/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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
 *
 *     http://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.hcatalog.cli.SemanticAnalysis;

import java.io.IOException;
import java.io.Serializable;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.metastore.api.FieldSchema;
import org.apache.hadoop.hive.ql.exec.DDLTask;
import org.apache.hadoop.hive.ql.exec.Task;
import org.apache.hadoop.hive.ql.io.RCFileInputFormat;
import org.apache.hadoop.hive.ql.io.RCFileOutputFormat;
import org.apache.hadoop.hive.ql.metadata.Hive;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.metadata.Table;
import org.apache.hadoop.hive.ql.parse.ASTNode;
import org.apache.hadoop.hive.ql.parse.BaseSemanticAnalyzer;
import org.apache.hadoop.hive.ql.parse.HiveParser;
import org.apache.hadoop.hive.ql.parse.HiveSemanticAnalyzerHookContext;
import org.apache.hadoop.hive.ql.parse.SemanticException;
import org.apache.hadoop.hive.ql.plan.CreateTableDesc;
import org.apache.hadoop.hive.ql.security.authorization.Privilege;
import org.apache.hcatalog.common.HCatConstants;
import org.apache.hcatalog.common.HCatUtil;
import org.apache.hcatalog.mapreduce.HCatStorageHandler;

final class CreateTableHook extends HCatSemanticAnalyzerBase {

    private String tableName;

    @Override
    public ASTNode preAnalyze(HiveSemanticAnalyzerHookContext context,
                              ASTNode ast) throws SemanticException {

        Hive db;
        try {
            db = context.getHive();
        } catch (HiveException e) {
            throw new SemanticException(
                "Couldn't get Hive DB instance in semantic analysis phase.",
                e);
        }

        // Analyze and create tbl properties object
        int numCh = ast.getChildCount();

        String inputFormat = null, outputFormat = null;
        tableName = BaseSemanticAnalyzer.getUnescapedName((ASTNode) ast
            .getChild(0));
        boolean likeTable = false;

        for (int num = 1; num < numCh; num++) {
            ASTNode child = (ASTNode) ast.getChild(num);

            switch (child.getToken().getType()) {

            case HiveParser.TOK_QUERY: // CTAS
                throw new SemanticException(
                    "Operation not supported. Create table as " +
                        "Select is not a valid operation.");

            case HiveParser.TOK_TABLEBUCKETS:
                break;

            case HiveParser.TOK_TBLSEQUENCEFILE:
                inputFormat = HCatConstants.SEQUENCEFILE_INPUT;
                outputFormat = HCatConstants.SEQUENCEFILE_OUTPUT;
                break;

            case HiveParser.TOK_TBLTEXTFILE:
                inputFormat = org.apache.hadoop.mapred.TextInputFormat.class.getName();
                outputFormat = org.apache.hadoop.hive.ql.io.IgnoreKeyTextOutputFormat.class.getName();

                break;

            case HiveParser.TOK_LIKETABLE:
                likeTable = true;
                break;

            case HiveParser.TOK_IFNOTEXISTS:
                try {
                    List<String> tables = db.getTablesByPattern(tableName);
                    if (tables != null && tables.size() > 0) { // table
                        // exists
                        return ast;
                    }
                } catch (HiveException e) {
                    throw new SemanticException(e);
                }
                break;

            case HiveParser.TOK_TABLEPARTCOLS:
                List<FieldSchema> partCols = BaseSemanticAnalyzer
                    .getColumns((ASTNode) child.getChild(0), false);
                for (FieldSchema fs : partCols) {
                    if (!fs.getType().equalsIgnoreCase("string")) {
                        throw new SemanticException(
                            "Operation not supported. HCatalog only " +
                                "supports partition columns of type string. "
                                + "For column: "
                                + fs.getName()
                                + " Found type: " + fs.getType());
                    }
                }
                break;

            case HiveParser.TOK_STORAGEHANDLER:
                String storageHandler = BaseSemanticAnalyzer
                    .unescapeSQLString(child.getChild(0).getText());
                if (org.apache.commons.lang.StringUtils
                    .isNotEmpty(storageHandler)) {
                    return ast;
                }

                break;

            case HiveParser.TOK_TABLEFILEFORMAT:
                if (child.getChildCount() < 2) {
                    throw new SemanticException(
                        "Incomplete specification of File Format. " +
                            "You must provide InputFormat, OutputFormat.");
                }
                inputFormat = BaseSemanticAnalyzer.unescapeSQLString(child
                    .getChild(0).getText());
                outputFormat = BaseSemanticAnalyzer.unescapeSQLString(child
                    .getChild(1).getText());
                break;

            case HiveParser.TOK_TBLRCFILE:
                inputFormat = RCFileInputFormat.class.getName();
                outputFormat = RCFileOutputFormat.class.getName();
                break;

            }
        }

        if (!likeTable && (inputFormat == null || outputFormat == null)) {
            throw new SemanticException(
                "STORED AS specification is either incomplete or incorrect.");
        }


        return ast;
    }

    @Override
    public void postAnalyze(HiveSemanticAnalyzerHookContext context,
                            List<Task<? extends Serializable>> rootTasks)
        throws SemanticException {

        if (rootTasks.size() == 0) {
            // There will be no DDL task created in case if its CREATE TABLE IF
            // NOT EXISTS
            return;
        }
        CreateTableDesc desc = ((DDLTask) rootTasks.get(rootTasks.size() - 1))
            .getWork().getCreateTblDesc();
        if (desc == null) {
            // Desc will be null if its CREATE TABLE LIKE. Desc will be
            // contained in CreateTableLikeDesc. Currently, HCat disallows CTLT in
            // pre-hook. So, desc can never be null.
            return;
        }
        Map<String, String> tblProps = desc.getTblProps();
        if (tblProps == null) {
            // tblProps will be null if user didnt use tblprops in his CREATE
            // TABLE cmd.
            tblProps = new HashMap<String, String>();

        }

        // first check if we will allow the user to create table.
        String storageHandler = desc.getStorageHandler();
        if (StringUtils.isEmpty(storageHandler)) {
        } else {
            try {
                HCatStorageHandler storageHandlerInst = HCatUtil
                    .getStorageHandler(context.getConf(),
                        desc.getStorageHandler(),
                        desc.getSerName(),
                        desc.getInputFormat(),
                        desc.getOutputFormat());
                //Authorization checks are performed by the storageHandler.getAuthorizationProvider(), if  
                //StorageDelegationAuthorizationProvider is used.
            } catch (IOException e) {
                throw new SemanticException(e);
            }
        }

        if (desc != null) {
            try {
                Table table = context.getHive().newTable(desc.getTableName());
                if (desc.getLocation() != null) {
                    table.setDataLocation(new Path(desc.getLocation()).toUri());
                }
                if (desc.getStorageHandler() != null) {
                    table.setProperty(
                        org.apache.hadoop.hive.metastore.api.Constants.META_TABLE_STORAGE,
                        desc.getStorageHandler());
                }
                for (Map.Entry<String, String> prop : tblProps.entrySet()) {
                    table.setProperty(prop.getKey(), prop.getValue());
                }
                for (Map.Entry<String, String> prop : desc.getSerdeProps().entrySet()) {
                    table.setSerdeParam(prop.getKey(), prop.getValue());
                }
                //TODO: set other Table properties as needed

                //authorize against the table operation so that location permissions can be checked if any

                if (HiveConf.getBoolVar(context.getConf(),
                    HiveConf.ConfVars.HIVE_AUTHORIZATION_ENABLED)) {
                    authorize(table, Privilege.CREATE);
                }
            } catch (HiveException ex) {
                throw new SemanticException(ex);
            }
        }

        desc.setTblProps(tblProps);
        context.getConf().set(HCatConstants.HCAT_CREATE_TBL_NAME, tableName);
    }
}