/*
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 * 
 *  http://aws.amazon.com/apache2.0
 * 
 * or in the "license" file accompanying this file. This file 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.
 */
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Text;

#pragma warning disable 1591

namespace Amazon.ElasticMapReduce.Model
{
    /// <summary>
    /// This class provides helper methods for creating common Elastic MapReduce step
    /// types. To use StepFactory, you should construct it with the appropriate bucket
    /// for your region. The official bucket format is "&lt;region&gt;.elasticmapreduce", so
    /// us-east-1 would use the bucket "us-east-1.elasticmapreduce".
    /// </summary>
    /// <example>Create an interactive Hive job flow with debugging enabled:
    /// <code>
    ///  IAmazonElasticMapReduce emr = AWSClientFactory.CreateAmazonElasticMapReduceClient(accessKey, secretKey);
    ///
    ///  StepFactory stepFactory = new StepFactory();
    ///
    ///  StepConfig enableDebugging = new StepConfig {
    ///     Name = "Enable Debugging",
    ///     ActionOnFailure = "TERMINATE_JOB_FLOW",
    ///     HadoopJarStep = stepFactory.NewEnableDebuggingStep()
    ///  };
    ///
    ///  StepConfig installHive = new StepConfig {
    ///     Name = "Install Hive",
    ///     ActionOnFailure = "TERMINATE_JOB_FLOW",
    ///     HadoopJarStep = stepFactory.NewInstallHiveStep()
    ///  };
    ///  
    ///  RunJobFlowRequest request = new RunJobFlowRequest {
    ///     Name = "Hive Interactive",
    ///     Steps = new List&lt;StepConfig> { enableDebugging, installHive },
    ///     LogUri = "s3://log-bucket/",
    ///     Instances = new JobFlowInstancesConfig {
    ///         Ec2KeyName = "keypair",
    ///         HadoopVersion = "0.20",
    ///         InstanceCount = 5,
    ///         KeepJobFlowAliveWhenNoSteps = true,
    ///         MasterInstanceType = "m1.small",
    ///         SlaveInstanceType = "m1.small"
    ///     }
    ///  };
    ///
    /// RunJobFlowResponse response = emr.RunJobFlow(request);
    /// </code>
    /// </example>
    public class StepFactory
    {
        private string bucket;

        private const string
            SWITCH_BASE_PATH       = "--base-path",
            SWITCH_INSTALL_HIVE    = "--install-hive",
            SWITCH_INSTALL_PIG     = "--install-pig",
            SWITCH_HIVE_VERSIONS   = "--hive-versions",
            SWITCH_RUN_HIVE_SCRIPT = "--run-hive-script",
            SWITCH_RUN_PIG_SCRIPT  = "--run-pig-script",
            SWITCH_ARGS            = "--args",
            SWITCH_F               = "-f";

        private const string
            TOOL_HIVE = "hive",
            TOOL_PIG  = "pig";

        private const string 
            DEFAULT_BUCKET = "us-east-1.elasticmapreduce";


        /// <summary>
        /// Constructor that gets its resources from the S3 bucket specified 
        /// </summary>
        /// <param name="bucket">The bucket that contains the resources used by the step factory</param>
        public StepFactory(string bucket) 
        {
            this.bucket = bucket;
        }

        /// <summary>
        /// Constructor that gets its resources EMR bucket in the specified region. 
        /// </summary>
        /// <param name="region">The region of the EMR bucket to use.</param>
        public StepFactory(RegionEndpoint region)
        {
            this.bucket = string.Format(CultureInfo.InvariantCulture,"{0}.elasticmapreduce", region.SystemName);
        }

        /// <summary>
        /// Default constructor that gets its resources from the S3 in us-east-1. 
        /// </summary>
        public StepFactory() 
            : this(DEFAULT_BUCKET)
        {
        }

        /// <summary>
        /// Runs a specified script on the master node of your cluster.
        /// </summary>
        /// <param name="script">The script to run</param>
        /// <param name="args">Arguments to be passed to the script.</param>
        /// <returns>HadoopJarStepConfig that can be passed to your job flow.</returns>
        public HadoopJarStepConfig NewScriptRunnerStep(string script, params string[] args)
        {
            List<string> appendedArgs = new List<string>();
            appendedArgs.Add(script);
            foreach (var a in args)
                appendedArgs.Add(a);

            return new HadoopJarStepConfig
            {
                Jar = string.Format(CultureInfo.InvariantCulture, "s3://{0}/libs/script-runner/script-runner.jar", bucket),
                Args = appendedArgs
            };
        }

        /// <summary>
        /// When run as the first step in your job flow, enables the Hadoop debugging UI
        /// in the AWS Management Console.
        /// </summary>
        /// <returns>HadoopJarStepConfig that can be passed to your job flow.</returns>
        public HadoopJarStepConfig NewEnableDebuggingStep() 
        {
            return NewScriptRunnerStep(string.Format(CultureInfo.InvariantCulture, "s3://{0}/libs/state-pusher/0.1/fetch", bucket));
        }

        private HadoopJarStepConfig newHivePigStep(string type, params string[] args) 
        {
            String[] argsArray = new String[args.Length + 2];
            argsArray[0] = SWITCH_BASE_PATH;
            argsArray[1] = string.Format(CultureInfo.InvariantCulture, "s3://{0}/libs/{1}/", bucket, type);
            Array.Copy(args, 0, argsArray, 2, args.Length);
            return NewScriptRunnerStep(string.Format(CultureInfo.InvariantCulture, "s3://{0}/libs/{1}/{1}-script", bucket, type), argsArray);
        }

        /// <summary>
        /// Step that installs Hive on your job flow.
        /// </summary>
        /// <param name="hiveVersions">The versions of Hive to install.</param>
        /// <returns>HadoopJarStepConfig that can be passed to your job flow.</returns>
        public HadoopJarStepConfig NewInstallHiveStep(params HiveVersion[] hiveVersions)
        {
            if (hiveVersions.Length > 0)
            {
                string[] versionStrings = new String[hiveVersions.Length];
                
                for (int i = 0; i < hiveVersions.Length; i++)
                {
                    versionStrings[i] = hiveVersions[i].VersionString;
                }
                return newHivePigStep(TOOL_HIVE, SWITCH_INSTALL_HIVE, SWITCH_HIVE_VERSIONS, string.Join(",", versionStrings));
            }

            return newHivePigStep(TOOL_HIVE, SWITCH_INSTALL_HIVE);
        }

        /// <summary>
        /// Step that installs Hive on your job flow.
        /// </summary>
        /// <returns>HadoopJarStepConfig that can be passed to your job flow.</returns>
        public HadoopJarStepConfig NewInstallHiveStep() 
        {
            return NewInstallHiveStep(HiveVersion.Hive_0_5);
        }

        /// <summary>
        /// Step that runs a Hive script on your job flow.
        /// </summary>
        /// <param name="script">The script to run.</param>
        /// <param name="args">Arguments that get passed to the script.</param>
        /// <returns>HadoopJarStepConfig that can be passed to your job flow.</returns>
        public HadoopJarStepConfig NewRunHiveScriptStep(string script, params string[] args) 
        {
            return NewRunHiveScriptStepVersioned(script, HiveVersion.Hive_Latest.VersionString, args);
        }

        /// <summary>
        /// Step that runs a Hive script on your job flow with a specific verson of Hive.
        /// </summary>
        /// <param name="script">The script to run.</param>
        /// <param name="version">The version of Hive to run.</param>
        /// <param name="args">Arguments that get passed to the script.</param>
        /// <returns>HadoopJarStepConfig that can be passed to your job flow.</returns>
        public HadoopJarStepConfig NewRunHiveScriptStepVersioned(string script, string version, params string[] args)
        {
            string[] argsArray = new String[args.Length + 6];
            argsArray[0] = SWITCH_HIVE_VERSIONS;
            argsArray[1] = version;
            argsArray[2] = SWITCH_RUN_HIVE_SCRIPT;
            argsArray[3] = SWITCH_ARGS;
            argsArray[4] = SWITCH_F;
            argsArray[5] = script;
            Array.Copy(args, 0, argsArray, 6, args.Length);
            return newHivePigStep(TOOL_HIVE, argsArray);
        }

        /// <summary>
        /// Step that installs Pig on your job flow.
        /// </summary>
        /// <returns>HadoopJarStepConfig that can be passed to your job flow.</returns>
        public HadoopJarStepConfig NewInstallPigStep()
        {
            return newHivePigStep(TOOL_PIG, SWITCH_INSTALL_PIG);
        }

        /// <summary>
        /// Step that runs a Pig script on your job flow.
        /// </summary>
        /// <param name="script">The script to run.</param>
        /// <param name="args">Arguments that get passed to the script.</param>
        /// <returns>HadoopJarStepConfig that can be passed to your job flow.</returns>
        public HadoopJarStepConfig NewRunPigScriptStep(string script, params string[] args) 
        {
            string[] argsArray = new string[args.Length + 4];
            argsArray[0] = SWITCH_RUN_PIG_SCRIPT;
            argsArray[1] = SWITCH_ARGS;
            argsArray[2] = SWITCH_F;
            argsArray[3] = script;
            Array.Copy(args, 0, argsArray, 4, args.Length);
            return newHivePigStep(TOOL_PIG, argsArray);
        }

        /// <summary>
        /// The available Hive versions.
        /// For reference: http://docs.aws.amazon.com/ElasticMapReduce/latest/DeveloperGuide/UsingEMR_SupportedHiveVersions.html
        /// </summary>
        public class HiveVersion
        {
            public static readonly HiveVersion Hive_0_4 = new HiveVersion("0.4");
            public static readonly HiveVersion Hive_0_5 = new HiveVersion("0.5");
            public static readonly HiveVersion Hive_0_7 = new HiveVersion("0.7");
            public static readonly HiveVersion Hive_0_7_1 = new HiveVersion("0.7.1");
            public static readonly HiveVersion Hive_0_7_1_1 = new HiveVersion("0.7.1.1");
            public static readonly HiveVersion Hive_0_7_1_2 = new HiveVersion("0.7.1.2");
            public static readonly HiveVersion Hive_0_7_1_3 = new HiveVersion("0.7.1.3");
            public static readonly HiveVersion Hive_0_7_1_4 = new HiveVersion("0.7.1.4");
            public static readonly HiveVersion Hive_0_8_1 = new HiveVersion("0.8.1");
            public static readonly HiveVersion Hive_0_8_1_1 = new HiveVersion("0.8.1.1");
            public static readonly HiveVersion Hive_0_8_1_2 = new HiveVersion("0.8.1.2");
            public static readonly HiveVersion Hive_0_8_1_3 = new HiveVersion("0.8.1.3");
            public static readonly HiveVersion Hive_0_8_1_4 = new HiveVersion("0.8.1.4");
            public static readonly HiveVersion Hive_0_8_1_5 = new HiveVersion("0.8.1.5");
            public static readonly HiveVersion Hive_0_8_1_6 = new HiveVersion("0.8.1.6");
            public static readonly HiveVersion Hive_0_8_1_7 = new HiveVersion("0.8.1.7");
            public static readonly HiveVersion Hive_0_8_1_8 = new HiveVersion("0.8.1.8");
            public static readonly HiveVersion Hive_0_11_0 = new HiveVersion("0.11.0");
            public static readonly HiveVersion Hive_0_11_0_1 = new HiveVersion("0.11.0.1");
            public static readonly HiveVersion Hive_Latest = new HiveVersion("latest");

            string _version;

            public HiveVersion(string version)
            {
                this._version = version;
            }

            public string VersionString
            {
                get { return this._version; }
            }
        }
    }
}