const utils = require('../../utils');

const trigger = {
  renameColumnTrigger: function (logger, tableName, columnName, to) {
    const triggerName = utils.generateCombinedName(
      logger,
      'autoinc_trg',
      tableName
    );
    const sequenceName = utils.generateCombinedName(logger, 'seq', tableName);
    return (
      `DECLARE ` +
      `PK_NAME VARCHAR(200); ` +
      `IS_AUTOINC NUMBER := 0; ` +
      `BEGIN` +
      `  EXECUTE IMMEDIATE ('ALTER TABLE "${tableName}" RENAME COLUMN "${columnName}" TO "${to}"');` +
      `  SELECT COUNT(*) INTO IS_AUTOINC from "USER_TRIGGERS" where trigger_name = '${triggerName}';` +
      `  IF (IS_AUTOINC > 0) THEN` +
      `    SELECT cols.column_name INTO PK_NAME` +
      `    FROM all_constraints cons, all_cons_columns cols` +
      `    WHERE cons.constraint_type = 'P'` +
      `    AND cons.constraint_name = cols.constraint_name` +
      `    AND cons.owner = cols.owner` +
      `    AND cols.table_name = '${tableName}';` +
      `    IF ('${to}' = PK_NAME) THEN` +
      `      EXECUTE IMMEDIATE ('DROP TRIGGER "${triggerName}"');` +
      `      EXECUTE IMMEDIATE ('create or replace trigger "${triggerName}"` +
      `      BEFORE INSERT on "${tableName}" for each row` +
      `        declare` +
      `        checking number := 1;` +
      `        begin` +
      `          if (:new."${to}" is null) then` +
      `            while checking >= 1 loop` +
      `              select "${sequenceName}".nextval into :new."${to}" from dual;` +
      `              select count("${to}") into checking from "${tableName}"` +
      `              where "${to}" = :new."${to}";` +
      `            end loop;` +
      `          end if;` +
      `        end;');` +
      `    end if;` +
      `  end if;` +
      `END;`
    );
  },

  createAutoIncrementTrigger: function (logger, tableName, schemaName) {
    const tableQuoted = `"${tableName}"`;
    const tableUnquoted = tableName;
    const schemaQuoted = schemaName ? `"${schemaName}".` : '';
    const constraintOwner = schemaName ? `'${schemaName}'` : 'cols.owner';
    const triggerName = utils.generateCombinedName(
      logger,
      'autoinc_trg',
      tableName
    );
    const sequenceNameUnquoted = utils.generateCombinedName(
      logger,
      'seq',
      tableName
    );
    const sequenceNameQuoted = `"${sequenceNameUnquoted}"`;
    return (
      `DECLARE ` +
      `PK_NAME VARCHAR(200); ` +
      `BEGIN` +
      `  EXECUTE IMMEDIATE ('CREATE SEQUENCE ${schemaQuoted}${sequenceNameQuoted}');` +
      `  SELECT cols.column_name INTO PK_NAME` + // TODO : support autoincrement on table with multiple primary keys
      `  FROM all_constraints cons, all_cons_columns cols` +
      `  WHERE cons.constraint_type = 'P'` +
      `  AND cons.constraint_name = cols.constraint_name` +
      `  AND cons.owner = ${constraintOwner}` +
      `  AND cols.table_name = '${tableUnquoted}';` +
      `  execute immediate ('create or replace trigger ${schemaQuoted}"${triggerName}"` +
      `  BEFORE INSERT on ${schemaQuoted}${tableQuoted}` +
      `  for each row` +
      `  declare` +
      `  checking number := 1;` +
      `  begin` +
      `    if (:new."' || PK_NAME || '" is null) then` +
      `      while checking >= 1 loop` +
      `        select ${schemaQuoted}${sequenceNameQuoted}.nextval into :new."' || PK_NAME || '" from dual;` +
      `        select count("' || PK_NAME || '") into checking from ${schemaQuoted}${tableQuoted}` +
      `        where "' || PK_NAME || '" = :new."' || PK_NAME || '";` +
      `      end loop;` +
      `    end if;` +
      `  end;'); ` +
      `END;`
    );
  },

  renameTableAndAutoIncrementTrigger: function (logger, tableName, to) {
    const triggerName = utils.generateCombinedName(
      logger,
      'autoinc_trg',
      tableName
    );
    const sequenceName = utils.generateCombinedName(logger, 'seq', tableName);
    const toTriggerName = utils.generateCombinedName(logger, 'autoinc_trg', to);
    const toSequenceName = utils.generateCombinedName(logger, 'seq', to);
    return (
      `DECLARE ` +
      `PK_NAME VARCHAR(200); ` +
      `IS_AUTOINC NUMBER := 0; ` +
      `BEGIN` +
      `  EXECUTE IMMEDIATE ('RENAME "${tableName}" TO "${to}"');` +
      `  SELECT COUNT(*) INTO IS_AUTOINC from "USER_TRIGGERS" where trigger_name = '${triggerName}';` +
      `  IF (IS_AUTOINC > 0) THEN` +
      `    EXECUTE IMMEDIATE ('DROP TRIGGER "${triggerName}"');` +
      `    EXECUTE IMMEDIATE ('RENAME "${sequenceName}" TO "${toSequenceName}"');` +
      `    SELECT cols.column_name INTO PK_NAME` +
      `    FROM all_constraints cons, all_cons_columns cols` +
      `    WHERE cons.constraint_type = 'P'` +
      `    AND cons.constraint_name = cols.constraint_name` +
      `    AND cons.owner = cols.owner` +
      `    AND cols.table_name = '${to}';` +
      `    EXECUTE IMMEDIATE ('create or replace trigger "${toTriggerName}"` +
      `    BEFORE INSERT on "${to}" for each row` +
      `      declare` +
      `      checking number := 1;` +
      `      begin` +
      `        if (:new."' || PK_NAME || '" is null) then` +
      `          while checking >= 1 loop` +
      `            select "${toSequenceName}".nextval into :new."' || PK_NAME || '" from dual;` +
      `            select count("' || PK_NAME || '") into checking from "${to}"` +
      `            where "' || PK_NAME || '" = :new."' || PK_NAME || '";` +
      `          end loop;` +
      `        end if;` +
      `      end;');` +
      `  end if;` +
      `END;`
    );
  },
};

module.exports = trigger;
