import express from 'express';
import { query } from '../config.js';
import { asyncHandler } from '../middleware/errorHandler.js';
import { requireAuth, requireAdmin } from '../middleware/auth.js';
import AuditLog from '../models/AuditLog.js';

const router = express.Router();

/**
 * GET /api/llm-config
 * 取得當前 LLM 配置（所有使用者可見）
 */
router.get('/', requireAuth, asyncHandler(async (req, res) => {
  const configs = await query(
    `SELECT id, provider_name, model_name, is_active, created_at, updated_at
     FROM llm_configs
     ORDER BY is_active DESC, created_at DESC`
  );

  res.json({
    success: true,
    data: configs
  });
}));

/**
 * GET /api/llm-config/active
 * 取得當前啟用的 LLM 配置
 */
router.get('/active', requireAuth, asyncHandler(async (req, res) => {
  const [config] = await query(
    `SELECT id, provider_name, api_endpoint, model_name, temperature, max_tokens, timeout_seconds
     FROM llm_configs
     WHERE is_active = 1
     LIMIT 1`
  );

  if (!config) {
    return res.status(404).json({
      success: false,
      error: '未找到啟用的 LLM 配置'
    });
  }

  res.json({
    success: true,
    data: config
  });
}));

/**
 * POST /api/llm-config
 * 新增 LLM 配置（僅管理員）
 */
router.post('/', requireAdmin, asyncHandler(async (req, res) => {
  const {
    provider_name,
    api_endpoint,
    api_key,
    model_name,
    temperature,
    max_tokens,
    timeout_seconds
  } = req.body;

  // 驗證必填欄位
  if (!provider_name || !api_endpoint || !model_name) {
    return res.status(400).json({
      success: false,
      error: '請填寫所有必填欄位'
    });
  }

  const result = await query(
    `INSERT INTO llm_configs
     (provider_name, api_endpoint, api_key, model_name, temperature, max_tokens, timeout_seconds)
     VALUES (?, ?, ?, ?, ?, ?, ?)`,
    [
      provider_name,
      api_endpoint,
      api_key || null,
      model_name,
      temperature || 0.7,
      max_tokens || 6000,
      timeout_seconds || 120
    ]
  );

  // 記錄稽核日誌
  await AuditLog.logCreate(
    req.session.userId,
    'llm_config',
    result.insertId,
    { provider_name, model_name },
    req.ip,
    req.get('user-agent')
  );

  res.json({
    success: true,
    message: '已新增 LLM 配置',
    data: { id: result.insertId }
  });
}));

/**
 * PUT /api/llm-config/:id
 * 更新 LLM 配置（僅管理員）
 */
router.put('/:id', requireAdmin, asyncHandler(async (req, res) => {
  const configId = parseInt(req.params.id);
  const {
    provider_name,
    api_endpoint,
    api_key,
    model_name,
    temperature,
    max_tokens,
    timeout_seconds
  } = req.body;

  // 驗證必填欄位
  if (!provider_name || !api_endpoint || !model_name) {
    return res.status(400).json({
      success: false,
      error: '請填寫所有必填欄位'
    });
  }

  // 檢查配置是否存在
  const [existing] = await query('SELECT id FROM llm_configs WHERE id = ?', [configId]);
  if (!existing) {
    return res.status(404).json({
      success: false,
      error: '找不到此 LLM 配置'
    });
  }

  await query(
    `UPDATE llm_configs
     SET provider_name = ?, api_endpoint = ?, api_key = ?, model_name = ?,
         temperature = ?, max_tokens = ?, timeout_seconds = ?, updated_at = NOW()
     WHERE id = ?`,
    [
      provider_name,
      api_endpoint,
      api_key || null,
      model_name,
      temperature || 0.7,
      max_tokens || 6000,
      timeout_seconds || 120,
      configId
    ]
  );

  // 記錄稽核日誌
  await AuditLog.logUpdate(
    req.session.userId,
    'llm_config',
    configId,
    {},
    { provider_name, model_name },
    req.ip,
    req.get('user-agent')
  );

  res.json({
    success: true,
    message: '已更新 LLM 配置'
  });
}));

/**
 * PUT /api/llm-config/:id/activate
 * 啟用特定 LLM 配置（僅管理員）
 */
router.put('/:id/activate', requireAdmin, asyncHandler(async (req, res) => {
  const configId = parseInt(req.params.id);

  // 檢查配置是否存在
  const [existing] = await query('SELECT id, provider_name FROM llm_configs WHERE id = ?', [configId]);
  if (!existing) {
    return res.status(404).json({
      success: false,
      error: '找不到此 LLM 配置'
    });
  }

  // 先停用所有配置
  await query('UPDATE llm_configs SET is_active = 0');

  // 啟用指定配置
  await query('UPDATE llm_configs SET is_active = 1, updated_at = NOW() WHERE id = ?', [configId]);

  // 記錄稽核日誌
  await AuditLog.logUpdate(
    req.session.userId,
    'llm_config',
    configId,
    { is_active: 0 },
    { is_active: 1 },
    req.ip,
    req.get('user-agent')
  );

  res.json({
    success: true,
    message: `已啟用 ${existing.provider_name} 配置`
  });
}));

/**
 * DELETE /api/llm-config/:id
 * 刪除 LLM 配置（僅管理員）
 */
router.delete('/:id', requireAdmin, asyncHandler(async (req, res) => {
  const configId = parseInt(req.params.id);

  // 檢查是否為啟用中的配置
  const [existing] = await query('SELECT is_active FROM llm_configs WHERE id = ?', [configId]);
  if (!existing) {
    return res.status(404).json({
      success: false,
      error: '找不到此 LLM 配置'
    });
  }

  if (existing.is_active) {
    return res.status(400).json({
      success: false,
      error: '無法刪除啟用中的配置'
    });
  }

  await query('DELETE FROM llm_configs WHERE id = ?', [configId]);

  // 記錄稽核日誌
  await AuditLog.logDelete(
    req.session.userId,
    'llm_config',
    configId,
    {},
    req.ip,
    req.get('user-agent')
  );

  res.json({
    success: true,
    message: '已刪除 LLM 配置'
  });
}));

/**
 * POST /api/llm-config/test
 * 測試 LLM 配置連線（僅管理員）
 */
router.post('/test', requireAdmin, asyncHandler(async (req, res) => {
  const { api_endpoint, api_key, model_name } = req.body;

  if (!api_endpoint || !model_name) {
    return res.status(400).json({
      success: false,
      error: '請提供 API 端點和模型名稱'
    });
  }

  try {
    const axios = (await import('axios')).default;

    const response = await axios.post(
      `${api_endpoint}/v1/chat/completions`,
      {
        model: model_name,
        messages: [
          { role: 'user', content: 'Hello' }
        ],
        max_tokens: 10
      },
      {
        timeout: 10000,
        headers: {
          'Content-Type': 'application/json',
          ...(api_key && { 'Authorization': `Bearer ${api_key}` })
        }
      }
    );

    if (response.data && response.data.choices) {
      res.json({
        success: true,
        message: 'LLM API 連線測試成功'
      });
    } else {
      throw new Error('Invalid API response format');
    }
  } catch (error) {
    res.status(500).json({
      success: false,
      error: 'LLM API 連線測試失敗',
      message: error.message
    });
  }
}));

export default router;