using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;

namespace DatabaseExport
{
    public abstract class DbTimeStampBase : IDbTimeStampAware, INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        protected bool SetProperty<T>(ref T storage, T value, String propertyName = null)
        {
            if (Equals(storage, value)) return false;

            storage = value;
            OnPropertyChanged(propertyName);
            return true;
        }
        protected void OnPropertyChanged(string propertyName = null)
        {
            var eventHandler = PropertyChanged;
            if (eventHandler != null)
            {
                eventHandler(this, new PropertyChangedEventArgs(propertyName));
            }
        }

        protected long DbTimeStamp;
        public long GetTimeStampMemory()
        {
            return DbTimeStamp;
        }
        public void SetTimeStampMemory(long value) { DbTimeStamp = value; }
        public void SetTimeStampMemory(System.Data.DataRow row)
        {
            DbTimeStamp = 0;
        }

        public void SetTimeStampMemory(IDataReader reader)
        {
            DbTimeStamp = 0;
        }
        public long GetTimeStampDb(Dictionary<string, long> lookup)
        {
            //var constraints = GetConstraints();
            return 0; //lookup.ContainsKey(constraints[0].DbValue.ToString()) ? lookup[constraints[0].DbValue.ToString()] : GetTimeStampDb();
        }

        public Dictionary<string, long> GetAllTimeStampDb()
        {
            var lookup = new Dictionary<string, long>();
            return lookup;
            //try
            //{
            //    var constraints = GetConstraints();
            //    if (1 == constraints.Length)
            //    {
            //        using (var cmd = DbOperations.GetSQLCommand())
            //        {
            //            cmd.CommandText = string.Format("SELECT [{0}], DbTimeStamp from {1}", constraints[0].ColumnName, LookupTable);
            //            using (var ds = DbOperations.Connection.QueryDataSet(cmd))
            //            {
            //                foreach (System.Data.DataRow dr in ds.Tables[0].Rows)
            //                {
            //                    var s = Convert.ToString(dr[constraints[0].ColumnName]);
            //                    if (DBNull.Value.Equals(dr["DbTimeStamp"])) { continue; }
            //                    var res = BitConverter.ToInt64((dr["DbTimeStamp"] as byte[]), 0);
            //                    lookup[s] = res;
            //                }
            //            }
            //        }
            //    }
            //}
            //catch (Exception ex) { APILogger.Log(ex); }
            //return lookup;
        }
        public long GetTimeStampDb()
        {
            return 0;
            //using (var sql = DbOperations.GetSQLCommand())
            //{
            //    var sb = new StringBuilder(50);
            //    sb.AppendFormat("SELECT DbTimeStamp as A FROM {0} ", LookupTable);

            //    var constraints = GetConstraints();
            //    for (var i = 0; i < constraints.Length; i++)
            //    {
            //        sb.Append(0 == i ? "WHERE " : " AND ");
            //        sb.AppendFormat("{0}=@{1}", constraints[i].ColumnName, i);
            //        DbOperations.CreateParam(sql, string.Format("@{0}", i), constraints[i].DbType, constraints[i].DbValue);
            //    }
            //    sql.CommandText = sb.ToString();
            //    using (var ds = DbOperations.Connection.QueryDataSet(sql))
            //    {
            //        if (ds.Tables.Count <= 0 || ds.Tables[0].Rows.Count <= 0) return 0;
            //        if (DBNull.Value.Equals(ds.Tables[0].Rows[0]["A"])) return 0;
            //        try
            //        {
            //            var res = BitConverter.ToInt64(ds.Tables[0].Rows[0]["A"] as byte[], 0);
            //            System.Diagnostics.Trace.WriteLine(string.Format("Db: {0}", res));
            //            return res;
            //        }
            //        catch (Exception ex) { APILogger.Log(ex); return 0; }
            //    }
            //}
        }

        public abstract string LookupTable
        {
            get;
        }

        public class ConstraintHelper
        {
            public string ColumnName { get; set; }
            public System.Data.SqlDbType DbType { get; set; }
            public object DbValue { get; set; }
        }

        public abstract ConstraintHelper[] GetConstraints();

        public bool IsNotInDb()
        {
            return GetTimeStampDb() == 0;
        }

        public bool IsOutOfDate()
        {
            var db = GetTimeStampDb();
            var mem = GetTimeStampMemory();
            //if there's no record in the db, don't mark as out of date
            if (db == 0) { return false; }
            //if is in db, but in memory is new, allow overwrite...
            if (mem == 0 && db != 0) { mem = db; SetTimeStampMemory(db); }
            return db != mem;
        }
    }

    public interface IDbTimeStampAware
    {
        long GetTimeStampMemory();
        void SetTimeStampMemory(long value);
        long GetTimeStampDb();
        bool IsOutOfDate();
    }
    public class DbItemOutOfDateException : Exception
    {
        public DbItemOutOfDateException(string msg)
            : base(msg)
        {
        }
    }
}