                        </div>
                                    )}
                                </div>

                                <div className="seed-card-actions">
                                    <button className="btn-primary" onClick={() => handleDownload(seed.seed_id)}>下载</button>
                                    <Link href={`/seed/${seed.seed_id}`} className="btn-secondary">详情</Link>
                                    <button className="btn-outline">收藏</button>
                                </div>
                            </div>
                        ))}
                    </div>
                )}
            </div>
        </div>
    );
};

export default SeedList;