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

using Microsoft.Build.Framework;
using Microsoft.Build.Utilities;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace Microsoft.DotNet.SharedFramework.Sdk;

[MSBuildMultiThreadableTask]
public class GeneratePlatformManifestEntriesFromTemplate : Task, IMultiThreadableTask
{
    /// <summary>Injected by MSBuild so paths resolve against the project directory in multithreaded builds.</summary>
    public TaskEnvironment TaskEnvironment { get; set; } = TaskEnvironment.Fallback;

    [Required]
    public ITaskItem[] PlatformManifestEntryTemplates { get; set; }

    [Required]
    public ITaskItem[] Files { get; set; }

    public string FallbackAssemblyVersion { get; set; }

    public string FallbackFileVersion { get; set; }

    [Output]
    public ITaskItem[] PlatformManifestEntries { get; set; }

    public override bool Execute()
    {
        List<PlatformManifestEntry> entries = new List<PlatformManifestEntry>();
        var files = Files.ToLookup(file => Path.GetFileName(file.ItemSpec)).ToDictionary(l => l.Key, l=> l.First());
        foreach (var entryTemplate in PlatformManifestEntryTemplates)
        {
            if (files.TryGetValue(entryTemplate.ItemSpec, out ITaskItem existingFile))
            {
                // This file in the platform manifest template exists on this platform.
                // Use the information from the file itself in its entry.
                FileInfo existingFilePath = new(TaskEnvironment.GetAbsolutePath(existingFile.ItemSpec));
                entries.Add(new PlatformManifestEntry
                {
                    Name = entryTemplate.ItemSpec,
                    AssemblyVersion = FileUtilities.GetAssemblyName(existingFilePath)?.Version.ToString() ?? string.Empty,
                    FileVersion = FileUtilities.GetFileVersion(existingFilePath)?.ToString() ?? string.Empty
                });
            }
            else
            {
                // This file does not exist on this platform. It only exists on another platform.
                var isNativeEntry = entryTemplate.GetMetadata("IsNative") == "true";
                var entryTemplateExtension = Path.GetExtension(entryTemplate.ItemSpec);
                // Use file version 0.0.0.0 for non-Windows executable and shared library files
                bool useFileVersionZero = isNativeEntry && entryTemplateExtension != ".dll" && entryTemplateExtension != ".exe";
                string assemblyVersion = string.Empty;
                string fileVersion = string.Empty;
                if (isNativeEntry)
                {
                    assemblyVersion = "";
                }
                else
                {
                    string localAssemblyVersionFallback = entryTemplate.GetMetadata("FallbackAssemblyVersion");
                    assemblyVersion = !string.IsNullOrEmpty(localAssemblyVersionFallback) ? localAssemblyVersionFallback : FallbackAssemblyVersion;
                }
                if (useFileVersionZero)
                {
                    fileVersion = "0.0.0.0";
                }
                else
                {
                    string localFileVersionFallback = entryTemplate.GetMetadata("FallbackFileVersion");
                    fileVersion = !string.IsNullOrEmpty(localFileVersionFallback) ? localFileVersionFallback : FallbackFileVersion;
                }
                entries.Add(new PlatformManifestEntry
                {
                    Name = entryTemplate.ItemSpec,
                    AssemblyVersion = assemblyVersion,
                    FileVersion = fileVersion,
                    IsNative = isNativeEntry
                });
            }
        }

        PlatformManifestEntries = entries.Select(entry =>
            {
                var item = new TaskItem(entry.Name);
                if (string.IsNullOrEmpty(entry.AssemblyVersion) && !entry.IsNative)
                {
                    Log.LogError($"The platform manifest entry for '{entry.Name}' does not have a fallback assembly version specified and is not built on this platform.");
                }
                item.SetMetadata("AssemblyVersion", entry.AssemblyVersion);
                if (string.IsNullOrEmpty(entry.FileVersion))
                {
                    Log.LogError($"The platform manifest entry for '{entry.Name}' does not have a fallback file version specified and is not built on this platform.");
                }
                item.SetMetadata("FileVersion", entry.FileVersion);
                return item;
            }).ToArray();
        return !Log.HasLoggedErrors;
    }
}