//
//  Class:			IDatabaseEntity
//	Current CLR:	4.0.30319.34209
//	System:			Microsoft Visual Studio 10.0
//	Author:			dani
// 	Created:		3/2/2015 9:08:47 PM
//
//	Copyright (c) 2015 Informatikbüro Daniel Schick. All rights reserved.

using System;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Collections.Generic;
using System.Reflection;
using System.Text.RegularExpressions;

namespace bsmd.database
{

    public abstract class DatabaseEntity : IMessageParagraph, IEquatable<DatabaseEntity>
    {
        protected Guid? id;        
        protected string tablename;
        private Guid instance_id = Guid.NewGuid(); // Comparison id in case entity has not been saved

        #region enum ValidationBlock

        public enum ValidationBlock
        {
            BLOCK1,
            BLOCK2
        }

        #endregion

        #region Properties

        /// <summary>
        /// Nachrichtentyp der abgeleiteten Meldeklassen
        /// </summary>
        public Message.NotificationClass MessageNotificationClass { get; set; }

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

        /// <summary>
        /// Referenz zur eigentlichen Schiffankunft
        /// </summary>
        public MessageCore MessageCore { get; set; }

        /// <summary>
        /// gemeinschaftliche Daten
        /// </summary>
        public Message MessageHeader { get; set; }                

        /// <summary>
        /// SQL Table name to construct queries
        /// </summary>
        public virtual string Tablename { get { return this.tablename; } }

        /// <summary>
        /// primary key
        /// </summary>        
        public Guid? Id { get  {  return this.id; } }

        /// <summary>
        /// IsNew Flag
        /// </summary>
        public bool IsNew { get { return !this.id.HasValue; } }

        #endregion

        #region public funcs

        /// <summary>
        /// when it's time (during save), create id
        /// </summary>
        public void CreateId() { this.id = Guid.NewGuid(); }

        public abstract void PrepareSave(IDbCommand cmd);

        public virtual void PrepareDelete(IDbCommand cmd) 
        {
            SqlCommand scmd = cmd as SqlCommand;
            scmd.CommandText = string.Format("DELETE FROM {0} WHERE Id = @ID", Tablename);
            scmd.Parameters.AddWithValue("@ID", this.Id);
        }

        /// <summary>
        /// Ergebnismenge begrenzen: NULL = kein Limit. Abgeleitete Klassen *können* diesen Parameter berücksichtigen
        /// </summary>
        public int? ResultLimit { get; set; }

        public abstract void PrepareLoadCommand(IDbCommand cmd, Message.LoadFilter filter, params object[] criteria);

        public abstract List<DatabaseEntity> LoadList(IDataReader reader);

        public virtual void PrepareCountCmd(IDbCommand cmd, Message.LoadFilter filter, params object[] criteria)
        {
            SqlCommand scmd = cmd as SqlCommand;
            scmd.CommandText = string.Format("SELECT COUNT(*) FROM {0}", Tablename);
        }

        /// <summary>
        /// Überprüft eingegangene Meldeklassen auf Fehlerkonditionen
        /// </summary>
        /// <param name="errors"></param>
        /// <param name="violations"></param>
        public virtual void Validate(List<MessageError> errors, List<MessageViolation> violations)
        {
            errors = new List<MessageError>();
            violations = new List<MessageViolation>();
        }

        /// <summary>
        /// Diese Methode sollte eigentlich nie einen Effekt haben und dient nur dazu, dass keine Situation
        /// auftreten kann in der ein Insert/Update an fehlender Datenvalidierung kracht
        /// </summary>
        /// <param name="truncated"></param>
        public virtual void TruncateFields(List<string> truncated)
        {
            List<PropertyInfo> props = new List<PropertyInfo>();

            // add flagged properties to check list
            props.AddRange(this.GetType().GetProperties().Where(prop => Attribute.IsDefined(prop, typeof(MaxLengthAttribute))));            
            foreach (PropertyInfo property in props)
            {
                object propValue = property.GetValue(this, null);
                string value = (propValue == null) ? string.Empty : propValue.ToString();

                MaxLengthAttribute maxLengthAttribute = Attribute.GetCustomAttribute(property, typeof(MaxLengthAttribute))
                           as MaxLengthAttribute;

                if(value.Length > maxLengthAttribute.MaxLength) // truncate situation
                {
                    string maxLengthValue = value.Substring(0, maxLengthAttribute.MaxLength);
                    truncated.Add(string.Format("[{0} ({1})]: {2}", property.Name, maxLengthAttribute.MaxLength, value));
                    property.SetValue(this, maxLengthValue);
                }
            }
        }

        /// <summary>
        /// Kann überschrieben werden, wenn abhängig von den Daten (einem Flag) andere Regeln gelten (Bsp. wenn schon eine
        /// MDH Meldung abgegeben wurde)
        /// </summary>
        /// <returns></returns>
        public virtual ValidationBlock GetValidationBlock()
        {
            return ValidationBlock.BLOCK1;
        }

        #endregion

        #region public static funcs

        /// <summary>
        /// Wenn Positionen manuell (ENI-2) angelegt werden, kann mit dieser Funktion der neue "Identifier"
        /// festgelegt werden
        /// </summary>
        /// <param name="sublist">Vorhandene Position</param>
        /// <returns>Name des neuen Identifiers, der so nicht in der Liste vorkommt</returns>
        public static string GetNewIdentifier(IEnumerable<DatabaseEntity> sublist)
        {            
            int maxVal = -1;
            string maxString = null;

            // das sieht riskanter aus als es ist, diese Funktion wird aber nur für Elemente angewendet, die
            // ISublistElement implementieren
            foreach(ISublistElement element in sublist)
            {
                if (element.Identifier.IsNullOrEmpty()) continue;
                int elementIdent;

                // TODO: Beim Parsen auch Text- und allerlei bunte Erweiterungen tolerieren
                // (z.B. MARPOL-000001)
                Regex re = new Regex(@"\d+");
                Match m = re.Match(element.Identifier);

                if (m.Success)
                {
                    elementIdent = Int32.Parse(m.Value);
                    if (elementIdent > maxVal)
                    {
                        maxVal = elementIdent;
                        maxString = element.Identifier.Replace(m.Value, (maxVal + 1).ToString());
                    }
                }
            }

            if (maxVal == -1)
            {
                // Spezialbalkone
                try
                {
                    Type type = sublist.GetType().GetGenericArguments()[0];
                    if (type == typeof(IMDGPosition)) return "IMDG-1";
                    if (type == typeof(IBCPosition)) return "IBC-1";
                    if (type == typeof(IGCPosition)) return "IGC-1";
                    if (type == typeof(IMSBCPosition)) return "IMSBC-1";
                    if (type == typeof(MARPOL_Annex_I_Position)) return "MARPOL-1";
                }
                catch
                {                    
                }

                return 1.ToString();

            }
            return maxString;                        
        }

        public static void ResetIdentifiers(IList<DatabaseEntity> sublist)
        {
            List<DatabaseEntity> tmpList = new List<DatabaseEntity>(sublist);
            sublist.Clear();
            foreach(ISublistElement element in tmpList)
            {
                element.Identifier = DatabaseEntity.GetNewIdentifier(sublist);
                sublist.Add(element as DatabaseEntity);
            }
        }

        #endregion

        #region IEquatable<T> implementation

        public bool Equals(DatabaseEntity other)
        {
            if (other == null) return false;
            if (this.Id.HasValue && other.Id.HasValue && (this.Id.Value != Guid.Empty) && (other.Id.Value != Guid.Empty))
                return this.Id == other.Id;
            return this.GetHashCode() == other.GetHashCode();
        }

        public override bool Equals(object obj)
        {
            return this.Equals(obj as DatabaseEntity);
        }

        public override int GetHashCode()
        {
            if (!this.Id.HasValue || this.Id.Value == Guid.Empty)
                return this.instance_id.GetHashCode();
            return this.Id.GetHashCode();
        }

        #endregion

        #region IMessageParagraph implementation

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

        public virtual string Subtitle
        {
            get { return string.Empty; }
        }

        public virtual bool ShowChildrenAsTable
        {
            get { return false; }
        }

        /// <summary>
        /// must be overridden if it must make sense
        /// </summary>
        public virtual List<KeyValuePair<string, string>> MessageText
        {
            get {
                List<KeyValuePair<string, string>> result = new List<KeyValuePair<string, string>>();

                Type objType = this.GetType();                

                var props = objType.GetProperties().Where(
                    prop => Attribute.IsDefined(prop, typeof(ShowReportAttribute)));

                foreach (PropertyInfo property in props)
                {
                    bool isDouble = (property.PropertyType == typeof(Nullable<double>));
                    object propValue = property.GetValue(this, null);
                    string value = (propValue == null) ? string.Empty : (isDouble ? ((double) propValue).ToString("N2") : propValue.ToString());
                    string displayName = property.Name;
                    if(Attribute.IsDefined(property, typeof(ReportDisplayNameAttribute))) {
                        ReportDisplayNameAttribute reportDisplayNameAttribute = Attribute.GetCustomAttribute(property, typeof(ReportDisplayNameAttribute))
                            as ReportDisplayNameAttribute;
                        displayName = reportDisplayNameAttribute.DisplayName;
                    }

                    result.Add(new KeyValuePair<string, string>(displayName, value));                    
                }                

                return result;                 
            }
        }

        public virtual List<IMessageParagraph> ChildParagraphs { get { return null; } }

        #endregion

    }
}