// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * Copyright (C) 2018  NetDEF, Inc.

 *                     Renato Westphal

 */

#include <zebra.h>

#include "libfrr.h"

#include "log.h"

#include "lib_errors.h"

#include "command.h"

#include "db.h"

#include "northbound.h"

#include "northbound_db.h"

int nb_db_init(void)

{

#ifdef HAVE_CONFIG_ROLLBACKS

  /*

   * NOTE: the delete_tail SQL trigger is used to implement a ring buffer

   * where only the last N transactions are recorded in the configuration

   * log.

   */

  if (db_execute(

        "BEGIN TRANSACTION;\n"

        "  CREATE TABLE IF NOT EXISTS transactions(\n"

        "    client         CHAR(32)             NOT NULL,\n"

        "    date           DATETIME             DEFAULT CURRENT_TIMESTAMP,\n"

        "    comment        CHAR(80)             ,\n"

        "    configuration  TEXT                 NOT NULL\n"

        "  );\n"

        "  CREATE TRIGGER IF NOT EXISTS delete_tail\n"

        "    AFTER INSERT ON transactions\n"

        "    FOR EACH ROW\n"

        "    BEGIN\n"

        "    DELETE\n"

        "    FROM\n"

        "      transactions\n"

        "    WHERE\n"

        "      rowid%%%u=NEW.rowid%%%u AND rowid!=NEW.rowid;\n"

        "    END;\n"

        "COMMIT;",

        NB_DLFT_MAX_CONFIG_ROLLBACKS, NB_DLFT_MAX_CONFIG_ROLLBACKS)

      != 0)

    return NB_ERR;

#endif /* HAVE_CONFIG_ROLLBACKS */

  return NB_OK;

}

int nb_db_transaction_save(const struct nb_transaction *transaction,

         uint32_t *transaction_id)

{

#ifdef HAVE_CONFIG_ROLLBACKS

  struct sqlite3_stmt *ss;

  const char *client_name;

  char *config_str = NULL;

  int ret = NB_ERR;

  /*

   * Use a transaction to ensure consistency between the INSERT and SELECT

   * queries.

   */

  if (db_execute("BEGIN TRANSACTION;") != 0)

    return NB_ERR;

  ss = db_prepare(

    "INSERT INTO transactions\n"

    "  (client, comment, configuration)\n"

    "VALUES\n"

    "  (?, ?, ?);");

  if (!ss)

    goto exit;

  client_name = nb_client_name(transaction->context.client);

  /*

   * Always record configurations in the XML format, save the default

   * values too, as this covers the case where defaults may change.

   */

  if (lyd_print_mem(&config_str, transaction->config->dnode, LYD_XML,

        LYD_PRINT_WITHSIBLINGS | LYD_PRINT_WD_ALL)

      != 0)

    goto exit;

  if (db_bindf(ss, "%s%s%s", client_name, strlen(client_name),

         transaction->comment, strlen(transaction->comment),

         config_str ? config_str : "",

         config_str ? strlen(config_str) : 0)

      != 0)

    goto exit;

  if (db_run(ss) != SQLITE_OK)

    goto exit;

  db_finalize(&ss);

  /*

   * transaction_id is an optional output parameter that provides the ID

   * of the recorded transaction.

   */

  if (transaction_id) {

    ss = db_prepare("SELECT last_insert_rowid();");

    if (!ss)

      goto exit;

    if (db_run(ss) != SQLITE_ROW)

      goto exit;

    if (db_loadf(ss, "%i", transaction_id) != 0)

      goto exit;

    db_finalize(&ss);

  }

  if (db_execute("COMMIT;") != 0)

    goto exit;

  ret = NB_OK;

exit:

  if (config_str)

    free(config_str);

  if (ss)

    db_finalize(&ss);

  if (ret != NB_OK)

    (void)db_execute("ROLLBACK TRANSACTION;");

  return ret;

#else  /* HAVE_CONFIG_ROLLBACKS */

  return NB_OK;

#endif /* HAVE_CONFIG_ROLLBACKS */

}

struct nb_config *nb_db_transaction_load(uint32_t transaction_id)

{

  struct nb_config *config = NULL;

#ifdef HAVE_CONFIG_ROLLBACKS

  struct lyd_node *dnode;

  const char *config_str;

  struct sqlite3_stmt *ss;

  LY_ERR err;

  ss = db_prepare(

    "SELECT\n"

    "  configuration\n"

    "FROM\n"

    "  transactions\n"

    "WHERE\n"

    "  rowid=?;");

  if (!ss)

    return NULL;

  if (db_bindf(ss, "%d", transaction_id) != 0)

    goto exit;

  if (db_run(ss) != SQLITE_ROW)

    goto exit;

  if (db_loadf(ss, "%s", &config_str) != 0)

    goto exit;

  err = lyd_parse_data_mem(ly_native_ctx, config_str, LYD_XML,

         LYD_PARSE_STRICT | LYD_PARSE_NO_STATE,

         LYD_VALIDATE_NO_STATE, &dnode);

  if (err || !dnode)

    flog_warn(EC_LIB_LIBYANG, "%s: lyd_parse_data_mem() failed",

        __func__);

  else

    config = nb_config_new(dnode);

exit:

  db_finalize(&ss);

#endif /* HAVE_CONFIG_ROLLBACKS */

  return config;

}

int nb_db_clear_transactions(unsigned int n_oldest)

{

#ifdef HAVE_CONFIG_ROLLBACKS

  /* Delete oldest N entries. */

  if (db_execute("DELETE\n"

           "FROM\n"

           "  transactions\n"

           "WHERE\n"

           "  ROWID IN (\n"

           "    SELECT\n"

           "      ROWID\n"

           "    FROM\n"

           "      transactions\n"

           "    ORDER BY ROWID ASC LIMIT %u\n"

           "  );",

           n_oldest)

      != 0)

    return NB_ERR;

#endif /* HAVE_CONFIG_ROLLBACKS */

  return NB_OK;

}

int nb_db_set_max_transactions(unsigned int max)

{

#ifdef HAVE_CONFIG_ROLLBACKS

  /*

   * Delete old entries if necessary and update the SQL trigger that

   * auto-deletes old entries.

   */

  if (db_execute("BEGIN TRANSACTION;\n"

           "  DELETE\n"

           "  FROM\n"

           "    transactions\n"

           "  WHERE\n"

           "    ROWID IN (\n"

           "      SELECT\n"

           "        ROWID\n"

           "      FROM\n"

           "        transactions\n"

           "      ORDER BY ROWID DESC LIMIT -1 OFFSET %u\n"

           "    );\n"

           "  DROP TRIGGER delete_tail;\n"

           "  CREATE TRIGGER delete_tail\n"

           "  AFTER INSERT ON transactions\n"

           "    FOR EACH ROW\n"

           "    BEGIN\n"

           "    DELETE\n"

           "    FROM\n"

           "      transactions\n"

           "    WHERE\n"

           "      rowid%%%u=NEW.rowid%%%u AND rowid!=NEW.rowid;\n"

           "    END;\n"

           "COMMIT;",

           max, max, max)

      != 0)

    return NB_ERR;

#endif /* HAVE_CONFIG_ROLLBACKS */

  return NB_OK;

}

int nb_db_transactions_iterate(void (*func)(void *arg, int transaction_id,

              const char *client_name,

              const char *date,

              const char *comment),

             void *arg)

{

#ifdef HAVE_CONFIG_ROLLBACKS

  struct sqlite3_stmt *ss;

  /* Send SQL query and parse the result. */

  ss = db_prepare(

    "SELECT\n"

    "  rowid, client, date, comment\n"

    "FROM\n"

    "  transactions\n"

    "ORDER BY\n"

    "  rowid DESC;");

  if (!ss)

    return NB_ERR;

  while (db_run(ss) == SQLITE_ROW) {

    int transaction_id;

    const char *client_name;

    const char *date;

    const char *comment;

    int ret;

    ret = db_loadf(ss, "%i%s%s%s", &transaction_id, &client_name,

             &date, &comment);

    if (ret != 0)

      continue;

    (*func)(arg, transaction_id, client_name, date, comment);

  }

  db_finalize(&ss);

#endif /* HAVE_CONFIG_ROLLBACKS */

  return NB_OK;

}