/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2013-2016, Regents of the University of California.
 *
 * This file is part of ChronoShare, a decentralized file sharing application over NDN.
 *
 * ChronoShare 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, either
 * version 3 of the License, or (at your option) any later version.
 *
 * ChronoShare 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 copies of the GNU General Public License along with
 * ChronoShare, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 *
 * See AUTHORS.md for complete list of ChronoShare authors and contributors.
 */

#include "sync-log.hpp"
#include "logging.hpp"
#include <utility>

#include <boost/make_shared.hpp>
#include <boost/thread.hpp>

INIT_LOGGER ("Sync.Log");

using namespace boost;
using namespace std;
using namespace Ndnx;

// static  void xTrace (void*, const char* q)
// {
//   cout << q << endl;
// }

const std::string INIT_DATABASE = "\
CREATE TABLE                                                    \n\
    SyncNodes(                                                  \n\
        device_id       INTEGER PRIMARY KEY AUTOINCREMENT,      \n\
        device_name     BLOB NOT NULL,                          \n\
        description     TEXT,                                   \n\
        seq_no          INTEGER NOT NULL,                       \n\
        last_known_locator  BLOB,                               \n\
        last_update     TIMESTAMP                               \n\
    );                                                          \n\
                                                                \n\
CREATE TRIGGER SyncNodesUpdater_trigger                                \n\
    BEFORE INSERT ON SyncNodes                                         \n\
    FOR EACH ROW                                                       \n\
    WHEN (SELECT device_id                                             \n\
             FROM SyncNodes                                            \n\
             WHERE device_name=NEW.device_name)                        \n\
         IS NOT NULL                                                   \n\
    BEGIN                                                              \n\
        UPDATE SyncNodes                                               \n\
            SET seq_no=max(seq_no,NEW.seq_no)                          \n\
            WHERE device_name=NEW.device_name;                         \n\
        SELECT RAISE(IGNORE);                                          \n\
    END;                                                               \n\
                                                                       \n\
CREATE INDEX SyncNodes_device_name ON SyncNodes (device_name);         \n\
                                                                       \n\
CREATE TABLE SyncLog(                                                  \n\
        state_id    INTEGER PRIMARY KEY AUTOINCREMENT,                 \n\
        state_hash  BLOB NOT NULL UNIQUE,                              \n\
        last_update TIMESTAMP NOT NULL                                 \n\
    );                                                                 \n\
                                                                       \n\
CREATE TABLE                                                            \n\
    SyncStateNodes(                                                     \n\
        id          INTEGER PRIMARY KEY AUTOINCREMENT,                  \n\
        state_id    INTEGER NOT NULL                                    \n\
            REFERENCES SyncLog (state_id) ON UPDATE CASCADE ON DELETE CASCADE, \n\
        device_id   INTEGER NOT NULL                                    \n\
            REFERENCES SyncNodes (device_id) ON UPDATE CASCADE ON DELETE CASCADE, \n\
        seq_no      INTEGER NOT NULL                                    \n\
    );                                                                  \n\
                                                                        \n\
CREATE INDEX SyncStateNodes_device_id ON SyncStateNodes (device_id);    \n\
CREATE INDEX SyncStateNodes_state_id  ON SyncStateNodes (state_id);     \n\
CREATE INDEX SyncStateNodes_seq_no    ON SyncStateNodes (seq_no);       \n\
                                                                        \n\
CREATE TRIGGER SyncLogGuard_trigger                                     \n\
    BEFORE INSERT ON SyncLog                                            \n\
    FOR EACH ROW                                                        \n\
    WHEN (SELECT state_hash                                             \n\
            FROM SyncLog                                                \n\
            WHERE state_hash=NEW.state_hash)                            \n\
        IS NOT NULL                                                     \n\
    BEGIN                                                               \n\
        DELETE FROM SyncLog WHERE state_hash=NEW.state_hash;            \n\
    END;                                                                \n\
";


SyncLog::SyncLog (const boost::filesystem::path &path, const Ndnx::Name &localName)
  : DbHelper (path / ".chronoshare", "sync-log.db")
  , m_localName (localName)
{
  sqlite3_exec (m_db, INIT_DATABASE.c_str (), NULL, NULL, NULL);
  _LOG_DEBUG_COND (sqlite3_errcode (m_db) != SQLITE_OK, sqlite3_errmsg (m_db));

  UpdateDeviceSeqNo (localName, 0);

  sqlite3_stmt *stmt;
  int res = sqlite3_prepare_v2 (m_db, "SELECT device_id, seq_no FROM SyncNodes WHERE device_name=?", -1, &stmt, 0);

  Ndnx::NdnxCharbufPtr name = m_localName;
  sqlite3_bind_blob (stmt, 1, name->buf (), name->length (), SQLITE_STATIC);

  if (sqlite3_step (stmt) == SQLITE_ROW)
    {
      m_localDeviceId = sqlite3_column_int64 (stmt, 0);
    }
  else
    {
      BOOST_THROW_EXCEPTION (Error::Db ()
                             << errmsg_info_str ("Impossible thing in SyncLog::SyncLog"));
    }
  sqlite3_finalize (stmt);
}

sqlite3_int64
SyncLog::GetNextLocalSeqNo ()
{
  sqlite3_stmt *stmt_seq;
  sqlite3_prepare_v2 (m_db, "SELECT seq_no FROM SyncNodes WHERE device_id = ?", -1, &stmt_seq, 0);
  sqlite3_bind_int64 (stmt_seq, 1, m_localDeviceId);

  if (sqlite3_step (stmt_seq) != SQLITE_ROW)
    {
      BOOST_THROW_EXCEPTION (Error::Db ()
                             << errmsg_info_str ("Impossible thing in SyncLog::GetNextLocalSeqNo"));
    }

  _LOG_DEBUG_COND (sqlite3_errcode (m_db) != SQLITE_DONE, sqlite3_errmsg (m_db));

  sqlite3_int64 seq_no = sqlite3_column_int64 (stmt_seq, 0) + 1;
  sqlite3_finalize (stmt_seq);

  UpdateDeviceSeqNo (m_localDeviceId, seq_no);

  return seq_no;
}

HashPtr
SyncLog::RememberStateInStateLog ()
{
  WriteLock lock (m_stateUpdateMutex);

  int res = sqlite3_exec (m_db, "BEGIN TRANSACTION;", 0,0,0);

  res += sqlite3_exec (m_db, "\
INSERT INTO SyncLog                                                \
    (state_hash, last_update)                                      \
    SELECT                                                         \
       hash(device_name, seq_no), datetime('now')                  \
    FROM (SELECT * FROM SyncNodes                                  \
              ORDER BY device_name);                               \
", 0,0,0);

  _LOG_DEBUG_COND (sqlite3_errcode (m_db) != SQLITE_OK, "DbError: " << sqlite3_errmsg (m_db));

  if (res != SQLITE_OK)
    {
      sqlite3_exec (m_db, "ROLLBACK TRANSACTION;", 0,0,0);
      BOOST_THROW_EXCEPTION (Error::Db ()
                             << errmsg_info_str (sqlite3_errmsg(m_db)));
    }

  sqlite3_int64 rowId = sqlite3_last_insert_rowid (m_db);

  sqlite3_stmt *insertStmt;
  res += sqlite3_prepare (m_db, "\
INSERT INTO SyncStateNodes                              \
      (state_id, device_id, seq_no)                     \
      SELECT ?, device_id, seq_no                       \
            FROM SyncNodes;                             \
", -1, &insertStmt, 0);

  res += sqlite3_bind_int64 (insertStmt, 1, rowId);
  sqlite3_step (insertStmt);

  _LOG_DEBUG_COND (sqlite3_errcode (m_db) != SQLITE_DONE, "DbError: " << sqlite3_errmsg (m_db));
  if (res != SQLITE_OK)
    {
      sqlite3_exec (m_db, "ROLLBACK TRANSACTION;", 0,0,0);
      BOOST_THROW_EXCEPTION (Error::Db ()
                             << errmsg_info_str (sqlite3_errmsg(m_db)));
    }
  sqlite3_finalize (insertStmt);

  sqlite3_stmt *getHashStmt;
  res += sqlite3_prepare (m_db, "\
SELECT state_hash FROM SyncLog WHERE state_id = ?\
", -1, &getHashStmt, 0);
  res += sqlite3_bind_int64 (getHashStmt, 1, rowId);

  HashPtr retval;
  int stepRes = sqlite3_step (getHashStmt);
  if (stepRes == SQLITE_ROW)
    {
      retval = make_shared<Hash> (sqlite3_column_blob (getHashStmt, 0),
                                  sqlite3_column_bytes (getHashStmt, 0));
    }
  else
    {
      sqlite3_exec (m_db, "ROLLBACK TRANSACTION;", 0,0,0);

      _LOG_ERROR ("DbError: " << sqlite3_errmsg (m_db));
      BOOST_THROW_EXCEPTION (Error::Db ()
                             << errmsg_info_str ("Not a valid hash in rememberStateInStateLog"));
    }
  sqlite3_finalize (getHashStmt);
  res += sqlite3_exec (m_db, "COMMIT;", 0,0,0);

  if (res != SQLITE_OK)
    {
      sqlite3_exec (m_db, "ROLLBACK TRANSACTION;", 0,0,0);
      BOOST_THROW_EXCEPTION (Error::Db ()
                             << errmsg_info_str ("Some error with rememberStateInStateLog"));
    }

  return retval;
}

sqlite3_int64
SyncLog::LookupSyncLog (const std::string &stateHash)
{
  return LookupSyncLog (*Hash::FromString (stateHash));
}

sqlite3_int64
SyncLog::LookupSyncLog (const Hash &stateHash)
{
  sqlite3_stmt *stmt;
  int res = sqlite3_prepare (m_db, "SELECT state_id FROM SyncLog WHERE state_hash = ?",
                             -1, &stmt, 0);

  if (res != SQLITE_OK)
    {
      BOOST_THROW_EXCEPTION (Error::Db ()
                             << errmsg_info_str ("Cannot prepare statement"));
    }

  res = sqlite3_bind_blob (stmt, 1, stateHash.GetHash (), stateHash.GetHashBytes (), SQLITE_STATIC);
  if (res != SQLITE_OK)
    {
      BOOST_THROW_EXCEPTION (Error::Db ()
                             << errmsg_info_str ("Cannot bind"));
    }

  sqlite3_int64 row = 0; // something bad

  if (sqlite3_step (stmt) == SQLITE_ROW)
    {
      row = sqlite3_column_int64 (stmt, 0);
    }

  sqlite3_finalize (stmt);

  return row;
}

void
SyncLog::UpdateDeviceSeqNo (const Ndnx::Name &name, sqlite3_int64 seqNo)
{
  sqlite3_stmt *stmt;
  // update is performed using trigger
  int res = sqlite3_prepare (m_db, "INSERT INTO SyncNodes (device_name, seq_no) VALUES (?,?);",
                             -1, &stmt, 0);

  Ndnx::NdnxCharbufPtr nameBuf = name;
  res += sqlite3_bind_blob  (stmt, 1, nameBuf->buf (), nameBuf->length (), SQLITE_STATIC);
  res += sqlite3_bind_int64 (stmt, 2, seqNo);
  sqlite3_step (stmt);

  if (res != SQLITE_OK)
    {
      BOOST_THROW_EXCEPTION (Error::Db ()
                             << errmsg_info_str ("Some error with UpdateDeviceSeqNo (name)"));
    }
  sqlite3_finalize (stmt);
}

void
SyncLog::UpdateLocalSeqNo (sqlite3_int64 seqNo)
{
  return UpdateDeviceSeqNo (m_localDeviceId, seqNo);
}

void
SyncLog::UpdateDeviceSeqNo (sqlite3_int64 deviceId, sqlite3_int64 seqNo)
{
  sqlite3_stmt *stmt;
  // update is performed using trigger
  int res = sqlite3_prepare (m_db, "UPDATE SyncNodes SET seq_no=MAX(seq_no,?) WHERE device_id=?;",
                             -1, &stmt, 0);

  res += sqlite3_bind_int64 (stmt, 1, seqNo);
  res += sqlite3_bind_int64 (stmt, 2, deviceId);
  sqlite3_step (stmt);

  if (res != SQLITE_OK)
    {
      BOOST_THROW_EXCEPTION (Error::Db ()
                             << errmsg_info_str ("Some error with UpdateDeviceSeqNo (id)"));
    }

  _LOG_DEBUG_COND (sqlite3_errcode (m_db) != SQLITE_OK, sqlite3_errmsg (m_db));

  sqlite3_finalize (stmt);
}

Name
SyncLog::LookupLocator (const Name &deviceName)
{
  sqlite3_stmt *stmt;
  sqlite3_prepare_v2 (m_db, "SELECT last_known_locator FROM SyncNodes WHERE device_name=?;", -1, &stmt, 0);
  Ndnx::NdnxCharbufPtr nameBuf = deviceName;
  sqlite3_bind_blob (stmt, 1, nameBuf->buf(), nameBuf->length(), SQLITE_STATIC);
  int res = sqlite3_step (stmt);
  Name locator;
  switch (res)
  {
  case SQLITE_ROW:
    {
      locator = Name((const unsigned char *)sqlite3_column_blob(stmt, 0), sqlite3_column_bytes(stmt, 0));
    }
  case SQLITE_DONE: break;
  default:
    BOOST_THROW_EXCEPTION(Error::Db() << errmsg_info_str("Error in LookupLocator()"));
  }

  sqlite3_finalize(stmt);

  return locator;
}

Ndnx::Name
SyncLog::LookupLocalLocator ()
{
  return LookupLocator (m_localName);
}

void
SyncLog::UpdateLocator(const Name &deviceName, const Name &locator)
{
  sqlite3_stmt *stmt;
  sqlite3_prepare_v2 (m_db, "UPDATE SyncNodes SET last_known_locator=?,last_update=datetime('now') WHERE device_name=?;", -1, &stmt, 0);
  Ndnx::NdnxCharbufPtr nameBuf = deviceName;
  Ndnx::NdnxCharbufPtr locatorBuf = locator;
  sqlite3_bind_blob (stmt, 1, locatorBuf->buf(), locatorBuf->length(), SQLITE_STATIC);
  sqlite3_bind_blob (stmt, 2, nameBuf->buf(), nameBuf->length(),       SQLITE_STATIC);
  int res = sqlite3_step (stmt);

  if (res != SQLITE_OK && res != SQLITE_DONE)
  {
    BOOST_THROW_EXCEPTION(Error::Db() << errmsg_info_str("Error in UpdateLoactor()"));
  }

  sqlite3_finalize(stmt);
}

void
SyncLog::UpdateLocalLocator (const Ndnx::Name &forwardingHint)
{
  return UpdateLocator (m_localName, forwardingHint);
}

SyncStateMsgPtr
SyncLog::FindStateDifferences (const std::string &oldHash, const std::string &newHash, bool includeOldSeq)
{
  return FindStateDifferences (*Hash::FromString (oldHash), *Hash::FromString (newHash), includeOldSeq);
}

SyncStateMsgPtr
SyncLog::FindStateDifferences (const Hash &oldHash, const Hash &newHash, bool includeOldSeq)
{
  sqlite3_stmt *stmt;

  int res = sqlite3_prepare_v2 (m_db, "\
SELECT sn.device_name, sn.last_known_locator, s_old.seq_no, s_new.seq_no\
    FROM (SELECT *                                                      \
            FROM SyncStateNodes                                         \
            WHERE state_id=(SELECT state_id                             \
                                FROM SyncLog                            \
                                WHERE state_hash=:old_hash)) s_old      \
    LEFT JOIN (SELECT *                                                 \
                FROM SyncStateNodes                                     \
                WHERE state_id=(SELECT state_id                         \
                                    FROM SyncLog                        \
                                    WHERE state_hash=:new_hash)) s_new  \
                                                                        \
        ON s_old.device_id = s_new.device_id                            \
    JOIN SyncNodes sn ON sn.device_id = s_old.device_id                 \
                                                                        \
    WHERE s_new.seq_no IS NULL OR                                       \
          s_old.seq_no != s_new.seq_no                                  \
                                                                        \
UNION ALL                                                               \
                                                                        \
SELECT sn.device_name, sn.last_known_locator, s_old.seq_no, s_new.seq_no\
    FROM (SELECT *                                                      \
            FROM SyncStateNodes                                         \
            WHERE state_id=(SELECT state_id                             \
                                FROM SyncLog                            \
                                WHERE state_hash=:new_hash )) s_new     \
    LEFT JOIN (SELECT *                                                 \
                FROM SyncStateNodes                                     \
                WHERE state_id=(SELECT state_id                         \
                                    FROM SyncLog                        \
                                    WHERE state_hash=:old_hash)) s_old  \
                                                                        \
        ON s_old.device_id = s_new.device_id                            \
    JOIN SyncNodes sn ON sn.device_id = s_new.device_id                 \
                                                                        \
    WHERE s_old.seq_no IS NULL                                          \
", -1, &stmt, 0);

  if (res != SQLITE_OK)
    {
      BOOST_THROW_EXCEPTION (Error::Db ()
                             << errmsg_info_str ("Some error with FindStateDifferences"));
    }

  res += sqlite3_bind_blob  (stmt, 1, oldHash.GetHash (), oldHash.GetHashBytes (), SQLITE_STATIC);
  res += sqlite3_bind_blob  (stmt, 2, newHash.GetHash (), newHash.GetHashBytes (), SQLITE_STATIC);

  SyncStateMsgPtr msg = make_shared<SyncStateMsg> ();

  // sqlite3_trace(m_db, xTrace, NULL);

  while (sqlite3_step (stmt) == SQLITE_ROW)
    {
      SyncState *state = msg->add_state ();

      // set name
      state->set_name (reinterpret_cast<const char*> (sqlite3_column_blob (stmt, 0)), sqlite3_column_bytes (stmt, 0));

      // locator is optional, so must check if it is null
      if (sqlite3_column_type(stmt, 1) == SQLITE_BLOB)
      {
        state->set_locator (reinterpret_cast<const char*> (sqlite3_column_blob (stmt, 1)), sqlite3_column_bytes (stmt, 1));
      }

      // set old seq
      if (includeOldSeq)
      {
        if (sqlite3_column_type (stmt, 2) == SQLITE_NULL)
        {
          // old seq is zero; we always have an initial action of zero seq
          // other's do not need to fetch this action
          state->set_old_seq(0);
        }
        else
        {
          sqlite3_int64 oldSeqNo = sqlite3_column_int64 (stmt, 2);
          state->set_old_seq(oldSeqNo);
        }
      }

      // set new seq
      if (sqlite3_column_type (stmt, 3) == SQLITE_NULL)
        {
        state->set_type (SyncState::DELETE);
        }
      else
        {
          sqlite3_int64 newSeqNo = sqlite3_column_int64 (stmt, 3);
          state->set_type (SyncState::UPDATE);
          state->set_seq (newSeqNo);
        }

      // std::cout << sqlite3_column_text (stmt, 0) <<
      //   ": from "  << sqlite3_column_int64 (stmt, 1) <<
      //   " to "     << sqlite3_column_int64 (stmt, 2) <<
      //   std::endl;
    }
  sqlite3_finalize (stmt);

  // sqlite3_trace(m_db, NULL, NULL);

  return msg;
}

sqlite3_int64
SyncLog::SeqNo(const Name &name)
{
  sqlite3_stmt *stmt;
  sqlite3_int64 seq = -1;
  sqlite3_prepare_v2 (m_db, "SELECT seq_no FROM SyncNodes WHERE device_name=?;", -1, &stmt, 0);
  Ndnx::NdnxCharbufPtr nameBuf = name;
  sqlite3_bind_blob (stmt, 1, nameBuf->buf (), nameBuf->length (), SQLITE_STATIC);
  if (sqlite3_step (stmt) == SQLITE_ROW)
  {
    seq = sqlite3_column_int64 (stmt, 0);
  }

  return seq;
}

sqlite3_int64
SyncLog::LogSize ()
{
  sqlite3_stmt *stmt;
  sqlite3_prepare_v2 (m_db, "SELECT count(*) FROM SyncLog", -1, &stmt, 0);

  sqlite3_int64 retval = -1;
  if (sqlite3_step (stmt) == SQLITE_ROW)
  {
    retval = sqlite3_column_int64 (stmt, 0);
  }

  return retval;
}