using System.Net.Http.Headers;

namespace VFXReviewWorker;

/// <summary>
/// `VFXReviewWorker.exe --check` — install verification for a new machine.
/// Resolves every path and dependency the worker needs, reports what is
/// missing, and exits non-zero if anything would stop it running. Cheaper than
/// installing the service and reading logs to find a typo'd path.
/// </summary>
public static class Preflight
{
    public static async Task<int> RunAsync(string? configPath)
    {
        var ok = true;
        Console.WriteLine("VFXReview RenderWorker preflight");
        Console.WriteLine();

        var resolvedConfigPath = configPath ?? WorkerOptions.DefaultConfigPath;
        WorkerOptions? options = null;
        try
        {
            options = WorkerOptions.Load(configPath);
            ok &= Report("config file", resolvedConfigPath, true);
        }
        catch (Exception ex)
        {
            Report("config file", resolvedConfigPath, false, ex.Message);
            Console.WriteLine();
            Console.WriteLine("Cannot continue without a config file. See RenderWorker/README.md.");
            return 1;
        }

        Console.WriteLine($"  machine name   : {options.MachineName}");
        Console.WriteLine($"  server         : {options.ServerUrl}");
        Console.WriteLine($"  api key        : {(string.IsNullOrWhiteSpace(options.ApiKey) ? "(missing)" : "set")}");
        Console.WriteLine();

        ok &= Report("aerender.exe", options.AerenderPath, File.Exists(options.AerenderPath));
        var afterFx = options.ResolveAfterFxPath();
        ok &= Report("AfterFX.com", afterFx, File.Exists(afterFx),
            "needed for preview builds only");
        var script = options.ResolvePreviewScriptPath();
        ok &= Report("preview script", script, File.Exists(script),
            "needed for preview builds only");

        if (!string.IsNullOrWhiteSpace(options.FfmpegPath))
        {
            Report("ffmpeg", options.FfmpegPath!, File.Exists(options.FfmpegPath!),
                "optional — thumbnails are skipped without it");
        }
        else
        {
            Console.WriteLine("  [ - ] ffmpeg           not configured (thumbnails will be skipped)");
        }

        // Path mappings: prove the mapped roots are actually reachable here.
        Console.WriteLine();
        if (options.PathMappings.Count == 0)
        {
            Console.WriteLine("  [ ! ] no pathMappings configured — manifest UNC paths will be used as-is");
        }
        foreach (var m in options.PathMappings)
        {
            var reachable = Directory.Exists(m.To);
            Report($"path map {m.From}", m.To, reachable, "target must be reachable from this machine");
            ok &= reachable;
        }

        // Server reachability + API key validity in one call.
        Console.WriteLine();
        try
        {
            using var http = new HttpClient { BaseAddress = new Uri(options.ServerUrl.TrimEnd('/') + "/"), Timeout = TimeSpan.FromSeconds(15) };
            http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", options.ApiKey);
            var res = await http.GetAsync("api/ext/projects");
            if (res.IsSuccessStatusCode)
            {
                Console.WriteLine("  [ok ] server reachable and API key accepted");
            }
            else if ((int)res.StatusCode == 401)
            {
                Console.WriteLine("  [FAIL] server reachable but API key was rejected (401)");
                ok = false;
            }
            else
            {
                Console.WriteLine($"  [FAIL] server responded {(int)res.StatusCode}");
                ok = false;
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"  [FAIL] cannot reach {options.ServerUrl}: {ex.Message}");
            ok = false;
        }

        Console.WriteLine();
        Console.WriteLine(ok
            ? "All checks passed — safe to install the service."
            : "One or more checks FAILED — fix the above before installing.");
        return ok ? 0 : 1;
    }

    private static bool Report(string label, string path, bool exists, string? note = null)
    {
        var status = exists ? "ok " : "FAIL";
        Console.WriteLine($"  [{status}] {label,-16} {path}");
        if (!exists && note is not null)
        {
            Console.WriteLine($"         ({note})");
        }
        return exists;
    }
}