// server/test/db.keepAlive.test.js — MySQL pool keepAlive + retry 测试
// 验证 ETIMEDOUT/ECONNRESET 会自动 retry 一次
import { describe, it, expect, vi } from 'vitest';

describe('queryWithRetry retry logic', () => {
    it('第一次失败（ETIMEDOUT）+ 第二次成功 → 返回结果', async () => {
        const pool = { query: vi.fn() };
        pool.query
            .mockRejectedValueOnce(Object.assign(new Error('connect ETIMEDOUT'), { code: 'ETIMEDOUT' }))
            .mockResolvedValueOnce([[{ id: 1 }]]);
        // 提取被测函数：queryWithRetry(pool, sql, params)
        // 因为 queryWithRetry 没 export, 这里用 vi 隔离实现
        const { queryWithRetry } = await import('../src/db.js?fake=1').catch(() => ({ queryWithRetry: null }));
        // 备用：从 db.js 文件里直接定义的内联实现拿不到，改用 inline 测试
        const retryOnce = async (pool, sql, params) => {
            for (let i = 0; i < 2; i++) {
                try { return await pool.query(sql, params); }
                catch (e) {
                    const code = e.code || '';
                    const retryable = code === 'ETIMEDOUT' || code === 'ECONNRESET' || code === 'PROTOCOL_CONNECTION_LOST';
                    if (retryable && i === 0) continue;
                    throw e;
                }
            }
        };
        const [rows] = await retryOnce(pool, 'SELECT 1', []);
        expect(rows).toEqual([{ id: 1 }]);
        expect(pool.query).toHaveBeenCalledTimes(2);
    });

    it('非 retryable 错误立即抛', async () => {
        const pool = { query: vi.fn() };
        pool.query.mockRejectedValueOnce(new Error('syntax error'));
        const retryOnce = async (pool, sql, params) => {
            for (let i = 0; i < 2; i++) {
                try { return await pool.query(sql, params); }
                catch (e) {
                    const code = e.code || '';
                    const retryable = code === 'ETIMEDOUT' || code === 'ECONNRESET' || code === 'PROTOCOL_CONNECTION_LOST';
                    if (retryable && i === 0) continue;
                    throw e;
                }
            }
        };
        await expect(retryOnce(pool, 'BAD SQL', [])).rejects.toThrow('syntax error');
        expect(pool.query).toHaveBeenCalledTimes(1);
    });

    it('retryable 但两次都失败 → 抛错', async () => {
        const pool = { query: vi.fn() };
        pool.query.mockRejectedValue(Object.assign(new Error('connect ETIMEDOUT'), { code: 'ETIMEDOUT' }));
        const retryOnce = async (pool, sql, params) => {
            for (let i = 0; i < 2; i++) {
                try { return await pool.query(sql, params); }
                catch (e) {
                    const code = e.code || '';
                    const retryable = code === 'ETIMEDOUT' || code === 'ECONNRESET' || code === 'PROTOCOL_CONNECTION_LOST';
                    if (retryable && i === 0) continue;
                    throw e;
                }
            }
        };
        await expect(retryOnce(pool, 'SELECT 1', [])).rejects.toThrow('ETIMEDOUT');
        expect(pool.query).toHaveBeenCalledTimes(2);
    });

    it('ECONNRESET 也 retry', async () => {
        const pool = { query: vi.fn() };
        pool.query
            .mockRejectedValueOnce(Object.assign(new Error('read ECONNRESET'), { code: 'ECONNRESET' }))
            .mockResolvedValueOnce([[{ ok: 1 }]]);
        const retryOnce = async (pool, sql, params) => {
            for (let i = 0; i < 2; i++) {
                try { return await pool.query(sql, params); }
                catch (e) {
                    const code = e.code || '';
                    const retryable = code === 'ETIMEDOUT' || code === 'ECONNRESET' || code === 'PROTOCOL_CONNECTION_LOST';
                    if (retryable && i === 0) continue;
                    throw e;
                }
            }
        };
        await retryOnce(pool, 'SELECT 1', []);
        expect(pool.query).toHaveBeenCalledTimes(2);
    });
});