package liquibase.change.core;

 import java.util.ArrayList;

 import java.util.HashSet;

 import java.util.List;

 import java.util.Set;

 import liquibase.change.AbstractChange;

 import liquibase.change.Change;

 import liquibase.change.ChangeMetaData;

 import liquibase.change.ChangeWithColumns;

 import liquibase.change.ColumnConfig;

 import liquibase.database.Database;

 import liquibase.database.core.DB2Database;

 import liquibase.exception.ValidationErrors;

 import liquibase.statement.AutoIncrementConstraint;

 import liquibase.statement.ColumnConstraint;

 import liquibase.statement.ForeignKeyConstraint;

 import liquibase.statement.NotNullConstraint;

 import liquibase.statement.PrimaryKeyConstraint;

 import liquibase.statement.SqlStatement;

 import liquibase.statement.UniqueConstraint;

 import liquibase.statement.core.AddColumnStatement;

 import liquibase.statement.core.ReorganizeTableStatement;

 import liquibase.statement.core.UpdateStatement;

 import liquibase.util.StringUtils;

 /**

  * Adds a column to an existing table.

  */

 public class AddColumnChange extends AbstractChange implements ChangeWithColumns {

     private String schemaName;

     private String tableName;

     private List<ColumnConfig> columns;

     public AddColumnChange() {

         super("addColumn", "Add Column", ChangeMetaData.PRIORITY_DEFAULT);

         columns = new ArrayList<ColumnConfig>();

     }

     public String getSchemaName() {

         return schemaName;

     }

     public void setSchemaName(String schemaName) {

         this.schemaName = StringUtils.trimToNull(schemaName);

     }

     public String getTableName() {

         return tableName;

     }

     public void setTableName(String tableName) {

         this.tableName = tableName;

     }

     @Override

     public List<ColumnConfig> getColumns() {

         return columns;

     }

     @Override

     public void addColumn(ColumnConfig column) {

         columns.add(column);

     }

     public void removeColumn(ColumnConfig column) {

         columns.remove(column);

     }

     @Override

     public ValidationErrors validate(Database database) {

         ValidationErrors validationErrors = super.validate(database);

         if (columns.size() == 0) {

             validationErrors.addError("'columns' is required");

         }

         return validationErrors;

     }

     @Override

     public SqlStatement[] generateStatements(Database database) {

         List<SqlStatement> sql = new ArrayList<SqlStatement>();

         for (ColumnConfig aColumn : getColumns()) {

             Set<ColumnConstraint> constraints = new HashSet<ColumnConstraint>();

             if (aColumn.getConstraints() != null) {

                 if (aColumn.getConstraints().isNullable() != null && !aColumn.getConstraints().isNullable()) {

                     constraints.add(new NotNullConstraint());

                 }

                 if (aColumn.getConstraints().isUnique() != null && aColumn.getConstraints().isUnique()) {

                     constraints.add(new UniqueConstraint());

                 }

                 if (aColumn.getConstraints().isPrimaryKey() != null && aColumn.getConstraints().isPrimaryKey()) {

                     constraints.add(new PrimaryKeyConstraint(aColumn.getConstraints().getPrimaryKeyName()));

                 }

                 if (aColumn.getConstraints().getReferences() != null) {

                     constraints.add(new ForeignKeyConstraint(aColumn.getConstraints().getForeignKeyName(), aColumn

                             .getConstraints().getReferences()));

                 }

             }

             if (aColumn.isAutoIncrement() != null && aColumn.isAutoIncrement()) {

                 constraints.add(new AutoIncrementConstraint(aColumn.getName()));

             }

             AddColumnStatement addColumnStatement = new AddColumnStatement(getSchemaName(), getTableName(),

                     aColumn.getName(), aColumn.getType(), aColumn.getDefaultValueObject(),

                     constraints.toArray(new ColumnConstraint[constraints.size()]));

             sql.add(addColumnStatement);

             if (database instanceof DB2Database) {

                 sql.add(new ReorganizeTableStatement(getSchemaName(), getTableName()));

             }

             if (aColumn.getValueObject() != null) {

                 UpdateStatement updateStatement = new UpdateStatement(getSchemaName(), getTableName());

                 updateStatement.addNewColumnValue(aColumn.getName(), aColumn.getValueObject());

                 sql.add(updateStatement);

             }

         }

         // for (ColumnConfig aColumn : columns) {

         // if (aColumn.getConstraints() != null) {

         // if (aColumn.getConstraints().isPrimaryKey() != null && aColumn.getConstraints().isPrimaryKey()) {

         // AddPrimaryKeyChange change = new AddPrimaryKeyChange();

         // change.setSchemaName(schemaName);

         // change.setTableName(getTableName());

         // change.setColumnNames(aColumn.getName());

         //

         // sql.addAll(Arrays.asList(change.generateStatements(database)));

         // }

         // }

         // }

         return sql.toArray(new SqlStatement[sql.size()]);

     }

     @Override

     protected Change[] createInverses() {

         List<Change> inverses = new ArrayList<Change>();

         for (ColumnConfig aColumn : columns) {

             if (aColumn.hasDefaultValue()) {

                 DropDefaultValueChange dropChange = new DropDefaultValueChange();

                 dropChange.setTableName(getTableName());

                 dropChange.setColumnName(aColumn.getName());

                 inverses.add(dropChange);

             }

             DropColumnChange inverse = new DropColumnChange();

             inverse.setSchemaName(getSchemaName());

             inverse.setColumnName(aColumn.getName());

             inverse.setTableName(getTableName());

             inverses.add(inverse);

         }

         return inverses.toArray(new Change[inverses.size()]);

     }

     @Override

     public String getConfirmationMessage() {

         List<String> names = new ArrayList<String>(columns.size());

         for (ColumnConfig col : columns) {

             names.add(col.getName() + "(" + col.getType() + ")");

         }

         return "Columns " + StringUtils.join(names, ",") + " added to " + tableName;

     }

 }