using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.BL;
using Tango.BL.Entities;
using Tango.BL.Enumerations;
using Tango.Core;
using Tango.Integration.Operation;

namespace Tango.Integration.JobRuns
{
    /// <summary>
    /// Represents a basic database job runs logger.
    /// </summary>
    /// <seealso cref="Tango.Integration.JobRuns.IJobRunsLogger" />
    public class BasicJobRunsLogger : ExtendedObject, IJobRunsLogger
    {
        private DateTime _start_date;
        private Job _job;

        #region Properties

        /// <summary>
        /// Gets the machine operator.
        /// </summary>
        public IMachineOperator MachineOperator { get; private set; }

        /// <summary>
        /// Gets a value indicating whether this instance is started.
        /// </summary>
        public bool IsStarted { get; private set; }

        /// <summary>
        /// Gets or sets the job designations of which the logger should log (supports multiple flags).
        /// </summary>
        public JobDesignations JobDesignation { get; set; }

        #endregion

        #region Constructors

        /// <summary>
        /// Initializes a new instance of the <see cref="BasicJobRunsLogger"/> class.
        /// </summary>
        /// <param name="machineOperator">The machine operator.</param>
        public BasicJobRunsLogger(IMachineOperator machineOperator)
        {
            JobDesignation = JobDesignations.Default;
            MachineOperator = machineOperator;
            Init();
        }

        #endregion

        #region Private Methods

        /// <summary>
        /// Initializes this instance.
        /// </summary>
        private void Init()
        {
            MachineOperator.PrintingStarted -= Machine_PrintingStarted;
            MachineOperator.PrintingStarted += Machine_PrintingStarted;
            MachineOperator.PrintingCompleted -= Machine_PrintingCompleted;
            MachineOperator.PrintingCompleted += Machine_PrintingCompleted;
            MachineOperator.PrintingAborted -= Machine_PrintingAborted;
            MachineOperator.PrintingAborted += Machine_PrintingAborted;
            MachineOperator.PrintingFailed -= Machine_PrintingFailed;
            MachineOperator.PrintingFailed += Machine_PrintingFailed;
        }

        private bool ShouldLog()
        {
            return IsStarted && _job != null && JobDesignation.HasFlag(_job.Designation);
        }

        #endregion

        #region Public Methods

        /// <summary>
        /// Starts the logger.
        /// </summary>
        public void Start()
        {
            IsStarted = true;
        }

        /// <summary>
        /// Stops the logger.
        /// </summary>
        public void Stop()
        {
            IsStarted = false;
        }

        #endregion

        #region Event Handlers

        private void Machine_PrintingFailed(object sender, PrintingFailedEventArgs e)
        {
            if (ShouldLog())
            {
                if (e.Job.Guid == _job.Guid)
                {
                    Task.Factory.StartNew(() =>
                    {
                        try
                        {
                            using (var db = ObservablesContext.CreateDefault())
                            {
                                db.JobRuns.Add(new JobRun()
                                {
                                    StartDate = _start_date,
                                    EndDate = DateTime.UtcNow,
                                    JobGuid = _job.Guid,
                                    JobRunStatus = JobRunStatus.Failed,
                                    EndPosition = e.JobHandler.Status.Progress,
                                    FailedMessage = e.Exception.Message,
                                });

                                e.Job.LastRun = DateTime.UtcNow;
                                _job.LastRun = DateTime.UtcNow;

                                var job = db.Jobs.SingleOrDefault(x => x.Guid == _job.Guid);

                                if (job != null)
                                {
                                    job.LastRun = DateTime.UtcNow;
                                }

                                db.SaveChanges();
                            }
                        }
                        catch (Exception ex)
                        {
                            LogManager.Log(ex, "Error logging the current job run to the database.");
                        }
                    });
                }
            }
        }

        private void Machine_PrintingAborted(object sender, PrintingEventArgs e)
        {
            if (ShouldLog())
            {
                if (e.Job.Guid == _job.Guid)
                {
                    Task.Factory.StartNew(() =>
                    {
                        try
                        {
                            using (var db = ObservablesContext.CreateDefault())
                            {
                                db.JobRuns.Add(new JobRun()
                                {
                                    StartDate = _start_date,
                                    EndDate = DateTime.UtcNow,
                                    JobGuid = _job.Guid,
                                    EndPosition = e.JobHandler.Status.Progress,
                                    JobRunStatus = JobRunStatus.Aborted,
                                });

                                e.Job.LastRun = DateTime.UtcNow;
                                _job.LastRun = DateTime.UtcNow;

                                var job = db.Jobs.SingleOrDefault(x => x.Guid == _job.Guid);

                                if (job != null)
                                {
                                    job.LastRun = DateTime.UtcNow;
                                }

                                db.SaveChanges();
                            }
                        }
                        catch (Exception ex)
                        {
                            LogManager.Log(ex, "Error logging the current job run to the database.");
                        }
                    });
                }
            }
        }

        private void Machine_PrintingCompleted(object sender, PrintingEventArgs e)
        {
            if (ShouldLog())
            {
                if (e.Job.Guid == _job.Guid)
                {
                    Task.Factory.StartNew(() =>
                    {
                        try
                        {
                            using (var db = ObservablesContext.CreateDefault())
                            {
                                db.JobRuns.Add(new JobRun()
                                {
                                    StartDate = _start_date,
                                    EndDate = DateTime.UtcNow,
                                    JobGuid = _job.Guid,
                                    EndPosition = e.JobHandler.Status.Progress,
                                    JobRunStatus = JobRunStatus.Completed,
                                });

                                e.Job.LastRun = DateTime.UtcNow;
                                _job.LastRun = DateTime.UtcNow;

                                var job = db.Jobs.SingleOrDefault(x => x.Guid == _job.Guid);

                                if (job != null)
                                {
                                    job.LastRun = DateTime.UtcNow;
                                }

                                db.SaveChanges();
                            }
                        }
                        catch (Exception ex)
                        {
                            LogManager.Log(ex, "Error logging the current job run to the database.");
                        }
                    });
                }
            }
        }

        private void Machine_PrintingStarted(object sender, PrintingEventArgs e)
        {
            _job = e.Job;
            _start_date = DateTime.UtcNow;
        }

        #endregion
    }
}