/*

 * This file is part of mpv.

 *

 * mpv 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.

 *

 * mpv 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 mpv.  If not, see <http://www.gnu.org/licenses/>.

 */

#include <libavformat/avformat.h>

#include <libavformat/avio.h>

#include <libavutil/opt.h>

#include "options/path.h"

#include "common/common.h"

#include "common/msg.h"

#include "common/tags.h"

#include "common/av_common.h"

#include "demux/demux.h"

#include "misc/charset_conv.h"

#include "misc/thread_tools.h"

#include "stream.h"

#include "options/m_config.h"

#include "options/m_option.h"

#include "cookies.h"

#include "misc/bstr.h"

#include "mpv_talloc.h"

#define OPT_BASE_STRUCT struct stream_lavf_params

struct stream_lavf_params {

    char **avopts;

    bool cookies_enabled;

    char *cookies_file;

    char *useragent;

    char *referrer;

    char **http_header_fields;

    bool tls_verify;

    char *tls_ca_file;

    char *tls_cert_file;

    char *tls_key_file;

    double timeout;

    char *http_proxy;

};

const struct m_sub_options stream_lavf_conf = {

    .opts = (const m_option_t[]) {

        {"stream-lavf-o", OPT_KEYVALUELIST(avopts)},

        {"http-header-fields", OPT_STRINGLIST(http_header_fields)},

        {"user-agent", OPT_STRING(useragent)},

        {"referrer", OPT_STRING(referrer)},

        {"cookies", OPT_BOOL(cookies_enabled)},

        {"cookies-file", OPT_STRING(cookies_file), .flags = M_OPT_FILE},

        {"tls-verify", OPT_BOOL(tls_verify)},

        {"tls-ca-file", OPT_STRING(tls_ca_file), .flags = M_OPT_FILE},

        {"tls-cert-file", OPT_STRING(tls_cert_file), .flags = M_OPT_FILE},

        {"tls-key-file", OPT_STRING(tls_key_file), .flags = M_OPT_FILE},

        {"network-timeout", OPT_DOUBLE(timeout), M_RANGE(0, DBL_MAX)},

        {"http-proxy", OPT_STRING(http_proxy)},

        {0}

    },

    .size = sizeof(struct stream_lavf_params),

    .defaults = &(const struct stream_lavf_params){

        .useragent = "libmpv",

        .timeout = 60,

    },

};

static const char *const http_like[] =

    {"http", "https", "mmsh", "mmshttp", "httproxy", NULL};

static int open_f(stream_t *stream);

static struct mp_tags *read_icy(stream_t *stream);

static int fill_buffer(stream_t *s, void *buffer, int max_len)

{

    AVIOContext *avio = s->priv;

    int r = avio_read_partial(avio, buffer, max_len);

    return (r <= 0) ? -1 : r;

}

static int write_buffer(stream_t *s, void *buffer, int len)

{

    AVIOContext *avio = s->priv;

    avio_write(avio, buffer, len);

    avio_flush(avio);

    if (avio->error)

        return -1;

    return len;

}

static int seek(stream_t *s, int64_t newpos)

{

    AVIOContext *avio = s->priv;

    if (avio_seek(avio, newpos, SEEK_SET) < 0) {

        return 0;

    }

    return 1;

}

static int64_t get_size(stream_t *s)

{

    AVIOContext *avio = s->priv;

    return avio_size(avio);

}

static void close_f(stream_t *stream)

{

    AVIOContext *avio = stream->priv;

    /* NOTE: As of 2011 write streams must be manually flushed before close.

     * Currently write_buffer() always flushes them after writing.

     * avio_close() could return an error, but we have no way to return that

     * with the current stream API.

     */

    if (avio)

        avio_close(avio);

}

static int control(stream_t *s, int cmd, void *arg)

{

    AVIOContext *avio = s->priv;

    switch(cmd) {

    case STREAM_CTRL_AVSEEK: {

        struct stream_avseek *c = arg;

        int64_t r = avio_seek_time(avio, c->stream_index, c->timestamp, c->flags);

        if (r >= 0) {

            stream_drop_buffers(s);

            return 1;

        }

        break;

    }

    case STREAM_CTRL_HAS_AVSEEK: {

        // Starting at some point, read_seek is always available, and runtime

        // behavior decides whether it exists or not. FFmpeg's API doesn't

        // return anything helpful to determine seekability upfront, so here's

        // a hardcoded whitelist. Not our fault.

        // In addition we also have to jump through ridiculous hoops just to

        // get the fucking protocol name.

        const char *proto = NULL;

        if (avio->av_class && avio->av_class->child_next) {

            // This usually yields the URLContext (why does it even exist?),

            // which holds the name of the actual protocol implementation.

            void *child = avio->av_class->child_next(avio, NULL);

            AVClass *cl = *(AVClass **)child;

            if (cl && cl->item_name)

                proto = cl->item_name(child);

        }

        static const char *const has_read_seek[] = {

            "rtmp", "rtmpt", "rtmpe", "rtmpte", "rtmps", "rtmpts", "mmsh", 0};

        for (int n = 0; has_read_seek[n]; n++) {

            if (avio->read_seek && proto && strcmp(proto, has_read_seek[n]) == 0)

                return 1;

        }

        break;

    }

    case STREAM_CTRL_GET_METADATA: {

        *(struct mp_tags **)arg = read_icy(s);

        if (!*(struct mp_tags **)arg)

            break;

        return 1;

    }

    }

    return STREAM_UNSUPPORTED;

}

static int interrupt_cb(void *ctx)

{

    struct stream *stream = ctx;

    return mp_cancel_test(stream->cancel);

}

static const char * const prefix[] = { "lavf://", "ffmpeg://" };

void mp_setup_av_network_options(AVDictionary **dict, const char *target_fmt,

                                 struct mpv_global *global, struct mp_log *log)

{

    void *temp = talloc_new(NULL);

    struct stream_lavf_params *opts =

        mp_get_config_group(temp, global, &stream_lavf_conf);

    // HTTP specific options (other protocols ignore them)

    if (opts->useragent)

        av_dict_set(dict, "user_agent", opts->useragent, 0);

    if (opts->cookies_enabled) {

        char *file = opts->cookies_file;

        if (file && file[0])

            file = mp_get_user_path(temp, global, file);

        char *cookies = cookies_lavf(temp, global, log, file);

        if (cookies && cookies[0])

            av_dict_set(dict, "cookies", cookies, 0);

    }

    av_dict_set(dict, "tls_verify", opts->tls_verify ? "1" : "0", 0);

    if (opts->tls_ca_file) {

        char *file = mp_get_user_path(temp, global, opts->tls_ca_file);

        av_dict_set(dict, "ca_file", file, 0);

    }

    if (opts->tls_cert_file) {

        char *file = mp_get_user_path(temp, global, opts->tls_cert_file);

        av_dict_set(dict, "cert_file", file, 0);

    }

    if (opts->tls_key_file) {

        char *file = mp_get_user_path(temp, global, opts->tls_key_file);

        av_dict_set(dict, "key_file", file, 0);

    }

    char *cust_headers = talloc_strdup(temp, "");

    if (opts->referrer) {

        cust_headers = talloc_asprintf_append(cust_headers, "Referer: %s\r\n",

                                              opts->referrer);

    }

    if (opts->http_header_fields) {

        for (int n = 0; opts->http_header_fields[n]; n++) {

            cust_headers = talloc_asprintf_append(cust_headers, "%s\r\n",

                                                  opts->http_header_fields[n]);

        }

    }

    if (strlen(cust_headers))

        av_dict_set(dict, "headers", cust_headers, 0);

    av_dict_set(dict, "icy", "1", 0);

    // So far, every known protocol uses microseconds for this

    // Except rtsp.

    if (opts->timeout > 0) {

        if (target_fmt && strcmp(target_fmt, "rtsp") == 0) {

            mp_verbose(log, "Broken FFmpeg RTSP API => not setting timeout.\n");

        } else {

            char buf[80];

            snprintf(buf, sizeof(buf), "%lld", (long long)(opts->timeout * 1e6));

            av_dict_set(dict, "timeout", buf, 0);

        }

    }

    if (opts->http_proxy && opts->http_proxy[0])

        av_dict_set(dict, "http_proxy", opts->http_proxy, 0);

    mp_set_avdict(dict, opts->avopts);

    talloc_free(temp);

}

#define PROTO(...) (const char *[]){__VA_ARGS__, NULL}

// List of safe protocols and their aliases

static const char **safe_protos[] = {

    PROTO("data"),

    PROTO("gopher"),

    PROTO("gophers"),

    PROTO("http", "dav", "webdav"),

    PROTO("httpproxy"),

    PROTO("https", "davs", "webdavs"),

    PROTO("ipfs"),

    PROTO("ipns"),

    PROTO("mmsh", "mms", "mmshttp"),

    PROTO("mmst"),

    PROTO("rist"),

    PROTO("rtmp"),

    PROTO("rtmpe"),

    PROTO("rtmps"),

    PROTO("rtmpt"),

    PROTO("rtmpte"),

    PROTO("rtmpts"),

    PROTO("rtp"),

    PROTO("srt"),

    PROTO("srtp"),

    NULL,

};

static char **get_safe_protocols(void)

{

    int num = 0;

    char **protocols = NULL;

    char **ffmpeg_demuxers = mp_get_lavf_demuxers();

    char **ffmpeg_protos = mp_get_lavf_protocols();

    for (int i = 0; ffmpeg_protos[i]; i++) {

        for (int j = 0; safe_protos[j]; j++) {

            if (strcmp(ffmpeg_protos[i], safe_protos[j][0]) != 0)

                continue;

            for (int k = 0; safe_protos[j][k]; k++)

                MP_TARRAY_APPEND(NULL, protocols, num, talloc_strdup(protocols, safe_protos[j][k]));

            break;

        }

    }

    // rtsp is a demuxer not protocol in ffmpeg so it is handled separately

    for (int i = 0; ffmpeg_demuxers[i]; i++) {

        if (strcmp("rtsp", ffmpeg_demuxers[i]) == 0) {

            MP_TARRAY_APPEND(NULL, protocols, num, talloc_strdup(protocols, "rtsp"));

            MP_TARRAY_APPEND(NULL, protocols, num, talloc_strdup(protocols, "rtsps"));

            break;

        }

    }

    MP_TARRAY_APPEND(NULL, protocols, num, NULL);

    talloc_free(ffmpeg_demuxers);

    talloc_free(ffmpeg_protos);

    return protocols;

}

static char **get_unsafe_protocols(void)

{

    int num = 0;

    char **protocols = NULL;

    char **safe_protocols = get_safe_protocols();

    char **ffmpeg_protos = mp_get_lavf_protocols();

    for (int i = 0; ffmpeg_protos[i]; i++) {

        bool safe_protocol = false;

        for (int j = 0; safe_protocols[j]; j++) {

            if (strcmp(ffmpeg_protos[i], safe_protocols[j]) == 0) {

                safe_protocol = true;

                break;

            }

        }

        // Skip to avoid name conflict with builtin mpv protocol.

        if (strcmp(ffmpeg_protos[i], "bluray") == 0 || strcmp(ffmpeg_protos[i], "dvd") == 0)

            continue;

        if (!safe_protocol)

            MP_TARRAY_APPEND(NULL, protocols, num, talloc_strdup(protocols, ffmpeg_protos[i]));

    }

    MP_TARRAY_APPEND(NULL, protocols, num, talloc_strdup(protocols, "ffmpeg"));

    MP_TARRAY_APPEND(NULL, protocols, num, talloc_strdup(protocols, "lavf"));

    MP_TARRAY_APPEND(NULL, protocols, num, NULL);

    talloc_free(ffmpeg_protos);

    talloc_free(safe_protocols);

    return protocols;

}

// Escape http URLs with unescaped, invalid characters in them.

// libavformat's http protocol does not do this, and a patch to add this

// in a 100% safe case (spaces only) was rejected.

static char *normalize_url(void *ta_parent, const char *filename)

{

    bstr proto = mp_split_proto(bstr0(filename), NULL);

    for (int n = 0; http_like[n]; n++) {

        if (bstr_equals0(proto, http_like[n]))

            // Escape everything but reserved characters.

            // Also don't double-scape, so include '%'.

            return mp_url_escape(ta_parent, filename, ":/?#[]@!$&'()*+,;=%");

    }

    return (char *)filename;

}

static int open_f(stream_t *stream)

{

    AVIOContext *avio = NULL;

    int res = STREAM_ERROR;

    AVDictionary *dict = NULL;

    void *temp = talloc_new(NULL);

    stream->seek = NULL;

    stream->seekable = false;

    int flags = stream->mode == STREAM_WRITE ? AVIO_FLAG_WRITE : AVIO_FLAG_READ;

    const char *filename = stream->url;

    if (!filename) {

        MP_ERR(stream, "No URL\n");

        goto out;

    }

    for (int i = 0; i < MP_ARRAY_SIZE(prefix); i++)

        if (!strncmp(filename, prefix[i], strlen(prefix[i])))

            filename += strlen(prefix[i]);

    if (!strncmp(filename, "rtsp:", 5) || !strncmp(filename, "rtsps:", 6)) {

        /* This is handled as a special demuxer, without a separate

         * stream layer. demux_lavf will do all the real work. Note

         * that libavformat doesn't even provide a protocol entry for

         * this (the rtsp demuxer's probe function checks for a "rtsp:"

         * filename prefix), so it has to be handled specially here.

         */

        stream->demuxer = "lavf";

        stream->lavf_type = "rtsp";

        talloc_free(temp);

        return STREAM_OK;

    }

    // Replace "mms://" with "mmsh://", so that most mms:// URLs just work.

    // Replace "dav://" or "webdav://" with "http://" and "davs://" or "webdavs://" with "https://"

    bstr b_filename = bstr0(filename);

    if (bstr_eatstart0(&b_filename, "mms://") ||

        bstr_eatstart0(&b_filename, "mmshttp://"))

    {

        filename = talloc_asprintf(temp, "mmsh://%.*s", BSTR_P(b_filename));

    } else if (bstr_eatstart0(&b_filename, "dav://") || bstr_eatstart0(&b_filename, "webdav://"))

    {

        filename = talloc_asprintf(temp, "http://%.*s", BSTR_P(b_filename));

    } else if (bstr_eatstart0(&b_filename, "davs://") || bstr_eatstart0(&b_filename, "webdavs://"))

    {

        filename = talloc_asprintf(temp, "https://%.*s", BSTR_P(b_filename));

    }

    av_dict_set(&dict, "reconnect", "1", 0);

    av_dict_set(&dict, "reconnect_delay_max", "7", 0);

    mp_setup_av_network_options(&dict, NULL, stream->global, stream->log);

    AVIOInterruptCB cb = {

        .callback = interrupt_cb,

        .opaque = stream,

    };

    filename = normalize_url(stream, filename);

    if (strncmp(filename, "rtmp", 4) == 0) {

        stream->demuxer = "lavf";

        stream->lavf_type = "flv";

        // Setting timeout enables listen mode - force it to disabled.

        av_dict_set(&dict, "timeout", "0", 0);

    }

    int err = avio_open2(&avio, filename, flags, &cb, &dict);

    if (err < 0) {

        if (err == AVERROR_PROTOCOL_NOT_FOUND)

            MP_ERR(stream, "Protocol not found. Make sure"

                   " FFmpeg is compiled with networking support.\n");

        goto out;

    }

    mp_avdict_print_unset(stream->log, MSGL_V, dict);

    if (avio->av_class) {

        uint8_t *mt = NULL;

        if (av_opt_get(avio, "mime_type", AV_OPT_SEARCH_CHILDREN, &mt) >= 0) {

            stream->mime_type = talloc_strdup(stream, mt);

            av_free(mt);

        }

    }

    stream->priv = avio;

    stream->seekable = avio->seekable & AVIO_SEEKABLE_NORMAL;

    stream->seek = stream->seekable ? seek : NULL;

    stream->fill_buffer = fill_buffer;

    stream->write_buffer = write_buffer;

    stream->get_size = get_size;

    stream->control = control;

    stream->close = close_f;

    // enable cache (should be avoided for files, but no way to detect this)

    stream->streaming = true;

    if (stream->info->stream_origin == STREAM_ORIGIN_NET)

        stream->is_network = true;

    res = STREAM_OK;

out:

    av_dict_free(&dict);

    talloc_free(temp);

    return res;

}

static struct mp_tags *read_icy(stream_t *s)

{

    AVIOContext *avio = s->priv;

    if (!avio->av_class)

        return NULL;

    uint8_t *icy_header = NULL;

    if (av_opt_get(avio, "icy_metadata_headers", AV_OPT_SEARCH_CHILDREN,

                   &icy_header) < 0)

        icy_header = NULL;

    uint8_t *icy_packet;

    if (av_opt_get(avio, "icy_metadata_packet", AV_OPT_SEARCH_CHILDREN,

                   &icy_packet) < 0)

        icy_packet = NULL;

    // Send a metadata update only 1. on start, and 2. on a new metadata packet.

    // To detect new packages, set the icy_metadata_packet to "-" once we've

    // read it (a bit hacky, but works).

    struct mp_tags *res = NULL;

    if ((!icy_header || !icy_header[0]) && (!icy_packet || !icy_packet[0]))

        goto done;

    bstr packet = bstr0(icy_packet);

    if (bstr_equals0(packet, "-"))

        goto done;

    res = talloc_zero(NULL, struct mp_tags);

    bstr header = bstr0(icy_header);

    while (header.len) {

        bstr line = bstr_strip_linebreaks(bstr_getline(header, &header));

        bstr name, val;

        if (bstr_split_tok(line, ": ", &name, &val))

            mp_tags_set_bstr(res, name, val);

    }

    bstr head = bstr0("StreamTitle='");

    int i = bstr_find(packet, head);

    if (i >= 0) {

        packet = bstr_cut(packet, i + head.len);

        int end = bstr_find(packet, bstr0("\';"));

        packet = bstr_splice(packet, 0, end);

        bool allocated = false;

        struct demux_opts *opts = mp_get_config_group(NULL, s->global, &demux_conf);

        const char *charset = mp_charset_guess(s, s->log, packet, opts->meta_cp, 0);

        if (charset && !mp_charset_is_utf8(charset)) {

            bstr conv = mp_iconv_to_utf8(s->log, packet, charset, 0);

            if (conv.start && conv.start != packet.start) {

                allocated = true;

                packet = conv;

            }

        }

        mp_tags_set_bstr(res, bstr0("icy-title"), packet);

        talloc_free(opts);

        if (allocated)

            talloc_free(packet.start);

    }

    av_opt_set(avio, "icy_metadata_packet", "-", AV_OPT_SEARCH_CHILDREN);

done:

    av_free(icy_header);

    av_free(icy_packet);

    return res;

}

const stream_info_t stream_info_ffmpeg = {

    .name = "ffmpeg",

    .open = open_f,

    .get_protocols = get_safe_protocols,

    .can_write = true,

    .stream_origin = STREAM_ORIGIN_NET,

};

// Unlike above, this is not marked as safe, and can contain protocols which

// may do insecure things. (Such as "ffmpeg", which can access the "lavfi"

// pseudo-demuxer, which in turn gives access to filters that can access the

// local filesystem.)

const stream_info_t stream_info_ffmpeg_unsafe = {

    .name = "ffmpeg",

    .open = open_f,

    .get_protocols = get_unsafe_protocols,

    .stream_origin = STREAM_ORIGIN_UNSAFE,

    .can_write = true,

};