import { createClient } from '@clickhouse/client';
import type { EventsQueryParams } from './types';

// ClickHouse 客户端配置
const clickhouse = createClient({
  url: process.env.CLICKHOUSE_URL,
  username: process.env.CLICKHOUSE_USER ,
  password: process.env.CLICKHOUSE_PASSWORD ,
  database: process.env.CLICKHOUSE_DATABASE 
});

// 构建日期过滤条件
function buildDateFilter(startTime?: string, endTime?: string): string {
  const filters = [];
  
  if (startTime) {
    filters.push(`event_time >= parseDateTimeBestEffort('${startTime}')`);
  }
  
  if (endTime) {
    filters.push(`event_time <= parseDateTimeBestEffort('${endTime}')`);
  }
  
  return filters.length > 0 ? `WHERE ${filters.join(' AND ')}` : '';
}

// 字符串转义函数
function escapeString(str: string): string {
  return str.replace(/'/g, "\\'");
}

// 构建通用过滤条件
export function buildFilter(params: Partial<EventsQueryParams>): string {
  const filters = [];
  
  // 时间范围过滤
  if (params.startTime || params.endTime) {
    const dateFilter = buildDateFilter(params.startTime, params.endTime).replace('WHERE ', '');
    if (dateFilter) {
      filters.push(dateFilter);
    }
  }
  
  // 事件类型过滤
  if (params.eventType) {
    filters.push(`event_type = '${escapeString(params.eventType)}'`);
  }
  
  // 链接ID过滤
  if (params.linkId) {
    filters.push(`link_id = '${escapeString(params.linkId)}'`);
  }
  
  // 链接短码过滤
  if (params.linkSlug) {
    filters.push(`link_slug = '${escapeString(params.linkSlug)}'`);
  }
  
  // 用户ID过滤
  if (params.userId) {
    filters.push(`user_id = '${escapeString(params.userId)}'`);
  }
  
  // 团队ID过滤
  if (params.teamId) {
    filters.push(`team_id = '${escapeString(params.teamId)}'`);
  }
  
  // 项目ID过滤
  if (params.projectId) {
    filters.push(`project_id = '${escapeString(params.projectId)}'`);
  }

  // 标签筛选
  if (params.tags && params.tags.length > 0) {
    const tagConditions = params.tags.map(tag => 
      `JSONHas(JSONExtractArrayRaw(link_tags), JSON_QUOTE('${escapeString(tag)}'))`
    );
    filters.push(`(${tagConditions.join(' OR ')})`);
  }

  // Slug 模糊搜索
  if (params.searchSlug) {
    filters.push(`positionCaseInsensitive(link_slug, '${escapeString(params.searchSlug)}') > 0`);
  }
  
  return filters.length > 0 ? `WHERE ${filters.join(' AND ')}` : '';
}

// 构建分页
export function buildPagination(page?: number, pageSize?: number): string {
  const limit = pageSize || 20;
  const offset = ((page || 1) - 1) * limit;
  return `LIMIT ${limit} OFFSET ${offset}`;
}

// 构建排序
export function buildOrderBy(sortBy?: string, sortOrder?: 'asc' | 'desc'): string {
  if (!sortBy) {
    return 'ORDER BY event_time DESC';
  }
  return `ORDER BY ${sortBy} ${sortOrder || 'desc'}`;
}

// 执行查询并处理错误
export async function executeQuery<T>(query: string): Promise<T[]> {
  try {
    const resultSet = await clickhouse.query({
      query,
      format: 'JSONEachRow'
    });
    
    const rows = await resultSet.json<T>();
    return Array.isArray(rows) ? rows : [rows];
  } catch (error) {
    console.error('ClickHouse query error:', error);
    throw error;
  }
}

// 执行查询并返回单个结果
export async function executeQuerySingle<T>(query: string): Promise<T | null> {
  const results = await executeQuery<T>(query);
  return results.length > 0 ? results[0] : null;
}

export default clickhouse;