using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Serilog;
using ShareeBike.Model.Connector;
using ShareeBike.Repository.Exception;
using ShareeBike.Services.BluetoothLock;
using ShareeBike.Services.BluetoothLock.Exception;
using ShareeBike.Services.BluetoothLock.Tdo;
using ShareeBike.Services.Geolocation;
using ShareeBike.ViewModel.Bikes.Bike.BluetoothLock.RequestHandler;

namespace ShareeBike.Model.Bikes.BikeInfoNS.BluetoothLock.Command
{
	public static class OpenCommand
	{
		/// <summary>
		/// Possible steps of opening a lock.
		/// </summary>
		public enum Step
		{
			OpeningLock,
			WaitStopPolling,
			GetLockInfos,
			UpdateLockingState,
		}

		/// <summary>
		/// Possible states of opening a lock.
		/// </summary>
		public enum State
		{
			StopPollingFailed,
			OutOfReachError,
			CouldntOpenBoldStatusIsUnknownError,
			CouldntOpenBoldIsBlockedError,
			CouldntOpenInconsistentStateError,
			GeneralOpenError,
			WebConnectFailed,
			ResponseIsInvalid,
			BackendUpdateFailed
		}

		/// <summary>
		/// Interface to notify view model about steps/ state changes of opening process.
		/// </summary>
		public interface IOpenCommandListener
		{
			/// <summary>
			/// Reports current step.
			/// </summary>
			/// <param name="currentStep">Current step to report.</param>
			void ReportStep(Step currentStep);

			/// <summary>
			/// Reports current state.
			/// </summary>
			/// <param name="currentState">Current state to report.</param>
			/// <param name="message">Message describing the current state.</param>
			/// <returns></returns>
			Task ReportStateAsync(State currentState, string message);
		}

		/// <summary>
		/// Opens the lock and updates copri.
		/// </summary>
		/// <param name="listener">Interface to notify view model about steps/ state changes of opening process.</param>
		/// <param name="stopPolling">Task which stops polling.</param>
		public static async Task InvokeAsync<T>(
			IBikeInfoMutable bike,
			ILocksService lockService,
			Func<bool> isConnectedDelegate,
			Func<bool, IConnector> connectorFactory,
			IOpenCommandListener listener,
			Task stopPollingTask)
		{
			// Invokes member to notify about step being started.
			void InvokeCurrentStep(Step step)
			{
				if (listener == null)
					return;

				try
				{
					listener.ReportStep(step);
				}
				catch (Exception exception)
				{
					Log.ForContext<T>().Error("An exception {@exception} was thrown invoking step-action for step {step} ", exception, step);
				}
			}

			// Invokes member to notify about state change.
			async Task InvokeCurrentStateAsync(State state, string message)
			{
				if (listener == null)
					return;

				try
				{
					await listener.ReportStateAsync(state, message);
				}
				catch (Exception exception)
				{
					Log.ForContext<T>().Error("An exception {@exception} was thrown invoking state-action for state {state} ", exception, state);
				}
			}

			// Wait polling task to stop (on finished or on canceled).
			async Task WaitForPendingTasks()
			{
				// Step: Wait until getting geolocation has completed.
				InvokeCurrentStep(Step.WaitStopPolling);
				Log.ForContext<T>().Information($"Waiting on stop polling to finish...");
				try
				{
					await Task.WhenAll(new List<Task> { stopPollingTask ?? Task.CompletedTask });
				}
				catch (Exception exception)
				{
					Log.ForContext<T>().Information("Wait for polling task to finish failed. {@exception}", exception);
					await InvokeCurrentStateAsync(State.StopPollingFailed, exception.Message);
					return;
				}

				Log.ForContext<T>().Information($"Stop polling finished.");
				return;
			}

			// Get lock infos
			async Task GetLockInfos()
			{
				Log.ForContext<T>().Debug($"Starting step {Step.GetLockInfos}...");
				InvokeCurrentStep(Step.GetLockInfos);
				// get current charging level
				try
				{
					bike.LockInfo.BatteryPercentage = await lockService[bike.LockInfo.Id].GetBatteryPercentageAsync();
					Log.ForContext<T>().Information("Lock infos of bike {bikeId} read successfully.", bike.Id);
				}
				catch (Exception exception)
				{
					Log.ForContext<T>().Information("Lock infos could not be read.", bike.Id);
					if (exception is OutOfReachException)
					{
						Log.ForContext<T>().Debug("Lock is out of reach");
					}
					else
					{
						Log.ForContext<T>().Debug("{@exception}", exception);
					}
				}
				// get version infos.
				var versionTdo = lockService[bike.LockInfo.Id].VersionInfo;
				if (versionTdo != null)
				{
					bike.LockInfo.VersionInfo = new VersionInfo.Builder
					{
						FirmwareVersion = versionTdo.FirmwareVersion,
						HardwareVersion = versionTdo.HardwareVersion,
						LockVersion = versionTdo.LockVersion,
					}.Build();
				}
			}

			// Updates locking state
			async Task UpdateLockingState()
			{
				// Step: Update backend.
				InvokeCurrentStep(Step.UpdateLockingState);
				try
				{
					await connectorFactory(true).Command.UpdateLockingStateAsync(bike);
					Log.ForContext<T>().Information("Backend updated for bike {bikeId} successfully.", bike.Id);
				}
				catch (Exception exception)
				{
					Log.ForContext<ReservedOpen>().Information("Updating backend for bike {bikeId} failed.", bike.Id);
					//BikesViewModel.RentalProcess.Result = CurrentStepStatus.Failed;
					if (exception is WebConnectFailureException)
					{
						// Copri server is not reachable.
						Log.ForContext<T>().Debug("Copri server not reachable.");
						await InvokeCurrentStateAsync(State.WebConnectFailed, exception.Message);
						return;
					}
					else if (exception is ResponseException copriException)
					{
						// Copri server is not reachable.
						Log.ForContext<T>().Debug("Message: {Message} Details: {Details}", copriException.Message, copriException.Response);
						await InvokeCurrentStateAsync(State.ResponseIsInvalid, exception.Message);
						return;
					}
					else
					{
						Log.ForContext<T>().Error("User locked bike {bike} in order to pause ride but updating failed. {@l_oException}", bike.Id, exception);
						await InvokeCurrentStateAsync(State.BackendUpdateFailed, exception.Message);
						return;
					}
				}
			}

	//// Start Action

		//// Step: Open lock.
			Log.ForContext<T>().Information($"Starting step {Step.OpeningLock}...");
			InvokeCurrentStep(Step.OpeningLock);
			LockitLockingState? lockingState;
			try
			{
				lockingState = await lockService[bike.LockInfo.Id].OpenAsync();
				Log.ForContext<T>().Information("Lock of bike {bikeId} opened successfully.", bike.Id);
			}
			catch (Exception exception)
			{
				Log.ForContext<T>().Information("Lock of bike {bikeId} can not be opened.", bike.Id);
				if (exception is OutOfReachException)
				{
					Log.ForContext<T>().Debug("Lock is out of reach");
					await InvokeCurrentStateAsync(State.OutOfReachError, exception.Message);
				}
				else if (exception is CouldntOpenBoldStatusIsUnknownException)
				{
					Log.ForContext<T>().Debug("Lock status is unknown.");
					await InvokeCurrentStateAsync(State.CouldntOpenBoldStatusIsUnknownError, exception.Message);
				}
				else if (exception is CouldntOpenBoldIsBlockedException)
				{
					Log.ForContext<T>().Debug("Bold is blocked.}");
					await InvokeCurrentStateAsync(State.CouldntOpenBoldIsBlockedError, exception.Message);
				}
				else if (exception is CouldntOpenInconsistentStateExecption inconsistentState
						&& inconsistentState.State == LockingState.Closed)
				{
					Log.ForContext<T>().Debug("Lock reports that it is still closed.}");
					await InvokeCurrentStateAsync(State.CouldntOpenInconsistentStateError, exception.Message);
				}
				else
				{
					Log.ForContext<T>().Debug("{@exception}", exception);
					await InvokeCurrentStateAsync(State.GeneralOpenError, exception.Message);
				}

				// Update current state from exception
				bike.LockInfo.State = exception is StateAwareException stateAwareException
					? stateAwareException.State
					: LockingState.UnknownDisconnected;

				if (!isConnectedDelegate())
				{
					// Lock state can not be updated because there is no connected.
					throw;
				}

				if (exception is OutOfReachException)
				{
					// Locking state can not be updated because lock is not connected.
					throw;
				}

				//// Step: Get Lock Battery and Version info
				await GetLockInfos();

				//// Step: Wait for stop polling finished
				await WaitForPendingTasks();

				//// Step: Update backend.
				//Do this even if current lock state is closed (lock state must not necessarily be closed before try to close, i.e. something undefined between open and opened).
				await UpdateLockingState();

				throw;
			}

			bike.LockInfo.State = lockingState?.GetLockingState() ?? LockingState.UnknownDisconnected;

			if (!isConnectedDelegate())
			{
				return;
			}

			//// Step: Get Lock Battery and Version info
			await GetLockInfos();

			//// Step: Wait for stop polling finished
			await WaitForPendingTasks();

			//// Step: Update backend.
			await UpdateLockingState();
		}
	}
}