//------------------------------------------------------------------------------
// <copyright file="TimeSpanStorage.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
// <owner current="true" primary="false">Microsoft</owner>
// <owner current="false" primary="false">Microsoft</owner>
//------------------------------------------------------------------------------

namespace System.Data.Common {
    using System;
    using System.Xml;
    using System.Data.SqlTypes;
    using System.Collections;

    internal sealed class TimeSpanStorage : DataStorage {

        private static readonly TimeSpan defaultValue = TimeSpan.Zero;

        private TimeSpan[] values;

        public TimeSpanStorage(DataColumn column)
        : base(column, typeof(TimeSpan), defaultValue, StorageType.TimeSpan) {
        }

        override public Object Aggregate(int[] records, AggregateType kind) {
            bool hasData = false;
            try {
                switch (kind) {
                    case AggregateType.Min:
                        TimeSpan min = TimeSpan.MaxValue;
                        for (int i = 0; i < records.Length; i++) {
                            int record = records[i];
                            if (IsNull(record))
                                continue;
                            min=(TimeSpan.Compare(values[record],min) < 0) ? values[record] : min;
                            hasData = true;
                        }
                        if (hasData) {
                            return min;
                        }
                        return NullValue;

                    case AggregateType.Max:
                        TimeSpan max = TimeSpan.MinValue;
                        for (int i = 0; i < records.Length; i++) {
                            int record = records[i];
                            if (IsNull(record))
                                continue;
                            max=(TimeSpan.Compare(values[record],max) >= 0) ? values[record] : max;
                            hasData = true;
                        }
                        if (hasData) {
                            return max;
                        }
                        return NullValue;

                    case AggregateType.First:
                        if (records.Length > 0) {
                            return values[records[0]];
                        }
                        return null;

                    case AggregateType.Count:
                        return base.Aggregate(records, kind);

                    case AggregateType.Sum: {
                            decimal sum = 0;
                            foreach (int record in records) {
                                if (IsNull(record))
                                    continue;
                                sum += values[record].Ticks; 
                                hasData = true;
                            }
                            if (hasData) {
                                return TimeSpan.FromTicks((long)Math.Round(sum));
                            }
                            return null;
                        }

                    case AggregateType.Mean: {
                            decimal meanSum = 0;
                            int meanCount = 0;
                            foreach (int record in records) {
                                if (IsNull(record))
                                    continue;
                                meanSum += values[record].Ticks; 
                                meanCount++;
                            }
                            if (meanCount > 0) {
                                return TimeSpan.FromTicks((long)Math.Round(meanSum / meanCount));
                            }
                            return null;
                        }

                    case AggregateType.StDev: {
                           int count = 0;
                            decimal meanSum = 0;                            

                            foreach (int record in records) {
                                if (IsNull(record))
                                    continue;
                                meanSum += values[record].Ticks; 
                                count++;
                            }

                            if (count > 1) {
                                double varSum = 0;
                                decimal mean=meanSum/count;
                                foreach (int record in records) {
                                    if (IsNull(record))
                                        continue;
                                    double x = (double)(values[record].Ticks - mean);
                                    varSum += x * x;
                                }
                                ulong stDev = (ulong)Math.Round(Math.Sqrt(varSum / (count - 1)));
                                if (stDev > long.MaxValue) {
                                    stDev = long.MaxValue;
                                }
                                return TimeSpan.FromTicks((long)stDev);
                            }
                            return null;
                        }
                }
            }
            catch (OverflowException) {
                throw ExprException.Overflow(typeof(TimeSpan));
            }
            throw ExceptionBuilder.AggregateException(kind, DataType);
        }

        override public int Compare(int recordNo1, int recordNo2) {
            TimeSpan valueNo1 = values[recordNo1];
            TimeSpan valueNo2 = values[recordNo2];

            if (valueNo1 == defaultValue || valueNo2 == defaultValue) {
                int bitCheck = CompareBits(recordNo1, recordNo2);
                if (0 != bitCheck)
                    return bitCheck;
            }
            return TimeSpan.Compare(valueNo1, valueNo2);
        }

        public override int CompareValueTo(int recordNo, object value) {
            System.Diagnostics.Debug.Assert(0 <= recordNo, "Invalid record");
            System.Diagnostics.Debug.Assert(null != value, "null value");

            if (NullValue == value) {
                if (IsNull(recordNo)) {
                    return 0;
                }
                return 1;
            }

            TimeSpan valueNo1 = values[recordNo];
            if ((defaultValue == valueNo1) && IsNull(recordNo)) {
                return -1;
            }
            return valueNo1.CompareTo((TimeSpan)value);
        }

        private static TimeSpan ConvertToTimeSpan(object value) {
            // Webdata 94686: Do not change this checks
            Type typeofValue= value.GetType();

            if (typeofValue == typeof(string)) {
                return TimeSpan.Parse((string)value);
            }
            else if (typeofValue == typeof(Int32)) {
                return new TimeSpan((Int64)((Int32)value));
            }
            else if (typeofValue == typeof(Int64))  {
                return new TimeSpan((Int64)value);
            }
            else {
                return (TimeSpan) value;
            }
        }

        public override object ConvertValue(object value) {
            if (NullValue != value) {
                if (null != value) {
                    value = ConvertToTimeSpan(value);
                }
                else {
                    value = NullValue;
                }
            }
            return value;
        }


        override public void Copy(int recordNo1, int recordNo2) {
            CopyBits(recordNo1, recordNo2);
            values[recordNo2] = values[recordNo1];
        }

        override public Object Get(int record) {
            TimeSpan value = values[record];
            if (value != defaultValue) {
                return value;
            }
            return GetBits(record);
        }

        override public void Set(int record, Object value) {
            System.Diagnostics.Debug.Assert(null != value, "null value");
            if (NullValue == value) {
                values[record] = defaultValue;
                SetNullBit(record, true);
            }
            else {
                values[record] = ConvertToTimeSpan(value);
                SetNullBit(record, false);
            }
        }

        override public void SetCapacity(int capacity) {
            TimeSpan[] newValues = new TimeSpan[capacity];
            if (null != values) {
                Array.Copy(values, 0, newValues, 0, Math.Min(capacity, values.Length));
            }
            values = newValues;
            base.SetCapacity(capacity);
        }

        override public object ConvertXmlToObject(string s) {
            return XmlConvert.ToTimeSpan(s);
        }

        override public string ConvertObjectToXml(object value) {
            return XmlConvert.ToString((TimeSpan)value);
        }

        override protected object GetEmptyStorage(int recordCount) {
            return new TimeSpan[recordCount];
        }

        override protected void CopyValue(int record, object store, BitArray nullbits, int storeIndex) {
            TimeSpan[] typedStore = (TimeSpan[]) store;
            typedStore[storeIndex] = values[record];
            nullbits.Set(storeIndex, IsNull(record));
        }

        override protected void SetStorage(object store, BitArray nullbits) {
            values = (TimeSpan[]) store;
            SetNullStorage(nullbits);
        }
    }
}