#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>


#define BUF_SIZE    4096
#define BODY_BUF    2048

// 域名转IP
static int domain_to_ip(const char *domain, char *ip_buf) {
    struct hostent *host = gethostbyname(domain);
    if (!host) return -1;
    struct in_addr **addr_list = (struct in_addr **)host->h_addr_list;
    strcpy(ip_buf, inet_ntoa(*addr_list[0]));
    return 0;
}

// 从 HTTP 完整响应中提取正文（跳过头部）
void extract_http_body(const char *response, char *body) {
    const char *split = "\r\n\r\n";
    char *pos = strstr(response, split);
    if (pos) {
        strcpy(body, pos + 4); // 跳过 \r\n\r\n
    } else {
        strcpy(body, "parse error");
    }
}

// HTTP GET，返回完整响应字符串
int http_get(const char *host, const char *path, int port, char *response) {
    int sock;
    struct sockaddr_in addr;
    char ip[64], req[512];
    int total_len = 0;

    if (domain_to_ip(host, ip) < 0) return -1;

    sock = socket(AF_INET, SOCK_STREAM, 0);
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    addr.sin_addr.s_addr = inet_addr(ip);

    if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        close(sock);
        return -2;
    }

    snprintf(req, sizeof(req),
        "GET %s HTTP/1.1\r\n"
        "Host: %s\r\n"
        "Connection: close\r\n\r\n",
        path, host);

    send(sock, req, strlen(req), 0);

    // 接收完整数据
    while (1) {
        int len = recv(sock, response + total_len, BUF_SIZE - 1 - total_len, 0);
        if (len <= 0) break;
        total_len += len;
    }

    response[total_len] = 0;
    close(sock);
    return total_len;
}

// HTTP POST
int http_post(const char *host, const char *path, int port, const char *data, int data_len, char *response) {
    int sock;
    struct sockaddr_in addr;
    char ip[64], req[1024];
    int total_len = 0;

    if (domain_to_ip(host, ip) < 0) return -1;

    sock = socket(AF_INET, SOCK_STREAM, 0);
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    addr.sin_addr.s_addr = inet_addr(ip);

    if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        close(sock);
        return -2;
    }

    snprintf(req, sizeof(req),
        "POST %s HTTP/1.1\r\n"
        "Host: %s\r\n"
        "Content-Type: application/x-www-form-urlencoded\r\n"
        "Content-Length: %d\r\n"
        "Connection: close\r\n\r\n%s",
        path, host, data_len, data);

    send(sock, req, strlen(req), 0);

    while (1) {
        int len = recv(sock, response + total_len, BUF_SIZE - 1 - total_len, 0);
        if (len <= 0) break;
        total_len += len;
    }

    response[total_len] = 0;
    close(sock);
    return total_len;
}