const Transaction = require('../models/Transaction');
const Group = require('../models/Group');
const { pool } = require('../config/database');

// @desc    获取交易列表
// @route   GET /api/transactions
// @access  Private
const getTransactions = async (req, res) => {
    try {
        const { page = 1, limit = 10, startDate, endDate, type, groupId } = req.query;
        const result = await Transaction.findAll(
            { startDate, endDate, type, groupId },
            parseInt(page),
            parseInt(limit)
        );
        res.json(result);
    } catch (error) {
        res.status(500).json({ message: '服务器错误' });
    }
};

// @desc    创建交易
// @route   POST /api/transactions
// @access  Private
const createTransaction = async (req, res) => {
    try {
        const { groupId, type, amount } = req.body;
        const group = await Group.findByGroupId(groupId);

        if (!group) {
            return res.status(404).json({ message: '群组不存在' });
        }

        const id = await Transaction.create({
            groupId,
            groupName: group.group_name,
            type,
            amount
        });

        const transaction = await Transaction.findById(id);
        res.status(201).json(transaction);
    } catch (error) {
        res.status(500).json({ message: '服务器错误' });
    }
};

// @desc    删除交易
// @route   DELETE /api/transactions/:id
// @access  Private
const deleteTransaction = async (req, res) => {
    try {
        const transaction = await Transaction.findById(req.params.id);
        if (!transaction) {
            return res.status(404).json({ message: '交易不存在' });
        }

        await Transaction.delete(req.params.id);
        res.json({ message: '交易已删除' });
    } catch (error) {
        res.status(500).json({ message: '服务器错误' });
    }
};

// @desc    获取仪表板数据
// @route   GET /api/transactions/dashboard
// @access  Private
const getDashboardData = async (req, res) => {
    try {
        // 获取总群组数
        const [groupResult] = await pool.query('SELECT COUNT(*) as total FROM groups WHERE is_active = true');
        const totalGroups = groupResult[0].total;

        // 获取总交易数
        const [transactionResult] = await pool.query('SELECT COUNT(*) as total FROM transactions');
        const totalTransactions = transactionResult[0].total;

        // 获取总金额
        const [amountResult] = await pool.query(`
            SELECT 
                COALESCE(SUM(CASE WHEN type = 'deposit' THEN amount ELSE -amount END), 0) as total
            FROM transactions
        `);
        const totalAmount = parseFloat(amountResult[0].total) || 0;

        // 获取今日交易数
        const [todayResult] = await pool.query(`
            SELECT COUNT(*) as total 
            FROM transactions 
            WHERE DATE(time) = CURDATE()
        `);
        const todayTransactions = todayResult[0].total;

        // 获取最近交易
        const [recentTransactions] = await pool.query(`
            SELECT 
                t.*,
                u.username as operator_name,
                g.group_name
            FROM transactions t
            LEFT JOIN users u ON t.operator_id = u.id
            LEFT JOIN groups g ON t.group_id = g.group_id
            ORDER BY t.time DESC
            LIMIT 5
        `);

        // 获取活跃群组
        const [activeGroups] = await pool.query(`
            SELECT 
                g.group_id,
                g.group_name,
                COUNT(t.id) as totalTransactions,
                COUNT(CASE WHEN DATE(t.time) = CURDATE() THEN 1 END) as todayTransactions
            FROM groups g
            LEFT JOIN transactions t ON g.group_id = t.group_id
            WHERE g.is_active = true
            GROUP BY g.group_id, g.group_name
            ORDER BY todayTransactions DESC, totalTransactions DESC
            LIMIT 5
        `);

        res.json({
            totalGroups,
            totalTransactions,
            totalAmount,
            todayTransactions,
            recentTransactions,
            activeGroups
        });
    } catch (error) {
        console.error('获取仪表板数据失败:', error);
        res.status(500).json({ message: '服务器错误' });
    }
};

// @desc    导出交易数据
// @route   GET /api/transactions/export
// @access  Private
const exportTransactions = async (req, res) => {
    try {
        const { startDate, endDate, type, groupId } = req.query;
        const result = await Transaction.findAll(
            { startDate, endDate, type, groupId },
            1,
            1000000 // 导出所有数据
        );

        // 生成 CSV 数据
        const csvData = [
            ['时间', '群组', '类型', '金额'].join(','),
            ...result.transactions.map(t => [
                new Date(t.time).toLocaleString(),
                t.group_name,
                t.type === 'deposit' ? '入款' : '下发',
                t.amount.toFixed(2)
            ].join(','))
        ].join('\n');

        res.setHeader('Content-Type', 'text/csv');
        res.setHeader('Content-Disposition', 'attachment; filename=transactions.csv');
        res.send(csvData);
    } catch (error) {
        res.status(500).json({ message: '服务器错误' });
    }
};

module.exports = {
    getTransactions,
    createTransaction,
    deleteTransaction,
    getDashboardData,
    exportTransactions
};