using DocumentService.Application.Common.DTOs;
using DocumentService.Client.Interfaces;
using DocumentService.Client.Models.Results;

namespace DocumentService.Client.Clients;

/// <summary>
/// Orchestrated multi-step workflows that compose multiple DocumentService clients
/// into single, higher-level operations.
/// </summary>
public class WorkflowsClient(IPdfValidationClient validation, ISwissQrCodeClient swissQrCode) : IWorkflowsClient
{
    /// <inheritdoc />
    public async Task<SwissQrCodeResult> InspectSwissQrCodeAsync(
        byte[] pdfBytes,
        bool raw = false,
        CancellationToken cancellationToken = default)
    {
        var validationResult = await validation.ValidateAsync(pdfBytes, cancellationToken);
        var qrCode = validationResult.IsValid
            ? await swissQrCode.ExtractAsync(pdfBytes, raw, cancellationToken)
            : null;
        return new SwissQrCodeResult(qrCode, validationResult);
    }

    /// <inheritdoc />
    public async Task<SwissQrCodeResult> InspectSwissQrCodeAsync(
        Stream pdfStream,
        bool raw = false,
        CancellationToken cancellationToken = default)
    {
        var validationResult = await validation.ValidateAsync(pdfStream, cancellationToken);

        if (!validationResult.IsValid)
            return new SwissQrCodeResult(null, validationResult);

        // Stream was consumed by validation – reset if possible, otherwise re-open is caller's responsibility.
        if (pdfStream.CanSeek)
            pdfStream.Position = 0;

        var qrCode = await swissQrCode.ExtractAsync(pdfStream, raw, cancellationToken);
        return new SwissQrCodeResult(qrCode, validationResult);
    }
}

/// <summary>
/// Convenience extensions for <see cref="IWorkflowsClient"/> that accept a file path as input.
/// Defined alongside <see cref="WorkflowsClient"/> so they are discoverable without an additional using directive.
/// </summary>
public static class WorkflowsClientExtensions
{
    /// <summary>
    /// Validates the PDF at <paramref name="filePath"/> and attempts Swiss QR Code extraction
    /// in a single call. Opens a <see cref="FileStream"/> and delegates to
    /// <see cref="IWorkflowsClient.InspectSwissQrCodeAsync(Stream, bool, CancellationToken)"/>.
    /// </summary>
    /// <param name="client">The workflows client.</param>
    /// <param name="filePath">Absolute or relative path to the PDF file.</param>
    /// <param name="raw">
    /// <c>false</c> (default) – returns a parsed Bill object.<br/>
    /// <c>true</c> – returns raw QR text lines without parsing.
    /// </param>
    /// <param name="cancellationToken">Cancellation token.</param>
    public static async Task<SwissQrCodeResult> InspectSwissQrCodeAsync(
        this IWorkflowsClient client,
        string filePath,
        bool raw = false,
        CancellationToken cancellationToken = default)
    {
        using var stream = File.OpenRead(filePath);
        return await client.InspectSwissQrCodeAsync(stream, raw, cancellationToken);
    }
}