quantconnect--lean/Common/Commands/Command.cs

/*
 * QUANTCONNECT.COM - Democratizing Finance, Empowering Individuals.
 * Lean Algorithmic Trading Engine v2.0. Copyright 2014 QuantConnect Corporation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
*/

using System;
using Python.Runtime;
using QuantConnect.Data;
using System.Collections.Generic;
using System.Dynamic;
using System.Linq.Expressions;
using System.Reflection;
using QuantConnect.Interfaces;

namespace QuantConnect.Commands
{
    /// <summary>
    /// Base generic dynamic command class
    /// </summary>
    public class Command : DynamicObject
    {
        private static readonly MethodInfo SetPropertyMethodInfo = typeof(Command).GetMethod("SetProperty");
        private static readonly MethodInfo GetPropertyMethodInfo = typeof(Command).GetMethod("GetProperty");

        private readonly IDictionary<string, object> _snakeNameStorage = new Dictionary<string, object>();
        private readonly IDictionary<string, object> _storage = new Dictionary<string, object>();

        /// <summary>
        /// Get the metaObject required for Dynamism.
        /// </summary>
        public override DynamicMetaObject GetMetaObject(Expression parameter)
        {
            return new GetSetPropertyDynamicMetaObject(parameter, this, SetPropertyMethodInfo, GetPropertyMethodInfo);
        }

        /// <summary>
        /// Sets the property with the specified name to the value. This is a case-insensitve search.
        /// </summary>
        /// <param name="name">The property name to set</param>
        /// <param name="value">The new property value</param>
        /// <returns>Returns the input value back to the caller</returns>
        public object SetProperty(string name, object value)
        {
            // let's be polite and support snake name access for the given object value too
            var snakeName = name.ToSnakeCase();
            name = name.LazyToLower();

            _storage[name] = value;
            if (snakeName != name)
            {
                _snakeNameStorage[snakeName] = value;
            }
            return value;
        }

        /// <summary>
        /// Gets the property's value with the specified name. This is a case-insensitve search.
        /// </summary>
        /// <param name="name">The property name to access</param>
        /// <returns>object value of BaseData</returns>
        public object GetProperty(string name)
        {
            name = name.ToLowerInvariant();

            object value;
            if (!_storage.TryGetValue(name, out value) && !_snakeNameStorage.TryGetValue(name, out value))
            {
                // let the user know the property name that we couldn't find
                throw new KeyNotFoundException(
                    $"Property with name \'{name}\' does not exist. Properties: Time, Symbol, Value {string.Join(", ", _storage.Keys)}"
                );
            }

            return value;
        }

        /// <summary>
        /// Run this command using the target algorithm
        /// </summary>
        /// <param name="algorithm">The algorithm instance</param>
        /// <returns>True if success, false otherwise. Returning null will disable command feedback</returns>
        public virtual bool? Run(IAlgorithm algorithm)
        {
            throw new NotImplementedException($"Please implement the 'Command.run(algorithm)' method");
        }
    }
}