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/*

 * RTMP HTTP network protocol

 * Copyright (c) 2012 Samuel Pitoiset

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg 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 of the License, or (at your option) any later version.

 *

 * FFmpeg 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * RTMP HTTP protocol

 */

#include "libavutil/avstring.h"

#include "libavutil/intfloat.h"

#include "libavutil/opt.h"

#include "libavutil/time.h"

#include "internal.h"

#include "http.h"

#include "rtmp.h"

#define RTMPT_DEFAULT_PORT 80

#define RTMPTS_DEFAULT_PORT RTMPS_DEFAULT_PORT

/* protocol handler context */

typedef struct RTMP_HTTPContext {

    const AVClass *class;

    URLContext   *stream;           ///< HTTP stream

    char         host[256];         ///< hostname of the server

    int          port;              ///< port to connect (default is 80)

    char         client_id[64];     ///< client ID used for all requests except the first one

    int          seq;               ///< sequence ID used for all requests

    uint8_t      *out_data;         ///< output buffer

    int          out_size;          ///< current output buffer size

    int          out_capacity;      ///< current output buffer capacity

    int          initialized;       ///< flag indicating when the http context is initialized

    int          finishing;         ///< flag indicating when the client closes the connection

    int          nb_bytes_read;     ///< number of bytes read since the last request

    int          tls;               ///< use Transport Security Layer (RTMPTS)

} RTMP_HTTPContext;

static int rtmp_http_send_cmd(URLContext *h, const char *cmd)

{

    RTMP_HTTPContext *rt = h->priv_data;

    char uri[2048];

    uint8_t c;

    int ret;

    ff_url_join(uri, sizeof(uri), "http", NULL, rt->host, rt->port,

                "/%s/%s/%d", cmd, rt->client_id, rt->seq++);

    av_opt_set_bin(rt->stream->priv_data, "post_data", rt->out_data,

                   rt->out_size, 0);

    /* send a new request to the server */

    if ((ret = ff_http_do_new_request(rt->stream, uri)) < 0)

        return ret;

    /* re-init output buffer */

    rt->out_size = 0;

    /* read the first byte which contains the polling interval */

    if ((ret = ffurl_read(rt->stream, &c, 1)) < 0)

        return ret;

    /* re-init the number of bytes read */

    rt->nb_bytes_read = 0;

    return ret;

}

static int rtmp_http_write(URLContext *h, const uint8_t *buf, int size)

{

    RTMP_HTTPContext *rt = h->priv_data;

    if (rt->out_size + size > rt->out_capacity) {

        int err;

        rt->out_capacity = (rt->out_size + size) * 2;

        if ((err = av_reallocp(&rt->out_data, rt->out_capacity)) < 0) {

            rt->out_size = 0;

            rt->out_capacity = 0;

            return err;

        }

    }

    memcpy(rt->out_data + rt->out_size, buf, size);

    rt->out_size += size;

    return size;

}

static int rtmp_http_read(URLContext *h, uint8_t *buf, int size)

{

    RTMP_HTTPContext *rt = h->priv_data;

    int ret, off = 0;

    /* try to read at least 1 byte of data */

    do {

        ret = ffurl_read(rt->stream, buf + off, size);

        if (ret < 0 && ret != AVERROR_EOF)

            return ret;

        if (ret == AVERROR_EOF) {

            if (rt->finishing) {

                /* Do not send new requests when the client wants to

                 * close the connection. */

                return AVERROR(EAGAIN);

            }

            /* When the client has reached end of file for the last request,

             * we have to send a new request if we have buffered data.

             * Otherwise, we have to send an idle POST. */

            if (rt->out_size > 0) {

                if ((ret = rtmp_http_send_cmd(h, "send")) < 0)

                    return ret;

            } else {

                if (rt->nb_bytes_read == 0) {

                    /* Wait 50ms before retrying to read a server reply in

                     * order to reduce the number of idle requets. */

                    av_usleep(50000);

                }

                if ((ret = rtmp_http_write(h, "", 1)) < 0)

                    return ret;

                if ((ret = rtmp_http_send_cmd(h, "idle")) < 0)

                    return ret;

            }

            if (h->flags & AVIO_FLAG_NONBLOCK) {

                /* no incoming data to handle in nonblocking mode */

                return AVERROR(EAGAIN);

            }

        } else {

            off  += ret;

            size -= ret;

            rt->nb_bytes_read += ret;

        }

    } while (off <= 0);

    return off;

}

static int rtmp_http_close(URLContext *h)

{

    RTMP_HTTPContext *rt = h->priv_data;

    uint8_t tmp_buf[2048];

    int ret = 0;

    if (rt->initialized) {

        /* client wants to close the connection */

        rt->finishing = 1;

        do {

            ret = rtmp_http_read(h, tmp_buf, sizeof(tmp_buf));

        } while (ret > 0);

        /* re-init output buffer before sending the close command */

        rt->out_size = 0;

        if ((ret = rtmp_http_write(h, "", 1)) == 1)

            ret = rtmp_http_send_cmd(h, "close");

    }

    av_freep(&rt->out_data);

    ffurl_close(rt->stream);

    return ret;

}

static int rtmp_http_open(URLContext *h, const char *uri, int flags)

{

    RTMP_HTTPContext *rt = h->priv_data;

    char headers[1024], url[1024];

    int ret, off = 0;

    av_url_split(NULL, 0, NULL, 0, rt->host, sizeof(rt->host), &rt->port,

                 NULL, 0, uri);

    /* This is the first request that is sent to the server in order to

     * register a client on the server and start a new session. The server

     * replies with a unique id (usually a number) that is used by the client

     * for all future requests.

     * Note: the reply doesn't contain a value for the polling interval.

     * A successful connect resets the consecutive index that is used

     * in the URLs. */

    if (rt->tls) {

        if (rt->port < 0)

            rt->port = RTMPTS_DEFAULT_PORT;

        ff_url_join(url, sizeof(url), "https", NULL, rt->host, rt->port, "/open/1");

    } else {

        if (rt->port < 0)

            rt->port = RTMPT_DEFAULT_PORT;

        ff_url_join(url, sizeof(url), "http", NULL, rt->host, rt->port, "/open/1");

    }

    /* alloc the http context */

    if ((ret = ffurl_alloc(&rt->stream, url, AVIO_FLAG_READ_WRITE, NULL)) < 0)

        goto fail;

    /* set options */

    snprintf(headers, sizeof(headers),

             "Cache-Control: no-cache\r\n"

             "Content-type: application/x-fcs\r\n"

             "User-Agent: Shockwave Flash\r\n");

    av_opt_set(rt->stream->priv_data, "headers", headers, 0);

    av_opt_set(rt->stream->priv_data, "multiple_requests", "1", 0);

    av_opt_set_bin(rt->stream->priv_data, "post_data", "", 1, 0);

    /* open the http context */

    if ((ret = ffurl_connect(rt->stream, NULL)) < 0)

        goto fail;

    /* read the server reply which contains a unique ID */

    for (;;) {

        ret = ffurl_read(rt->stream, rt->client_id + off, sizeof(rt->client_id) - off);

        if (ret == AVERROR_EOF)

            break;

        if (ret < 0)

            goto fail;

        off += ret;

        if (off == sizeof(rt->client_id)) {

            ret = AVERROR(EIO);

            goto fail;

        }

    }

    while (off > 0 && av_isspace(rt->client_id[off - 1]))

        off--;

    rt->client_id[off] = '\0';

    /* http context is now initialized */

    rt->initialized = 1;

    return 0;

fail:

    rtmp_http_close(h);

    return ret;

}

#define OFFSET(x) offsetof(RTMP_HTTPContext, x)

#define DEC AV_OPT_FLAG_DECODING_PARAM

static const AVOption ffrtmphttp_options[] = {

    {"ffrtmphttp_tls", "Use a HTTPS tunneling connection (RTMPTS).", OFFSET(tls), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC},

    { NULL },

};

static const AVClass ffrtmphttp_class = {

    .class_name = "ffrtmphttp",

    .item_name  = av_default_item_name,

    .option     = ffrtmphttp_options,

    .version    = LIBAVUTIL_VERSION_INT,

};

URLProtocol ff_ffrtmphttp_protocol = {

    .name           = "ffrtmphttp",

    .url_open       = rtmp_http_open,

    .url_read       = rtmp_http_read,

    .url_write      = rtmp_http_write,

    .url_close      = rtmp_http_close,

    .priv_data_size = sizeof(RTMP_HTTPContext),

    .flags          = URL_PROTOCOL_FLAG_NETWORK,

    .priv_data_class= &ffrtmphttp_class,

};