// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using Aspire.Shared;
 
namespace Aspire.Cli.Utils;
 
internal static class AspireRepositoryDetector
{
#if DEBUG
    private const string AspireSolutionFileName = "Aspire.slnx";
 
    private static string? s_cachedRepoRoot;
    private static bool s_cacheInitialized;
#endif
 
    public static string? DetectRepositoryRoot(string? startPath = null)
    {
#if !DEBUG
        // In release builds, only check the environment variable to avoid
        // filesystem walking on every call in production scenarios.
        var envRoot = Environment.GetEnvironmentVariable(BundleDiscovery.RepoRootEnvVar);
        if (!string.IsNullOrEmpty(envRoot) && Directory.Exists(envRoot))
        {
            return Path.GetFullPath(envRoot);
        }
 
        return null;
#else
        if (s_cacheInitialized)
        {
            return s_cachedRepoRoot;
        }
 
        s_cachedRepoRoot = DetectRepositoryRootCore(startPath);
        s_cacheInitialized = true;
        return s_cachedRepoRoot;
#endif
    }
 
#if DEBUG
    internal static void ResetCache()
    {
        s_cachedRepoRoot = null;
        s_cacheInitialized = false;
    }
 
    private static string? DetectRepositoryRootCore(string? startPath)
    {
        var repoRoot = FindRepositoryRoot(startPath);
        if (!string.IsNullOrEmpty(repoRoot))
        {
            return repoRoot;
        }
 
        var envRoot = Environment.GetEnvironmentVariable(BundleDiscovery.RepoRootEnvVar);
        if (!string.IsNullOrEmpty(envRoot) && Directory.Exists(envRoot))
        {
            return Path.GetFullPath(envRoot);
        }
 
        var processPath = Environment.ProcessPath;
        if (!string.IsNullOrEmpty(processPath))
        {
            repoRoot = FindRepositoryRoot(Path.GetDirectoryName(processPath));
            if (!string.IsNullOrEmpty(repoRoot))
            {
                return repoRoot;
            }
        }
 
        return null;
    }
 
    private static string? FindRepositoryRoot(string? startPath)
    {
        if (string.IsNullOrEmpty(startPath))
        {
            return null;
        }
 
        var currentDirectory = ResolveSearchDirectory(startPath);
        while (!string.IsNullOrEmpty(currentDirectory))
        {
            if (File.Exists(Path.Combine(currentDirectory, AspireSolutionFileName)))
            {
                return currentDirectory;
            }
 
            currentDirectory = Directory.GetParent(currentDirectory)?.FullName;
        }
 
        return null;
    }
 
    private static string ResolveSearchDirectory(string path)
    {
        var fullPath = Path.GetFullPath(path);
 
        if (Directory.Exists(fullPath))
        {
            return fullPath;
        }
 
        if (File.Exists(fullPath))
        {
            return Path.GetDirectoryName(fullPath)!;
        }
 
        var parentDirectory = Path.GetDirectoryName(fullPath);
        return string.IsNullOrEmpty(parentDirectory) ? fullPath : parentDirectory;
    }
#endif
}