import express from 'express';
import { promises as fs } from 'fs';
import path from 'path';

const app = express();
const PORT = process.env.PORT || 3001;
const SCORES_FILE = path.join(__dirname, 'scores.json');

// 分数数据类型
interface ScoreEntry {
    name: string;
    time: number;
    region: string;
    store: string;
    timestamp: number;
}

// 中间件
app.use(express.json());
app.use(express.static('dist')); // 服务静态文件

// 初始化分数文件
async function initScoresFile() {
    try {
        await fs.access(SCORES_FILE);
    } catch {
        // 文件不存在，创建空数组
        await fs.writeFile(SCORES_FILE, JSON.stringify([]));
    }
}

// 读取分数数据
async function readScores(): Promise<ScoreEntry[]> {
    try {
        const data = await fs.readFile(SCORES_FILE, 'utf-8');
        return JSON.parse(data);
    } catch {
        return [];
    }
}

// 写入分数数据
async function writeScores(scores: ScoreEntry[]): Promise<void> {
    await fs.writeFile(SCORES_FILE, JSON.stringify(scores, null, 2));
}

// POST /api/score - 提交分数
app.post('/api/score', async (req, res) => {
    try {
        const { region, store, name, time } = req.body;

        // 验证必要字段
        if (!region || !store || !name || typeof time !== 'number') {
            return res.status(400).json({ 
                error: '缺少必要字段: region, store, name, time' 
            });
        }

        // 验证时间值
        if (time <= 0) {
            return res.status(400).json({ 
                error: '时间必须大于0' 
            });
        }

        const scores = await readScores();
        
        // 创建新的分数记录
        const newScore: ScoreEntry = {
            name: String(name).trim(),
            time: Number(time),
            region: String(region).trim(),
            store: String(store).trim(),
            timestamp: Date.now()
        };

        // 检查是否已有相同用户的记录
        const existingIndex = scores.findIndex(
            score => score.name === newScore.name && 
                    score.region === newScore.region && 
                    score.store === newScore.store
        );

        if (existingIndex !== -1) {
            // 如果新时间更好（更短），则更新记录
            if (newScore.time < scores[existingIndex].time) {
                scores[existingIndex] = newScore;
            }
        } else {
            // 添加新记录
            scores.push(newScore);
        }

        await writeScores(scores);

        res.json({ 
            success: true, 
            message: '分数提交成功',
            score: newScore 
        });
    } catch (error) {
        console.error('提交分数时出错:', error);
        res.status(500).json({ 
            error: '服务器内部错误' 
        });
    }
});

// GET /api/score - 获取排行榜（前8名）
app.get('/api/score', async (req, res) => {
    try {
        const scores = await readScores();
        
        // 按时间排序（时间短的在前）并取前8名
        const leaderBoard = scores
            .sort((a, b) => a.time - b.time)
            .slice(0, 8)
            .map(score => ({
                name: score.name,
                time: score.time,
                region: score.region,
                store: score.store
            }));

        res.json(leaderBoard);
    } catch (error) {
        console.error('获取排行榜时出错:', error);
        res.status(500).json({ 
            error: '服务器内部错误' 
        });
    }
});

// GET /api/score/all - 获取所有分数（可选，用于管理）
app.get('/api/score/all', async (req, res) => {
    try {
        const scores = await readScores();
        res.json(scores.sort((a, b) => a.time - b.time));
    } catch (error) {
        console.error('获取所有分数时出错:', error);
        res.status(500).json({ 
            error: '服务器内部错误' 
        });
    }
});

// 健康检查端点
app.get('/api/health', (req, res) => {
    res.json({ 
        status: 'ok', 
        timestamp: new Date().toISOString() 
    });
});

// 处理 SPA 路由 - 将所有未匹配的路由返回 index.html
app.get('/*', (req, res) => {
    try {
        res.sendFile(path.join(__dirname, 'dist', 'index.html'));
    } catch (error) {
        res.status(404).send('Page not found');
    }
});

// 启动服务器
async function startServer() {
    await initScoresFile();
    
    app.listen(PORT, () => {
        console.log(`🚀 服务器运行在 http://localhost:${PORT}`);
        console.log(`📊 API 端点:`);
        console.log(`   POST /api/score - 提交分数`);
        console.log(`   GET  /api/score - 获取排行榜`);
        console.log(`   GET  /api/health - 健康检查`);
    });
}

startServer().catch(console.error);