// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;
using System.Collections.Generic;
using Microsoft.Build.BackEnd.Logging;
using Microsoft.Build.Execution;

#nullable disable

namespace Microsoft.Build.BackEnd
{
    /// <summary>
    /// A class that evaluates an ItemGroup or PropertyGroup that is within a target.
    /// </summary>
    internal abstract class IntrinsicTask
    {
        /// <summary>
        /// Initializes this base class.
        /// </summary>
        /// <param name="loggingContext">The logging context</param>
        /// <param name="projectInstance">The project instance</param>
        /// <param name="logTaskInputs">Flag to determine whether or not to log task inputs.</param>
        protected IntrinsicTask(TargetLoggingContext loggingContext, ProjectInstance projectInstance, bool logTaskInputs)
        {
            this.LoggingContext = loggingContext;
            this.Project = projectInstance;
            this.LogTaskInputs = logTaskInputs;
        }

        /// <summary>
        /// Gets or sets the logging context.
        /// </summary>
        internal TargetLoggingContext LoggingContext
        {
            get;
            private set;
        }

        /// <summary>
        /// Gets or sets the project instance.
        /// </summary>
        internal ProjectInstance Project
        {
            get;
            private set;
        }

        /// <summary>
        /// Flag to determine whether or not to log task inputs.
        /// </summary>
        protected bool LogTaskInputs
        {
            get;
            private set;
        }

        /// <summary>
        /// Factory for intrinsic tasks.
        /// </summary>
        /// <param name="taskInstance">The task instance object.</param>
        /// <param name="loggingContext">The logging context.</param>
        /// <param name="projectInstance">The project instance.</param>
        /// <param name="logTaskInputs"><code>true</code> to log task inputs, otherwise <code>false</code>.</param>
        /// <returns>An instantiated intrinsic task.</returns>
        internal static IntrinsicTask InstantiateTask(ProjectTargetInstanceChild taskInstance, TargetLoggingContext loggingContext, ProjectInstance projectInstance, bool logTaskInputs)
            => taskInstance switch
            {
                ProjectPropertyGroupTaskInstance propertyGroupTaskInstance => new PropertyGroupIntrinsicTask(propertyGroupTaskInstance, loggingContext, projectInstance, logTaskInputs),
                ProjectItemGroupTaskInstance itemGroupTaskInstance => new ItemGroupIntrinsicTask(itemGroupTaskInstance, loggingContext, projectInstance, logTaskInputs),

                _ => InternalError.Throw<IntrinsicTask>($"Unhandled intrinsic task type {taskInstance.GetType().BaseType}"),
            };

        /// <summary>
        /// Called to execute a task within a target. This method instantiates the task, sets its parameters, and executes it.
        /// </summary>
        /// <param name="lookup">The lookup used for expansion and to receive created items and properties.</param>
        internal abstract void ExecuteTask(Lookup lookup);

        /// <summary>
        /// If value is not an empty string, adds it to list.
        /// </summary>
        /// <param name="list">The list of strings to which this should be added, if it is not empty.</param>
        /// <param name="value">The string to add.</param>
        protected static void AddIfNotEmptyString(List<string> list, string value)
        {
            if (!String.IsNullOrEmpty(value))
            {
                list.Add(value);
            }
        }
    }
}