// Copyright (C) 2024, The Duplicati Team
// https://duplicati.com, hello@duplicati.com
// 
// Permission is hereby granted, free of charge, to any person obtaining a 
// copy of this software and associated documentation files (the "Software"), 
// to deal in the Software without restriction, including without limitation 
// the rights to use, copy, modify, merge, publish, distribute, sublicense, 
// and/or sell copies of the Software, and to permit persons to whom the 
// Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in 
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.

using System;
using System.IO;
using System.Collections.Generic;
using Duplicati.Library.Utility;
using Duplicati.Library.Interface;
using Duplicati.Library.Modules.Builtin.ResultSerialization;
using System.Threading.Tasks;
using System.Text.RegularExpressions;
using System.Linq;

namespace Duplicati.Library.Modules.Builtin
{
    public class RunScript : IGenericCallbackModule
    {
        /// <summary>
        /// The tag used for logging
        /// </summary>
        private static readonly string LOGTAG = Logging.Log.LogTagFromType<RunScript>();
        /// <summary>
        /// The default log level
        /// </summary>
        private const Logging.LogMessageType DEFAULT_LOG_LEVEL = Logging.LogMessageType.Warning;

        /// <summary>
        /// The regex used to parse arguments
        /// </summary>
        private static readonly Regex ARGREGEX = new Regex(
            @"(?<arg>(?<=\s|^)(""(?<value>[^""\\]*(?:\\.[^""\\]*)*)""|'(?<value>[^'\\]*(?:\\.[^'\\]*)*)'|(?<value>[^\s]+))\s?)",
            RegexOptions.Compiled | RegexOptions.ExplicitCapture
        );


        private const string STARTUP_OPTION = "run-script-before";
        private const string FINISH_OPTION = "run-script-after";
        private const string REQUIRED_OPTION = "run-script-before-required";
        private const string TIMEOUT_OPTION = "run-script-timeout";
        private const string ENABLE_ARGUMENTS_OPTION = "run-script-with-arguments";
        /// <summary>
        /// Option used to set the log level for mail reports
        /// </summary>
        private const string OPTION_LOG_LEVEL = "run-script-log-level";
        /// <summary>
        /// Option used to set the log filters for mail reports
        /// </summary>
        private const string OPTION_LOG_FILTER = "run-script-log-filter";

        private const string RESULT_FORMAT_OPTION = "run-script-result-output-format";

        private const string DEFAULT_TIMEOUT = "60s";

        private string m_requiredScript = null;
        private string m_startScript = null;
        private string m_finishScript = null;
        private int m_timeout = 0;
        private bool m_enableArguments = false;

        private string m_operationName;
        private string m_remoteurl;
        private string[] m_localpath;
        private IDictionary<string, string> m_options;
        private IResultFormatSerializer resultFormatSerializer;

        /// <summary>
        /// The log scope that should be disposed
        /// </summary>
        private IDisposable m_logscope;
        /// <summary>
        /// The log storage
        /// </summary>
        private FileBackedStringList m_logstorage;


        #region IGenericModule implementation
        public void Configure(IDictionary<string, string> commandlineOptions)
        {
            commandlineOptions.TryGetValue(STARTUP_OPTION, out m_startScript);
            commandlineOptions.TryGetValue(REQUIRED_OPTION, out m_requiredScript);
            commandlineOptions.TryGetValue(FINISH_OPTION, out m_finishScript);
            m_enableArguments = Utility.Utility.ParseBoolOption(commandlineOptions, ENABLE_ARGUMENTS_OPTION);

            ResultExportFormat resultFormat;
            if (!commandlineOptions.TryGetValue(RESULT_FORMAT_OPTION, out var tmpResultFormat))
            {
                resultFormat = ResultExportFormat.Duplicati;
            }
            else if (!Enum.TryParse(tmpResultFormat, true, out resultFormat))
            {
                resultFormat = ResultExportFormat.Duplicati;
            }

            resultFormatSerializer = ResultFormatSerializerProvider.GetSerializer(resultFormat);

            if (!commandlineOptions.TryGetValue(TIMEOUT_OPTION, out var t))
                t = DEFAULT_TIMEOUT;

            m_timeout = (int)Utility.Timeparser.ParseTimeSpan(t).TotalMilliseconds;

            m_options = commandlineOptions;

            m_options.TryGetValue(OPTION_LOG_FILTER, out var logfilterstring);
            var filter = FilterExpression.ParseLogFilter(logfilterstring);
            var logLevel = Utility.Utility.ParseEnumOption(m_options, OPTION_LOG_LEVEL, DEFAULT_LOG_LEVEL);

            m_logstorage = new FileBackedStringList();
            m_logscope = Logging.Log.StartScope(m => m_logstorage.Add(m.AsString(true)), m =>
            {

                if (filter.Matches(m.FilterTag, out var result, out var match))
                    return result;
                else if (m.Level < logLevel)
                    return false;

                return true;
            });
        }

        public string Key { get { return "runscript"; } }
        public string DisplayName { get { return Strings.RunScript.DisplayName; } }
        public string Description { get { return Strings.RunScript.Description; } }
        public bool LoadAsDefault { get { return true; } }

        public IList<ICommandLineArgument> SupportedCommands
        {
            get
            {
                string[] resultOutputFormatOptions = [ResultExportFormat.Duplicati.ToString(), ResultExportFormat.Json.ToString()];
                return new List<ICommandLineArgument>([
                    new CommandLineArgument(STARTUP_OPTION, CommandLineArgument.ArgumentType.Path, Strings.RunScript.StartupoptionShort, Strings.RunScript.StartupoptionLong),
                    new CommandLineArgument(FINISH_OPTION, CommandLineArgument.ArgumentType.Path, Strings.RunScript.FinishoptionShort, Strings.RunScript.FinishoptionLong),
                    new CommandLineArgument(REQUIRED_OPTION, CommandLineArgument.ArgumentType.Path, Strings.RunScript.RequiredoptionShort, Strings.RunScript.RequiredoptionLong),
                    new CommandLineArgument(ENABLE_ARGUMENTS_OPTION, CommandLineArgument.ArgumentType.Boolean, Strings.RunScript.EnableArgumentsShort, Strings.RunScript.EnableArgumentsLong),
                    new CommandLineArgument(RESULT_FORMAT_OPTION,
                        CommandLineArgument.ArgumentType.Enumeration,
                        Strings.RunScript.ResultFormatShort,
                        Strings.RunScript.ResultFormatLong(resultOutputFormatOptions),
                        ResultExportFormat.Duplicati.ToString(),
                        null,
                        resultOutputFormatOptions),
                    new CommandLineArgument(TIMEOUT_OPTION, CommandLineArgument.ArgumentType.Timespan, Strings.RunScript.TimeoutoptionShort, Strings.RunScript.TimeoutoptionLong, DEFAULT_TIMEOUT),

                    new CommandLineArgument(OPTION_LOG_LEVEL, CommandLineArgument.ArgumentType.Enumeration, Strings.ReportHelper.OptionLoglevellShort, Strings.ReportHelper.OptionLoglevelLong, DEFAULT_LOG_LEVEL.ToString(), null, Enum.GetNames(typeof(Logging.LogMessageType))),
                    new CommandLineArgument(OPTION_LOG_FILTER, CommandLineArgument.ArgumentType.String, Strings.ReportHelper.OptionLogfilterShort, Strings.ReportHelper.OptionLogfilterLong),
                ]);
            }
        }
        #endregion

        #region IGenericCallbackModule implementation

        public void OnStart(string operationname, ref string remoteurl, ref string[] localpath)
        {
            if (!string.IsNullOrEmpty(m_requiredScript))
                Execute(m_requiredScript, "BEFORE", operationname, ref remoteurl, ref localpath, m_timeout, true, m_enableArguments, m_options, null, null);

            if (!string.IsNullOrEmpty(m_startScript))
                Execute(m_startScript, "BEFORE", operationname, ref remoteurl, ref localpath, m_timeout, false, m_enableArguments, m_options, null, null);

            // Save options that might be set by a --run-script-before script so that the OnFinish method
            // references the same values.
            m_operationName = operationname;
            m_remoteurl = remoteurl;
            m_localpath = localpath;
        }

        public void OnFinish(object result, Exception exception)
        {
            // Dispose the current log scope
            if (m_logscope != null)
            {
                try { m_logscope.Dispose(); }
                catch { }
                m_logscope = null;
            }

            if (string.IsNullOrEmpty(m_finishScript))
                return;

            ParsedResultType level;
            OperationAbortException oae = result as OperationAbortException ?? exception as OperationAbortException;
            if (oae != null)
            {
                switch (oae.AbortReason)
                {
                    case OperationAbortReason.Error:
                        level = ParsedResultType.Error;
                        break;
                    case OperationAbortReason.Normal:
                        level = ParsedResultType.Success;
                        break;
                    case OperationAbortReason.Warning:
                        level = ParsedResultType.Warning;
                        break;
                    default:
                        level = ParsedResultType.Unknown;
                        break;
                }
            }
            else if (result is Exception || exception != null)
                level = ParsedResultType.Fatal;
            else if (result != null && result is IBasicResults results)
                level = results.ParsedResult;
            else
                level = ParsedResultType.Error;

            using (TempFile tmpfile = new TempFile())
            {
                using (var streamWriter = new StreamWriter(tmpfile))
                    streamWriter.Write(resultFormatSerializer.Serialize(result, exception, m_logstorage, null));

                Execute(m_finishScript, "AFTER", m_operationName, ref m_remoteurl, ref m_localpath, m_timeout, false, m_enableArguments, m_options, tmpfile, level);
            }
        }
        #endregion

        private static void Execute(string scriptpath, string eventname, string operationname, ref string remoteurl, ref string[] localpath, int timeout, bool requiredScript, bool enableArguments, IDictionary<string, string> options, string datafile, ParsedResultType? level)
        {
            try
            {
                var arguments = new List<string>();
                if (enableArguments)
                {
                    var args = ARGREGEX.Matches(scriptpath);
                    if (args.Any())
                    {
                        arguments = args.AsEnumerable().Select(m => m.Groups["value"].Value).ToList();
                        scriptpath = arguments[0];
                        arguments.RemoveAt(0);
                    }
                }

                var psi = new System.Diagnostics.ProcessStartInfo(scriptpath, arguments)
                {
                    WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden,
                    CreateNoWindow = true,
                    UseShellExecute = false,
                    RedirectStandardOutput = true,
                    RedirectStandardError = true,
                    RedirectStandardInput = false
                };

                foreach (KeyValuePair<string, string> kv in options)
                    psi.EnvironmentVariables["DUPLICATI__" + kv.Key.Replace('-', '_')] = kv.Value;

                if (!options.ContainsKey("backup-name"))
                    psi.EnvironmentVariables["DUPLICATI__backup_name"] = System.IO.Path.GetFileNameWithoutExtension(Duplicati.Library.Utility.Utility.getEntryAssembly().Location);

                psi.EnvironmentVariables["DUPLICATI__EVENTNAME"] = eventname;
                psi.EnvironmentVariables["DUPLICATI__OPERATIONNAME"] = operationname;
                psi.EnvironmentVariables["DUPLICATI__REMOTEURL"] = remoteurl;
                if (level != null)
                    psi.EnvironmentVariables["DUPLICATI__PARSED_RESULT"] = level.Value.ToString();

                if (localpath != null)
                    psi.EnvironmentVariables["DUPLICATI__LOCALPATH"] = string.Join(System.IO.Path.PathSeparator.ToString(), localpath);

                string stderr = null;
                string stdout = null;

                if (!string.IsNullOrEmpty(datafile))
                    psi.EnvironmentVariables["DUPLICATI__RESULTFILE"] = datafile;

                using (System.Diagnostics.Process p = System.Diagnostics.Process.Start(psi))
                {
                    var cs = new ConsoleDataHandler(p);

                    if (timeout <= 0)
                        p.WaitForExit();
                    else
                        p.WaitForExit(timeout);

                    if (requiredScript)
                    {
                        if (!p.HasExited)
                            throw new UserInformationException(Strings.RunScript.ScriptTimeoutError(scriptpath), "RunScriptTimeout");
                        else if (p.ExitCode != 0)
                            throw new UserInformationException(Strings.RunScript.InvalidExitCodeError(scriptpath, p.ExitCode), "RunScriptInvalidExitCode");
                    }

                    if (p.HasExited)
                    {
                        cs.WaitForCompletion();

                        stderr = cs.StandardError;
                        stdout = cs.StandardOutput;
                        if (p.ExitCode != 0)
                        {
                            if (!requiredScript)
                            {
                                // We log a warning or an error depending on the exit code
                                switch (p.ExitCode)
                                {
                                    case 0:
                                    case 1:
                                        // No messages here
                                        break;

                                    case 2:
                                    case 3:
                                        Logging.Log.WriteWarningMessage(LOGTAG, "InvalidExitCode", null, Strings.RunScript.ExitCodeError(scriptpath, p.ExitCode, stderr));
                                        stderr = null;
                                        break;

                                    case 4:
                                    case 5:
                                    default:
                                        Logging.Log.WriteErrorMessage(LOGTAG, "InvalidExitCode", null, Strings.RunScript.ExitCodeError(scriptpath, p.ExitCode, stderr));
                                        stderr = null;
                                        break;
                                }

                                // If this is the start event, we abort the backup 
                                if (eventname == "BEFORE")
                                {
                                    switch (p.ExitCode)
                                    {
                                        case 0: // OK, run operation
                                        case 2: // Warning, run operation
                                        case 4: // Error, run operation
                                            break;
                                        case 1: // OK, don't run operation
                                            throw new OperationAbortException(OperationAbortReason.Normal, Strings.RunScript.InvalidExitCodeError(scriptpath, p.ExitCode));
                                        case 3: // Warning, don't run operation
                                            throw new OperationAbortException(OperationAbortReason.Warning, Strings.RunScript.InvalidExitCodeError(scriptpath, p.ExitCode));
                                        default: // Error don't run operation
                                            throw new OperationAbortException(OperationAbortReason.Error, Strings.RunScript.InvalidExitCodeError(scriptpath, p.ExitCode));
                                    }
                                }
                            }
                            else
                                Logging.Log.WriteWarningMessage(LOGTAG, "InvalidExitCode", null, Strings.RunScript.InvalidExitCodeError(scriptpath, p.ExitCode));
                        }
                    }
                    else
                    {
                        Logging.Log.WriteWarningMessage(LOGTAG, "ScriptTimeout", null, Strings.RunScript.ScriptTimeoutError(scriptpath));
                    }
                }

                if (!string.IsNullOrEmpty(stderr))
                    Logging.Log.WriteWarningMessage(LOGTAG, "StdErrorNotEmpty", null, Strings.RunScript.StdErrorReport(scriptpath, stderr));

                //We only allow setting parameters on startup
                if (eventname == "BEFORE" && stdout != null)
                {
                    foreach (string rawline in stdout.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries))
                    {
                        string line = rawline.Trim();
                        if (!line.StartsWith("--", StringComparison.Ordinal))
                            continue; //Ignore anything that does not start with --

                        line = line.Substring(2);
                        int lix = line.IndexOf('=');
                        if (lix == 0) //Skip --= as that makes no sense
                            continue;

                        string key;
                        string value;

                        if (lix < 0)
                        {
                            key = line.Trim();
                            value = "";
                        }
                        else
                        {
                            key = line.Substring(0, lix).Trim();
                            value = line.Substring(lix + 1).Trim();

                            if (value.Length >= 2 && value.StartsWith("\"", StringComparison.Ordinal) && value.EndsWith("\"", StringComparison.Ordinal))
                                value = value.Substring(1, value.Length - 2);
                        }

                        if (string.Equals(key, "remoteurl", StringComparison.OrdinalIgnoreCase))
                        {
                            remoteurl = value;
                        }
                        else if (string.Equals(key, "localpath", StringComparison.OrdinalIgnoreCase))
                        {
                            localpath = value.Split(System.IO.Path.PathSeparator);
                        }
                        else if (
                            string.Equals(key, "eventname", StringComparison.OrdinalIgnoreCase) ||
                            string.Equals(key, "operationname", StringComparison.OrdinalIgnoreCase) ||
                            string.Equals(key, "main-action", StringComparison.OrdinalIgnoreCase) ||
                            key == ""
                        )
                        {
                            //Ignore
                        }
                        else
                            options[key] = value;
                    }
                }
            }
            catch (OperationAbortException)
            {
                // Do not log this, it is already logged
                throw;
            }
            catch (Exception ex)
            {
                Logging.Log.WriteWarningMessage(LOGTAG, "ScriptExecuteError", ex, Strings.RunScript.ScriptExecuteError(scriptpath, ex.Message));
                if (requiredScript)
                    throw;
            }
        }

        /// <summary>
        /// Helper class to extract output from the program
        /// </summary>
        private class ConsoleDataHandler
        {
            public ConsoleDataHandler(System.Diagnostics.Process p)
            {
                m_task = Task.WhenAll(
                    Task.Run(async () => StandardOutput = await p.StandardOutput.ReadToEndAsync()),
                    Task.Run(async () => StandardError = await p.StandardError.ReadToEndAsync())
                );
            }

            private readonly Task m_task;
            public string StandardOutput { get; private set; }
            public string StandardError { get; private set; }
            public void WaitForCompletion()
            {
                // NOTE: This is ugly, but there is a race where "HasExited" is set, 
                // but the stdout/stderr streams have not yet completed.
                // If we wait a little here, we eventually get the data.
                // If the streams have completed we do not wait.
                m_task.Wait(TimeSpan.FromSeconds(5));
            }
        }
    }
}