/*
 * Copyright 2002-2017 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.springframework.jdbc.datasource.init;

import java.sql.Connection;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.sql.DataSource;

import org.springframework.core.io.Resource;
import org.springframework.core.io.support.EncodedResource;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

/**
 * Populates, initializes, or cleans up a database using SQL scripts defined in
 * external resources.
 *
 * <ul>
 * <li>Call {@link #addScript} to add a single SQL script location.
 * <li>Call {@link #addScripts} to add multiple SQL script locations.
 * <li>Consult the setter methods in this class for further configuration options.
 * <li>Call {@link #populate} or {@link #execute} to initialize or clean up the
 * database using the configured scripts.
 * </ul>
 *
 * @author Keith Donald
 * @author Dave Syer
 * @author Juergen Hoeller
 * @author Chris Beams
 * @author Oliver Gierke
 * @author Sam Brannen
 * @author Chris Baldwin
 * @since 3.0
 * @see DatabasePopulatorUtils
 * @see ScriptUtils
 */
public class ResourceDatabasePopulator implements DatabasePopulator {

        List<Resource> scripts = new ArrayList<Resource>();

        private String sqlScriptEncoding;

        private String separator = ScriptUtils.DEFAULT_STATEMENT_SEPARATOR;

        private String commentPrefix = ScriptUtils.DEFAULT_COMMENT_PREFIX;

        private String blockCommentStartDelimiter = ScriptUtils.DEFAULT_BLOCK_COMMENT_START_DELIMITER;

        private String blockCommentEndDelimiter = ScriptUtils.DEFAULT_BLOCK_COMMENT_END_DELIMITER;

        private boolean continueOnError = false;

        private boolean ignoreFailedDrops = false;


        /**
         * Construct a new {@code ResourceDatabasePopulator} with default settings.
         * @since 4.0.3
         */
        public ResourceDatabasePopulator() {
                /* no-op */
        }

        /**
         * Construct a new {@code ResourceDatabasePopulator} with default settings
         * for the supplied scripts.
         * @param scripts the scripts to execute to initialize or clean up the database
         * (never {@code null})
         * @since 4.0.3
         */
        public ResourceDatabasePopulator(Resource... scripts) {
                this();
                setScripts(scripts);
        }

        /**
         * Construct a new {@code ResourceDatabasePopulator} with the supplied values.
         * @param continueOnError flag to indicate that all failures in SQL should be
         * logged but not cause a failure
         * @param ignoreFailedDrops flag to indicate that a failed SQL {@code DROP}
         * statement can be ignored
         * @param sqlScriptEncoding the encoding for the supplied SQL scripts; may
         * be {@code null} or <em>empty</em> to indicate platform encoding
         * @param scripts the scripts to execute to initialize or clean up the database
         * (never {@code null})
         * @since 4.0.3
         */
        public ResourceDatabasePopulator(boolean continueOnError, boolean ignoreFailedDrops,
                        String sqlScriptEncoding, Resource... scripts) {

                this(scripts);
                this.continueOnError = continueOnError;
                this.ignoreFailedDrops = ignoreFailedDrops;
                setSqlScriptEncoding(sqlScriptEncoding);
        }


        /**
         * Add a script to execute to initialize or clean up the database.
         * @param script the path to an SQL script (never {@code null})
         */
        public void addScript(Resource script) {
                Assert.notNull(script, "Script must not be null");
                this.scripts.add(script);
        }

        /**
         * Add multiple scripts to execute to initialize or clean up the database.
         * @param scripts the scripts to execute (never {@code null})
         */
        public void addScripts(Resource... scripts) {
                assertContentsOfScriptArray(scripts);
                this.scripts.addAll(Arrays.asList(scripts));
        }

        /**
         * Set the scripts to execute to initialize or clean up the database,
         * replacing any previously added scripts.
         * @param scripts the scripts to execute (never {@code null})
         */
        public void setScripts(Resource... scripts) {
                assertContentsOfScriptArray(scripts);
                // Ensure that the list is modifiable
                this.scripts = new ArrayList<Resource>(Arrays.asList(scripts));
        }

        private void assertContentsOfScriptArray(Resource... scripts) {
                Assert.notNull(scripts, "Scripts array must not be null");
                Assert.noNullElements(scripts, "Scripts array must not contain null elements");
        }

        /**
         * Specify the encoding for the configured SQL scripts, if different from the
         * platform encoding.
         * @param sqlScriptEncoding the encoding used in scripts; may be {@code null}
         * or empty to indicate platform encoding
         * @see #addScript(Resource)
         */
        public void setSqlScriptEncoding(String sqlScriptEncoding) {
                this.sqlScriptEncoding = (StringUtils.hasText(sqlScriptEncoding) ? sqlScriptEncoding : null);
        }

        /**
         * Specify the statement separator, if a custom one.
         * <p>Defaults to {@code ";"} if not specified and falls back to {@code "\n"}
         * as a last resort; may be set to {@link ScriptUtils#EOF_STATEMENT_SEPARATOR}
         * to signal that each script contains a single statement without a separator.
         * @param separator the script statement separator
         */
        public void setSeparator(String separator) {
                this.separator = separator;
        }

        /**
         * Set the prefix that identifies single-line comments within the SQL scripts.
         * <p>Defaults to {@code "--"}.
         * @param commentPrefix the prefix for single-line comments
         */
        public void setCommentPrefix(String commentPrefix) {
                this.commentPrefix = commentPrefix;
        }

        /**
         * Set the start delimiter that identifies block comments within the SQL
         * scripts.
         * <p>Defaults to {@code "/*"}.
         * @param blockCommentStartDelimiter the start delimiter for block comments
         * (never {@code null} or empty)
         * @since 4.0.3
         * @see #setBlockCommentEndDelimiter
         */
        public void setBlockCommentStartDelimiter(String blockCommentStartDelimiter) {
                Assert.hasText(blockCommentStartDelimiter, "BlockCommentStartDelimiter must not be null or empty");
                this.blockCommentStartDelimiter = blockCommentStartDelimiter;
        }

        /**
         * Set the end delimiter that identifies block comments within the SQL
         * scripts.
         * <p>Defaults to <code>"*&#47;"</code>.
         * @param blockCommentEndDelimiter the end delimiter for block comments
         * (never {@code null} or empty)
         * @since 4.0.3
         * @see #setBlockCommentStartDelimiter
         */
        public void setBlockCommentEndDelimiter(String blockCommentEndDelimiter) {
                Assert.hasText(blockCommentEndDelimiter, "BlockCommentEndDelimiter must not be null or empty");
                this.blockCommentEndDelimiter = blockCommentEndDelimiter;
        }

        /**
         * Flag to indicate that all failures in SQL should be logged but not cause a failure.
         * <p>Defaults to {@code false}.
         * @param continueOnError {@code true} if script execution should continue on error
         */
        public void setContinueOnError(boolean continueOnError) {
                this.continueOnError = continueOnError;
        }

        /**
         * Flag to indicate that a failed SQL {@code DROP} statement can be ignored.
         * <p>This is useful for a non-embedded database whose SQL dialect does not
         * support an {@code IF EXISTS} clause in a {@code DROP} statement.
         * <p>The default is {@code false} so that if the populator runs accidentally, it will
         * fail fast if a script starts with a {@code DROP} statement.
         * @param ignoreFailedDrops {@code true} if failed drop statements should be ignored
         */
        public void setIgnoreFailedDrops(boolean ignoreFailedDrops) {
                this.ignoreFailedDrops = ignoreFailedDrops;
        }


        /**
         * {@inheritDoc}
         * @see #execute(DataSource)
         */
        @Override
        public void populate(Connection connection) throws ScriptException {
                Assert.notNull(connection, "Connection must not be null");
                for (Resource script : this.scripts) {
                        EncodedResource encodedScript = new EncodedResource(script, this.sqlScriptEncoding);
                        ScriptUtils.executeSqlScript(connection, encodedScript, this.continueOnError, this.ignoreFailedDrops,
                                        this.commentPrefix, this.separator, this.blockCommentStartDelimiter, this.blockCommentEndDelimiter);
                }
        }

        /**
         * Execute this {@code ResourceDatabasePopulator} against the given
         * {@link DataSource}.
         * <p>Delegates to {@link DatabasePopulatorUtils#execute}.
         * @param dataSource the {@code DataSource} to execute against (never {@code null})
         * @throws ScriptException if an error occurs
         * @since 4.1
         * @see #populate(Connection)
         */
        public void execute(DataSource dataSource) throws ScriptException {
                DatabasePopulatorUtils.execute(this, dataSource);
        }

}