package com.example.processor;

import com.example.model.AdvancedSearchRequest;
import com.example.model.PageRequest;
import com.example.model.PageResponse;
import org.apache.camel.Exchange;
import org.apache.camel.Processor;
import org.apache.camel.Configuration;
import org.apache.camel.BindToRegistry;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * 分页结果聚合处理器
 * 适用于Camel Karavan低代码平台
 */
@Configuration
@BindToRegistry("paginationAggregator")
public class PaginationAggregator implements Processor {
    private static final Logger LOGGER = LoggerFactory.getLogger(PaginationAggregator.class);

    @Override
    public void process(Exchange exchange) throws Exception {
        createPageResponse(exchange);
    }
    
    /**
     * 从普通分页请求创建分页响应
     * 通用方法，适用于任何实体类型
     */
    public void createPageResponse(Exchange exchange) throws Exception {
        // 获取数据和总数
        @SuppressWarnings("unchecked")
        List<?> data = exchange.getIn().getBody(List.class);
        Long total = exchange.getProperty("total", Long.class);
        
        // 创建分页响应
        PageResponse<Object> response = new PageResponse<>();
        
        // 根据请求类型设置分页信息
        if (exchange.getProperty("pageRequest") != null) {
            PageRequest pageRequest = exchange.getProperty("pageRequest", PageRequest.class);
            response.setPage(pageRequest.getPage());
            response.setSize(pageRequest.getSize());
        } else if (exchange.getProperty("searchRequest") != null) {
            AdvancedSearchRequest searchRequest = exchange.getProperty("searchRequest", AdvancedSearchRequest.class);
            response.setPage(searchRequest.getPage());
            response.setSize(searchRequest.getSize());
        }
        
        // 设置数据和总数
        response.setTotal(total != null ? total : 0L);
        response.setData((List<Object>)(data != null ? data : Collections.emptyList()));
        
        // 将分页响应设置为消息体
        exchange.getIn().setBody(response);
    }
    
    /**
     * 创建空分页响应
     */
    public void createEmptyPageResponse(Exchange exchange) {
        PageResponse<Object> response = new PageResponse<>();
        
        // 尝试从请求中获取分页信息
        if (exchange.getProperty("pageRequest") != null) {
            PageRequest pageRequest = exchange.getProperty("pageRequest", PageRequest.class);
            response.setPage(pageRequest.getPage());
            response.setSize(pageRequest.getSize());
        } else {
            // 使用默认值
            response.setPage(1);
            response.setSize(10);
        }
        
        // 设置空数据和0总数
        response.setTotal(0L);
        response.setData(Collections.emptyList());
        
        // 将空分页响应设置为消息体
        exchange.getIn().setBody(response);
    }
    
    /**
     * 处理成功响应（200 OK）
     */
    public void setSuccessResponse(Exchange exchange) {
        exchange.getIn().setHeader(Exchange.HTTP_RESPONSE_CODE, 200);
    }
    
    /**
     * 设置创建成功的HTTP状态码和响应（201 Created）
     */
    public void setCreatedResponse(Exchange exchange) {
        exchange.getIn().setHeader(Exchange.HTTP_RESPONSE_CODE, 201);
    }
    
    /**
     * 设置删除成功的HTTP状态码和响应（204 No Content）
     */
    public void setDeletedResponse(Exchange exchange) {
        exchange.getIn().setHeader(Exchange.HTTP_RESPONSE_CODE, 204);
        exchange.getIn().setBody(null);
    }
    
    /**
     * 设置未找到资源的HTTP状态码和响应（404 Not Found）
     */
    public void setNotFoundResponse(Exchange exchange, String entityName) {
        Map<String, String> response = new HashMap<>();
        response.put("error", entityName + "不存在");
        exchange.getIn().setHeader(Exchange.HTTP_RESPONSE_CODE, 404);
        exchange.getIn().setBody(response);
    }
    
    /**
     * 设置冲突的HTTP状态码和响应（409 Conflict）
     */
    public void setConflictResponse(Exchange exchange, String field) {
        Map<String, String> response = new HashMap<>();
        response.put("error", field + "已存在");
        exchange.getIn().setHeader(Exchange.HTTP_RESPONSE_CODE, 409);
        exchange.getIn().setBody(response);
    }
    
    /**
     * 设置服务器错误HTTP状态码和响应（500 Internal Server Error）
     */
    public void setErrorResponse(Exchange exchange, String message) {
        Map<String, String> response = new HashMap<>();
        response.put("error", message);
        exchange.getIn().setHeader(Exchange.HTTP_RESPONSE_CODE, 500);
        exchange.getIn().setBody(response);
    }
}