using System.Collections.Generic;
using System.Threading;

using MfGames.Gallium;

namespace MfGames.Nitride.Pipelines;

/// <summary>
/// A basic pipeline that is configured through properties and methods.
/// </summary>
public abstract class PipelineBase : IPipeline
{
    private readonly List<IPipeline> dependencies;

    protected PipelineBase()
    {
        this.dependencies = new List<IPipeline>();
    }

    /// <summary>
    /// Adds one or more pipeline dependencies into the current one. All of
    /// the dependencies are guaranteed to run before this pipeline's RunAsync
    /// is called.
    /// </summary>
    /// <param name="pipelines">The pipelines to add as a dependency.</param>
    /// <returns>The same object for chaining operations.</returns>
    public PipelineBase AddDependency(params IPipeline[] pipelines)
    {
        foreach (IPipeline pipeline in pipelines)
        {
            this.dependencies.Add(pipeline);
        }

        return this;
    }

    /// <inheritdoc />
    public IEnumerable<IPipeline> GetDependencies()
    {
        return this.dependencies;
    }

    /// <inheritdoc />
    public abstract IAsyncEnumerable<Entity> RunAsync(
        IEnumerable<Entity> entities,
        CancellationToken cancellationToken = default);

    /// <inheritdoc />
    public override string ToString()
    {
        return this.GetType().Name;
    }
}