/* Icecast
 *
 *  This program is distributed under the GNU General Public License,
 *  version 2. A copy of this license is included with this source.
 *  At your option, this specific source file can also be distributed
 *  under the GNU GPL version 3.
 *
 * Copyright 2012,      David Richards, Mozilla Foundation,
 *                      and others (see AUTHORS for details).
 */


/* Ogg codec handler for opus streams */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdlib.h>
#include <string.h>
#include <ogg/ogg.h>

typedef struct source_tag source_t;

#include "format_opus.h"
#include "stats.h"
#include "refbuf.h"
#include "client.h"

#define CATMODULE "format-opus"
#include "logging.h"

static void opus_codec_free (ogg_state_t *ogg_info, ogg_codec_t *codec)
{
    stats_event(ogg_info->mount, "audio_channels", NULL);
    stats_event(ogg_info->mount, "audio_samplerate", NULL);
    ogg_stream_clear(&codec->os);
    free(codec);
}

static uint32_t __read_header_u32be_unaligned(const unsigned char *in)
{
    uint32_t ret = 0;
    ret += in[3];
    ret <<= 8;
    ret += in[2];
    ret <<= 8;
    ret += in[1];
    ret <<= 8;
    ret += in[0];
    return ret;
}

static void __handle_header_opushead(ogg_state_t *ogg_info, ogg_packet *packet)
{
    if (packet->bytes < 19) {
        ICECAST_LOG_WARN("Bad Opus header: header too small, expected at least 19 byte, got %li", (long int)packet->bytes);
        return; /* Invalid OpusHead */
    }

    if ((packet->packet[8] & 0xF0) != 0) {
        ICECAST_LOG_WARN("Bad Opus header: bad header version, expected major 0, got %i", (int)packet->packet[8]);
        return; /* Invalid OpusHead Version */
    }

    stats_event_args(ogg_info->mount, "audio_channels", "%ld", (long int)packet->packet[9]);
    stats_event_args(ogg_info->mount, "audio_samplerate", "%ld", (long int)__read_header_u32be_unaligned(packet->packet+12));
}

static void __handle_header_opustags(ogg_state_t *ogg_info, ogg_packet *packet, format_plugin_t *plugin) 
{
    size_t comments;
    size_t next;
    size_t left = packet->bytes;
    size_t buflen = 0;
    char *buf = NULL;
    char *buf_new;
    const void *p = packet->packet;

    if (packet->bytes < 16) {
        ICECAST_LOG_WARN("Bad Opus header: header too small, expected at least 16 byte, got %li", (long int)packet->bytes);
        return; /* Invalid OpusHead */
    }

    /* Skip header "OpusTags" */
    p += 8;
    left -= 8;

    /* Now the vendor string follows. We just skip it. */
    next = __read_header_u32be_unaligned(p);
    p += 4;
    left -= 4;

    if (left < (next + 4)) {
        ICECAST_LOG_WARN("Bad Opus header: corrupted OpusTags header.");
        return;
    }
    p += next;
    left -= next;

    /* Next is the comment counter. */
    comments = __read_header_u32be_unaligned(p);
    p += 4;
    left -= 4;

    /* Ok, next (comments) blocks follows, each composed of 4 byte length followed by the data */
    if (left < (comments * 4)) {
        ICECAST_LOG_WARN("Bad Opus header: corrupted OpusTags header.");
        return;
    }

    vorbis_comment_clear(&plugin->vc);
    vorbis_comment_init(&plugin->vc);

    while (comments) {
        next = __read_header_u32be_unaligned(p);
        p += 4;
        left -= 4;

        if (left < next) {
            if (buf)
                free(buf);
            vorbis_comment_clear(&plugin->vc);
            vorbis_comment_init(&plugin->vc);
            ICECAST_LOG_WARN("Bad Opus header: corrupted OpusTags header.");
            return;
        }

        if ((next + 1) > buflen) {
            buf_new = realloc(buf, next + 1);
            if (buf_new) {
                buf = buf_new;
                buflen = next + 1;
            }
        }

        if (buflen >= (next + 1)) {
            memcpy(buf, p, next);
            buf[next] = 0;
            vorbis_comment_add(&plugin->vc, buf);
        }

        p += next;
        left -= next;

        comments--;
        if (comments && left < 4) {
            if (buf)
                free(buf);
            vorbis_comment_clear(&plugin->vc);
            vorbis_comment_init(&plugin->vc);
            ICECAST_LOG_WARN("Bad Opus header: corrupted OpusTags header.");
            return;
        }
    }

    if (buf)
        free(buf);

    ogg_info->log_metadata = 1;
}

static void __handle_header(ogg_state_t *ogg_info,
        ogg_codec_t *codec, ogg_packet *packet, format_plugin_t *plugin)
{
    ICECAST_LOG_DEBUG("Got Opus header");
    if (packet->bytes < 8) {
        ICECAST_LOG_DEBUG("Not a real header, less than 8 bytes in size.");
        return; /* packet is not a header */
    }

    if (strncmp((const char*)packet->packet, "OpusHead", 8) == 0) {
        ICECAST_LOG_DEBUG("Got Opus header: OpusHead");
        __handle_header_opushead(ogg_info, packet);
    } else if (strncmp((const char*)packet->packet, "OpusTags", 8) == 0) {
        ICECAST_LOG_DEBUG("Got Opus header: OpusTags");
        __handle_header_opustags(ogg_info, packet, plugin);
    } else {
        ICECAST_LOG_DEBUG("Unknown header or data.");
        return; /* Unknown header or data */
    }
}

static refbuf_t *process_opus_page (ogg_state_t *ogg_info,
        ogg_codec_t *codec, ogg_page *page, format_plugin_t *plugin)
{
    refbuf_t *refbuf;

    if (codec->headers < 2)
    {
        ogg_packet packet;

        ogg_stream_pagein (&codec->os, page);
        while (ogg_stream_packetout (&codec->os, &packet) > 0)
        {
           /* first time around (normal case) yields comments */
           codec->headers++;
            __handle_header(ogg_info, codec, &packet, plugin);
        }
        /* add header page to associated list */
        format_ogg_attach_header (ogg_info, page);
        return NULL;
    }
    refbuf = make_refbuf_with_page (page);
    return refbuf;
}


ogg_codec_t *initial_opus_page (format_plugin_t *plugin, ogg_page *page)
{
    ogg_state_t *ogg_info = plugin->_state;
    ogg_codec_t *codec = calloc(1, sizeof (ogg_codec_t));
    ogg_packet packet;

    ogg_stream_init(&codec->os, ogg_page_serialno (page));
    ogg_stream_pagein(&codec->os, page);

    ogg_stream_packetout(&codec->os, &packet);

    ICECAST_LOG_DEBUG("checking for opus codec");
    if (packet.bytes < 8 || strncmp((char *)packet.packet, "OpusHead", 8) != 0)
    {
        ogg_stream_clear(&codec->os);
        free(codec);
        return NULL;
    }
    __handle_header(ogg_info, codec, &packet, plugin);
    ICECAST_LOG_INFO("seen initial opus header");
    codec->process_page = process_opus_page;
    codec->codec_free = opus_codec_free;
    codec->name = "Opus";
    codec->headers = 1;
    format_ogg_attach_header (ogg_info, page);
    return codec;
}

