/* Copyright 2016 Codership Oy <http://www.codership.com>

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program 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 General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#ifndef WSREP_TRANS_OBSERVER_H
#define WSREP_TRANS_OBSERVER_H

#include "my_global.h"
#include "mysql/service_wsrep.h"
#include "wsrep_applier.h" /* wsrep_apply_error */
#include "wsrep_xid.h"
#include "wsrep_thd.h"

#include "my_dbug.h"

class THD;

/*
   Return true if THD has active wsrep transaction.
 */
static inline bool wsrep_is_active(THD* thd)
{
  return (thd->wsrep_cs().state() != wsrep::client_state::s_none  &&
	  thd->wsrep_cs().transaction().active());
}

/*
  Return true if THD is either committing a transaction or statement
  is autocommit.
 */
static inline bool wsrep_is_real(THD* thd, bool all)
{
  return (all || thd->transaction.all.ha_list == 0);
}

/*
  Check if a transaction has generated changes.
 */
static inline bool wsrep_has_changes(THD* thd, my_bool all)
{
  return (thd->wsrep_trx().is_empty() == false);
}

/*
  Check if an active transaction has been BF aborted.
 */
static inline bool wsrep_is_bf_aborted(THD* thd)
{
  return (thd->wsrep_trx().active() && thd->wsrep_trx().bf_aborted());
}

static inline int wsrep_check_pk(THD* thd)
{
  if (!wsrep_certify_nonPK)
  {
    for (TABLE* table= thd->open_tables; table != NULL; table= table->next)
    {
      if (table->key_info == NULL || table->s->primary_key == MAX_KEY)
      {
        WSREP_DEBUG("No primary key found for table %s.%s",
                    table->s->db.str, table->s->table_name.str);
        wsrep_override_error(thd, ER_LOCK_DEADLOCK);
        return 1;
      }
    }
  }
  return 0;
}

static inline bool wsrep_streaming_enabled(THD* thd)
{
  return (thd->wsrep_sr().fragment_size() > 0);
}

/*
  Return number of fragments succesfully certified for the
  current statement.
 */
static inline size_t wsrep_fragments_certified_for_stmt(THD* thd)
{
    return thd->wsrep_trx().fragments_certified_for_statement();
}

static inline int wsrep_start_transaction(THD* thd, wsrep_trx_id_t trx_id)
{
  return (thd->wsrep_cs().state() != wsrep::client_state::s_none  ?
          thd->wsrep_cs().start_transaction(wsrep::transaction_id(trx_id)) :
          0);
}

/**/
static inline int wsrep_start_trx_if_not_started(THD* thd)
{
  int ret= 0;
  DBUG_ASSERT(thd->wsrep_next_trx_id() != WSREP_UNDEFINED_TRX_ID);
  DBUG_ASSERT(thd->wsrep_cs().mode() == Wsrep_client_state::m_local);
  if (thd->wsrep_trx().active() == false)
  {
    ret= wsrep_start_transaction(thd, thd->wsrep_next_trx_id());
  }
  return ret;
}

/*
  Called after each row operation.

  Return zero on succes, non-zero on failure.
 */
static inline int wsrep_after_row(THD* thd, bool)
{
  if (thd->wsrep_cs().state() != wsrep::client_state::s_none  &&
      wsrep_thd_is_local(thd))
  {
    if (wsrep_check_pk(thd))
    {
      return 1;
    }
    else if (wsrep_streaming_enabled(thd))
    {
      return thd->wsrep_cs().after_row();
    }
  }
  return 0;
}

/*
  Helper method to determine whether commit time hooks
  should be run for the transaction.
 */
static inline bool wsrep_run_commit_hook(THD* thd, bool all)
{
  return (wsrep_is_real(thd, all) && wsrep_is_active(thd) &&
          (wsrep_thd_is_applying(thd) || wsrep_has_changes(thd, all)));
}

/*
  Called before the transaction is prepared.

  Return zero on succes, non-zero on failure.
 */
static inline int wsrep_before_prepare(THD* thd, bool all)
{
  DBUG_ENTER("wsrep_before_prepare");
  WSREP_DEBUG("wsrep_before_prepare: %d", wsrep_is_real(thd, all));
  int ret= 0;
  if (wsrep_run_commit_hook(thd, all))
  {
    if ((ret= thd->wsrep_cs().before_prepare()) == 0)
    {
      DBUG_ASSERT(!thd->wsrep_trx().ws_meta().gtid().is_undefined());
      wsrep_xid_init(&thd->wsrep_xid,
                     thd->wsrep_trx().ws_meta().gtid());
    }
  }
  DBUG_RETURN(ret);
}

/*
  Called after the transaction has been prepared.

  Return zero on succes, non-zero on failure.
 */
static inline int wsrep_after_prepare(THD* thd, bool all)
{
  DBUG_ENTER("wsrep_after_prepare");
  WSREP_DEBUG("wsrep_after_prepare: %d", wsrep_is_real(thd, all));
  int ret= (wsrep_run_commit_hook(thd, all) ?
            thd->wsrep_cs().after_prepare() : 0);
  DBUG_ASSERT(ret == 0 || thd->wsrep_cs().current_error() ||
              thd->wsrep_cs().transaction().state() == wsrep::transaction::s_must_replay);
  DBUG_RETURN(ret);
}


/*
  Called before the transaction is committed.

  This function must be called from both client and
  applier contexts before commit.

  Return zero on succes, non-zero on failure.
 */
static inline int wsrep_before_commit(THD* thd, bool all)
{
  DBUG_ENTER("wsrep_before_commit");
  WSREP_DEBUG("wsrep_before_commit: %d, %lld",
              wsrep_is_real(thd, all),
              (long long)wsrep_thd_trx_seqno(thd));
  int ret= 0;
  if (wsrep_run_commit_hook(thd, all))
  {
    if ((ret= thd->wsrep_cs().before_commit()) == 0)
    {
      DBUG_ASSERT(!thd->wsrep_trx().ws_meta().gtid().is_undefined());
      wsrep_xid_init(&thd->wsrep_xid,
                     thd->wsrep_trx().ws_meta().gtid());
    }
  }
  DBUG_RETURN(ret);
}

/*
  Called after the transaction has been ordered for commit.

  This function must be called from both client and
  applier contexts after the commit has been ordered.

  @param thd Pointer to THD
  @param all 
  @param err Error buffer in case of applying error

  Return zero on succes, non-zero on failure.
 */
static inline int wsrep_ordered_commit(THD* thd,
                                      bool all,
                                      const wsrep_apply_error&)
{
  DBUG_ENTER("wsrep_ordered_commit");
  WSREP_DEBUG("wsrep_ordered_commit: %d", wsrep_is_real(thd, all));
  DBUG_RETURN(wsrep_run_commit_hook(thd, all) ?
              thd->wsrep_cs().ordered_commit() : 0);
}

/*
  Called after the transaction has been committed.

  Return zero on succes, non-zero on failure.
 */
static inline int wsrep_after_commit(THD* thd, bool all)
{
  DBUG_ENTER("wsrep_after_commit");
  WSREP_DEBUG("wsrep_after_commit: %d, %d, %lld, %d",
              wsrep_is_real(thd, all),
              wsrep_is_active(thd),
              (long long)wsrep_thd_trx_seqno(thd),
              wsrep_has_changes(thd, all));
  if (wsrep_run_commit_hook(thd, all))
  {
    DBUG_RETURN((wsrep_ordered_commit_if_no_binlog(thd, all) ||
                 (thd->wsrep_xid.null(),
                  thd->wsrep_cs().after_commit())));
  }
  DBUG_RETURN(0);
}

/*
  Called before the transaction is rolled back.

  Return zero on succes, non-zero on failure.
 */
static inline int wsrep_before_rollback(THD* thd, bool all)
{
  DBUG_ENTER("wsrep_before_rollback");
  int ret= 0;
  if (wsrep_is_active(thd))
  {
    if (!all && thd->in_active_multi_stmt_transaction() &&
        thd->wsrep_trx().is_streaming() &&
        !wsrep_stmt_rollback_is_safe(thd))
    {
      /* Non-safe statement rollback during SR multi statement
         transasction. Self abort the transaction, the actual rollback
         and error handling will be done in after statement phase. */
      wsrep_thd_self_abort(thd);
      ret= 0;
    }
    else if (wsrep_is_real(thd, all) &&
             thd->wsrep_trx().state() != wsrep::transaction::s_aborted)
    {
      /* Real transaction rolling back and wsrep abort not completed
         yet */
      /* Reset XID so that it does not trigger writing serialization
         history in InnoDB. This needs to be avoided because rollback
         may happen out of order and replay may follow. */
      thd->wsrep_xid.null();
      ret= thd->wsrep_cs().before_rollback();
    }
  }
  DBUG_RETURN(ret);
}

/*
  Called after the transaction has been rolled back.

  Return zero on succes, non-zero on failure.
 */
static inline int wsrep_after_rollback(THD* thd, bool all)
{
  DBUG_ENTER("wsrep_after_rollback");
  DBUG_RETURN((wsrep_is_real(thd, all) && wsrep_is_active(thd) &&
               thd->wsrep_cs().transaction().state() !=
               wsrep::transaction::s_aborted) ?
              thd->wsrep_cs().after_rollback() : 0);
}

static inline int wsrep_before_statement(THD* thd)
{
  return (thd->wsrep_cs().state() != wsrep::client_state::s_none ?
	  thd->wsrep_cs().before_statement() : 0);
}

static inline
int wsrep_after_statement(THD* thd)
{
  DBUG_ENTER("wsrep_after_statement");
  DBUG_RETURN(thd->wsrep_cs().state() != wsrep::client_state::s_none ?
              thd->wsrep_cs().after_statement() : 0);
}

static inline void wsrep_after_apply(THD* thd)
{
  DBUG_ASSERT(wsrep_thd_is_applying(thd));
  WSREP_DEBUG("wsrep_after_apply %lld", thd->thread_id);
  thd->wsrep_cs().after_applying();
}

static inline void wsrep_open(THD* thd)
{
  DBUG_ENTER("wsrep_open");
  if (wsrep_on(thd))
  {
    thd->wsrep_cs().open(wsrep::client_id(thd->thread_id));
    thd->wsrep_cs().debug_log_level(wsrep_debug);
    if (!thd->wsrep_applier && thd->variables.wsrep_trx_fragment_size)
    {
      thd->wsrep_cs().enable_streaming(
        wsrep_fragment_unit(thd->variables.wsrep_trx_fragment_unit),
        size_t(thd->variables.wsrep_trx_fragment_size));
    }
  }
  DBUG_VOID_RETURN;
}

static inline void wsrep_close(THD* thd)
{
  DBUG_ENTER("wsrep_close");
  if (thd->wsrep_cs().state() != wsrep::client_state::s_none)
  {
    thd->wsrep_cs().close();
  }
  DBUG_VOID_RETURN;
}

static inline int wsrep_before_command(THD* thd)
{
  return (thd->wsrep_cs().state() != wsrep::client_state::s_none ?
	  thd->wsrep_cs().before_command() : 0);
}
/*
  Called after each command.

  Return zero on success, non-zero on failure.
*/
static inline void wsrep_after_command_before_result(THD* thd)
{
  if (thd->wsrep_cs().state() != wsrep::client_state::s_none)
  {
    thd->wsrep_cs().after_command_before_result();
  }
}

static inline void wsrep_after_command_after_result(THD* thd)
{
  if (thd->wsrep_cs().state() != wsrep::client_state::s_none)
  {
    thd->wsrep_cs().after_command_after_result();
  }
}

static inline void wsrep_after_command_ignore_result(THD* thd)
{
  wsrep_after_command_before_result(thd);
  DBUG_ASSERT(!thd->wsrep_cs().current_error());
  wsrep_after_command_after_result(thd);
}

static inline enum wsrep::client_error wsrep_current_error(THD* thd)
{
  return thd->wsrep_cs().current_error();
}

static inline enum wsrep::provider::status
wsrep_current_error_status(THD* thd)
{
  return thd->wsrep_cs().current_error_status();
}


/*
  Commit an empty transaction.

  If the transaction is real and the wsrep transaction is still active,
  the transaction did not generate any rows or keys and is committed
  as empty. Here the wsrep transaction is rolled back and after statement
  step is performed to leave the wsrep transaction in the state as it
  never existed.
*/
static inline void wsrep_commit_empty(THD* thd, bool all)
{
  DBUG_ENTER("wsrep_commit_empty");
  WSREP_DEBUG("wsrep_commit_empty(%llu)", thd->thread_id);
  if (wsrep_is_real(thd, all) &&
      wsrep_thd_is_local(thd) &&
      thd->wsrep_trx().active() &&
      thd->wsrep_trx().state() != wsrep::transaction::s_committed)
  {
    bool have_error= wsrep_current_error(thd);
    int ret= wsrep_before_rollback(thd, all) ||
      wsrep_after_rollback(thd, all) ||
      wsrep_after_statement(thd);
    DBUG_ASSERT(have_error || !wsrep_current_error(thd));
    if (ret)
    {
      WSREP_DEBUG("wsrep_commit_empty failed: %d", wsrep_current_error(thd));
    }
  }
  DBUG_VOID_RETURN;
}

#endif /* WSREP_TRANS_OBSERVER */