using EnvelopeRenderer.Cli.Cli;
using EnvelopeRenderer.Cli.Progress;
using EnvelopeRenderer.Cli.Render;

const string Usage = """
    EnvelopeRenderer.Cli --template <path> --csv <path> --output <path>

    Required:
      --template <path>   Local or UNC path to the XML template.
      --csv <path>         Local or UNC path to the CSV data file.
      --output <path>      Local or UNC path to write the rendered PDF to.

    Other:
      -h, --help            Show this usage text and exit 0.

    Exit codes: 0 success, 1 template/CSV/render error, 2 invalid usage,
    3 input not found, 4 output path invalid.
    See CLI_CONTRACT.md for the full contract.
    """;

var result = CliArgumentParser.Parse(args);

switch (result.Kind)
{
    case CliOutcomeKind.HelpRequested:
        Console.Out.WriteLine(Usage);
        return ExitCodes.Success;

    case CliOutcomeKind.InvalidUsage:
        WriteErrors(result.Errors);
        Console.Error.WriteLine();
        Console.Error.WriteLine(Usage);
        return ExitCodes.InvalidUsage;

    case CliOutcomeKind.InputNotFound:
        WriteErrors(result.Errors);
        return ExitCodes.InputNotFound;

    case CliOutcomeKind.OutputPathInvalid:
        WriteErrors(result.Errors);
        return ExitCodes.OutputPathInvalid;

    case CliOutcomeKind.Success:
        return RunRender(result.Arguments!);

    default:
        throw new InvalidOperationException($"Unhandled outcome kind: {result.Kind}");
}

static int RunRender(CliArguments args)
{
    var progress = ConsoleProgressReporter.CreateDefault(Console.Out);
    progress.Startup();

    var templateResult = TemplateXmlParser.Parse(args.TemplatePath);
    if (!templateResult.Succeeded)
    {
        WriteErrors(templateResult.Errors);
        progress.Failure(0, string.Join("; ", templateResult.Errors));
        return ExitCodes.UnexpectedError;
    }

    var csv = new CsvRecordSource(args.CsvPath);
    IReadOnlyList<string> headers;
    try
    {
        headers = csv.ReadHeaders();
    }
    catch (Exception ex)
    {
        var message = $"Failed to read CSV headers from '{args.CsvPath}': {ex.Message}";
        Console.Error.WriteLine($"ERROR: {message}");
        progress.Failure(0, message);
        return ExitCodes.UnexpectedError;
    }

    var dllPath = Path.Combine(
        AppContext.BaseDirectory,
        Environment.Is64BitProcess ? "DebenuPDFLibrary64DLL1013.dll" : "DebenuPDFLibraryDLL1013.dll");
    var licenseKey = Environment.GetEnvironmentVariable("DEBENU_LICENSE_KEY");

    if (!DebenuPdfRenderer.TryCreate(dllPath, licenseKey, out var renderer, out var createError))
    {
        Console.Error.WriteLine($"ERROR: {createError}");
        progress.Failure(0, createError!);
        return ExitCodes.UnexpectedError;
    }

    using (renderer)
    {
        var renderResult = RenderEngine.Render(
            templateResult.Document!, headers, csv.ReadRecords(), renderer!, args.OutputPath, progress);

        if (!renderResult.Succeeded)
        {
            WriteErrors(renderResult.Errors);
            progress.Failure(renderResult.RecordsRendered, string.Join("; ", renderResult.Errors));
            return ExitCodes.UnexpectedError;
        }

        progress.Complete(renderResult.RecordsRendered);
    }

    return ExitCodes.Success;
}

static void WriteErrors(IReadOnlyList<string> errors)
{
    foreach (var error in errors)
    {
        Console.Error.WriteLine($"ERROR: {error}");
    }
}