const express = require('express');
const router = express.Router();
const db = require('../db');
const { authenticate } = require('../middleware/auth');

function generateCode(prefix) {
  const now = new Date();
  const dateStr = now.getFullYear().toString() +
    (now.getMonth() + 1).toString().padStart(2, '0') +
    now.getDate().toString().padStart(2, '0');
  const rand = Math.floor(Math.random() * 10000).toString().padStart(4, '0');
  return `${prefix}-${dateStr}-${rand}`;
}

router.get('/', authenticate, async (req, res) => {
  try {
    const {
      txn_type, category_level1, category_level2,
      project_id, user_id, source,
      date_from, date_to,
      page = 1, pageSize = 50
    } = req.query;

    let sql = 'SELECT fr.*, p.name as project_name FROM financial_records fr LEFT JOIN projects p ON fr.project_id = p.id WHERE 1=1';
    const params = [];
    let paramIdx = 1;

    if (txn_type) { params.push(txn_type); sql += ` AND fr.txn_type = $${paramIdx++}`; }
    if (category_level1) { params.push(category_level1); sql += ` AND fr.category_level1 = $${paramIdx++}`; }
    if (category_level2) { params.push(category_level2); sql += ` AND fr.category_level2 = $${paramIdx++}`; }
    if (project_id) { params.push(project_id); sql += ` AND fr.project_id = $${paramIdx++}`; }
    if (user_id) { params.push(user_id); sql += ` AND fr.user_id = $${paramIdx++}`; }
    if (source) { params.push(source); sql += ` AND fr.source = $${paramIdx++}`; }
    if (date_from) { params.push(date_from); sql += ` AND fr.record_date >= $${paramIdx++}`; }
    if (date_to) { params.push(date_to); sql += ` AND fr.record_date <= $${paramIdx++}`; }

    const countResult = await db.query(`SELECT COUNT(*) as total FROM (${sql}) sub`, params);
    const total = parseInt(countResult.rows[0].total);

    sql += ' ORDER BY fr.record_date DESC, fr.created_at DESC';
    const offset = (parseInt(page) - 1) * parseInt(pageSize);
    params.push(parseInt(pageSize));
    sql += ` LIMIT $${paramIdx++}`;
    params.push(offset);
    sql += ` OFFSET $${paramIdx++}`;

    const result = await db.query(sql, params);
    res.json({
      success: true,
      data: result.rows,
      pagination: {
        page: parseInt(page),
        pageSize: parseInt(pageSize),
        total,
        totalPages: Math.ceil(total / parseInt(pageSize))
      }
    });
  } catch (error) {
    console.error('查询财务记录失败:', error);
    res.status(500).json({ success: false, message: '查询财务记录失败' });
  }
});

router.get('/summary', authenticate, async (req, res) => {
  try {
    const { project_id, date_from, date_to } = req.query;
    let where = "WHERE status != 'voided'";
    const params = [];
    let paramIdx = 1;

    if (project_id) { params.push(project_id); where += ` AND project_id = $${paramIdx++}`; }
    if (date_from) { params.push(date_from); where += ` AND record_date >= $${paramIdx++}`; }
    if (date_to) { params.push(date_to); where += ` AND record_date <= $${paramIdx++}`; }

    const totalResult = await db.query(
      `SELECT
        COALESCE(SUM(CASE WHEN txn_type = 'income' THEN amount_cny ELSE 0 END), 0) as total_income,
        COALESCE(SUM(CASE WHEN txn_type = 'expense' THEN amount_cny ELSE 0 END), 0) as total_expense,
        COALESCE(SUM(CASE WHEN txn_type = 'income' THEN amount_cny ELSE -amount_cny END), 0) as net_profit
       FROM financial_records ${where}`,
      params
    );

    const byCategory = await db.query(
      `SELECT category_level1, category_level2,
        COALESCE(SUM(amount_cny), 0) as total_amount,
        COUNT(*) as count
       FROM financial_records ${where}
       GROUP BY category_level1, category_level2
       ORDER BY category_level1, total_amount DESC`,
      params
    );

    const byMonth = await db.query(
      `SELECT TO_CHAR(record_date, 'YYYY-MM') as month,
        COALESCE(SUM(CASE WHEN txn_type = 'income' THEN amount_cny ELSE 0 END), 0) as income,
        COALESCE(SUM(CASE WHEN txn_type = 'expense' THEN amount_cny ELSE 0 END), 0) as expense
       FROM financial_records ${where}
       GROUP BY TO_CHAR(record_date, 'YYYY-MM')
       ORDER BY month`,
      params
    );

    res.json({
      success: true,
      data: {
        totals: totalResult.rows[0],
        byCategory: byCategory.rows,
        byMonth: byMonth.rows
      }
    });
  } catch (error) {
    console.error('获取财务汇总失败:', error);
    res.status(500).json({ success: false, message: '获取财务汇总失败' });
  }
});

router.get('/project-profit/:projectId', authenticate, async (req, res) => {
  try {
    const { projectId } = req.params;
    const projectResult = await db.query('SELECT * FROM projects WHERE id = $1', [projectId]);
    if (projectResult.rows.length === 0) {
      return res.status(404).json({ success: false, message: '项目不存在' });
    }
    const project = projectResult.rows[0];

    const incomeResult = await db.query(
      `SELECT COALESCE(SUM(amount_cny), 0) as total
       FROM financial_records WHERE project_id = $1 AND txn_type = 'income' AND status != 'voided'`,
      [projectId]
    );
    const expenseResult = await db.query(
      `SELECT COALESCE(SUM(amount_cny), 0) as total
       FROM financial_records WHERE project_id = $1 AND txn_type = 'expense' AND status != 'voided'`,
      [projectId]
    );

    const expenseByCategory = await db.query(
      `SELECT category_level2, COALESCE(SUM(amount_cny), 0) as total_amount, COUNT(*) as count
       FROM financial_records
       WHERE project_id = $1 AND txn_type = 'expense' AND status != 'voided'
       GROUP BY category_level2 ORDER BY total_amount DESC`,
      [projectId]
    );

    const expenseByUser = await db.query(
      `SELECT user_name, COALESCE(SUM(amount_cny), 0) as total_amount, COUNT(*) as count
       FROM financial_records
       WHERE project_id = $1 AND txn_type = 'expense' AND status != 'voided' AND user_id IS NOT NULL
       GROUP BY user_name ORDER BY total_amount DESC`,
      [projectId]
    );

    const totalIncome = parseFloat(incomeResult.rows[0].total);
    const totalExpense = parseFloat(expenseResult.rows[0].total);
    const contractAmount = parseFloat(project.contract_amount || 0);

    res.json({
      success: true,
      data: {
        project_name: project.name,
        contract_amount: contractAmount,
        total_income: totalIncome,
        total_expense: totalExpense,
        gross_profit: totalIncome - totalExpense,
        gross_margin: totalIncome > 0 ? ((totalIncome - totalExpense) / totalIncome * 100).toFixed(2) : 0,
        expense_by_category: expenseByCategory.rows,
        expense_by_user: expenseByUser.rows
      }
    });
  } catch (error) {
    console.error('获取项目利润失败:', error);
    res.status(500).json({ success: false, message: '获取项目利润失败' });
  }
});

router.post('/', authenticate, async (req, res) => {
  try {
    const {
      txn_type, category_level1, category_level2,
      project_id, user_id, user_name,
      amount_original, currency, exchange_rate, amount_cny,
      record_date,
      counterparty_name, counterparty_type, counterparty_id,
      source, source_id, source_code,
      description, voucher_no, attachments
    } = req.body;

    if (!txn_type || !category_level1 || !category_level2 || !amount_original || !record_date) {
      return res.status(400).json({ success: false, message: '缺少必填字段' });
    }

    const record_code = generateCode('FIN');
    const calculated_amount_cny = amount_cny || (parseFloat(amount_original) * parseFloat(exchange_rate || 1));

    const result = await db.query(
      `INSERT INTO financial_records
       (record_code, txn_type, category_level1, category_level2,
        project_id, user_id, user_name,
        amount_original, currency, exchange_rate, amount_cny,
        record_date, counterparty_name, counterparty_type, counterparty_id,
        source, source_id, source_code,
        description, voucher_no, attachments)
       VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16,$17,$18,$19,$20,$21)
       RETURNING *`,
      [record_code, txn_type, category_level1, category_level2,
        project_id || null, user_id || null, user_name || null,
        amount_original, currency || 'CNY', exchange_rate || 1, calculated_amount_cny,
        record_date,
        counterparty_name || null, counterparty_type || null, counterparty_id || null,
        source || 'manual', source_id || null, source_code || null,
        description || null, voucher_no || null, attachments || null]
    );

    res.json({ success: true, data: result.rows[0] });
  } catch (error) {
    console.error('创建财务记录失败:', error);
    res.status(500).json({ success: false, message: '创建财务记录失败' });
  }
});

router.post('/batch', authenticate, async (req, res) => {
  try {
    if (req.user.role !== 'admin') {
      return res.status(403).json({ success: false, message: '无权限操作' });
    }

    const { records } = req.body;
    if (!Array.isArray(records) || records.length === 0) {
      return res.status(400).json({ success: false, message: '没有可导入的记录' });
    }

    const results = [];
    const errors = [];

    for (let i = 0; i < records.length; i++) {
      const r = records[i];
      try {
        if (!r.txn_type || !r.category_level1 || !r.category_level2 || !r.amount_original || !r.record_date) {
          errors.push({ row: i + 1, message: '缺少必填字段' });
          continue;
        }

        const record_code = generateCode('FIN');
        const calculated_amount_cny = r.amount_cny || (parseFloat(r.amount_original) * parseFloat(r.exchange_rate || 1));

        let projectId = r.project_id || null;
        if (!projectId && r.project_name) {
          const projResult = await db.query("SELECT id FROM projects WHERE name = $1", [r.project_name]);
          if (projResult.rows.length > 0) {
            projectId = projResult.rows[0].id;
          }
        }

        let userId = r.user_id || null;
        if (!userId && r.user_name) {
          const userResult = await db.query("SELECT id FROM users WHERE name = $1", [r.user_name]);
          if (userResult.rows.length > 0) {
            userId = userResult.rows[0].id;
          }
        }

        const result = await db.query(
          `INSERT INTO financial_records
           (record_code, txn_type, category_level1, category_level2,
            project_id, user_id, user_name,
            amount_original, currency, exchange_rate, amount_cny,
            record_date, counterparty_name, counterparty_type, counterparty_id,
            source, source_id, source_code,
            description, voucher_no)
           VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16,$17,$18,$19,$20)
           RETURNING *`,
          [record_code, r.txn_type, r.category_level1, r.category_level2,
            projectId, userId, r.user_name || null,
            r.amount_original, r.currency || 'CNY', r.exchange_rate || 1, calculated_amount_cny,
            r.record_date,
            r.counterparty_name || null, r.counterparty_type || null, r.counterparty_id || null,
            r.source || 'manual', r.source_id || null, r.source_code || null,
            r.description || null, r.voucher_no || null]
        );
        results.push(result.rows[0]);
      } catch (err) {
        errors.push({ row: i + 1, message: err.message });
      }
    }

    res.json({
      success: true,
      data: {
        imported: results.length,
        failed: errors.length,
        errors
      }
    });
  } catch (error) {
    console.error('批量导入失败:', error);
    res.status(500).json({ success: false, message: '批量导入失败' });
  }
});

router.put('/:id', authenticate, async (req, res) => {
  try {
    if (req.user.role !== 'admin') {
      return res.status(403).json({ success: false, message: '无权限操作' });
    }
    const { id } = req.params;
    const fields = req.body;
    const sets = [];
    const params = [];
    let idx = 1;

    const allowedFields = ['category_level1', 'category_level2', 'description', 'counterparty_name', 'counterparty_type', 'voucher_no', 'status'];
    for (const key of allowedFields) {
      if (fields[key] !== undefined) {
        params.push(fields[key]);
        sets.push(`${key} = $${idx++}`);
      }
    }

    if (sets.length === 0) {
      return res.status(400).json({ success: false, message: '没有可更新的字段' });
    }

    params.push(id);
    sets.push(`updated_at = CURRENT_TIMESTAMP`);
    const result = await db.query(
      `UPDATE financial_records SET ${sets.join(', ')} WHERE id = $${idx} RETURNING *`,
      params
    );
    if (result.rows.length === 0) {
      return res.status(404).json({ success: false, message: '记录不存在' });
    }
    res.json({ success: true, data: result.rows[0] });
  } catch (error) {
    console.error('更新财务记录失败:', error);
    res.status(500).json({ success: false, message: '更新财务记录失败' });
  }
});

module.exports = router;