using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

namespace ImageCatalog_2;

internal static class CommandLineOperationRunner
{
    private static readonly HashSet<string> HeadlessMarkers = new(StringComparer.OrdinalIgnoreCase)
    {
        "--operation",
        "--op",
        "--config",
        "--headless",
        "--cli"
    };

    public static bool IsHeadlessRequest(string[]? args)
    {
        return args?.Any(arg => HeadlessMarkers.Contains(arg) || arg.StartsWith("--operation=", StringComparison.OrdinalIgnoreCase) || arg.StartsWith("--config=", StringComparison.OrdinalIgnoreCase)) == true;
    }

    public static async Task<int> RunAsync(IServiceProvider services, string[] args)
    {
        var logger = services.GetRequiredService<ILoggerFactory>().CreateLogger("CommandLine");

        try
        {
            var options = Parse(args);
            if (options.ShowHelp)
            {
                WriteUsage();
                return 0;
            }

            if (string.IsNullOrWhiteSpace(options.ConfigPath))
            {
                throw new ArgumentException("Missing required --config <path> argument.");
            }

            if (string.IsNullOrWhiteSpace(options.Operation))
            {
                throw new ArgumentException("Missing required --operation <image-processing|number-ai|face-ai|race-upload> argument.");
            }

            if (!File.Exists(options.ConfigPath))
            {
                throw new FileNotFoundException("Configuration file not found.", options.ConfigPath);
            }

            var model = services.GetRequiredService<DataModel>();
            await model.LoadSettingsFromFileAsync(options.ConfigPath).ConfigureAwait(false);
            ApplyOverrides(model, options);

            using var cancellationTokenSource = new CancellationTokenSource();
            Console.CancelKeyPress += (_, eventArgs) =>
            {
                eventArgs.Cancel = true;
                cancellationTokenSource.Cancel();
            };

            logger.LogInformation("Running ImageCatalog operation {Operation} with config {ConfigPath}", options.Operation, options.ConfigPath);

            switch (NormalizeOperation(options.Operation))
            {
                case "image-processing":
                    await model.ProcessImages().ConfigureAwait(false);
                    break;
                case "number-ai":
                    await model.RunNumberAiAsync(cancellationTokenSource.Token).ConfigureAwait(false);
                    break;
                case "face-ai":
                    await model.RunFaceAiAsync(cancellationTokenSource.Token).ConfigureAwait(false);
                    break;
                case "race-upload":
                    throw new NotSupportedException("race-upload is not available in headless mode yet because the upload workflow still lives in the Avalonia view layer.");
                default:
                    throw new ArgumentException($"Unknown operation: {options.Operation}");
            }

            logger.LogInformation("ImageCatalog operation {Operation} completed", options.Operation);
            return 0;
        }
        catch (OperationCanceledException)
        {
            logger.LogWarning("Command-line operation canceled.");
            return 130;
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "Command-line operation failed.");
            return 1;
        }
    }

    private static void ApplyOverrides(DataModel model, CommandLineOptions options)
    {
        if (!string.IsNullOrWhiteSpace(options.ModelsPath))
        {
            model.ModelsFolderPath = options.ModelsPath;
        }

        if (!string.IsNullOrWhiteSpace(options.CsvPath))
        {
            model.CsvOutputPath = options.CsvPath;
        }

        if (options.UseGpu.HasValue)
        {
            model.UseNumberAiGpu = options.UseGpu.Value;
            if (model.FaceGpuOptionEnabled || !options.UseGpu.Value)
            {
                model.UseFaceGpu = options.UseGpu.Value;
            }
        }

        if (options.IncludeThumbnails.HasValue)
        {
            model.IncludeNumberAiThumbnails = options.IncludeThumbnails.Value;
        }

        if (options.NumberAiWorkloadLevel.HasValue)
        {
            model.NumberAiWorkloadLevel = options.NumberAiWorkloadLevel.Value;
        }
    }

    private static string NormalizeOperation(string operation)
    {
        return operation.Trim().ToLowerInvariant() switch
        {
            "images" or "image" or "process-images" or "image-processing" => "image-processing",
            "ai" or "ocr" or "number" or "number-ai" => "number-ai",
            "face" or "face-ai" => "face-ai",
            "race" or "race-upload" => "race-upload",
            var normalized => normalized
        };
    }

    private static CommandLineOptions Parse(string[] args)
    {
        var options = new CommandLineOptions();

        for (var i = 0; i < args.Length; i++)
        {
            var arg = args[i];
            switch (arg.ToLowerInvariant())
            {
                case "--help":
                case "-h":
                case "/?":
                    options.ShowHelp = true;
                    break;
                case "--operation":
                case "--op":
                    options.Operation = ReadValue(args, ref i, arg);
                    break;
                case "--config":
                    options.ConfigPath = ReadValue(args, ref i, arg);
                    break;
                case "--models":
                    options.ModelsPath = ReadValue(args, ref i, arg);
                    break;
                case "--csv":
                    options.CsvPath = ReadValue(args, ref i, arg);
                    break;
                case "--gpu":
                    options.UseGpu = true;
                    break;
                case "--cpu":
                    options.UseGpu = false;
                    break;
                case "--include-thumbnails":
                case "--include-tn":
                    options.IncludeThumbnails = true;
                    break;
                case "--no-thumbnails":
                case "--no-tn":
                    options.IncludeThumbnails = false;
                    break;
                case "--workload":
                case "--ai-workload":
                    options.NumberAiWorkloadLevel = int.Parse(ReadValue(args, ref i, arg));
                    break;
                case "--headless":
                case "--cli":
                    break;
                default:
                    ApplyInlineArgument(options, arg);
                    break;
            }
        }

        return options;
    }

    private static void ApplyInlineArgument(CommandLineOptions options, string arg)
    {
        var separatorIndex = arg.IndexOf('=');
        if (separatorIndex < 0)
        {
            throw new ArgumentException($"Unknown argument: {arg}");
        }

        var name = arg[..separatorIndex].ToLowerInvariant();
        var value = arg[(separatorIndex + 1)..];
        switch (name)
        {
            case "--operation":
            case "--op":
                options.Operation = value;
                break;
            case "--config":
                options.ConfigPath = value;
                break;
            case "--models":
                options.ModelsPath = value;
                break;
            case "--csv":
                options.CsvPath = value;
                break;
            case "--workload":
            case "--ai-workload":
                options.NumberAiWorkloadLevel = int.Parse(value);
                break;
            default:
                throw new ArgumentException($"Unknown argument: {arg}");
        }
    }

    private static string ReadValue(string[] args, ref int index, string name)
    {
        if (index + 1 >= args.Length)
        {
            throw new ArgumentException($"Missing value for {name}.");
        }

        return args[++index];
    }

    private static void WriteUsage()
    {
        Console.WriteLine("Usage: ImageCatalog --config <settings.xml> --operation <image-processing|number-ai|face-ai|race-upload> [--models <folder>] [--csv <path>] [--cpu|--gpu] [--include-thumbnails|--no-thumbnails] [--workload <1-5>]");
    }

    private sealed class CommandLineOptions
    {
        public bool ShowHelp { get; set; }
        public string Operation { get; set; } = string.Empty;
        public string ConfigPath { get; set; } = string.Empty;
        public string ModelsPath { get; set; } = string.Empty;
        public string CsvPath { get; set; } = string.Empty;
        public bool? UseGpu { get; set; }
        public bool? IncludeThumbnails { get; set; }
        public int? NumberAiWorkloadLevel { get; set; }
    }
}