/trunk/source/Bindable.Linq/Extensions/Aggregators/BindableEnumerable.Aggregate.cs

using System;

using System.Linq.Expressions;

using Bindable.Linq.Aggregators;

using Bindable.Linq.Helpers;

using Bindable.Linq.Interfaces;

using Bindable.Linq.Dependencies;



namespace Bindable.Linq

{

	public static partial class BindableEnumerable

	{

        /// <summary>

        /// Applies an accumulator function over a sequence.

        /// </summary>

        /// <typeparam name="TSource">The type of the elements of <paramref name="source"/>.</typeparam>

        /// <typeparam name="TResult">The type of the result.</typeparam>

        /// <param name="source">An <see cref="IBindableCollection{TSource}"/> to aggregate over.</param>

        /// <param name="func">An accumulator function to be invoked on each element.</param>

        /// <returns>The final accumulator value.</returns>

        public static IBindable<TResult> Aggregate<TSource, TResult>(this IBindableCollection<TSource> source, Expression<Func<IBindableCollection<TSource>, TResult>> func)

        {

            return source.Aggregate(func, DefaultDependencyAnalysis);

        }



        /// <summary>

        /// Applies an accumulator function over a sequence.

        /// </summary>

        /// <typeparam name="TSource">The type of the elements of <paramref name="source"/>.</typeparam>

        /// <param name="source">An <see cref="IBindableCollection{TSource}"/> to aggregate over.</param>

        /// <param name="func">An accumulator function to be invoked on each element.</param>

        /// <returns>The final accumulator value.</returns>

        public static IBindable<TSource> Aggregate<TSource>(this IBindableCollection<TSource> source, Expression<Func<IBindableCollection<TSource>, TSource>> func)

        {

            return source.Aggregate(func, DefaultDependencyAnalysis);

        }



        /// <summary>

        /// Applies an accumulator function over a sequence. The specified seed value is used as the 

        /// initial accumulator value.

        /// </summary>

        /// <param name="source">An <see cref="IBindableCollection{TElement}" /> to aggregate over.</param>

        /// <param name="seed">The initial accumulator value.</param>

        /// <param name="func">An accumulator function to be invoked on each element.</param>

        /// <typeparam name="TSource">The type of the elements of <paramref name="source" />.</typeparam>

        /// <typeparam name="TAccumulate">The type of the accumulator value.</typeparam>

        /// <returns>The final accumulator value.</returns>

        public static IBindable<TAccumulate> Aggregate<TSource, TAccumulate>(this IBindableCollection<TSource> source, TAccumulate seed, Expression<Func<TAccumulate, TSource, TAccumulate>> func)

        {

            return source.Aggregate(seed, func, DefaultDependencyAnalysis);

        }



        /// <summary>

        /// Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value, and the specified function is used to select the result value.

        /// </summary>

        /// <param name="source">An <see cref="IBindableCollection{TElement}" /> to aggregate over.</param>

        /// <param name="seed">The initial accumulator value.</param>

        /// <param name="func">An accumulator function to be invoked on each element.</param>

        /// <param name="resultSelector">A function to transform the final accumulator value into the result value.</param>

        /// <typeparam name="TSource">The type of the elements of <paramref name="source" />.</typeparam>

        /// <typeparam name="TAccumulate">The type of the accumulator value.</typeparam>

        /// <typeparam name="TResult">The type of the resulting value.</typeparam>

        /// <returns>The transformed final accumulator value.</returns>

        public static IBindable<TResult> Aggregate<TSource, TAccumulate, TResult>(this IBindableCollection<TSource> source, TAccumulate seed, Expression<Func<TAccumulate, TSource, TAccumulate>> func, Expression<Func<TAccumulate, TResult>> resultSelector)

        {

            return source.Aggregate(seed, func, resultSelector, DefaultDependencyAnalysis);

        }



        /// <summary>

        /// Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value, and the specified function is used to select the result value.

        /// </summary>

        /// <typeparam name="TSource">The type of the elements of <paramref name="source"/>.</typeparam>

        /// <typeparam name="TAccumulate">The type of the accumulator value.</typeparam>

        /// <typeparam name="TResult">The type of the resulting value.</typeparam>

        /// <param name="source">An <see cref="IBindableCollection{TElement}"/> to aggregate over.</param>

        /// <param name="seed">The initial accumulator value.</param>

        /// <param name="func">An accumulator function to be invoked on each element.</param>

        /// <param name="resultSelector">A function to transform the final accumulator value into the result value.</param>

        /// <param name="dependencyAnalysisMode">The dependency analysis mode.</param>

        /// <returns>The transformed final accumulator value.</returns>

        public static IBindable<TResult> Aggregate<TSource, TAccumulate, TResult>(this IBindableCollection<TSource> source, TAccumulate seed, Expression<Func<TAccumulate, TSource, TAccumulate>> func, Expression<Func<TAccumulate, TResult>> resultSelector, DependencyDiscovery dependencyAnalysisMode)

        {

            return source.Aggregate(seed, func, dependencyAnalysisMode).Project(resultSelector, dependencyAnalysisMode);

        }



        /// <summary>

        /// Applies an accumulator function over a sequence.

        /// </summary>

        /// <typeparam name="TSource">The type of the elements of <paramref name="source"/>.</typeparam>

        /// <typeparam name="TResult">The type of the result.</typeparam>

        /// <param name="source">An <see cref="IBindableCollection{TSource}"/> to aggregate over.</param>

        /// <param name="func">An accumulator function to be invoked on each element.</param>

        /// <param name="dependencyAnalysisMode">The dependency analysis mode.</param>

        /// <returns>The final accumulator value.</returns>

        public static IBindable<TResult> Aggregate<TSource, TResult>(this IBindableCollection<TSource> source, Expression<Func<IBindableCollection<TSource>, TResult>> func, DependencyDiscovery dependencyAnalysisMode)

        {

            source.ShouldNotBeNull("source");

            func.ShouldNotBeNull("func");

            var result = new CustomAggregator<TSource, TResult>(source, func.Compile(), source.Dispatcher);

            if (dependencyAnalysisMode == DependencyDiscovery.Enabled)

            {

                return result.DependsOnExpression(func, func.Parameters[0]);

            }

            return result;

        }



        /// <summary>

        /// Applies an accumulator function over a sequence. The specified seed value is used as the

        /// initial accumulator value.

        /// </summary>

        /// <typeparam name="TSource">The type of the elements of <paramref name="source"/>.</typeparam>

        /// <typeparam name="TAccumulate">The type of the accumulator value.</typeparam>

        /// <param name="source">An <see cref="IBindableCollection{TElement}"/> to aggregate over.</param>

        /// <param name="seed">The initial accumulator value.</param>

        /// <param name="func">An accumulator function to be invoked on each element.</param>

        /// <param name="dependencyAnalysisMode">The dependency analysis mode.</param>

        /// <returns>The final accumulator value.</returns>

        public static IBindable<TAccumulate> Aggregate<TSource, TAccumulate>(this IBindableCollection<TSource> source, TAccumulate seed, Expression<Func<TAccumulate, TSource, TAccumulate>> func, DependencyDiscovery dependencyAnalysisMode)

        {

            source.ShouldNotBeNull("source");

            func.ShouldNotBeNull("func");

            seed.ShouldNotBeNull("seed");



            var compiledAccumulator = func.Compile();

            var function = new Func<IBindableCollection<TSource>, TAccumulate>(

                sourceElements =>

                {

                    var current = seed;

                    foreach (var sourceElement in sourceElements)

                    {

                        current = compiledAccumulator(current, sourceElement);

                    }

                    return current;

                }

                );



            var result = new CustomAggregator<TSource, TAccumulate>(source, function, source.Dispatcher);

            if (dependencyAnalysisMode == DependencyDiscovery.Enabled)

            {

                return result.DependsOnExpression(func, func.Parameters[1]);

            }

            return result;

        }

	}

}