#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <cjson/cJSON.h>

// 读取HTTP POST数据
char* read_post_data() {
    char* content_length_str = getenv("CONTENT_LENGTH");
    if (!content_length_str) {
        return NULL;
    }

    int content_length = atoi(content_length_str);
    if (content_length <= 0) {
        return NULL;
    }

    char* data = (char*)malloc(content_length + 1);
    if (!data) {
        return NULL;
    }

    fread(data, 1, content_length, stdin);
    data[content_length] = '\0';
    
    return data;
}

// 处理JSON请求并生成响应
cJSON* process_request(cJSON* request) {
    cJSON* response = cJSON_CreateObject();
    
    // 检查请求是否包含"action"字段
    cJSON* action = cJSON_GetObjectItemCaseSensitive(request, "action");
    if (cJSON_IsString(action) && (action->valuestring != NULL)) {
        cJSON_AddStringToObject(response, "received_action", action->valuestring);
        
        // 根据不同的action执行不同的操作
        if (strcmp(action->valuestring, "echo") == 0) {
            cJSON* message = cJSON_GetObjectItemCaseSensitive(request, "message");
            if (cJSON_IsString(message) && (message->valuestring != NULL)) {
                cJSON_AddStringToObject(response, "message", message->valuestring);
                cJSON_AddStringToObject(response, "status", "success");
            } else {
                cJSON_AddStringToObject(response, "error", "Missing or invalid 'message' field");
                cJSON_AddStringToObject(response, "status", "error");
            }
        } else if (strcmp(action->valuestring, "ping") == 0) {
            cJSON_AddStringToObject(response, "message", "pong");
            cJSON_AddStringToObject(response, "status", "success");
        } else {
            cJSON_AddStringToObject(response, "error", "Unknown action");
            cJSON_AddStringToObject(response, "status", "error");
        }
    } else {
        cJSON_AddStringToObject(response, "error", "Missing or invalid 'action' field");
        cJSON_AddStringToObject(response, "status", "error");
    }
    
    return response;
}

int main() {
    // 设置HTTP响应头，指定JSON格式
    printf("Content-Type: application/json\n\n");

    // 读取POST数据
    char* post_data = read_post_data();
    if (!post_data) {
        cJSON* error = cJSON_CreateObject();
        cJSON_AddStringToObject(error, "error", "No data received");
        cJSON_AddStringToObject(error, "status", "error");
        printf("%s", cJSON_Print(error));
        cJSON_Delete(error);
        free(post_data);
        return 0;
    }

    // 解析JSON
    cJSON* request = cJSON_Parse(post_data);
    free(post_data);
    
    if (!request) {
        const char* error_ptr = cJSON_GetErrorPtr();
        cJSON* error = cJSON_CreateObject();
        cJSON_AddStringToObject(error, "error", "Invalid JSON");
        cJSON_AddStringToObject(error, "details", error_ptr ? error_ptr : "Unknown error");
        cJSON_AddStringToObject(error, "status", "error");
        printf("%s", cJSON_Print(error));
        cJSON_Delete(error);
        return 0;
    }

    // 处理请求并生成响应
    cJSON* response = process_request(request);
    cJSON_Delete(request);

    // 输出响应
    printf("%s", cJSON_Print(response));
    cJSON_Delete(response);

    return 0;
}