/*
 *  Copyright (C) 2009-2010 Howard Chu
 *
 *  This file is part of librtmp.
 *
 *  librtmp is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as
 *  published by the Free Software Foundation; either version 2.1,
 *  or (at your option) any later version.
 *
 *  librtmp is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with librtmp see the file COPYING.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA  02110-1301, USA.
 *  http://www.gnu.org/copyleft/lgpl.html
 */

#include "rtmp_sys.h"
#include "log.h"
#include "http.h"

#ifdef CRYPTO

#ifdef __APPLE__
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
#endif

#ifdef USE_POLARSSL
#include <polarssl/sha2.h>
#ifndef SHA256_DIGEST_LENGTH
#define SHA256_DIGEST_LENGTH	32
#endif
#define HMAC_CTX	sha2_context
#define HMAC_setup(ctx, key, len)	sha2_hmac_starts(&ctx, (unsigned char *)key, len, 0)
#define HMAC_crunch(ctx, buf, len)	sha2_hmac_update(&ctx, buf, len)
#define HMAC_finish(ctx, dig, dlen)	dlen = SHA256_DIGEST_LENGTH; sha2_hmac_finish(&ctx, dig)
#define HMAC_close(ctx)
#elif defined(USE_GNUTLS)
#include <nettle/hmac.h>
#ifndef SHA256_DIGEST_LENGTH
#define SHA256_DIGEST_LENGTH	32
#endif
#undef HMAC_CTX
#define HMAC_CTX	struct hmac_sha256_ctx
#define HMAC_setup(ctx, key, len)	hmac_sha256_set_key(&ctx, len, key)
#define HMAC_crunch(ctx, buf, len)	hmac_sha256_update(&ctx, len, buf)
#define HMAC_finish(ctx, dig, dlen)	dlen = SHA256_DIGEST_LENGTH; hmac_sha256_digest(&ctx, SHA256_DIGEST_LENGTH, dig)
#define HMAC_close(ctx)
#else	/* USE_OPENSSL */
#include <openssl/ssl.h>
#include <openssl/sha.h>
#include <openssl/hmac.h>
#include <openssl/rc4.h>
#define HMAC_setup(ctx, key, len)	HMAC_CTX_init(&ctx); HMAC_Init_ex(&ctx, (unsigned char *)key, len, EVP_sha256(), 0)
#define HMAC_crunch(ctx, buf, len)	HMAC_Update(&ctx, (unsigned char *)buf, len)
#define HMAC_finish(ctx, dig, dlen)	HMAC_Final(&ctx, (unsigned char *)dig, &dlen);
#define HMAC_close(ctx)	HMAC_CTX_cleanup(&ctx)
#endif

extern void RTMP_TLS_Init();
extern TLS_CTX RTMP_TLS_ctx;

#include <zlib.h>

#endif /* CRYPTO */

#define	AGENT	"Mozilla/5.0"

HTTPResult
HTTP_get(struct HTTP_ctx *http, const char *url, HTTP_read_callback *cb)
{
    char *host, *path;
    char *p1, *p2;
    char hbuf[256];
    int port = 80;
#ifdef CRYPTO
    int ssl = 0;
#endif
    int hlen, flen = 0;
    int rc, i;
    int len_known;
    HTTPResult ret = HTTPRES_OK;
    struct sockaddr_in sa;
    RTMPSockBuf sb = {0};

    http->status = -1;

    memset(&sa, 0, sizeof(struct sockaddr_in));
    sa.sin_family = AF_INET;

    /* we only handle http here */
    if (strncasecmp(url, "http", 4))
        return HTTPRES_BAD_REQUEST;

    if (url[4] == 's')
    {
#ifdef CRYPTO
        ssl = 1;
        port = 443;
        if (!RTMP_TLS_ctx)
            RTMP_TLS_Init();
#else
        return HTTPRES_BAD_REQUEST;
#endif
    }

    p1 = strchr(url + 4, ':');
    if (!p1 || strncmp(p1, "://", 3))
        return HTTPRES_BAD_REQUEST;

    host = p1 + 3;
    path = strchr(host, '/');
    hlen = path - host;
    strncpy(hbuf, host, hlen);
    hbuf[hlen] = '\0';
    host = hbuf;
    p1 = strrchr(host, ':');
    if (p1)
    {
        *p1++ = '\0';
        port = atoi(p1);
    }

    sa.sin_addr.s_addr = inet_addr(host);
    if (sa.sin_addr.s_addr == INADDR_NONE)
    {
        struct hostent *hp = gethostbyname(host);
        if (!hp || !hp->h_addr)
            return HTTPRES_LOST_CONNECTION;
        sa.sin_addr = *(struct in_addr *)hp->h_addr;
    }
    sa.sin_port = htons(port);
    sb.sb_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (sb.sb_socket == INVALID_SOCKET)
        return HTTPRES_LOST_CONNECTION;
    i =
        sprintf(sb.sb_buf,
                "GET %s HTTP/1.0\r\nUser-Agent: %s\r\nHost: %s\r\nReferer: %.*s\r\n",
                path, AGENT, host, (int)(path - url + 1), url);
    if (http->date[0])
        i += sprintf(sb.sb_buf + i, "If-Modified-Since: %s\r\n", http->date);
    i += sprintf(sb.sb_buf + i, "\r\n");

    if (connect
            (sb.sb_socket, (struct sockaddr *)&sa, sizeof(struct sockaddr)) < 0)
    {
        ret = HTTPRES_LOST_CONNECTION;
        goto leave;
    }
#ifdef CRYPTO
    if (ssl)
    {
#ifdef NO_SSL
        RTMP_Log(RTMP_LOGERROR, "%s, No SSL/TLS support", __FUNCTION__);
        ret = HTTPRES_BAD_REQUEST;
        goto leave;
#else
        TLS_client(RTMP_TLS_ctx, sb.sb_ssl);
        TLS_setfd(sb.sb_ssl, sb.sb_socket);
        if (TLS_connect(sb.sb_ssl) < 0)
        {
            RTMP_Log(RTMP_LOGERROR, "%s, TLS_Connect failed", __FUNCTION__);
            ret = HTTPRES_LOST_CONNECTION;
            goto leave;
        }
#endif
    }
#endif
    RTMPSockBuf_Send(&sb, sb.sb_buf, i);

    /* set timeout */
#define HTTP_TIMEOUT	5
    {
        SET_RCVTIMEO(tv, HTTP_TIMEOUT);
        if (setsockopt
                (sb.sb_socket, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv, sizeof(tv)))
        {
            RTMP_Log(RTMP_LOGERROR, "%s, Setting socket timeout to %ds failed!",
                     __FUNCTION__, HTTP_TIMEOUT);
        }
    }

    sb.sb_size = 0;
    sb.sb_timedout = FALSE;
    if (RTMPSockBuf_Fill(&sb) < 1)
    {
        ret = HTTPRES_LOST_CONNECTION;
        goto leave;
    }
    if (strncmp(sb.sb_buf, "HTTP/1", 6))
    {
        ret = HTTPRES_BAD_REQUEST;
        goto leave;
    }

    p1 = strchr(sb.sb_buf, ' ');
    rc = atoi(p1 + 1);
    http->status = rc;

    if (rc >= 300)
    {
        if (rc == 304)
        {
            ret = HTTPRES_OK_NOT_MODIFIED;
            goto leave;
        }
        else if (rc == 404)
            ret = HTTPRES_NOT_FOUND;
        else if (rc >= 500)
            ret = HTTPRES_SERVER_ERROR;
        else if (rc >= 400)
            ret = HTTPRES_BAD_REQUEST;
        else
            ret = HTTPRES_REDIRECTED;
    }

    p1 = memchr(sb.sb_buf, '\n', sb.sb_size);
    if (!p1)
    {
        ret = HTTPRES_BAD_REQUEST;
        goto leave;
    }
    sb.sb_start = p1 + 1;
    sb.sb_size -= sb.sb_start - sb.sb_buf;

    while ((p2 = memchr(sb.sb_start, '\r', sb.sb_size)))
    {
        if (*sb.sb_start == '\r')
        {
            sb.sb_start += 2;
            sb.sb_size -= 2;
            break;
        }
        else if (!strncasecmp
                 (sb.sb_start, "Content-Length: ", sizeof("Content-Length: ") - 1))
        {
            flen = atoi(sb.sb_start + sizeof("Content-Length: ") - 1);
        }
        else if (!strncasecmp
                 (sb.sb_start, "Last-Modified: ", sizeof("Last-Modified: ") - 1))
        {
            *p2 = '\0';
            strcpy(http->date, sb.sb_start + sizeof("Last-Modified: ") - 1);
        }
        p2 += 2;
        sb.sb_size -= p2 - sb.sb_start;
        sb.sb_start = p2;
        if (sb.sb_size < 1)
        {
            if (RTMPSockBuf_Fill(&sb) < 1)
            {
                ret = HTTPRES_LOST_CONNECTION;
                goto leave;
            }
        }
    }

    len_known = flen > 0;
    while ((!len_known || flen > 0) &&
            (sb.sb_size > 0 || RTMPSockBuf_Fill(&sb) > 0))
    {
        cb(sb.sb_start, 1, sb.sb_size, http->data);
        if (len_known)
            flen -= sb.sb_size;
        http->size += sb.sb_size;
        sb.sb_size = 0;
    }

    if (flen > 0)
        ret = HTTPRES_LOST_CONNECTION;

leave:
    RTMPSockBuf_Close(&sb);
    return ret;
}

#ifdef CRYPTO

#define CHUNK	16384

struct info
{
    z_stream *zs;
    HMAC_CTX ctx;
    int first;
    int zlib;
    int size;
};

static size_t
swfcrunch(void *ptr, size_t size, size_t nmemb, void *stream)
{
    struct info *i = stream;
    char *p = ptr;
    size_t len = size * nmemb;

    if (i->first)
    {
        i->first = 0;
        /* compressed? */
        if (!strncmp(p, "CWS", 3))
        {
            *p = 'F';
            i->zlib = 1;
        }
        HMAC_crunch(i->ctx, (unsigned char *)p, 8);
        p += 8;
        len -= 8;
        i->size = 8;
    }

    if (i->zlib)
    {
        unsigned char out[CHUNK];
        i->zs->next_in = (unsigned char *)p;
        i->zs->avail_in = len;
        do
        {
            i->zs->avail_out = CHUNK;
            i->zs->next_out = out;
            inflate(i->zs, Z_NO_FLUSH);
            len = CHUNK - i->zs->avail_out;
            i->size += len;
            HMAC_crunch(i->ctx, out, len);
        }
        while (i->zs->avail_out == 0);
    }
    else
    {
        i->size += len;
        HMAC_crunch(i->ctx, (unsigned char *)p, len);
    }
    return size * nmemb;
}

static int tzoff;
static int tzchecked;

#define	JAN02_1980	318340800

static const char *monthtab[12] = { "Jan", "Feb", "Mar",
                                    "Apr", "May", "Jun",
                                    "Jul", "Aug", "Sep",
                                    "Oct", "Nov", "Dec"
                                  };
static const char *days[] =
{ "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" };

/* Parse an HTTP datestamp into Unix time */
static time_t
make_unix_time(char *s)
{
    struct tm time;
    int i, ysub = 1900, fmt = 0;
    char *month;
    char *n;
    time_t res;

    if (s[3] != ' ')
    {
        fmt = 1;
        if (s[3] != ',')
            ysub = 0;
    }
    for (n = s; *n; ++n)
        if (*n == '-' || *n == ':')
            *n = ' ';

    time.tm_mon = 0;
    n = strchr(s, ' ');
    if (fmt)
    {
        /* Day, DD-MMM-YYYY HH:MM:SS GMT */
        time.tm_mday = strtol(n + 1, &n, 0);
        month = n + 1;
        n = strchr(month, ' ');
        time.tm_year = strtol(n + 1, &n, 0);
        time.tm_hour = strtol(n + 1, &n, 0);
        time.tm_min = strtol(n + 1, &n, 0);
        time.tm_sec = strtol(n + 1, NULL, 0);
    }
    else
    {
        /* Unix ctime() format. Does not conform to HTTP spec. */
        /* Day MMM DD HH:MM:SS YYYY */
        month = n + 1;
        n = strchr(month, ' ');
        while (isspace(*n))
            n++;
        time.tm_mday = strtol(n, &n, 0);
        time.tm_hour = strtol(n + 1, &n, 0);
        time.tm_min = strtol(n + 1, &n, 0);
        time.tm_sec = strtol(n + 1, &n, 0);
        time.tm_year = strtol(n + 1, NULL, 0);
    }
    if (time.tm_year > 100)
        time.tm_year -= ysub;

    for (i = 0; i < 12; i++)
        if (!strncasecmp(month, monthtab[i], 3))
        {
            time.tm_mon = i;
            break;
        }
    time.tm_isdst = 0;		/* daylight saving is never in effect in GMT */

    /* this is normally the value of extern int timezone, but some
     * braindead C libraries don't provide it.
     */
    if (!tzchecked)
    {
        struct tm *tc;
        time_t then = JAN02_1980;
        tc = localtime(&then);
        tzoff = (12 - tc->tm_hour) * 3600 + tc->tm_min * 60 + tc->tm_sec;
        tzchecked = 1;
    }
    res = mktime(&time);
    /* Unfortunately, mktime() assumes the input is in local time,
     * not GMT, so we have to correct it here.
     */
    if (res != -1)
        res += tzoff;
    return res;
}

/* Convert a Unix time to a network time string
 * Weekday, DD-MMM-YYYY HH:MM:SS GMT
 */
static void
strtime(time_t * t, char *s)
{
    struct tm *tm;

    tm = gmtime((time_t *) t);
    sprintf(s, "%s, %02d %s %d %02d:%02d:%02d GMT",
            days[tm->tm_wday], tm->tm_mday, monthtab[tm->tm_mon],
            tm->tm_year + 1900, tm->tm_hour, tm->tm_min, tm->tm_sec);
}

#define HEX2BIN(a)      (((a)&0x40)?((a)&0xf)+9:((a)&0xf))

int
RTMP_HashSWF(const char *url, unsigned int *size, unsigned char *hash,
             int age)
{
    FILE *f = NULL;
    char *path, date[64], cctim[64];
    long pos = 0;
    time_t ctim = -1, cnow;
    int i, got = 0, ret = 0;
    unsigned int hlen;
    struct info in = { 0 };
    struct HTTP_ctx http = { 0 };
    HTTPResult httpres;
    z_stream zs = { 0 };
    AVal home, hpre;

    date[0] = '\0';
#ifdef _WIN32
#ifdef XBMC4XBOX
    hpre.av_val = "Q:";
    hpre.av_len = 2;
    home.av_val = "\\UserData";
#else
    hpre.av_val = getenv("HOMEDRIVE");
    hpre.av_len = strlen(hpre.av_val);
    home.av_val = getenv("HOMEPATH");
#endif
#define DIRSEP	"\\"

#else /* !_WIN32 */
    hpre.av_val = "";
    hpre.av_len = 0;
    home.av_val = getenv("HOME");
#define DIRSEP	"/"
#endif
    if (!home.av_val)
        home.av_val = ".";
    home.av_len = strlen(home.av_val);

    /* SWF hash info is cached in a fixed-format file.
     * url: <url of SWF file>
     * ctim: HTTP datestamp of when we last checked it.
     * date: HTTP datestamp of the SWF's last modification.
     * size: SWF size in hex
     * hash: SWF hash in hex
     *
     * These fields must be present in this order. All fields
     * besides URL are fixed size.
     */
    path = malloc(hpre.av_len + home.av_len + sizeof(DIRSEP ".swfinfo"));
    sprintf(path, "%s%s" DIRSEP ".swfinfo", hpre.av_val, home.av_val);

    f = fopen(path, "r+");
    while (f)
    {
        char buf[4096], *file, *p;

        file = strchr(url, '/');
        if (!file)
            break;
        file += 2;
        file = strchr(file, '/');
        if (!file)
            break;
        file++;
        hlen = file - url;
        p = strrchr(file, '/');
        if (p)
            file = p;
        else
            file--;

        while (fgets(buf, sizeof(buf), f))
        {
            char *r1;

            got = 0;

            if (strncmp(buf, "url: ", 5))
                continue;
            if (strncmp(buf + 5, url, hlen))
                continue;
            r1 = strrchr(buf, '/');
            i = strlen(r1);
            r1[--i] = '\0';
            if (strncmp(r1, file, i))
                continue;
            pos = ftell(f);
            while (got < 4 && fgets(buf, sizeof(buf), f))
            {
                if (!strncmp(buf, "size: ", 6))
                {
                    *size = strtol(buf + 6, NULL, 16);
                    got++;
                }
                else if (!strncmp(buf, "hash: ", 6))
                {
                    unsigned char *ptr = hash, *in = (unsigned char *)buf + 6;
                    int l = strlen((char *)in) - 1;
                    for (i = 0; i < l; i += 2)
                        *ptr++ = (HEX2BIN(in[i]) << 4) | HEX2BIN(in[i + 1]);
                    got++;
                }
                else if (!strncmp(buf, "date: ", 6))
                {
                    buf[strlen(buf) - 1] = '\0';
                    strncpy(date, buf + 6, sizeof(date));
                    got++;
                }
                else if (!strncmp(buf, "ctim: ", 6))
                {
                    buf[strlen(buf) - 1] = '\0';
                    ctim = make_unix_time(buf + 6);
                    got++;
                }
                else if (!strncmp(buf, "url: ", 5))
                    break;
            }
            break;
        }
        break;
    }

    cnow = time(NULL);
    /* If we got a cache time, see if it's young enough to use directly */
    if (age && ctim > 0)
    {
        ctim = cnow - ctim;
        ctim /= 3600 * 24;	/* seconds to days */
        if (ctim < age)		/* ok, it's new enough */
            goto out;
    }

    in.first = 1;
    HMAC_setup(in.ctx, "Genuine Adobe Flash Player 001", 30);
    inflateInit(&zs);
    in.zs = &zs;

    http.date = date;
    http.data = &in;

    httpres = HTTP_get(&http, url, swfcrunch);

    inflateEnd(&zs);

    if (httpres != HTTPRES_OK && httpres != HTTPRES_OK_NOT_MODIFIED)
    {
        ret = -1;
        if (httpres == HTTPRES_LOST_CONNECTION)
            RTMP_Log(RTMP_LOGERROR, "%s: connection lost while downloading swfurl %s",
                     __FUNCTION__, url);
        else if (httpres == HTTPRES_NOT_FOUND)
            RTMP_Log(RTMP_LOGERROR, "%s: swfurl %s not found", __FUNCTION__, url);
        else
            RTMP_Log(RTMP_LOGERROR, "%s: couldn't contact swfurl %s (HTTP error %d)",
                     __FUNCTION__, url, http.status);
    }
    else
    {
        if (got && pos)
            fseek(f, pos, SEEK_SET);
        else
        {
            char *q;
            if (!f)
                f = fopen(path, "w");
            if (!f)
            {
                int err = errno;
                RTMP_Log(RTMP_LOGERROR,
                         "%s: couldn't open %s for writing, errno %d (%s)",
                         __FUNCTION__, path, err, strerror(err));
                ret = -1;
                goto out;
            }
            fseek(f, 0, SEEK_END);
            q = strchr(url, '?');
            if (q)
                i = q - url;
            else
                i = strlen(url);

            fprintf(f, "url: %.*s\n", i, url);
        }
        strtime(&cnow, cctim);
        fprintf(f, "ctim: %s\n", cctim);

        if (!in.first)
        {
            HMAC_finish(in.ctx, hash, hlen);
            *size = in.size;

            fprintf(f, "date: %s\n", date);
            fprintf(f, "size: %08x\n", in.size);
            fprintf(f, "hash: ");
            for (i = 0; i < SHA256_DIGEST_LENGTH; i++)
                fprintf(f, "%02x", hash[i]);
            fprintf(f, "\n");
        }
    }
    HMAC_close(in.ctx);
out:
    free(path);
    if (f)
        fclose(f);
    return ret;
}
#else
int
RTMP_HashSWF(const char *url, unsigned int *size, unsigned char *hash,
             int age)
{
    (void)url;
    (void)size;
    (void)hash;
    (void)age;
    return -1;
}
#endif
