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

#define MAX_DATAGRAM_SIZE 1350

int main(int argc, char *argv[]) {
    quiche_config *config = quiche_config_new(QUICHE_PROTOCOL_VERSION);
    if (config == NULL) return -1;
    
    quiche_config_verify_peer(config, false); 
    quiche_config_set_application_protos(config, (uint8_t *) "\x0ahq-interop\x05hq-29\x05hq-28\x05hq-27\x08http/0.9", 38);
    quiche_config_set_max_idle_timeout(config, 5000);
    quiche_config_set_max_recv_udp_payload_size(config, MAX_DATAGRAM_SIZE);
    quiche_config_set_max_send_udp_payload_size(config, MAX_DATAGRAM_SIZE);
    quiche_config_set_initial_max_data(config, 10000000);
    quiche_config_set_initial_max_stream_data_bidi_local(config, 1000000);
    quiche_config_set_initial_max_streams_bidi(config, 100);
    
    int sock = socket(AF_INET, SOCK_DGRAM, 0);
    if (sock < 0) return -1;
    
    struct sockaddr_in peer_addr;
    memset(&peer_addr, 0, sizeof(peer_addr));
    peer_addr.sin_family = AF_INET;
    peer_addr.sin_port = htons(8888);
    inet_pton(AF_INET, "127.0.0.1", &peer_addr.sin_addr);
    
    if (connect(sock, (struct sockaddr *)&peer_addr, sizeof(peer_addr)) < 0) {
        perror("connect");
        return -1;
    }
    
    int flags = fcntl(sock, F_GETFL, 0);
    fcntl(sock, F_SETFL, flags | O_NONBLOCK);
    
    uint8_t scid[QUICHE_MAX_CONN_ID_LEN];
    int rng = open("/dev/urandom", O_RDONLY);
    if (rng >= 0) {
        read(rng, scid, sizeof(scid));
        close(rng);
    }
    
    quiche_conn *conn = quiche_connect("127.0.0.1", (const uint8_t *)scid, sizeof(scid), NULL, 0, (struct sockaddr *)&peer_addr, sizeof(peer_addr), config);
    if (conn == NULL) {
        fprintf(stderr, "quiche_connect failed\n");
        return -1;
    }
    
    printf("Connecting to QUIC server...\n");
    
    uint8_t buf[65535];
    uint8_t out[MAX_DATAGRAM_SIZE];
    bool req_sent = false;
    
    while (1) {
        ssize_t read_len = recv(sock, buf, sizeof(buf), 0);
        if (read_len > 0) {
             quiche_conn_recv(conn, buf, read_len, &(quiche_recv_info){
                 .to = NULL, 
                 .to_len = 0,
                 .from = (struct sockaddr *)&peer_addr,
                 .from_len = sizeof(peer_addr),
             });
        }
        
        if (quiche_conn_is_closed(conn)) {
            printf("Connection closed.\n");
            break;
        }
        
        if (quiche_conn_is_established(conn)) {
            if (!req_sent) {
                const char *msg = "Hello from QUIC Client!";
                uint64_t err_code = 0;
                quiche_conn_stream_send(conn, 4, (uint8_t*)msg, strlen(msg), true, &err_code);
                printf("Sent: %s\n", msg);
                req_sent = true;
            }
            
            uint64_t s = 0;
            quiche_stream_iter *readable = quiche_conn_readable(conn);
            while (quiche_stream_iter_next(readable, &s)) {
                uint8_t recv_buf[1024];
                bool fin = false;
                uint64_t err_code = 0;
                ssize_t len = quiche_conn_stream_recv(conn, s, recv_buf, sizeof(recv_buf), &fin, &err_code);
                if (len > 0) {
                    printf("Received: %.*s\n", (int)len, recv_buf);
                    quiche_conn_close(conn, true, 0, (const uint8_t *)"Done", 4);
                }
            }
            quiche_stream_iter_free(readable);
        }
        
        while (1) {
            quiche_send_info send_info;
            ssize_t written = quiche_conn_send(conn, out, sizeof(out), &send_info);
            if (written == QUICHE_ERR_DONE) break;
            if (written < 0) break;
            send(sock, out, written, 0);
        }
        
        quiche_conn_on_timeout(conn);
        usleep(1000);
    }

    quiche_conn_free(conn);
    quiche_config_free(config);
    return 0;
}