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

using System.Collections.Generic;
using System.IO;

namespace Microsoft.DotNet.Build.Tasks.Workloads;

/// <summary>
/// Base class to generate project templates and source files to produce workload artifacts.
/// </summary>
public abstract class WorkloadTemplateBase
{
    /// <summary>
    /// List of source files that have been added to the template.
    /// </summary>
    private List<string> _files = new();

    /// <summary>
    /// The root intermediate output directory. 
    /// </summary>
    public string OutputPath
    {
        get;
        init;
    }

    /// <summary>
    /// Dictionary to map replacement tokens and values.
    /// </summary>
    protected Dictionary<string, string> ReplacementTokens
    {
        get;
    } = new();

    /// <summary>
    /// List of source files that have been added to the template.
    /// </summary>
    protected IEnumerable<string> Files => _files;

    /// <summary>
    /// The path of the root directory where the template will be generated.
    /// </summary>
    protected string TemplateOutputPath
    {
        get;
        init;
    }

    /// <summary>
    /// The file system path where source files are generated.
    /// </summary>
    /// <remarks>
    /// Derived classes may extend the path to include additional directories as needed.
    /// </remarks>
    protected string SourcePath
    {
        get;
        init;
    }

    /// <summary>
    /// The file system path where intermediate outputs are generated.
    /// </summary>
    protected string IntermediateOutputPath
    {
        get;
        init;
    }

    /// <summary>
    /// Creates a new <see cref="WorkloadTemplateBase"/> instance.
    /// </summary>
    /// <param name="outputPath">The file system path where the template will be generated. </param>
    public WorkloadTemplateBase(string outputPath)
    {
        OutputPath = outputPath;
        SourcePath = Path.Combine(OutputPath, "src");
        IntermediateOutputPath = Path.Combine(OutputPath, "obj");
    }

    /// <summary>
    /// Builds the template.
    /// </summary>
    public virtual void Build()
    {

    }

    /// <summary>
    /// Generates the template content like project and source files.
    /// </summary>
    /// <returns>The path to the project file if applicable.</returns>
    public virtual string Create() => "";        

    /// <summary>
    /// Extracts the specified template file into the source directory and optionally replace tokens.
    /// </summary>
    /// <param name="templateFilename">The name of the template file to add to the source directory.</param>
    /// <param name="replaceTokens">When true, replace tokens in the generated file.</param>
    /// <returns>The full path of the file that was added.</returns>
    public string AddFile(string templateFilename, bool replaceTokens = true) =>
        AddFile(templateFilename, templateFilename, replaceTokens);

    /// <summary>
    /// Extracts the specified template file into the source directory using the specified filename and 
    /// optionally replace tokens.
    /// </summary>
    /// <param name="templateFilename">The name of the template file to add.</param>
    /// <param name="destinationFilename">The name of the file to be created in the source directory.</param>
    /// <param name="replaceTokens">When true, replace tokens in the generated file.</param>
    /// <returns>The full path of the file that was added.</returns>
    public string AddFile(string templateFilename, string destinationFilename, bool replaceTokens = true)
    {
        string templatePath = EmbeddedTemplates.Extract(templateFilename, SourcePath, destinationFilename);

        if (replaceTokens)
        {
            Utils.StringReplace(templatePath, ReplacementTokens);
        }

        AddSourceFile(templatePath);

        return templatePath;
    }

    /// <summary>
    /// Add an existing file to the list of source files associated with the template.
    /// </summary>
    /// <param name="path">The file system path of the file to add.</param>
    public void AddSourceFile(string path) => _files.Add(path);
}