namespace QuantConnect.Indicators
{
    /// <summary>
    ///     Represents a forward-only in time time series filter
    /// </summary>
    public interface IIndicator
    {
        /// <summary>
        ///     Gets a name for this indicator
        /// </summary>
        string Name { get; }

        /// <summary>
        ///     Gets a flag indicating when this indicator is ready and fully initialized
        /// </summary>
        bool IsReady { get; }

        /// <summary>
        ///     Gets the current state of this indicator. If the state has not been updated
        ///     then the time on the value will equal DateTime.MinValue.
        /// </summary>
        DataPoint<decimal> Value { get; }

        /// <summary>
        ///     Gets the number of samples processed by this indicator
        /// </summary>
        int Samples { get; }

        /// <summary>
        ///     Updates the state of this indicator with the given value and returns true
        ///     if this indicator is ready, false otherwise
        /// </summary>
        /// <param name="input">The value to use to update this indicator</param>
        /// <returns>True if this indicator is ready, false otherwise</returns>
        bool Update(DataPoint<decimal> input);

        /// <summary>
        ///     Resets this indicator to its initial state
        /// </summary>
        void Reset();
    }
}

using System;
using System.Collections.Generic;

namespace QuantConnect.Indicators
{
    /// <summary>
    ///     Provides static methods for creating DataPoint instances. These are purely
    ///     for convenience of the call site
    /// </summary>
    public static class DataPoint
    {
        /// <summary>
        ///     Creates a new instance of a DataPoint with the specified data
        /// </summary>
        /// <typeparam name="T">The type of data</typeparam>
        /// <param name="time"></param>
        /// <param name="value"></param>
        /// <returns></returns>
        public static DataPoint<T> Create<T>(DateTime time, T value)
        {
            // this method provides some type inference convience so we need not specify the type parameter
            return new DataPoint<T>(time, value);
        }

        /// <summary>
        ///     Provides a default value for a DataPoint
        /// </summary>
        /// <typeparam name="T">The type of data</typeparam>
        /// <returns>The default DataPoint</returns>
        public static DataPoint<T> Default<T>()
        {
            return new DataPoint<T>(DateTime.MinValue, default(T));
        }
    }

    /// <summary>
    ///     Represents a piece of data at a specific time
    /// </summary>
    /// <typeparam name="T">The type of data</typeparam>
    public struct DataPoint<T> : IEquatable<DataPoint<T>>
    {
        /// <summary>
        ///     Gets the data
        /// </summary>
        public T Data { get; private set; }

        /// <summary>
        ///     Gets the time associated wth this data
        /// </summary>
        public DateTime Time { get; private set; }

        /// <summary>
        ///     Initializes a new instance of the DataPoint type using the specified time/data
        /// </summary>
        /// <param name="time">The time this data was produced</param>
        /// <param name="data">The data</param>
        public DataPoint(DateTime time, T data)
            : this()
        {
            Time = time;
            Data = data;
        }

        /// <summary>
        ///     Indicates whether the current object is equal to another object of the same type.
        /// </summary>
        /// <returns>
        ///     true if the current object is equal to the <paramref name="other" /> parameter; otherwise, false.
        /// </returns>
        /// <param name="other">An object to compare with this object.</param>
        public bool Equals(DataPoint<T> other)
        {
            return EqualityComparer<T>.Default.Equals(Data, other.Data) && Time.Equals(other.Time);
        }

        /// <summary>
        ///     Returns a string representation of this DataPoint instance using ISO8601 formatting for the date
        /// </summary>
        /// <returns>
        ///     A <see cref="T:System.String" /> containing a fully qualified type name.
        /// </returns>
        /// <filterpriority>2</filterpriority>
        public override string ToString()
        {
            return string.Format("{0} - {1}", Time.ToString("s"), Data);
        }

        /// <summary>
        ///     Indicates whether this instance and a specified object are equal.
        /// </summary>
        /// <returns>
        ///     true if <paramref name="obj" /> and this instance are the same type and represent the same value; otherwise, false.
        /// </returns>
        /// <param name="obj">Another object to compare to. </param>
        /// <filterpriority>2</filterpriority>
        public override bool Equals(object obj)
        {
            if (ReferenceEquals(null, obj)) return false;
            return obj is DataPoint<T> && Equals((DataPoint<T>) obj);
        }

        /// <summary>
        ///     Returns the hash code for this instance.
        /// </summary>
        /// <returns>
        ///     A 32-bit signed integer that is the hash code for this instance.
        /// </returns>
        /// <filterpriority>2</filterpriority>
        public override int GetHashCode()
        {
            unchecked
            {
                return (EqualityComparer<T>.Default.GetHashCode(Data)*397) ^ Time.GetHashCode();
            }
        }

        /// <summary>
        ///     Compares the two specified data points for equality, returning true
        ///     if the times and data both compare equal
        /// </summary>
        /// <returns>
        ///     True if the two instances' time and data compare equal
        /// </returns>
        /// <param name="left">The DataPoint instance on the left of the operator</param>
        /// <param name="right">The DataPoint instance on the right of the operator</param>
        public static bool operator ==(DataPoint<T> left, DataPoint<T> right)
        {
            return left.Equals(right);
        }

        /// <summary>
        ///     Compares the two specified data points for equality, returning true
        ///     if the times and data both compare differently
        /// </summary>
        /// <returns>
        ///     True if the two instances' time and data compare differently
        /// </returns>
        /// <param name="left">The DataPoint instance on the left of the operator</param>
        /// <param name="right">The DataPoint instance on the right of the operator</param>
        public static bool operator !=(DataPoint<T> left, DataPoint<T> right)
        {
            return !(left == right);
        }
    }
}

using QuantConnect.Models;

namespace QuantConnect.Indicators
{
    /// <summary>
    ///     Represents a type capable of pulling data out of more complex data types for input
    ///     into the IIndicator infrastructure
    /// </summary>
    public interface IIndicatorDataSource
    {
        /// <summary>
        ///     Gets whether or not this IndicatorDataSource can process the specified object
        /// </summary>
        bool CanProcess(BaseData data);

        /// <summary>
        ///     Gets the value to be piped to an indicator from the source object. This source object type must
        ///     match the DataSourceType
        /// </summary>
        /// <param name="data">The source instance to pull data from (Tick, TradeBar, custom data)</param>
        /// <returns>The value to be piped to an indicator</returns>
        decimal GetValue(BaseData data);
    }
}

using System;
using QuantConnect.Models;

namespace QuantConnect.Indicators
{
    /// <summary>
    ///     Provides a means of defining what type and how to select data for an indicator
    /// </summary>
    public class IndicatorDataSource<T> : IIndicatorDataSource
        where T : BaseData
    {
        /// <summary>
        ///     Defines how to pull data from instances of T
        /// </summary>
        private readonly Func<T, decimal> _selector;

        /// <summary>
        ///     Defines how often we'll update an indicator
        /// </summary>
        private readonly TimeSpan _span;

        /// <summary>
        ///     Specifies the last time we selected data
        /// </summary>
        private DateTime _lastProcessedDataTime;

        /// <summary>
        ///     Initializes a new instance of the IndicatorDataSource class that uses the
        ///     specified selector to pull data from instances of T
        /// </summary>
        /// <param name="selector">Func used to select data from instances of T</param>
        /// <param name="span">Defines how often we 'CanProcess' data</param>
        public IndicatorDataSource(Func<T, decimal> selector, TimeSpan span)
        {
            _span = span;
            _selector = selector;
        }

        /// <summary>
        ///     Gets whether or not this IndicatorDataSource can process the specified object
        /// </summary>
        public bool CanProcess(BaseData data)
        {
            return data is T && (data.Time - _lastProcessedDataTime) >= _span;
        }

        /// <summary>
        ///     Gets the value to be piped to an indicator from the source object. This source object type must
        ///     match the DataSourceType
        /// </summary>
        /// <param name="data">The source instance to pull data from (Tick, TradeBar, custom data)</param>
        /// <returns>The value to be piped to an indicator</returns>
        public decimal GetValue(BaseData data)
        {
            if (!(data is T))
            {
                string message =
                    string.Format("CustomIndicatorDataSource received incorrect type. Expected {0} but received {1}",
                        typeof (T).FullName,
                        data.GetType().FullName
                        );

                throw new ArgumentException(message);
            }
            _lastProcessedDataTime = data.Time;
            return _selector((T) data);
        }
    }
}

using System.Collections.Generic;
using System.Linq;
using QuantConnect.Models;

namespace QuantConnect.Indicators
{
    /// <summary>
    ///     Provides methods for maintaining a collection of indicators defined
    ///     against a single symbol
    /// </summary>
    public class IndicatorCollection
    {
        private readonly Dictionary<string, IndicatorWithSource> _indicators;

        /// <summary>
        ///     Gets the symbol these indicators are defined against
        /// </summary>
        public string Symbol { get; private set; }

        /// <summary>
        ///     Initializes a new instance of the IndicatorCollection for the specified symbol
        /// </summary>
        /// <param name="symbol"></param>
        public IndicatorCollection(string symbol)
        {
            Symbol = symbol;
            _indicators = new Dictionary<string, IndicatorWithSource>();
        }

        /// <summary>
        /// Gets the indicator with the specified name
        /// </summary>
        /// <param name="name">The name of the indicator to get</param>
        /// <returns>The indicator with the specified name, or throws if none exists</returns>
        public IIndicator this[string name]
        {
            get { return _indicators[name].Indicator; }
        }

        /// <summary>
        ///     Adds the specified indicator to this collection and will use
        /// </summary>
        /// <param name="indicator">The indicator to add to this collection</param>
        /// <param name="indicatorDataSource">Defines how this indicator will be auto-updated, if at all</param>
        public void Add(IIndicator indicator, IIndicatorDataSource indicatorDataSource)
        {
            var indicatorWithSource = new IndicatorWithSource(indicator, indicatorDataSource);
            _indicators.Add(indicator.Name, indicatorWithSource);
        }

        /// <summary>
        ///     Updates indicators in this collection with the specified data. Only indicators whose IndicatorDataSource
        ///     returns true from the CanProcess call will be updated.
        /// </summary>
        /// <param name="data">The data used to update the indicators</param>
        public void Update(BaseData data)
        {
            // loop through all of our indicators and update the ones who can process this data
            foreach (IndicatorWithSource item in _indicators.Values.Where(x => x.DataSource.CanProcess(data)))
            {
                decimal value = item.DataSource.GetValue(data);
                item.Indicator.Update(DataPoint.Create(data.Time, value));
            }
        }

        /// <summary>
        ///     Small structure to join an IIndicator and an IndicatorDataSource
        /// </summary>
        private class IndicatorWithSource
        {
            /// <summary>
            ///     Gets the data source for the indicator
            /// </summary>
            public readonly IIndicatorDataSource DataSource;

            /// <summary>
            ///     Gets the indicator
            /// </summary>
            public readonly IIndicator Indicator;

            public IndicatorWithSource(IIndicator indicator, IIndicatorDataSource dataSource)
            {
                Indicator = indicator;
                DataSource = dataSource;
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using QuantConnect.Models;

namespace QuantConnect.Indicators
{
    /// <summary>
    ///     Provides methods for managing an algorithm's auto-update indicators
    /// </summary>
    public class IndicatorManager
    {
        // provides a map from symbol -> indicator collection
        private readonly Dictionary<string, IndicatorCollection> _indicators;

        /// <summary>
        ///     Gets the IndicatorCollection instance used to manage the indicators for the specified symbol.
        ///     This is a get or create operation
        /// </summary>
        /// <param name="symbol">The symbol</param>
        /// <returns>The IndicatorCollection associated with the specified symbol</returns>
        public IndicatorCollection this[string symbol]
        {
            get
            {
                IndicatorCollection collection;
                if (!_indicators.TryGetValue(symbol, out collection))
                {
                    collection = new IndicatorCollection(symbol);
                    _indicators[symbol] = collection;
                }
                return collection;
            }
        }

        /// <summary>
        ///     Initializes a new empty IndicatorManager
        /// </summary>
        public IndicatorManager()
        {
            _indicators = new Dictionary<string, IndicatorCollection>();
        }

        /// <summary>
        ///     Adds a new indicator for the specified symbol using the selector to pull data from a TradeBar instance
        /// </summary>
        /// <param name="symbol">The symbol to attach this indicator to</param>
        /// <param name="indicator">The indicator</param>
        /// <param name="selector">Func used to select data from the TradeBar and pipe into the indicator</param>
        /// <param name="timeSpan">Defines how often to update this indicator</param>
        public void AddTradeBarIndicator(string symbol, IIndicator indicator, Func<TradeBar, decimal> selector, TimeSpan timeSpan)
        {
            IndicatorCollection collection = this[symbol];
            var dataSource = new IndicatorDataSource<TradeBar>(selector, timeSpan);
            collection.Add(indicator, dataSource);
        }
        
        // define the warning so we remember to do this
        #warning AddTickIndicator and AddCustomDataIndicator functions need to be implemented

        /// <summary>
        /// Updates indicators who should be updated from this data basic on their registered IIndicatorDataSource
        /// </summary>
        /// <param name="data">TradeBar data</param>
        public void UpdateTradeBarIndicators(IDictionary<string, TradeBar> data)
        {
            // loop through all our IndicatorCollection instances
            foreach (var item in _indicators)
            {
                TradeBar bar;
                string symbol = item.Key;
                if (data.TryGetValue(symbol, out bar))
                {
                    // if we have data, let the collection update on it
                    // it will only update indicators whose CanProcess function returns true
                    item.Value.Update(bar);
                }
            }
        }

        /// <summary>
        /// Updates indicators who should be updated from this data basic on their registered IIndicatorDataSource
        /// </summary>
        /// <param name="data">Tick data</param>
        public void UpdateTickIndicators(IDictionary<string, Tick> data)
        {
            // loop through all our IndicatorCollection instances
            foreach (var item in _indicators)
            {
                Tick tick;
                string symbol = item.Key;
                if (data.TryGetValue(symbol, out tick))
                {
                    // if we have data, let the collection update on it
                    // it will only update indicators whose CanProcess function returns true
                    item.Value.Update(tick);
                }
            }
        }

        /// <summary>
        /// Updates indicators who should be updated from this data basic on their registered IIndicatorDataSource
        /// </summary>
        /// <param name="data">Custom data type</param>
        public void UpdateCustomIndicators(BaseData data)
        {
            // loop through all our IndicatorCollection instances matching the symbol
            foreach (var item in _indicators.Where(x => x.Key == data.Symbol))
            {
                // if we have data, let the collection update on it
                // it will only update indicators whose CanProcess function returns true
                item.Value.Update(data);
            }
        }
    }
}

using System;
using System.Collections;
using System.Collections.Generic;
using QuantConnect.Securities;
using QuantConnect.Models;
using QuantConnect.Indicators;

namespace QuantConnect {

    // this class contains edits that can be made to the QCAlgorithm type
    // to enable auto updating indicators, the only thing we're missing here
    // is intercepting the calls to OnData( ... ) which may need to be done
    // somewhere else depending on who is pumping the data to the IAlgorithm
    // instances
    public partial class AutoUpdatingIndicators
    {
        public override void Initialize()
        {
            SetStartDate(2014, 08, 01);
            SetEndDate(2014, 12, 05);
            
            // this creates an EMA and adds it to the IndicatorManager
            // using defaults of 1 day update interval and using closing prices
            EMA("SPY", 3);
            
            // this creates an EMA and adds it to the IndicatorManager
            // using a 2 day update interval and the low price, we also override the name
            // of the indicator to deconflict with the other SPY EMA3
            // an important note realized during testing, we may want a way to say '2 bars'
            // since a 2 day ema as defined like this ends up with double points over weekends,
            // imagine one sample is on a friday, well the next will be monday, but typically
            // a 2 day span we would expect it more as '2 bars' or '2 trading days' not '2 calendar days'
            EMA("SPY", 3, TimeSpan.FromDays(2), x => x.Low, "2day EMA3");
            
            // we can even define indicators on computed values! Here we define an indicator on
            // the average of OHLC data
            EMA("SPY", 9, TimeSpan.FromDays(1), x => (x.Open + x.High + x.Low + x.Close)/4);
            
            AddSecurity(SecurityType.Equity, "SPY");
        }
        
        private DateTime last = DateTime.MinValue;
        public void OnData(TradeBars data)
        {
            // whomever calls OnData( ... ) could make this function call to IndicatorManager
            // note that we update this on every bar, but the IndicatorCollection
            // has data that tells it when it should actually call update on each
            // indicator
            IndicatorManager.UpdateTradeBarIndicators(data);
            
            TradeBar bar;
            if (data.TryGetValue("SPY", out bar) && bar.Time.Date != last.Date)
            {
                last = bar.Time;
                Plot("SPY", "Price", bar.Close);
                Plot("SPY", "EMA3", IndicatorManager["SPY"]["EMA3"].Value.Data);
                Plot("SPY", "EMA9 Avg OHLC", IndicatorManager["SPY"]["EMA9"].Value.Data);
                Plot("SPY", "2day EMA3", IndicatorManager["SPY"]["2day EMA3"].Value.Data);
            }
        }
    }
}

using System;

namespace QuantConnect.Indicators
{
    /// <summary>
    ///     Represents the basic functionality of conforming to the IIndicator interface invariants
    /// </summary>
    public abstract class IndicatorBase : IIndicator
    {
        /// <summary>
        ///     the most recent time data was given to this indicator
        /// </summary>
        private DateTime _previous;

        /// <summary>
        ///     Initializes a new instance of the IndicatorBase class using the specified name.
        /// </summary>
        /// <param name="name">The name of this indicator</param>
        protected IndicatorBase(string name)
        {
            Name = name;
        }

        /// <summary>
        ///     Gets a name for this indicator
        /// </summary>
        public string Name { get; private set; }

        /// <summary>
        ///     Gets a flag indicating when this indicator is ready and fully initialized
        /// </summary>
        public abstract bool IsReady { get; }

        /// <summary>
        ///     Gets the current state of this indicator. If the state has not been updated
        ///     then the time on the value will equal DateTime.MinValue.
        /// </summary>
        public DataPoint<decimal> Value { get; private set; }

        /// <summary>
        ///     Gets the number of samples processed by this indicator
        /// </summary>
        public int Samples { get; private set; }

        /// <summary>
        ///     Updates the state of this indicator with the given value and returns true
        ///     if this indicator is ready, false otherwise
        /// </summary>
        /// <param name="input">The value to use to update this indicator</param>
        /// <returns>True if this indicator is ready, false otherwise</returns>
        public bool Update(DataPoint<decimal> input)
        {
            if (input.Time < _previous)
            {
                // if we receive a time in the past, throw
                throw new ArgumentException("This is a forward only indicator.");
            }
            if (input.Time != _previous)
            {
                // if the time isn't the current time, then it must be future,
                // compute a new value and update our previous time
                Samples++;
                _previous = input.Time;
                decimal nextValue = ComputeNextValue(Value, input);
                Value = DataPoint.Create(input.Time, nextValue);
            }
            // this is when _previous==time and we've already computed
            // so do nothing and return IsReady
            // else { } 
            return IsReady;
        }

        /// <summary>
        ///     Resets this indicator to its initial state
        /// </summary>
        public virtual void Reset()
        {
            Value = DataPoint.Create(DateTime.MinValue, default(decimal));
        }

        /// <summary>
        ///     Computes the next value of this indicator from the given state
        /// </summary>
        /// <param name="previousValue">The most recent value of this indicator</param>
        /// <param name="input">The input given to the indicator</param>
        /// <returns>A new value for this indicator</returns>
        protected abstract decimal ComputeNextValue(DataPoint<decimal> previousValue, DataPoint<decimal> input);
    }
}

namespace QuantConnect.Indicators
{
    /// <summary>
    /// Represents the traditional exponential moving average indicator (EMA)
    /// </summary>
    public class ExponentialMovingAverage : IndicatorBase
    {
        private readonly decimal _k;
        private readonly int _period;

        public ExponentialMovingAverage(string name, int period)
            : base(name)
        {
            _period = period;
            _k = 2 / ((decimal)period + 1);
        }

        public override bool IsReady
        {
            get { return Samples >= _period; }
        }

        protected override decimal ComputeNextValue(DataPoint<decimal> previousValue, DataPoint<decimal> input)
        {
            // our first data point just return identity
            if (Samples == 1)
            {
                return input.Data;
            }
            return input.Data * _k + previousValue.Data * (1 - _k);
        }
    }
}

using System;
using System.Collections;
using System.Collections.Generic;
using QuantConnect.Securities;
using QuantConnect.Models;
using QuantConnect.Indicators;

namespace QuantConnect {

    // this class contains edits that can be made to the QCAlgorithm type
    // to enable auto updating indicators, the only thing we're missing here
    // is intercepting the calls to OnData( ... ) which may need to be done
    // somewhere else depending on who is pumping the data to the IAlgorithm
    // instances
    public partial class AutoUpdatingIndicators : QuantConnect.QCAlgorithm
    {
        /// <summary>
        /// Gets the IndicatorManager
        /// </summary>
        public IndicatorManager IndicatorManager { get; set; }
        
        public AutoUpdatingIndicators() : base()
        {
            IndicatorManager = new IndicatorManager();
        }
        
        /// <summary>
        /// Creates a new simple moving average indicator for the specified symbol
        /// and period. You can optionally specify the update period (defaults to 1 day),
        /// and can also specify the source data (defaults to Close)
        /// </summary>
        public ExponentialMovingAverage EMA(string symbol, int period, TimeSpan? span = null, Func<TradeBar, decimal> valueSelector = null, string name = null)
        {
            // resolve default values
            span = span ?? TimeSpan.FromDays(1);
            valueSelector = valueSelector ?? (x => x.Close);
            
            name = name ?? string.Format("EMA{0}", period);
            var ema = new ExponentialMovingAverage(name, period);
            
            IndicatorManager.AddTradeBarIndicator(symbol, ema, valueSelector, span.Value);
            
            return ema;
        }
    }
}