/**
 * sesimos - secure, simple, modern web server
 * @brief Basic TCP and TLS socket
 * @file src/lib/sock.c
 * @author Lorenz Stechauner
 * @date 2021-01-07
 */

#include "sock.h"
#include "utils.h"
#include "error.h"

#include <errno.h>
#include <openssl/ssl.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>

int sock_set_socket_timeout_micros(sock *s, long recv_micros, long send_micros) {
    struct timeval recv_to = {.tv_sec = recv_micros / 1000000, .tv_usec = recv_micros % 1000000},
                   send_to = {.tv_sec = send_micros / 1000000, .tv_usec = send_micros % 1000000};

    if (setsockopt(s->socket, SOL_SOCKET, SO_RCVTIMEO, &recv_to, sizeof(recv_to)) != 0)
        return -1;

    if (setsockopt(s->socket, SOL_SOCKET, SO_SNDTIMEO, &send_to, sizeof(send_to)) != 0)
        return -1;

    return 0;
}

int sock_set_socket_timeout(sock *s, double sec) {
    return sock_set_socket_timeout_micros(s, (long) (sec * 1000000L), (long) (sec * 1000000L));
}

int sock_set_timeout_micros(sock *s, long micros) {
    if (micros < 0)
        return -1;

    s->timeout_us = micros;
    return 0;
}

int sock_set_timeout(sock *s, double sec) {
    return sock_set_timeout_micros(s, (long) (sec * 1000000));
}

long sock_send(sock *s, void *buf, unsigned long len, int flags) {
    long ret;
    if (s->enc) {
        ret = SSL_write(s->ssl, buf, (int) len);
        if (ret <= 0) error_ssl(SSL_get_error(s->ssl, (int) ret));
    } else {
        ret = send(s->socket, buf, len, flags);
    }

    if (ret >= 0) {
        s->ts_last = clock_micros();
        return ret;
    } else {
        return -1;
    }
}

long sock_recv(sock *s, void *buf, unsigned long len, int flags) {
    long ret;
    if (s->enc) {
        int (*func)(SSL*, void*, int) = (flags & MSG_PEEK) ? SSL_peek : SSL_read;
        ret = func(s->ssl, buf, (int) len);
        if (ret <= 0) error_ssl(SSL_get_error(s->ssl, (int) ret));
    } else {
        ret = recv(s->socket, buf, len, flags);
    }

    if (ret >= 0) {
        s->ts_last = clock_micros();
        return ret;
    } else {
        return -1;
    }
}

long sock_splice(sock *dst, sock *src, void *buf, unsigned long buf_len, unsigned long len) {
    long ret;
    unsigned long send_len = 0;
    unsigned long next_len;
    while (send_len < len) {
        next_len = (buf_len < (len - send_len)) ? buf_len : (len - send_len);
        ret = sock_recv(src, buf, next_len, 0);
        if (ret <= 0) return -2;
        next_len = ret;
        ret = sock_send(dst, buf, next_len, send_len + next_len < len ? MSG_MORE : 0);
        if (ret < 0) return -1;
        if (ret != next_len) return -3;
        send_len += next_len;
    }
    return (long) send_len;
}

long sock_splice_chunked(sock *dst, sock *src, void *buf, unsigned long buf_len) {
    long ret;
    unsigned long send_len = 0;
    unsigned long next_len;

    while (1) {
        ret = sock_get_chunk_header(src);
        if (ret < 0) return -2;

        next_len = ret;
        if (next_len <= 0) break;

        ret = sock_splice(dst, src, buf, buf_len, next_len);
        if (ret < 0) return ret;
    }

    return (long) send_len;
}

int sock_close(sock *s) {
    int e = errno;
    if (s->enc && s->ssl != NULL) {
        SSL_shutdown(s->ssl);
        SSL_free(s->ssl);
        s->ssl = NULL;
    }
    close(s->socket);
    s->socket = 0;
    s->enc = 0;
    errno = e;
    return 0;
}

int sock_has_pending(sock *s) {
    char buf[1];
    int e = errno;
    long ret = sock_recv(s, &buf, 1, MSG_PEEK | MSG_DONTWAIT);
    errno = e;
    return ret == 1;
}

long sock_parse_chunk_header(const char *buf, long len, long *ret_len) {
    for (int i = 0; i < len; i++) {
        char ch = buf[i];
        if (ch == '\r') {
            continue;
        } else if (ch == '\n') {
            if (ret_len != NULL) *ret_len = i + 1;
            return strtol(buf, NULL, 16);
        } else if (!((ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'f') || (ch >= 'A' && ch <= 'F'))) {
            return -2;
        }
    }

    return -1;
}

long sock_get_chunk_header(sock *s) {
    long ret, len;
    char buf[16];

    do {
        ret = sock_recv(s, buf, sizeof(buf), MSG_PEEK);
        if (ret <= 0) return -2;
        else if (ret < 2) continue;

        ret = sock_parse_chunk_header(buf, ret, &len);
        if (ret == -2) return -1;
    } while (ret < 0);

    if (sock_recv(s, buf, len, 0) != len)
        return -2;

    return ret;
}