/*
 * Copyright (c) 2006-2011 Nuxeo SA (http://nuxeo.com/) and others.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Florent Guillaume
 */
package org.eclipse.ecr.core.storage.sql.jdbc.db;

import java.io.Serializable;
import java.util.LinkedList;
import java.util.List;

import org.nuxeo.common.utils.StringUtils;

/**
 * An {@code UPDATE} statement.
 */
public class Update implements Serializable {

    private static final long serialVersionUID = 1L;

    protected final Table table;

    protected String newValues;

    protected String[] from;

    protected String where;

    public Update(Table table) {
        this.table = table;
    }

    public Table getTable() {
        return table;
    }

    public void setNewValues(String newValues) {
        this.newValues = newValues;
    }

    /** Alternative to {@link #setNewValues} */
    public void setUpdatedColumns(List<Column> columns) {
        List<String> updatedColumns = new LinkedList<String>();
        for (Column column : columns) {
            if (column.isIdentity()) {
                // identity column is never inserted
                continue;
            }
            updatedColumns.add(column.getQuotedName() + " = "
                    + column.getFreeVariableSetter());
        }
        newValues = StringUtils.join(updatedColumns, ", ");
    }

    /**
     * Sets additional table names with which to join for this update.
     */
    public void setFrom(String... from) {
        this.from = from;
    }

    public void setWhere(String where) {
        if (where == null || where.length() == 0) {
            throw new IllegalArgumentException("unexpected empty WHERE");
        }
        this.where = where;
    }

    public String getStatement() {
        StringBuilder buf = new StringBuilder(128);
        buf.append("UPDATE ");
        buf.append(table.getQuotedName());
        buf.append(" SET ");
        buf.append(newValues);
        if (from != null) {
            buf.append(" FROM ");
            if (table.getDialect().doesUpdateFromRepeatSelf()) {
                buf.append(table.getQuotedName());
                buf.append(", ");
            }
            buf.append(StringUtils.join(from, ", "));
        }
        if (where != null) {
            buf.append(" WHERE ");
            buf.append(where);
        } else {
            throw new IllegalArgumentException("unexpected empty WHERE");
        }
        return buf.toString();
    }
}