using System;
using System.Globalization;
using Wayne.Lib.Log;

namespace Wayne.Lib.StateEngine
{
    /// <summary>
    /// History type defines the way that a composite state is entered.     
    /// </summary> 
    public enum HistoryType
    {
        #region Fields

        /// <summary>
        /// Only the initial state is entered. No history is recalled
        /// </summary>
        None,
        /// <summary>
        /// If the composite has been active before, the state that was
        /// active last is entered. Shallow means that entering the 
        /// recalled last state but when entering that state, it is done with 
        /// no history.
        /// </summary>
        Shallow,
        /// <summary>
        /// If a composite state has been active before, the state that was active
        /// last is entered, Deep means that if the recalled state is a composite 
        /// it will also be entered with deep history.
        /// </summary>
        Deep,
        /// <summary>
        /// Explicit history type is *only* used when issuing explicit transitions. If
        /// a state machine is configured with this history type, an error will be thrown.
        /// </summary>
        Explicit

        #endregion
    }

    // StateType for future use.
    /// <summary>
    /// The state types as an enumeration. This can be used in a future design tool.
    /// </summary>
    public enum StateType
    {
        #region Fields

        /// <summary>
        /// Intial state
        /// </summary>
        InitialState,

        /// <summary>
        /// Pseudo state
        /// </summary>
        PseudoState,

        /// <summary>
        /// Ordinary state
        /// </summary>
        State,

        /// <summary>
        /// Composite state
        /// </summary>
        CompositeState,

        /// <summary>
        /// Final state
        /// </summary>
        FinalState

        #endregion
    }

    /// <summary>
    /// State is the base state of all states in the state machine. 
    /// </summary>    
    abstract public class State : IDisposable
    {
        #region Fields

        private Wayne.Lib.StateEngine.StateMachine parentStateMachine;
        private string createdByFactory = "";
        private bool active;
        private CompositeState parentState;
        private IDebugLogger debugLogger;
        private object logCategory;
        private string instanceName;
        private string factoryName;

        #endregion

        #region Methods

        /// <summary>
        /// Enter is called when the state machine enters the state. Override this method to be able to 
        /// run code at the state entry. If a transition should be performed, create a transition object
        /// and return it in the transition out property.
        /// </summary>
        /// <param name="stateEntry">Information about the entry of the state.</param>
        /// <param name="transition">Out parameter, that should be set to either the reference to a transition object or null.</param>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1045:DoNotPassTypesByReference", MessageId = "1#")]
        protected virtual void Enter(StateEntry stateEntry, ref Transition transition)
        {
        }

        /// <summary>
        /// Override this method to implement code that should be run at state exit. 
        /// </summary>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Globalization", "CA1303:DoNotPassLiteralsAsLocalizedParameters", MessageId = "Wayne.Lib.StateEngine.State.DebugLog(System.String)")]
        protected virtual void Exit()
        {
        }


        /// <summary>
        /// Override to receive incoming events. If the event is handled, the 
        /// application must set the event.Handled = true.         
        /// </summary>
        /// <param name="stateEngineEvent">The event object that should be handled.</param>
        /// <param name="transition">Out parameter that should be set to either the reference to a transition object or null.</param>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1045:DoNotPassTypesByReference", MessageId = "1#")]
        protected virtual void HandleEvent(StateEngineEvent stateEngineEvent, ref Transition transition)
        {
        }

        /// <summary>
        /// Activates the supplied timer.
        /// </summary>
        /// <param name="timer">The timer to activate.</param>
        /// <see cref="Timer"/>
        protected virtual void ActivateTimer(Timer timer)
        {
            if (parentStateMachine != null)
                parentStateMachine.ActivateTimer(timer);
        }

        /// <summary>
        /// Disposes the resources owned by the state object.
        /// </summary>
        /// <param name="disposing"></param>
        protected virtual void Dispose(bool disposing)
        {
            //Nothing in an ordinary state.
        }

        /// <summary>
        /// Clears all events waiting in the event queues.
        /// </summary>
        protected void ClearPendingEvents()
        {
            this.parentStateMachine.ClearPendingEvents();
        }

        /// <summary>
        /// Clears all the events in the resend queue that matches the eventType. 
        /// </summary>
        /// <param name="eventType"></param>
        protected void RemovePendingEventsOfType(object eventType)
        {
            this.parentStateMachine.RemovePendingEventsOfType(eventType);
        }

        /// <summary>
        /// Removes all pending event that matches the supplied predicate.
        /// </summary>
        /// <typeparam name="TComparisonObject">Type of the comparison object</typeparam>
        /// <param name="predicate">The predicate that is used to match the event.</param>
        /// <param name="comparisonObject">The comparison object that is used in the StateEngineEventPredicate.</param>
        protected void RemovePendingEvents<TComparisonObject>(StateEngineEventPredicate<TComparisonObject> predicate, TComparisonObject comparisonObject)
        {
            this.ParentStateMachine.RemovePendingEvents(predicate, comparisonObject);
        }

        /// <summary>
        /// Disposes all the owned resources in the state.
        /// </summary>
        public void Dispose()
        {
            Dispose(true);
        }
        #endregion

        #region Internal Methods

        /// <summary>
        /// Incoming event is called from the state machine when an event should be handled. 
        /// </summary>
        /// <param name="stateEngineEvent"></param>
        /// <param name="transition">Perform a transition by assigning a transition object to this reference parameter.</param>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes")]
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Globalization", "CA1303:DoNotPassLiteralsAsLocalizedParameters", MessageId = "Wayne.Lib.StateEngine.State.DebugLog(System.String)")]
        internal virtual void IncomingEvent(StateEngineEvent stateEngineEvent, ref Transition transition)
        {
            try
            {
                if (!(this is CompositeState))
                {
                    if ((debugLogger != null) && (debugLogger.IsActive(logCategory)))
                        debugLogger.Add(string.Format(System.Globalization.CultureInfo.InvariantCulture, " [{0}] HandleEvent: {1}", this.LogName, stateEngineEvent), logCategory);
                }

                if (!stateEngineEvent.Handled)
                {
                    //Call the HandleEvent method of the state
                    HandleEvent(stateEngineEvent, ref transition);
                }

                //If a transition was issued, equip it with the event as source event.
                if (transition != null)
                    transition.WritableSourceEvent = stateEngineEvent;
            }
            catch (Exception exception)
            {
                if ((debugLogger != null) && (debugLogger.IsActive(logCategory)))
                {
                    System.Text.StringBuilder stringBuilder = new System.Text.StringBuilder();
                    stringBuilder.Append("EXCEPTION IN HandleEvent (");
                    stringBuilder.Append(this.LogName);
                    stringBuilder.Append(")\r\n");
                    stringBuilder.Append(exception.ToString());
                    debugLogger.Add(stringBuilder, logCategory);
                }

                transition = new ExceptionTransition(this, BasicTransitionType.Error, exception);
            }
#if WindowsCE
            catch
            {
                if ((debugLogger != null) && (debugLogger.IsActive(logCategory)))
                {
                    debugLogger.Add("Unknown exception in HandleEvent (" + this.LogName + ")");
                }

                transition = new Transition(this, BasicTransitionType.Error);
            }
#endif
        }

        /// <summary>
        /// Called from the state machine when the state is entered. It is up to the state to 
        /// call the appropriate virtual Enter methods. If a transition should be performed it 
        /// is returned in the Transition ref parameter.
        /// </summary>
        /// <param name="stateEntry">State entry object containing information about the state entry.</param>
        /// <param name="transition">Perform a transition by assigning a transition object to this ref parameter.</param>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes")]
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Globalization", "CA1303:DoNotPassLiteralsAsLocalizedParameters", MessageId = "Wayne.Lib.StateEngine.State.DebugLog(System.String)")]
        internal virtual void PerformEnter(StateEntry stateEntry, ref Transition transition)
        {
            active = true;

            try
            {
                if (!(this is CompositeState))
                    if ((debugLogger != null) && (debugLogger.IsActive(logCategory)))
                        debugLogger.Add(string.Format(System.Globalization.CultureInfo.InvariantCulture, " [{0}] Enter: Transition={1}", this.LogName, stateEntry.SourceTransition.Name), logCategory);


                //Call the enter method of the state.
                Enter(stateEntry, ref transition);

                //If a transition was issued, equip it with the event as source event.
                if (transition != null)
                    if ((stateEntry != null) && (stateEntry.SourceTransition != null))
                        transition.WritableSourceEvent = stateEntry.SourceTransition.SourceEvent;
            }
            catch (Exception exception)
            {
                if ((debugLogger != null) && (debugLogger.IsActive(logCategory)))
                {
                    System.Text.StringBuilder stringBuilder = new System.Text.StringBuilder();
                    stringBuilder.Append("EXCEPTION IN Enter (");
                    stringBuilder.Append(this.LogName);
                    stringBuilder.Append(")\r\n");
                    stringBuilder.Append(exception.ToString());
                    debugLogger.Add(stringBuilder.ToString(), logCategory);
                }

                transition = new ExceptionTransition(this, BasicTransitionType.Error, exception);
            }
#if WindowsCE
            catch
            {
                if ((debugLogger != null) && (debugLogger.IsActive(logCategory)))
                    debugLogger.Add("Unknown exception in Enter (" + this.LogName + ")");

                transition = new Transition(this, BasicTransitionType.Error);
            }
#endif
        }

        /// <summary>
        /// This method is called by the state machine when the state should be exited. It contains the error handling 
        /// logic and logging of the exit.
        /// </summary>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes")]
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Globalization", "CA1303:DoNotPassLiteralsAsLocalizedParameters", MessageId = "Wayne.Lib.StateEngine.State.DebugLog(System.String)")]
        internal virtual void PerformExit()
        {
            active = false;

            try
            {
                Exit();
            }
            catch (Exception exception)
            {
                if ((debugLogger != null) && (debugLogger.IsActive(logCategory)))
                {
                    System.Text.StringBuilder stringBuilder = new System.Text.StringBuilder();
                    stringBuilder.Append("EXCEPTION IN Exit (");
                    stringBuilder.Append(this.LogName);
                    stringBuilder.Append(")\r\n");
                    stringBuilder.Append(exception.ToString());
                    debugLogger.Add(stringBuilder, logCategory);
                }
            }
#if WindowsCE
            catch
            {
                if ((debugLogger != null) && (debugLogger.IsActive(logCategory)))
                    debugLogger.Add("Unknown exception in Exit (" + this.LogName + ")");
            }
#endif
        }

        /// <summary>
        /// This function is used to locate a specific state in the state machine.
        /// In the state class it is simply compared to the state Factory Name. More complex comparisons
        /// is done in composite states.
        /// </summary>
        /// <param name="stateFactoryName">The factory name of the state that should be looked up.</param>
        /// <returns>True if the state is or contains a state with this name.</returns>
        internal virtual bool LookupState(string stateFactoryName)
        {
            return (stateFactoryName == this.FactoryName);
        }

        internal void AssignParentState(CompositeState parentState)
        {
            this.parentState = parentState;
        }

        #endregion

        #region Properties

        /// <summary>
        /// The factory name of the state (the full class name).
        /// </summary>
        public string FactoryName
        {
            get
            {
                return factoryName;
            }
        }

        /// <summary>
        /// Factory name of the class assigned after factory created the state.
        /// </summary>
        internal string WritableFactoryName
        {
            get { return factoryName; }
            set { this.factoryName = value; }
        }

        /// <summary>
        /// The name of this particular instance of this state (the hierarchical name of the state, 
        /// starting with the name of the statemachine, through all parent composite states up to this state).
        /// </summary>
        public string InstanceName
        {
            get
            {
                if (instanceName != null)
                {
                    return instanceName;
                }

                //I have a parent state - use that and append my name
                if (parentState != null)
                {
                    return instanceName = string.Format("{0}.{1}", parentState.InstanceName, this.Name);
                }
                //I'm on the root - just use state machine name and append my name
                return instanceName = string.Format("{0}.{1}", ParentStateMachine.Name, Name);
            }
        }

        public virtual string Name
        {
            get { return this.GetType().Name; }
        }

        /// <summary>
        /// The name of the state used for logging.
        /// </summary>
        public string LogName
        {
            get
            {
                if (parentStateMachine != null)
                {
                    switch (parentStateMachine.LogNameKind)
                    {
                        case StateNameKind.FactoryName: return FactoryName;
                        case StateNameKind.InstanceName: return InstanceName;
                    }
                }
                return FactoryName;
            }
        }

        /// <summary>
        /// Name of the state factory that created the state object.
        /// </summary>
        public string CreatedByFactory
        {
            get
            {
                return createdByFactory;
            }
            set
            {
                createdByFactory = value;
            }
        }

        /// <summary>
        /// Indicates that this is the current active state of the machine.
        /// </summary>
        public bool Active
        {
            get
            {
                return active;
            }
        }

        /// <summary>
        /// Provides a reference to the composite state this state is contained in. If it is in the root of the 
        /// state machine, it will be null.
        /// </summary>
        public CompositeState ParentState
        {
            get { return parentState; }
        }

        /// <summary>
        /// The StateType.
        /// </summary>
        public StateType StateType
        {
            get
            {
                if (this is InitialState)
                    return StateType.InitialState;
                else if (this is FinalState)
                    return StateType.FinalState;
                else if (this is PseudoState)
                    return StateType.PseudoState;
                else if (this is CompositeState)
                    return StateType.CompositeState;
                return StateType.State;
            }
        }

        /// <summary>
        /// The parent state machine for the state.
        /// </summary>
        public StateMachine ParentStateMachine
        {
            get { return parentStateMachine; }
        }

        /// <summary>
        /// An additional text that shows up in the visualizer, that for instance can 
        /// be used to point out application specific states.
        /// </summary>
        public virtual string ApplicationText
        {
            get;
            set;
        }

        #endregion

        #region Internal properties

        /// <summary>
        /// Set the parent state machine for the state.
        /// </summary>
        internal virtual void SetParentStateMachine(StateMachine parentStateMachine)
        {
            this.parentStateMachine = parentStateMachine;
        }

        /// <summary>
        /// Sets the debug logger.
        /// </summary>
        /// <param name="debugLogger"></param>
        /// <param name="logCategory"></param>
        internal virtual void SetDebugLogger(IDebugLogger debugLogger, object logCategory)
        {
            this.debugLogger = debugLogger;
            this.logCategory = logCategory;
        }

        #endregion

        /// <summary>
        /// Uses the debug logger passed in to the StateMachine upon creation to 
        /// log the supplied logging if the logger is active. 
        /// </summary>
        /// <param name="format"></param>
        /// <param name="params"></param>
        protected void DebugLog(string format, params object[] @params)
        {
            try
            {
                if (debugLogger.IsActive())
                {
                    var message = @params != null && @params.Length > 0 ?
                                  string.Format(CultureInfo.InvariantCulture, format, @params) :
                                  format;

                    debugLogger.Add(message);
                }
            }
            catch (FormatException)
            {
                if (debugLogger.IsActive())
                    debugLogger.Add("LOGERROR: Could not format string: " + format);
            }
        }

        /// <summary>
        /// Uses the debug logger passed in to the StateMachine upon creation to 
        /// log the supplied logging if the logger is active. 
        /// </summary>
        /// <param name="format"></param>
        /// <param name="params"></param>
        protected void DebugLogDetailed(string format, params object[] @params)
        {
            try
            {
                if (debugLogger.IsActive(DebugLogLevel.Detailed))
                {
                    var message = @params != null && @params.Length > 0 ?
                                  string.Format(CultureInfo.InvariantCulture, format, @params) :
                                  format;

                    debugLogger.Add(message, DebugLogLevel.Detailed);
                }
            }
            catch (FormatException)
            {
                if (debugLogger.IsActive(DebugLogLevel.Detailed))
                    debugLogger.Add("LOGERROR: Could not format string: " + format, DebugLogLevel.Detailed);
            }
        }

        /// <summary>
        /// Uses the debug logger passed in to the StateMachine upon creation to 
        /// log the supplied logging if the logger is active. 
        /// </summary>
        /// <param name="format"></param>
        /// <param name="params"></param>
        protected void DebugLogMaximized(string format, params object[] @params)
        {
            try
            {
                if (debugLogger.IsActive(DebugLogLevel.Detailed))
                {
                    var message = @params != null && @params.Length > 0 ?
                                  string.Format(CultureInfo.InvariantCulture, format, @params) :
                                  format;

                    debugLogger.Add(message, DebugLogLevel.Maximized);
                }
            }
            catch (FormatException)
            {
                if (debugLogger.IsActive(DebugLogLevel.Detailed))
                    debugLogger.Add("LOGERROR: Could not format string: " + format, DebugLogLevel.Maximized);
            }
        }
    }
}