// Copyright (c) 2015-2017 schick Informatik
// Description: Validierungsbedingung, die (als Gruppe) als Validierungsregel serialisiert und 
//              ausgewertet wird

using System;
using System.Collections.Generic;
using System.IO;
using System.Xml.Serialization;
using log4net;
using System.Collections.ObjectModel;
using System.Collections;
using System.Windows.Data;
using System.ComponentModel;
using System.Reflection;

namespace bsmd.database
{
    [Serializable]
    public class ValidationCondition : ICloneable
    {
        private static ILog log = LogManager.GetLogger(typeof(ValidationCondition));

        public ValidationCondition() { }

        public enum ConditionOperatorEnum
        {
            [Description("==")]
            EQUAL,
            [Description("!=")]
            NOT_EQUAL,
            [Description(">")]
            GREATER,
            [Description("<")]
            LESS,
            [Description("== NULL")]
            NULL,
            [Description("!= NULL")]
            NOT_NULL
        }

        #region Properties

        public string FieldName { get; set; }

        public ConditionOperatorEnum ConditionOperator { get; set; }

        public string Value { get; set; }        
        

        #endregion

        #region static methods

        public static bool? CheckConditions(MessageCore core, List<Message> messages, ConditionGroup cGroup, List<ValidationField> failedFieldList, 
            out string message)
        {
            bool? result = null;
            message = "";
            bool conditionResult = false;

            try
            {
                // Bedingungen validieren

                foreach (ValidationCondition condition in cGroup.Conditions)
                {
                    object[] otherargs = null;

                    // den aktuellen Wert bestimmen
                    if(!ValidationRule.ValidationFieldDict.ContainsKey(condition.FieldName))
                    {
                        // TODO: Warnung absetzen
                        continue;
                    }

                    ValidationField vf = ValidationRule.ValidationFieldDict[condition.FieldName];
                    
                    // Wert aus den Daten auslesen

                    // Dabei muss unterschieden werden: 1. skalarer Wert
                    //                                  2. Wert eines Listenelements
                    //

                    // als Rückgabe würde dann benötigt der Name des Property, die beteiligte Klasse und natürlich der Identifier (Index) wenn es eine Listenposition war


                    //if(vf.)
                    //object value = vf.PropertyInfo.GetValue()



                    switch(condition.ConditionOperator)
                    {
                        case ConditionOperatorEnum.EQUAL:

                            break;
                        case ConditionOperatorEnum.NOT_EQUAL:

                            break;
                        case ConditionOperatorEnum.LESS:

                            break;
                        case ConditionOperatorEnum.GREATER:

                            break;
                        case ConditionOperatorEnum.NULL:

                            break;
                        case ConditionOperatorEnum.NOT_NULL:

                            break;
                    }




                    string errorMessage = cGroup.ErrorMessage;
                    if (otherargs != null)
                        errorMessage = string.Format(errorMessage, otherargs);

                    result = ValidationCondition.CombineConditions(result, conditionResult, cGroup.GroupOperator);

                    // Fehlermeldung hinzufügen falls Bedingung verletzt wurde
                    if (!conditionResult && ((cGroup.GroupOperator == ConditionGroup.GroupOperatorEnum.AND) || (cGroup.GroupOperator == ConditionGroup.GroupOperatorEnum.OR)))
                        message += string.Format("- {0}{1}", errorMessage, Environment.NewLine);
                    //if (conditionResult && ((cGroup.GroupOperator == ConditionGroup.GroupOperatorEnum.NAND) || (cGroup.GroupOperator == ConditionGroup.GroupOperatorEnum.NOR)))
                    //    message += string.Format("- {0}{1}", errorMessage, Environment.NewLine);

                }

                // check internal groups recursively

                foreach (ConditionGroup subGroup in cGroup.SubGroups)
                {
                    string subMessage = "";
                    bool? subResult = ValidationCondition.CheckConditions(core, messages, subGroup, failedFieldList, out subMessage);
                    if (!subResult.HasValue) // an error occurred evaluating this element
                    {
                        return subResult;
                    }
                    else
                    {
                        result = ValidationCondition.CombineConditions(result, subResult.Value, cGroup.GroupOperator);
                        // Fehlermeldung hinzufügen falls Bedingung verletzt wurde
                        if (!subResult.Value && ((cGroup.GroupOperator == ConditionGroup.GroupOperatorEnum.AND) || (cGroup.GroupOperator == ConditionGroup.GroupOperatorEnum.OR)))
                            message += string.Format("- {0}{1}", subMessage, Environment.NewLine);
                        //if (subResult.Value && ((cGroup.GroupOperator == ConditionGroup.GroupOperatorEnum.NAND) || (cGroup.GroupOperator == ConditionGroup.GroupOperatorEnum.NOR)))
                        //    message += string.Format("- {0}{1}", subMessage, Environment.NewLine);
                    }
                }

                // falls in einer "OR" Gruppe eine Bedingung fehlschlägt aber die Condition nach true evaluiert
                // wird die Fehlermeldung zwecks Verwirrungsvermeidung gedroppt. Dasselbe natürl. auch für NAND
                if ((cGroup.GroupOperator == ConditionGroup.GroupOperatorEnum.OR) && result.Value) message = "";
                //if ((cGroup.GroupOperator == ConditionGroup.GroupOperatorEnum.NAND) && !result.Value) message = "";

            }

            catch (Exception ex)
            {
                message = string.Format("Validation threw exception: {0}", ex.ToString());
                log.Error(message);
                return false;
            }


            return result;
        }

        #region Serialization

        public static ConditionGroup LoadFromString(string serializedConditions)
        {
            if ((serializedConditions == null) ||
                (serializedConditions.Trim().Length == 0))
                return null;

            using (StringReader sr = new StringReader(serializedConditions))
            {
                try
                {
                    XmlSerializer serializer = new XmlSerializer(typeof(ConditionGroup));
                    ConditionGroup container = serializer.Deserialize(sr) as ConditionGroup;
                    container.CopyToObservable();
                    return container;
                }
                catch (Exception)
                {
                    return null;
                }
            }
        }

        public static string SaveToString(ConditionGroup group)
        {
            if (group == null) return null;

            using (StringWriter sw = new StringWriter())
            {
                try
                {
                    Type theType = Type.GetType("bsmd.database.ConditionGroup, bsmd.database");
                    XmlSerializer serializer = new XmlSerializer(theType);
                    group.CopyToXML();
                    serializer.Serialize(sw, group);
                    return sw.ToString();
                }
                catch (Exception)
                {
                    return null;
                }
            }
        }

        #endregion

        /// <summary>
        /// evaluate logical group operator
        /// </summary>
        private static bool CombineConditions(bool? c1, bool c2, ConditionGroup.GroupOperatorEnum op)
        {
            if (!c1.HasValue) return c2;
            switch (op)
            {
                case ConditionGroup.GroupOperatorEnum.AND:
                    return c1.Value & c2;
                case ConditionGroup.GroupOperatorEnum.OR:
                    return c1.Value | c2;
                case ConditionGroup.GroupOperatorEnum.NOT:
                    return !(c1.Value);
                case ConditionGroup.GroupOperatorEnum.XOR:
                    return (c1.Value ^ c2);
            }
            return false;
        }

        private static bool IsConditionTrue(string val1, string val2, ValidationCondition.ConditionOperatorEnum condition)
        {
            switch (condition)
            {
                case ValidationCondition.ConditionOperatorEnum.EQUAL:
                    return val1.Equals(val2);
                default:
                    return !val1.Equals(val2);
            }
        }

        private static bool IsConditionTrue(bool val1, bool val2, ValidationCondition.ConditionOperatorEnum condition)
        {
            switch (condition)
            {
                case ValidationCondition.ConditionOperatorEnum.EQUAL:
                    return val1.Equals(val2);
                default:
                    return !val1.Equals(val2);
            }
        }

        private static bool IsConditionTrue(DateTime val1, DateTime val2, ValidationCondition.ConditionOperatorEnum condition)
        {
            switch (condition)
            {
                case ValidationCondition.ConditionOperatorEnum.EQUAL:
                    return val1 == val2;
                case ValidationCondition.ConditionOperatorEnum.GREATER:
                    return val1 > val2;
                case ValidationCondition.ConditionOperatorEnum.LESS:
                    return val1 < val2;
                case ValidationCondition.ConditionOperatorEnum.NOT_EQUAL:
                    return val1 != val2;
            }
            return true;
        }

        private static bool IsConditionTrue(TimeSpan val1, TimeSpan val2, ValidationCondition.ConditionOperatorEnum condition)
        {
            switch (condition)
            {
                case ValidationCondition.ConditionOperatorEnum.EQUAL:
                    return val1 == val2;
                case ValidationCondition.ConditionOperatorEnum.GREATER:
                    return val1 > val2;
                case ValidationCondition.ConditionOperatorEnum.LESS:
                    return val1 < val2;
                case ValidationCondition.ConditionOperatorEnum.NOT_EQUAL:
                    return val1 != val2;
            }
            return true;
        }

        private static bool IsConditionTrue(double val1, double val2, ValidationCondition.ConditionOperatorEnum condition)
        {
            switch (condition)
            {
                case ValidationCondition.ConditionOperatorEnum.EQUAL:
                    return val1 == val2;
                case ValidationCondition.ConditionOperatorEnum.GREATER:
                    return val1 > val2;
                case ValidationCondition.ConditionOperatorEnum.LESS:
                    return val1 < val2;
                case ValidationCondition.ConditionOperatorEnum.NOT_EQUAL:
                    return val1 != val2;
            }
            return true;
        }

        #endregion

        #region ICloneable implementation

        public object Clone()
        {
            return this.MemberwiseClone();
        }

        #endregion

    }

    #region class ConditionGroup

    /// <summary>
    /// Diese Klasse benötigt (blöderweise) für eine Sache 2 Collections: einmal für die XML Serialisierung und einmal
    /// für die Hierarchie im WPF Treecontrol (ObservableCollection). Daher müssen die Inhalte beim Laden und Speichern hin und herkopiert
    /// werden. Was für ein Scheiß.
    /// </summary>
    [Serializable]
    public class ConditionGroup
    {

        public enum GroupOperatorEnum
        {
            AND,
            OR,
            NOT,
            XOR
        }

        public ConditionGroup() {
            Conditions = new ObservableCollection<ValidationCondition>();
            SubGroups = new ObservableCollection<ConditionGroup>();
            XMLConditions = new List<ValidationCondition>();
            XMLSubGroups = new List<ConditionGroup>();
        }

        #region Properties
        
        [XmlIgnore]
        public ObservableCollection<ValidationCondition> Conditions
        {
            get;
            set;
        }

        public List<ValidationCondition> XMLConditions { get; set; }

        public GroupOperatorEnum GroupOperator
        {
            get;
            set;
        }

        public string ErrorMessage { get; set; }

        [XmlIgnore]
        public ObservableCollection<ConditionGroup> SubGroups
        {
            get;
            set;
        }        

        public List<ConditionGroup> XMLSubGroups { get; set; }

        [XmlIgnore]
        public IList Children
        {
            get
            {
                return new CompositeCollection()
                {
                    new CollectionContainer() { Collection = SubGroups },
                    new CollectionContainer() { Collection = Conditions }                    
                };
            }
        }

        public string Name
        {
            get { return this.GroupOperator.ToString(); }
        }

        #endregion

        #region public recursive methods

        public void Remove(ConditionGroup group)
        {
            if(this.SubGroups.Contains(group))
            {
                this.SubGroups.Remove(group);
                return;
            }
            // try recursive
            foreach (ConditionGroup subGroup in this.SubGroups)
                subGroup.Remove(group);
        }

        public void RemoveCondition(ValidationCondition condition)
        {
            if(this.Conditions.Contains(condition))
            {
                this.Conditions.Remove(condition);
                return;
            }
            // try recursive
            foreach (ConditionGroup subGroup in this.SubGroups)
                subGroup.RemoveCondition(condition);
        }

        public void CopyToObservable()
        {
            this.SubGroups.Clear();
            foreach (ConditionGroup cg in this.XMLSubGroups)
                this.SubGroups.Add(cg);
            this.Conditions.Clear();
            foreach (ValidationCondition vc in this.XMLConditions)
                this.Conditions.Add(vc);
            foreach (ConditionGroup subGroup in this.XMLSubGroups)
                subGroup.CopyToObservable();
        }

        public void CopyToXML()
        {
            this.XMLSubGroups.Clear();
            this.XMLSubGroups.AddRange(this.SubGroups);
            this.XMLConditions.Clear();
            this.XMLConditions.AddRange(this.Conditions);
            foreach (ConditionGroup subGroup in this.SubGroups)
                subGroup.CopyToXML();

        }

        #endregion

    }

    #endregion

    #region class ValidationField

    /// <summary>
    /// Diese Klasse wird beim Bearbeiten im Regel-Editor verwendet (ENI-2)
    /// </summary>
    public class ValidationField
    {
        PropertyInfo _info;

        public ValidationField(PropertyInfo propertyInfo)
        {
            _info = propertyInfo;
        }

        public string PropertyName { get; set; }
        public string NotificationClassText { get; set; }

        public Message.NotificationClass? NotificationClass { get; set; }

        public bool IsInListType { get; set; }

        public PropertyInfo PropertyInfo { get { return _info; } }

        public string FullName
        {
            get { return this.ToString(); }
        }

        public override string ToString()
        {
            return string.Format("{0}.{1}", NotificationClassText, PropertyName);
        }
    }

    #endregion


    #region struct KeyValuePairS

    [Serializable]
    [XmlType(TypeName = "schickKeyValuePair")]
    public struct KeyValuePairS<K, V>
    {
        public K Key { get; set; }
        public V Value { get; set; }
    }

    #endregion

}