/*
    *    Copyright 2010-2023 the original author or authors.
    *
    *    Licensed under the Apache License, Version 2.0 (the "License");
    *    you may not use this file except in compliance with the License.
    *    You may obtain a copy of the License at
    *
    *       https://www.apache.org/licenses/LICENSE-2.0
    *
   *    Unless required by applicable law or agreed to in writing, software
   *    distributed under the License is distributed on an "AS IS" BASIS,
   *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *    See the License for the specific language governing permissions and
   *    limitations under the License.
   */
  package org.apache.ibatis.migration.operations;
  
  import java.io.PrintStream;
  import java.math.BigDecimal;
  import java.sql.Connection;
  import java.sql.SQLException;
  import java.util.Collections;
  import java.util.List;
  
  import org.apache.ibatis.migration.Change;
  import org.apache.ibatis.migration.ConnectionProvider;
  import org.apache.ibatis.migration.MigrationException;
  import org.apache.ibatis.migration.MigrationLoader;
  import org.apache.ibatis.migration.hook.MigrationHook;
  import org.apache.ibatis.migration.options.DatabaseOperationOption;
  
  public final class VersionOperation extends DatabaseOperation {
    private BigDecimal version;
  
    public VersionOperation(BigDecimal version) {
      this.version = version;
      if (version == null) {
        throw new IllegalArgumentException("The version must be null.");
      }
    }
  
    public VersionOperation operate(ConnectionProvider connectionProvider, MigrationLoader migrationsLoader,
        DatabaseOperationOption option, PrintStream printStream) {
      return operate(connectionProvider, migrationsLoader, option, printStream, null, null);
    }
  
    public VersionOperation operate(ConnectionProvider connectionProvider, MigrationLoader migrationsLoader,
        DatabaseOperationOption option, PrintStream printStream, MigrationHook upHook, MigrationHook downHook) {
      if (option == null) {
        option = new DatabaseOperationOption();
      }
      try (Connection con = connectionProvider.getConnection()) {
        List<Change> changesInDb = changelogExists(con, option) ? getChangelog(con, option) : Collections.emptyList();
        List<Change> migrations = migrationsLoader.getMigrations();
        Change specified = new Change(version);
        if (!migrations.contains(specified)) {
          throw new MigrationException("A migration for the specified version number does not exist.");
        }
        Change lastChangeInDb = changesInDb.isEmpty() ? null : changesInDb.get(changesInDb.size() - 1);
        if (lastChangeInDb == null || specified.compareTo(lastChangeInDb) > 0) {
          println(printStream, "Upgrading to: " + version);
          int steps = 0;
          for (Change change : migrations) {
            if ((lastChangeInDb == null || change.compareTo(lastChangeInDb) > 0) && change.compareTo(specified) < 1) {
              steps++;
            }
          }
          new UpOperation(steps).operate(connectionProvider, migrationsLoader, option, printStream, upHook);
        } else if (specified.compareTo(lastChangeInDb) < 0) {
          println(printStream, "Downgrading to: " + version);
          int steps = 0;
          for (Change change : migrations) {
            if (change.compareTo(specified) > -1 && change.compareTo(lastChangeInDb) < 0) {
              steps++;
            }
          }
          new DownOperation(steps).operate(connectionProvider, migrationsLoader, option, printStream, downHook);
        } else {
          println(printStream, "Already at version: " + version);
        }
        println(printStream);
        return this;
      } catch (SQLException e) {
        throw new MigrationException("Error creating connection.  Cause: " + e, e);
      }
    }
  }