// --------------------------------------------------------------------------------------------------------------------
// <copyright file="EncodeBase.cs" company="HandBrake Project (http://handbrake.fr)">
//   This file is part of the HandBrake source code - It may be used under the terms of the GNU General Public License.
// </copyright>
// <summary>
//   A Base Class for the Encode Services.
// </summary>
// --------------------------------------------------------------------------------------------------------------------

namespace HandBrake.ApplicationServices.Services.Base
{
    using System;
    using System.IO;
    using System.Text;

    using HandBrake.ApplicationServices.EventArgs;
    using HandBrake.ApplicationServices.Exceptions;
    using HandBrake.ApplicationServices.Model;
    using HandBrake.ApplicationServices.Services.Interfaces;
    using HandBrake.ApplicationServices.Utilities;

    /// <summary>
    /// A Base Class for the Encode Services.
    /// </summary>
    public class EncodeBase
    {
        #region Private Variables

        /// <summary>
        /// A Lock for the filewriter
        /// </summary>
        private static readonly object FileWriterLock = new object();

        /// <summary>
        /// The User Setting Service
        /// </summary>
        private readonly IUserSettingService userSettingService;

        /// <summary>
        /// Windows 7 API Pack wrapper
        /// </summary>
        private readonly Win7 windowsSeven = new Win7();

        /// <summary>
        /// The Log File Header
        /// </summary>
        private readonly StringBuilder header;

        /// <summary>
        /// The Log Buffer
        /// </summary>
        private StringBuilder logBuffer;

        /// <summary>
        /// The Log file writer
        /// </summary>
        private StreamWriter fileWriter;

        #endregion

        /// <summary>
        /// Initializes a new instance of the <see cref="EncodeBase"/> class.
        /// </summary>
        /// <param name="userSettingService">
        /// The user Setting Service.
        /// </param>
        public EncodeBase(IUserSettingService userSettingService)
        {
            this.userSettingService = userSettingService;
            this.logBuffer = new StringBuilder();
            header =
                GeneralUtilities.CreateCliLogHeader(
                    userSettingService.GetUserSetting<string>(ASUserSettingConstants.HandBrakeVersion),
                    userSettingService.GetUserSetting<int>(ASUserSettingConstants.HandBrakeBuild));
        }

        #region Events

        /// <summary>
        /// Fires when a new CLI QueueTask starts
        /// </summary>
        public event EventHandler EncodeStarted;

        /// <summary>
        /// Fires when a CLI QueueTask finishes.
        /// </summary>
        public event EncodeCompletedStatus EncodeCompleted;

        /// <summary>
        /// Encode process has progressed
        /// </summary>
        public event EncodeProgessStatus EncodeStatusChanged;

        #endregion

        #region Properties
        /// <summary>
        /// Gets or sets a value indicating whether IsEncoding.
        /// </summary>
        public bool IsEncoding { get; protected set; }

        /// <summary>
        /// Gets ActivityLog.
        /// </summary>
        public string ActivityLog
        {
            get
            {
                string noLog =
                    "No log data available... Log data will show when you start an encode. \n\nOpen the log file directory to get previous log files.";
                return string.IsNullOrEmpty(this.logBuffer.ToString())
                           ? this.header + noLog
                           : this.header + this.logBuffer.ToString();
            }
        }

        /// <summary>
        /// Gets LogBuffer.
        /// </summary>
        public StringBuilder LogBuffer
        {
            get
            {
                return this.logBuffer;
            }
        }

        /// <summary>
        /// Gets WindowsSeven.
        /// </summary>
        public Win7 WindowsSeven
        {
            get
            {
                return this.windowsSeven;
            }
        }

        #endregion

        #region Invoke Events

        /// <summary>
        /// Invoke the Encode Status Changed Event.
        /// </summary>
        /// <param name="e">
        /// The EncodeProgressEventArgs.
        /// </param>
        public void InvokeEncodeStatusChanged(EncodeProgressEventArgs e)
        {
            EncodeProgessStatus handler = this.EncodeStatusChanged;
            if (handler != null)
            {
                handler(this, e);
            }
        }

        /// <summary>
        /// Invoke the Encode Completed Event
        /// </summary>
        /// <param name="e">
        /// The EncodeCompletedEventArgs.
        /// </param>
        public void InvokeEncodeCompleted(EncodeCompletedEventArgs e)
        {
            EncodeCompletedStatus handler = this.EncodeCompleted;
            if (handler != null)
            {
                handler(this, e);
            }
        }

        /// <summary>
        /// Invoke the Encode Started Event
        /// </summary>
        /// <param name="e">
        /// The EventArgs.
        /// </param>
        public void InvokeEncodeStarted(EventArgs e)
        {
            EventHandler handler = this.EncodeStarted;
            if (handler != null)
            {
                handler(this, e);
            }
        }

        #endregion

        #region Methods

        /// <summary>
        /// A Stop Method to be implemeneted.
        /// </summary>
        /// <param name="exc">
        /// The Exception that occured that required a STOP action.
        /// </param>
        public virtual void Stop(Exception exc)
        {
            // Do Nothing
        }

        /// <summary>
        /// Save a copy of the log to the users desired location or a default location
        /// if this feature is enabled in options.
        /// </summary>
        /// <param name="destination">
        /// The Destination File Path
        /// </param>
        public void ProcessLogs(string destination)
        {
            try
            {
                string logDir = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData) +
                                "\\HandBrake\\logs";
                string tempLogFile = Path.Combine(logDir, string.Format("last_encode_log{0}.txt", GeneralUtilities.ProcessId));

                string encodeDestinationPath = Path.GetDirectoryName(destination);
                string destinationFile = Path.GetFileName(destination);
                string encodeLogFile = destinationFile + " " +
                                       DateTime.Now.ToString().Replace("/", "-").Replace(":", "-") + ".txt";

                // Make sure the log directory exists.
                if (!Directory.Exists(logDir))
                {
                    Directory.CreateDirectory(logDir);
                }

                // Copy the Log to HandBrakes log folder in the users applciation data folder.
                File.Copy(tempLogFile, Path.Combine(logDir, encodeLogFile));

                // Save a copy of the log file in the same location as the enocde.
                if (this.userSettingService.GetUserSetting<bool>(ASUserSettingConstants.SaveLogWithVideo))
                {
                    File.Copy(tempLogFile, Path.Combine(encodeDestinationPath, encodeLogFile));
                }

                // Save a copy of the log file to a user specified location
                if (Directory.Exists(this.userSettingService.GetUserSetting<string>(ASUserSettingConstants.SaveLogCopyDirectory)) &&
                    this.userSettingService.GetUserSetting<bool>(ASUserSettingConstants.SaveLogToCopyDirectory))
                {
                    File.Copy(
                        tempLogFile, Path.Combine(this.userSettingService.GetUserSetting<string>(ASUserSettingConstants.SaveLogCopyDirectory), encodeLogFile));
                }
            }
            catch (Exception)
            {
                // This exception doesn't warrent user interaction, but it should be logged (TODO)
            }
        }

        /// <summary>
        /// Setup the logging.
        /// </summary>
        /// <param name="encodeQueueTask">
        /// The encode QueueTask.
        /// </param>
        protected void SetupLogging(QueueTask encodeQueueTask)
        {
            ShutdownFileWriter();
            string logDir = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData) + "\\HandBrake\\logs";
            string logFile = Path.Combine(logDir, string.Format("last_encode_log{0}.txt", GeneralUtilities.ProcessId));
            string logFile2 = Path.Combine(logDir, string.Format("tmp_appReadable_log{0}.txt", GeneralUtilities.ProcessId));

            try
            {
                string query = QueryGeneratorUtility.GenerateQuery(new EncodeTask(encodeQueueTask.Task),
                    userSettingService.GetUserSetting<int>(ASUserSettingConstants.PreviewScanCount),
                    userSettingService.GetUserSetting<int>(ASUserSettingConstants.Verbosity),
                    userSettingService.GetUserSetting<bool>(ASUserSettingConstants.DisableLibDvdNav));
                this.logBuffer = new StringBuilder();
                this.logBuffer.AppendLine(String.Format("CLI Query: {0}", query));
                this.logBuffer.AppendLine(String.Format("User Query: {0}", encodeQueueTask.CustomQuery));
                this.logBuffer.AppendLine();

                // Clear the current Encode Logs)
                if (File.Exists(logFile))
                {
                    File.Delete(logFile);
                }

                if (File.Exists(logFile2))
                {
                    File.Delete(logFile2);
                }

                this.fileWriter = new StreamWriter(logFile) { AutoFlush = true };
                this.fileWriter.WriteLine(header);
                this.fileWriter.WriteLine(String.Format("CLI Query: {0}", query));
                this.fileWriter.WriteLine(String.Format("User Query: {0}", encodeQueueTask.CustomQuery));
                this.fileWriter.WriteLine();
            }
            catch (Exception)
            {
                if (this.fileWriter != null)
                {
                    this.fileWriter.Close();
                    this.fileWriter.Dispose();
                }

                throw;
            }
        }

        /// <summary>
        /// Process an Incomming Log Message.
        /// </summary>
        /// <param name="message">
        /// The message.
        /// </param>
        protected void ProcessLogMessage(string message)
        {
            if (!String.IsNullOrEmpty(message))
            {
                try
                {
                    lock (this.LogBuffer)
                    {
                        this.LogBuffer.AppendLine(message);
                    }

                    lock (FileWriterLock)
                    {
                        if (this.fileWriter != null && this.fileWriter.BaseStream.CanWrite)
                        {
                            this.fileWriter.WriteLine(message);

                            // If the logging grows past 100MB, kill the encode and stop.
                            if (this.fileWriter.BaseStream.Length > 100000000)
                            {
                                this.Stop(
                                    new GeneralApplicationException(
                                        "The encode has been stopped. The log file has grown to over 100MB which indicates a serious problem has occured with the encode.", 
                                        "Please check the encode log for an indication of what the problem is.", null));
                            }
                        }
                    }
                }
                catch (GeneralApplicationException)
                {
                    throw;
                }
                catch (Exception exc)
                {
                    // Do Nothing.
                }
            }
        }

        /// <summary>
        /// Shutdown and Dispose of the File Writer.
        /// </summary>
        protected void ShutdownFileWriter()
        {
            try
            {
                lock (FileWriterLock)
                {
                    if (this.fileWriter != null)
                    {
                        this.fileWriter.Close();
                        this.fileWriter.Dispose();
                    }

                    this.fileWriter = null;
                }
            }
            catch (Exception)
            {
                // This exception doesn't warrent user interaction, but it should be logged (TODO)
            }
        }

        /// <summary>
        /// Verify the Encode Destination path exists and if not, create it.
        /// </summary>
        /// <param name="task">
        /// The task.
        /// </param>
        /// <exception cref="Exception">
        /// If the creation fails, an exception is thrown.
        /// </exception>
        protected void VerifyEncodeDestinationPath(QueueTask task)
        {
            // Make sure the path exists, attempt to create it if it doesn't
            try
            {
                string path = Directory.GetParent(task.Task.Destination).ToString();
                if (!Directory.Exists(path))
                {
                    Directory.CreateDirectory(path);
                }
            }
            catch (Exception exc)
            {
                throw new GeneralApplicationException(
                    "Unable to create directory for the encoded output.", "Please verify that you have a valid path.", exc);
            }
        }

        #endregion
    }
}