/***
  This file is part of polypaudio.
 
  polypaudio 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 of the License,
  or (at your option) any later version.
 
  polypaudio 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 polypaudio; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  USA.
***/

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

#include <assert.h>
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>

#include <polyp/error.h>
#include <polyp/timeval.h>
#include <polyp/xmalloc.h>

#include <polypcore/module.h>
#include <polypcore/llist.h>
#include <polypcore/sink.h>
#include <polypcore/sink-input.h>
#include <polypcore/memblockq.h>
#include <polypcore/log.h>
#include <polypcore/core-util.h>
#include <polypcore/modargs.h>
#include <polypcore/namereg.h>
#include <polypcore/sample-util.h>

#include "module-rtp-recv-symdef.h"

#include "rtp.h"
#include "sdp.h"
#include "sap.h"

PA_MODULE_AUTHOR("Lennart Poettering")
PA_MODULE_DESCRIPTION("Recieve data from a network via RTP/SAP/SDP")
PA_MODULE_VERSION(PACKAGE_VERSION)
PA_MODULE_USAGE(
        "sink=<name of the sink> "
        "sap_address=<multicast address to listen on> "
)

#define SAP_PORT 9875
#define DEFAULT_SAP_ADDRESS "224.0.0.56"
#define MEMBLOCKQ_MAXLENGTH (1024*170)
#define MAX_SESSIONS 16
#define DEATH_TIMEOUT 20000000

static const char* const valid_modargs[] = {
    "sink",
    "sap_address",
    NULL
};

struct session {
    struct userdata *userdata;

    pa_sink_input *sink_input;
    pa_memblockq *memblockq;

    pa_time_event *death_event;

    int first_packet;
    uint32_t ssrc;
    uint32_t offset;

    struct pa_sdp_info sdp_info;

    pa_rtp_context rtp_context;
    pa_io_event* rtp_event;
};

struct userdata {
    pa_module *module;
    pa_core *core;

    pa_sap_context sap_context;
    pa_io_event* sap_event;

    pa_hashmap *by_origin;

    char *sink_name;

    int n_sessions;
};

static void session_free(struct session *s, int from_hash);

static int sink_input_peek(pa_sink_input *i, pa_memchunk *chunk) {
    struct session *s;
    assert(i);
    s = i->userdata;

    return pa_memblockq_peek(s->memblockq, chunk);
}

static void sink_input_drop(pa_sink_input *i, const pa_memchunk *chunk, size_t length) {
    struct session *s;
    assert(i);
    s = i->userdata;

    pa_memblockq_drop(s->memblockq, chunk, length);
}

static void sink_input_kill(pa_sink_input* i) {
    struct session *s;
    assert(i);
    s = i->userdata;

    session_free(s, 1);
}

static pa_usec_t sink_input_get_latency(pa_sink_input *i) {
    struct session *s;
    assert(i);
    s = i->userdata;

    return pa_bytes_to_usec(pa_memblockq_get_length(s->memblockq), &i->sample_spec);
}

static void rtp_event_cb(pa_mainloop_api *m, pa_io_event *e, int fd, pa_io_event_flags_t flags, void *userdata) {
    struct session *s = userdata;
    pa_memchunk chunk;
    int64_t k, j, delta;
    struct timeval tv;
    
    assert(m);
    assert(e);
    assert(s);
    assert(fd == s->rtp_context.fd);
    assert(flags == PA_IO_EVENT_INPUT);

    if (pa_rtp_recv(&s->rtp_context, &chunk, s->userdata->core->memblock_stat) < 0)
        return;

    if (s->sdp_info.payload != s->rtp_context.payload) {
        pa_memblock_unref(chunk.memblock);
        return;
    }
    
    if (!s->first_packet) {
        s->first_packet = 1;

        s->ssrc = s->rtp_context.ssrc;
        s->offset = s->rtp_context.timestamp;

        if (s->ssrc == s->userdata->core->cookie)
            pa_log_warn(__FILE__": WARNING! Detected RTP packet loop!");
    } else {
        if (s->ssrc != s->rtp_context.ssrc) {
            pa_memblock_unref(chunk.memblock);
            return;
        }
    }

    /* Check wheter there was a timestamp overflow */
    k = (int64_t) s->rtp_context.timestamp - (int64_t) s->offset;
    j = (int64_t) 0x100000000LL - (int64_t) s->offset + (int64_t) s->rtp_context.timestamp;

    if ((k < 0 ? -k : k) < (j < 0 ? -j : j))
        delta = k;
    else
        delta = j;
    
    pa_memblockq_seek(s->memblockq, delta * s->rtp_context.frame_size, PA_SEEK_RELATIVE);

    if (pa_memblockq_push(s->memblockq, &chunk) < 0) {
        /* queue overflow, let's flush it and try again */
        pa_memblockq_flush(s->memblockq);
        pa_memblockq_push(s->memblockq, &chunk);
    }
    
    /* The next timestamp we expect */
    s->offset = s->rtp_context.timestamp + (chunk.length / s->rtp_context.frame_size);
    
    pa_memblock_unref(chunk.memblock);

    /* Reset death timer */
    pa_gettimeofday(&tv);
    pa_timeval_add(&tv, DEATH_TIMEOUT);
    m->time_restart(s->death_event, &tv);
}

static void death_event_cb(pa_mainloop_api *m, pa_time_event *t, const struct timeval *tv, void *userdata) {
    struct session *s = userdata;
    
    assert(m);
    assert(t);
    assert(tv);
    assert(s);

    session_free(s, 1);
}

static int mcast_socket(const struct sockaddr* sa, socklen_t salen) {
    int af, fd = -1, r, one;
    
    af = sa->sa_family;
    if ((fd = socket(af, SOCK_DGRAM, 0)) < 0) {
        pa_log(__FILE__": Failed to create socket: %s", pa_cstrerror(errno));
        goto fail;
    }

    one = 1;
    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) < 0) {
        pa_log(__FILE__": SO_REUSEADDR failed: %s", pa_cstrerror(errno));
        goto fail;
    }
    
    if (af == AF_INET) {
        struct ip_mreq mr4;
        memset(&mr4, 0, sizeof(mr4));
        mr4.imr_multiaddr = ((const struct sockaddr_in*) sa)->sin_addr;
        r = setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mr4, sizeof(mr4));
    } else {
        struct ipv6_mreq mr6;
        memset(&mr6, 0, sizeof(mr6));
        mr6.ipv6mr_multiaddr = ((const struct sockaddr_in6*) sa)->sin6_addr;
        r = setsockopt(fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &mr6, sizeof(mr6));
    }

    if (r < 0) {
        pa_log_info(__FILE__": Joining mcast group failed: %s", pa_cstrerror(errno));
        goto fail;
    }
    
    if (bind(fd, sa, salen) < 0) {
        pa_log(__FILE__": bind() failed: %s", pa_cstrerror(errno));
        goto fail;
    }

    return fd;
    
fail:
    if (fd >= 0)
        close(fd);

    return -1;
}

static struct session *session_new(struct userdata *u, const pa_sdp_info *sdp_info) {
    struct session *s = NULL;
    struct timeval tv;
    char *c;
    pa_sink *sink;
    int fd = -1;
    pa_memblock *silence;

    if (u->n_sessions >= MAX_SESSIONS) {
        pa_log(__FILE__": session limit reached.");
        goto fail;
    }
    
    if (!(sink = pa_namereg_get(u->core, u->sink_name, PA_NAMEREG_SINK, 1))) {
        pa_log(__FILE__": sink does not exist.");
        goto fail;
    }

    s = pa_xnew0(struct session, 1);
    s->userdata = u;
    s->first_packet = 0;
    s->sdp_info = *sdp_info;

    if ((fd = mcast_socket((const struct sockaddr*) &sdp_info->sa, sdp_info->salen)) < 0)
        goto fail;

    c = pa_sprintf_malloc("RTP Stream%s%s%s",
                          sdp_info->session_name ? " (" : "",
                          sdp_info->session_name ? sdp_info->session_name : "", 
                          sdp_info->session_name ? ")" : "");

    s->sink_input = pa_sink_input_new(sink, __FILE__, c, &sdp_info->sample_spec, NULL, NULL, 0, PA_RESAMPLER_INVALID);
    pa_xfree(c);
        
    if (!s->sink_input) {
        pa_log(__FILE__": failed to create sink input.");
        goto fail;
    }

    s->sink_input->userdata = s;
    s->sink_input->owner = u->module;

    s->sink_input->peek = sink_input_peek;
    s->sink_input->drop = sink_input_drop;
    s->sink_input->kill = sink_input_kill;
    s->sink_input->get_latency = sink_input_get_latency;

    silence = pa_silence_memblock_new(&s->sink_input->sample_spec,
                                      (pa_bytes_per_second(&s->sink_input->sample_spec)/128/pa_frame_size(&s->sink_input->sample_spec))*
                                      pa_frame_size(&s->sink_input->sample_spec),
                                      s->userdata->core->memblock_stat);
    
    s->memblockq = pa_memblockq_new(
            0,
            MEMBLOCKQ_MAXLENGTH,
            MEMBLOCKQ_MAXLENGTH,
            pa_frame_size(&s->sink_input->sample_spec),
            pa_bytes_per_second(&s->sink_input->sample_spec)/10+1,
            0,
            silence,
            u->core->memblock_stat);

    pa_memblock_unref(silence);

    s->rtp_event = u->core->mainloop->io_new(u->core->mainloop, fd, PA_IO_EVENT_INPUT, rtp_event_cb, s);
    
    pa_gettimeofday(&tv);
    pa_timeval_add(&tv, DEATH_TIMEOUT);
    s->death_event = u->core->mainloop->time_new(u->core->mainloop, &tv, death_event_cb, s);

    pa_hashmap_put(s->userdata->by_origin, s->sdp_info.origin, s);

    pa_rtp_context_init_recv(&s->rtp_context, fd, pa_frame_size(&s->sdp_info.sample_spec));

    pa_log_info(__FILE__": Found new session '%s'", s->sdp_info.session_name);

    u->n_sessions++;
    
    return s;

fail:
    if (s) {
        if (fd >= 0)
            close(fd);
        
        pa_xfree(s);
    }

    return NULL;
}

static void session_free(struct session *s, int from_hash) {
    assert(s);

    pa_log_info(__FILE__": Freeing session '%s'", s->sdp_info.session_name);

    s->userdata->core->mainloop->time_free(s->death_event);
    s->userdata->core->mainloop->io_free(s->rtp_event);

    if (from_hash)
        pa_hashmap_remove(s->userdata->by_origin, s->sdp_info.origin);

    pa_sink_input_disconnect(s->sink_input);
    pa_sink_input_unref(s->sink_input);

    pa_memblockq_free(s->memblockq);
    pa_sdp_info_destroy(&s->sdp_info);
    pa_rtp_context_destroy(&s->rtp_context);

    assert(s->userdata->n_sessions >= 1);
    s->userdata->n_sessions--;
    
    pa_xfree(s);
}

static void sap_event_cb(pa_mainloop_api *m, pa_io_event *e, int fd, pa_io_event_flags_t flags, void *userdata) {
    struct userdata *u = userdata;
    int goodbye;
    pa_sdp_info info;
    struct session *s;
    
    assert(m);
    assert(e);
    assert(u);
    assert(fd == u->sap_context.fd);
    assert(flags == PA_IO_EVENT_INPUT);

    if (pa_sap_recv(&u->sap_context, &goodbye) < 0)
        return;

    if (!pa_sdp_parse(u->sap_context.sdp_data, &info, goodbye))
        return;

    if (goodbye) {

        if ((s = pa_hashmap_get(u->by_origin, info.origin)))
            session_free(s, 1);

        pa_sdp_info_destroy(&info);
    } else {

        if (!(s = pa_hashmap_get(u->by_origin, info.origin))) {
            if (!(s = session_new(u, &info)))
                pa_sdp_info_destroy(&info);
            
        } else {
            struct timeval tv;
            
            pa_gettimeofday(&tv);
            pa_timeval_add(&tv, DEATH_TIMEOUT);
            m->time_restart(s->death_event, &tv);
            
            pa_sdp_info_destroy(&info);
        }
    }
}

int pa__init(pa_core *c, pa_module*m) {
    struct userdata *u;
    pa_modargs *ma = NULL;
    struct sockaddr_in sa4;
    struct sockaddr_in6 sa6;
    struct sockaddr *sa;
    socklen_t salen;
    const char *sap_address;
    int fd = -1;
    
    assert(c);
    assert(m);

    if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
        pa_log(__FILE__": failed to parse module arguments");
        goto fail;
    }

    sap_address = pa_modargs_get_value(ma, "sap_address", DEFAULT_SAP_ADDRESS);
    
    if (inet_pton(AF_INET6, sap_address, &sa6.sin6_addr) > 0) {
        sa6.sin6_family = AF_INET6;
        sa6.sin6_port = htons(SAP_PORT);
        sa = (struct sockaddr*) &sa6;
        salen = sizeof(sa6);
    } else if (inet_pton(AF_INET, sap_address, &sa4.sin_addr) > 0) {
        sa4.sin_family = AF_INET;
        sa4.sin_port = htons(SAP_PORT);
        sa = (struct sockaddr*) &sa4;
        salen = sizeof(sa4);
    } else {
        pa_log(__FILE__": invalid SAP address '%s'", sap_address);
        goto fail;
    }

    if ((fd = mcast_socket(sa, salen)) < 0)
        goto fail;

    u = pa_xnew(struct userdata, 1);
    m->userdata = u;
    u->module = m;
    u->core = c;
    u->sink_name = pa_xstrdup(pa_modargs_get_value(ma, "sink", NULL));
    u->n_sessions = 0;

    u->sap_event = c->mainloop->io_new(c->mainloop, fd, PA_IO_EVENT_INPUT, sap_event_cb, u);

    u->by_origin = pa_hashmap_new(pa_idxset_string_hash_func, pa_idxset_string_compare_func);
    
    pa_sap_context_init_recv(&u->sap_context, fd);
    
    pa_modargs_free(ma);

    return 0;

fail:
    if (ma)
        pa_modargs_free(ma);

    if (fd >= 0)
        close(fd);
    
    return -1;
}

static void free_func(void *p, PA_GCC_UNUSED void *userdata) {
    session_free(p, 0);
}

void pa__done(pa_core *c, pa_module*m) {
    struct userdata *u;
    assert(c);
    assert(m);

    if (!(u = m->userdata))
        return;

    c->mainloop->io_free(u->sap_event);
    pa_sap_context_destroy(&u->sap_context);

    pa_hashmap_free(u->by_origin, free_func, NULL);
    
    pa_xfree(u->sink_name);
    pa_xfree(u);
}