package org.liquibase.maven.plugins;

 import java.io.File;

 import java.io.FileWriter;

 import java.io.IOException;

 import java.io.Writer;

 import java.text.DateFormat;

 import java.text.ParseException;

 import java.text.SimpleDateFormat;

 import liquibase.Liquibase;

 import liquibase.database.Database;

 import liquibase.exception.LiquibaseException;

 import liquibase.resource.ResourceAccessor;

 import org.apache.maven.plugin.MojoExecutionException;

 /**

  * Generates the SQL that is required to rollback the database to the specified pointing attributes 'rollbackCount',

  * 'rollbackTag'

  * 

  * @author Oleg Taranenko

  * @description Liquibase RollbackSQL Maven plugin

  * @goal rollbackSQL

  */

 public class LiquibaseRollbackSQL extends LiquibaseRollback {

     /**

      * The file to output the Rollback SQL script to, if it exists it will be overwritten.

      * 

      * @parameter expression="${liquibase.migrationSqlOutputFile}" default-value=

      *            "${project.build.directory}/liquibase/migrate.sql"

      */

     protected File migrationSqlOutputFile;

     /** The writer for writing the migration SQL. */

     private Writer outputWriter;

     @Override

     protected boolean isPromptOnNonLocalDatabase() {

         // Always run on an non-local database as we are not actually modifying

         // the database when run on it.

         return false;

     }

     @Override

     protected Liquibase createLiquibase(ResourceAccessor fo, Database db) throws MojoExecutionException {

         Liquibase liquibase = super.createLiquibase(fo, db);

         // Setup the output file writer

         try {

             if (!migrationSqlOutputFile.exists()) {

                 // Ensure the parent directories exist

                 migrationSqlOutputFile.getParentFile().mkdirs();

                 // Create the actual file

                 if (!migrationSqlOutputFile.createNewFile()) {

                     throw new MojoExecutionException("Cannot create the migration SQL file; "

                             + migrationSqlOutputFile.getAbsolutePath());

                 }

             }

             outputWriter = new FileWriter(migrationSqlOutputFile);

         } catch (IOException e) {

             getLog().error(e);

             throw new MojoExecutionException("Failed to create SQL output writer", e);

         }

         getLog().info("Output SQL Migration File: " + migrationSqlOutputFile.getAbsolutePath());

         return liquibase;

     }

     @Override

     protected void printSettings(String indent) {

         super.printSettings(indent);

         getLog().info(indent + "migrationSQLOutputFile: " + migrationSqlOutputFile);

     }

     @Override

     protected void cleanup(Database db) {

         super.cleanup(db);

         if (outputWriter != null) {

             try {

                 outputWriter.close();

             } catch (IOException e) {

                 getLog().error(e);

             }

         }

     }

     @Override

     protected void performLiquibaseTask(Liquibase liquibase) throws LiquibaseException {

         switch (type) {

         case COUNT: {

             liquibase.rollback(rollbackCount, contexts, outputWriter);

             break;

         }

         case DATE: {

             DateFormat format = DateFormat.getDateInstance();

             try {

                 liquibase.rollback(format.parse(rollbackDate), contexts, outputWriter);

             } catch (ParseException e) {

                 String message = "Error parsing rollbackDate: " + e.getMessage();

                 if (format instanceof SimpleDateFormat) {

                     message += "\nDate must match pattern: " + ((SimpleDateFormat) format).toPattern();

                 }

                 throw new LiquibaseException(message, e);

             }

             break;

         }

         case TAG: {

             liquibase.rollback(rollbackTag, contexts, outputWriter);

             break;

         }

         default: {

             throw new IllegalStateException("Unexpected rollback type, " + type);

         }

         }

     }

 }