#nullable enable

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

namespace ShrinkSDK.CodeGen;

public sealed class ShrinkWeaveTask : Task
{
    [Required]
    public string AssemblyPath { get; set; } = string.Empty;

    public string? PdbPath { get; set; }
    public ITaskItem[] ReferencePaths { get; set; } = Array.Empty<ITaskItem>();
    public string? StrongNameKeyFile { get; set; }

    [Output] public bool Changed { get; private set; }
    [Output] public int InstanceSubscriberCount { get; private set; }
    [Output] public int StaticSubscriberCount { get; private set; }
    [Output] public int RegistryEntryCount { get; private set; }

    public override bool Execute()
    {
        if (!File.Exists(AssemblyPath))
        {
            Log.LogError($"[ShrinkSDK.CodeGen] Intermediate assembly does not exist: {AssemblyPath}");
            return false;
        }

        var assemblyDirectory = Path.GetDirectoryName(Path.GetFullPath(AssemblyPath))!;
        var temporaryAssembly = Path.Combine(assemblyDirectory, $".{Path.GetFileName(AssemblyPath)}.{Guid.NewGuid():N}.tmp");
        var hasPdb = !string.IsNullOrWhiteSpace(PdbPath) && File.Exists(PdbPath);
        var temporaryPdb = hasPdb
            ? Path.Combine(assemblyDirectory, $".{Path.GetFileName(PdbPath)}.{Guid.NewGuid():N}.tmp")
            : null;
        try
        {
            var result = ShrinkAssemblyWeaver.Weave(
                AssemblyPath,
                hasPdb ? PdbPath : null,
                ReferencePaths.Select(item => item.ItemSpec),
                temporaryAssembly,
                temporaryPdb,
                ShrinkCodeGenPlatform.EngineNeutral,
                StrongNameKeyFile);
            foreach (var diagnostic in result.Diagnostics)
            {
                switch (diagnostic.Severity)
                {
                    case ShrinkCodeGenDiagnosticSeverity.Warning:
                        Log.LogWarning($"[ShrinkSDK.CodeGen] {diagnostic.Message}");
                        break;
                    case ShrinkCodeGenDiagnosticSeverity.Error:
                        Log.LogError($"[ShrinkSDK.CodeGen] {diagnostic.Message}");
                        break;
                    default:
                        Log.LogMessage(MessageImportance.Low, $"[ShrinkSDK.CodeGen] {diagnostic.Message}");
                        break;
                }
            }
            if (!result.Succeeded)
                return false;

            Changed = result.Changed;
            InstanceSubscriberCount = result.InstanceSubscribers;
            StaticSubscriberCount = result.StaticSubscribers;
            RegistryEntryCount = result.RegistryEntries;
            if (Changed)
            {
                File.Move(temporaryAssembly, AssemblyPath, true);
                if (hasPdb && temporaryPdb != null)
                    File.Move(temporaryPdb, PdbPath!, true);
            }
            Log.LogMessage(MessageImportance.High,
                $"[ShrinkSDK.CodeGen] {Path.GetFileName(AssemblyPath)} woven: instance={InstanceSubscriberCount}, static={StaticSubscriberCount}, registry={RegistryEntryCount}.");
            return true;
        }
        catch (Exception exception)
        {
            Log.LogErrorFromException(exception, true);
            return false;
        }
        finally
        {
            TryDelete(temporaryAssembly);
            if (temporaryPdb != null) TryDelete(temporaryPdb);
        }
    }

    private static void TryDelete(string path)
    {
        try { if (File.Exists(path)) File.Delete(path); }
        catch { }
    }
}