/*
 * Copyright(c) 2020 ADLINK Technology Limited and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
 * v. 1.0 which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 */
#include <assert.h>
#include <limits.h>
#include <string.h>

#include "dds/ddsrt/mh3.h"
#include "dds/ddsrt/md5.h"
#include "dds/ddsrt/bswap.h"

#include "dds/dds.h"
#include "dds/ddsi/ddsi_serdata.h"
#include "dds/ddsi/q_radmin.h"

#include "dds/dds.h"
#include "dds/ddsrt/atomics.h"
#include "dds/ddsrt/process.h"
#include "dds/ddsrt/threads.h"

struct sampletype {
  char *key;
  char *value;
};

struct stp {
  struct ddsi_sertopic c;
};

static bool stp_equal (const struct ddsi_sertopic *acmn, const struct ddsi_sertopic *bcmn)
{
  // no fields in stp beyond the common ones, and those are all checked for equality before this function is called
  (void) acmn; (void) bcmn;
  return true;
}

static uint32_t stp_hash (const struct ddsi_sertopic *tpcmn)
{
  // nothing beyond the common fields
  (void) tpcmn;
  return 0;
}

static void stp_free (struct ddsi_sertopic *tpcmn)
{
  struct stp * const stp = (struct stp *) tpcmn;
  ddsi_sertopic_fini (&stp->c);
  free (stp);
}

static void stp_zero_samples (const struct ddsi_sertopic *dcmn, void *samples, size_t count)
{
  (void) dcmn;
  memset (samples, 0, count * sizeof (struct sampletype));
}

static void stp_realloc_samples (void **ptrs, const struct ddsi_sertopic *dcmn, void *old, size_t oldcount, size_t count)
{
  (void) dcmn;
  const size_t size = sizeof (struct sampletype);
  char *new = (oldcount == count) ? old : dds_realloc (old, size * count);
  if (new && count > oldcount)
    memset (new + size * oldcount, 0, size * (count - oldcount));
  for (size_t i = 0; i < count; i++)
  {
    void *ptr = (char *) new + i * size;
    ptrs[i] = ptr;
  }
}

static void stp_free_samples (const struct ddsi_sertopic *dcmn, void **ptrs, size_t count, dds_free_op_t op)
{
  (void) dcmn;
  if (count == 0)
    return;

  char *ptr = ptrs[0];
  for (size_t i = 0; i < count; i++)
  {
    struct sampletype *s = (struct sampletype *) ptr;
    dds_free (s->key);
    dds_free (s->value);
    ptr += sizeof (struct sampletype);
  }

  if (op & DDS_FREE_ALL_BIT)
  {
    dds_free (ptrs[0]);
  }
}

static const struct ddsi_sertopic_ops stp_ops = {
  .free = stp_free,
  .zero_samples = stp_zero_samples,
  .realloc_samples = stp_realloc_samples,
  .free_samples = stp_free_samples,
  .equal = stp_equal,
  .hash = stp_hash
};

#if DDSRT_ENDIAN == DDSRT_LITTLE_ENDIAN
#define NATIVE_ENCODING CDR_LE
#elif DDSRT_ENDIAN == DDSRT_BIG_ENDIAN
#define NATIVE_ENCODING CDR_BE
#else
#error "DDSRT_ENDIAN neither LITTLE nor BIG"
#endif

struct sd {
  struct ddsi_serdata c;
  struct sampletype data;
  uint32_t keysz, pad0, valuesz, pad1;
};

static uint32_t sd_get_size (const struct ddsi_serdata *dcmn)
{
  // FIXME: 4 is DDSI CDR header size and shouldn't be included here; same is true for pad1
  const struct sd *d = (const struct sd *) dcmn;
  return 4 + 4 + d->keysz + d->pad0 + 4 + d->valuesz + d->pad1;
}

static bool sd_eqkey (const struct ddsi_serdata *acmn, const struct ddsi_serdata *bcmn)
{
  const struct sd *a = (const struct sd *) acmn;
  const struct sd *b = (const struct sd *) bcmn;
  return a->keysz == b->keysz && memcmp (a->data.key, b->data.key, a->keysz) == 0;
}

static void sd_free (struct ddsi_serdata *dcmn)
{
  struct sd *d = (struct sd *) dcmn;
  free (d->data.key);
  free (d->data.value);
  free (d);
}

static char *strdup_with_len (const char *x, size_t l)
{
  char *y = malloc (l);
  memcpy (y, x, l);
  return y;
}

static struct ddsi_serdata *sd_from_ser_iov (const struct ddsi_sertopic *tpcmn, enum ddsi_serdata_kind kind, ddsrt_msg_iovlen_t niov, const ddsrt_iovec_t *iov, size_t size)
{
  struct stp const * const stp = (const struct stp *) tpcmn;
  struct sd *sd = malloc (sizeof (*sd));
  ddsi_serdata_init (&sd->c, &stp->c, kind);
  (void) size;
  // assuming not fragmented, CDR Header specifies native encoding, input is valid and all that
  // CDR encoding of strings: uint32_t length-including-terminating-0 ; blob-including-terminating-0
  assert (niov == 1);
  (void) niov;
  size_t off = 0;
  const char *base = (const char *) iov[0].iov_base + 4;
  memcpy (&sd->keysz, base + off, sizeof (uint32_t));
  off += sizeof (uint32_t);
  sd->data.key = strdup_with_len (base + off, sd->keysz);
  off += sd->keysz;
  sd->pad0 = ((off % 4) == 0) ? 0 : 4 - (off % 4);
  off += sd->pad0;
  if (kind == SDK_DATA)
  {
    memcpy (&sd->valuesz, base + off, sizeof (uint32_t));
    off += sizeof (uint32_t);
    sd->data.value = strdup_with_len (base + off, sd->valuesz);
    off += sd->valuesz;
    // FIXME: not sure if this is still needed, it shouldn't be, but ...
    sd->pad1 = ((off % 4) == 0) ? 0 : 4 - (off % 4);
  }
  else
  {
    sd->data.value = NULL;
    sd->valuesz = sd->pad1 = 0;
  }
  sd->c.hash = ddsrt_mh3 (sd->data.key, sd->keysz, 0) ^ tpcmn->serdata_basehash;
  return &sd->c;
}

static struct ddsi_serdata *sd_from_ser (const struct ddsi_sertopic *tpcmn, enum ddsi_serdata_kind kind, const struct nn_rdata *fragchain, size_t size)
{
  assert (fragchain->nextfrag == NULL);
  ddsrt_iovec_t iov = {
    .iov_base = NN_RMSG_PAYLOADOFF (fragchain->rmsg, NN_RDATA_PAYLOAD_OFF (fragchain)),
    .iov_len = fragchain->maxp1 // fragchain->min = 0 for first fragment, by definition
  };
  return sd_from_ser_iov (tpcmn, kind, 1, &iov, size);
}

static struct ddsi_serdata *sd_from_keyhash (const struct ddsi_sertopic *tpcmn, const ddsi_keyhash_t *keyhash)
{
  // unbounded string, therefore keyhash is MD5 and we can't extract the value
  // (don't try disposing/unregistering in RTI and expect this to accept the data)
  (void) tpcmn; (void) keyhash;
  return NULL;
}

static struct ddsi_serdata *sd_from_sample (const struct ddsi_sertopic *tpcmn, enum ddsi_serdata_kind kind, const void *sample)
{
  const struct stp *tp = (const struct stp *) tpcmn;
  struct sd *sd = malloc (sizeof (*sd));
  const struct sampletype *s = sample;
  ddsi_serdata_init (&sd->c, &tp->c, kind);
  sd->keysz = (uint32_t) strlen (s->key) + 1;
  sd->data.key = strdup_with_len (s->key, sd->keysz);
  sd->pad0 = ((sd->keysz % 4) == 0) ? 0 : 4 - (sd->keysz % 4);
  if (kind == SDK_DATA)
  {
    sd->valuesz = (uint32_t) strlen (s->value) + 1;
    sd->data.value = strdup_with_len (s->value, sd->valuesz);
    sd->pad1 = ((sd->valuesz % 4) == 0) ? 0 : 4 - (sd->valuesz % 4);
  }
  else
  {
    sd->data.value = NULL;
    sd->valuesz = sd->pad1 = 0;
  }
  sd->c.hash = ddsrt_mh3 (sd->data.key, sd->keysz, 0) ^ tpcmn->serdata_basehash;
  return &sd->c;
}

static struct ddsi_serdata *sd_to_topicless (const struct ddsi_serdata *serdata_common)
{
  const struct sd *sd = (const struct sd *) serdata_common;
  const struct stp *tp = (const struct stp *) sd->c.topic;
  struct sd *sd_tl = malloc (sizeof (*sd_tl));
  ddsi_serdata_init (&sd_tl->c, &tp->c, SDK_KEY);
  sd_tl->c.topic = NULL;
  sd_tl->c.hash = sd->c.hash;
  sd_tl->c.timestamp.v = INT64_MIN;
  sd_tl->data.key = strdup_with_len (sd->data.key, sd->keysz);
  sd_tl->data.value = NULL;
  sd_tl->keysz = sd->keysz;
  sd_tl->pad0 = sd->pad0;
  sd_tl->valuesz = sd_tl->pad1 = 0;
  return &sd_tl->c;
}

static struct ddsi_serdata *sd_to_ser_ref (const struct ddsi_serdata *serdata_common, size_t cdr_off, size_t cdr_sz, ddsrt_iovec_t *ref)
{
  // The idea is that if the CDR is available already, one can return a reference (in which case
  // one probably should also increment the sample's refcount).  But here we generaete the CDR
  // on the fly
  const struct sd *sd = (const struct sd *) serdata_common;
  // fragmented data results in calls with different offsets and limits, but can't be bothered for this test
  assert (cdr_off == 0 && cdr_sz == sd_get_size (&sd->c));
  (void) cdr_off;
  (void) cdr_sz;
  ref->iov_len = sd_get_size (&sd->c);
  ref->iov_base = malloc (ref->iov_len);
  char * const header = ref->iov_base;
  header[0] = 0;
  header[1] = (DDSRT_ENDIAN == DDSRT_LITTLE_ENDIAN) ? 1 : 0;
  header[2] = 0;
  header[3] = 0;
  char * const base = header + 4;
  size_t off = 0;
  memcpy (base + off, &sd->keysz, sizeof (uint32_t));
  off += sizeof (uint32_t);
  memcpy (base + off, sd->data.key, sd->keysz);
  off += sd->keysz;
  for (uint32_t i = 0; i < sd->pad0; i++)
    base[off++] = 0;
  if (sd->c.kind == SDK_DATA)
  {
    memcpy (base + off, &sd->valuesz, sizeof (uint32_t));
    off += sizeof (uint32_t);
    memcpy (base + off, sd->data.value, sd->valuesz);
    off += sd->valuesz;
    for (uint32_t i = 0; i < sd->pad1; i++)
      base[off++] = 0;
  }
  assert(4 + off == ref->iov_len);
  return (struct ddsi_serdata *) &sd->c;
}

static void sd_to_ser_unref (struct ddsi_serdata *serdata_common, const ddsrt_iovec_t *ref)
{
  // const "ref" is a mistake in the interface ... it is owned by this code ...
  (void) serdata_common;
  free ((void *) ref->iov_base);
}

static void sd_to_ser (const struct ddsi_serdata *serdata_common, size_t off, size_t sz, void *buf)
{
  // being lazy and reusing code in sd_to_ser_ref, even though here we don't have to allocate anything
  ddsrt_iovec_t iov;
  (void) sd_to_ser_ref (serdata_common, off, sz, &iov);
  memcpy (buf, iov.iov_base, iov.iov_len);
  sd_to_ser_unref ((struct ddsi_serdata *) serdata_common, &iov);
}

static bool sd_to_sample (const struct ddsi_serdata *serdata_common, void *sample, void **bufptr, void *buflim)
{
  const struct sd *sd = (const struct sd *) serdata_common;
  struct sampletype *s = sample;
  if (bufptr) abort(); else { (void)buflim; } /* FIXME: haven't implemented that bit yet! */
  s->key = dds_realloc (s->key, sd->keysz);
  memcpy (s->key, sd->data.key, sd->keysz);
  if (sd->c.kind == SDK_DATA)
  {
    s->value = dds_realloc (s->value, sd->valuesz);
    memcpy (s->value, sd->data.value, sd->valuesz);
  }
  return true;
}

static bool sd_topicless_to_sample (const struct ddsi_sertopic *topic, const struct ddsi_serdata *serdata_common, void *sample, void **bufptr, void *buflim)
{
  (void) topic;
  const struct sd *sd = (const struct sd *) serdata_common;
  struct sampletype *s = sample;
  if (bufptr) abort(); else { (void)buflim; } /* FIXME: haven't implemented that bit yet! */
  s->key = dds_realloc (s->key, sd->keysz);
  memcpy (s->key, sd->data.key, sd->keysz);
  return true;
}

static size_t sd_print (const struct ddsi_sertopic *sertopic_common, const struct ddsi_serdata *serdata_common, char *buf, size_t size)
{
  (void) sertopic_common;
  const struct sd *sd = (const struct sd *) serdata_common;
  int cnt;
  if (sd->c.kind == SDK_DATA)
    cnt = snprintf (buf, size, "%s -> %s", sd->data.key, sd->data.value);
  else
    cnt = snprintf (buf, size, "%s", sd->data.key);
  return ((size_t) cnt > size) ? size : (size_t) cnt;
}

static void sd_get_keyhash (const struct ddsi_serdata *serdata_common, struct ddsi_keyhash *buf, bool force_md5)
{
  (void) force_md5; // unbounded string is always MD5
  struct sd const * const sd = (const struct sd *) serdata_common;
  const uint32_t keysz_be = ddsrt_toBE4u (sd->keysz);
  ddsrt_md5_state_t md5st;
  ddsrt_md5_init (&md5st);
  ddsrt_md5_append (&md5st, (ddsrt_md5_byte_t *) &keysz_be, sizeof (keysz_be));
  ddsrt_md5_append (&md5st, (ddsrt_md5_byte_t *) sd->data.key, sd->keysz);
  ddsrt_md5_finish (&md5st, (ddsrt_md5_byte_t *) (buf->value));
}

static const struct ddsi_serdata_ops sd_ops = {
  .get_size = sd_get_size,
  .eqkey = sd_eqkey,
  .free = sd_free,
  .from_ser = sd_from_ser,
  .from_ser_iov = sd_from_ser_iov,
  .from_keyhash = sd_from_keyhash,
  .from_sample = sd_from_sample,
  .to_ser = sd_to_ser,
  .to_sample = sd_to_sample,
  .to_ser_ref = sd_to_ser_ref,
  .to_ser_unref = sd_to_ser_unref,
  .to_topicless = sd_to_topicless,
  .topicless_to_sample = sd_topicless_to_sample,
  .print = sd_print,
  .get_keyhash = sd_get_keyhash
};

static struct ddsi_sertopic *make_sertopic (const char *topicname, const char *typename)
{
  struct stp *stp = malloc (sizeof (*stp));
  ddsi_sertopic_init (&stp->c, topicname, typename, &stp_ops, &sd_ops, false);
  return &stp->c;
}

char *create_unique_topic_name (const char *prefix, char *name, size_t size)
{
  static ddsrt_atomic_uint32_t count = DDSRT_ATOMIC_UINT64_INIT (0);
  const ddsrt_pid_t pid = ddsrt_getpid();
  const ddsrt_tid_t tid = ddsrt_gettid();
  const uint32_t nr = ddsrt_atomic_inc32_nv (&count);
  (void) snprintf (name, size, "%s%"PRIu32"_pid%" PRIdPID "_tid%" PRIdTID "", prefix, nr, 1, 1);
  return name;
}

int main(int argc, char *argv[])
{
  if (argc < 2) {
    printf("USAGE:\n\tpub <topic-name>\n");
    exit(1);  
  }

  dds_return_t rc;
  char topicname[100];

  const dds_entity_t pp = dds_create_participant (DDS_DOMAIN_DEFAULT, NULL, NULL);

  create_unique_topic_name ("ddsc_cdr_basic", topicname, sizeof topicname);
  printf("Topic: %s\n", topicname);

  struct ddsi_sertopic *st = make_sertopic (topicname, argv[1]);
  const dds_entity_t tp = dds_create_topic_generic (pp, &st, NULL, NULL, NULL);

  const dds_entity_t wr = dds_create_writer (pp, tp, NULL, NULL);

  // regular write (from_sample(DATA) + to_topicless)
  struct sampletype xs[] = {
    { .key = "/home/kitchen/sensor", .value = "23.0" },
    { .key = "/home/kitchen/C2O2", .value = "0.07" }
  };

  do
  {
    for (size_t i = 0; i < sizeof (xs) / sizeof (xs[0]); i++)
    {
      rc = dds_write (wr, &xs[i]);
    }
    printf("Writing message\n");
    dds_sleepfor (DDS_MSECS (1000));
  } while(true);

  rc = dds_delete (pp);
}