namespace DocumentService.Client.Interfaces;

/// <summary>
/// Client for PDF validation operations (validate, validate PDF/A).
/// </summary>
public interface IPdfValidationClient
{
    /// <summary>
    /// Validates a PDF from stream (multipart upload).
    /// </summary>
    /// <param name="pdfStream">PDF file stream</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>Validation result with metadata</returns>
    Task<PdfValidationResult> ValidatePdfAsync(Stream pdfStream, CancellationToken cancellationToken = default);

    /// <summary>
    /// Validates a PDF from byte array (Base64 JSON).
    /// </summary>
    /// <param name="pdfBytes">PDF file as byte array</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>Validation result with metadata</returns>
    Task<PdfValidationResult> ValidatePdfAsync(byte[] pdfBytes, CancellationToken cancellationToken = default);

    /// <summary>
    /// Validates a PDF/A from stream (multipart upload).
    /// </summary>
    /// <param name="pdfStream">PDF/A file stream</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>PDF/A validation result with conformance level and errors</returns>
    Task<PdfAValidationResult> ValidatePdfAAsync(Stream pdfStream, CancellationToken cancellationToken = default);

    /// <summary>
    /// Validates a PDF/A from byte array (Base64 JSON).
    /// </summary>
    /// <param name="pdfBytes">PDF/A file as byte array</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>PDF/A validation result with conformance level and errors</returns>
    Task<PdfAValidationResult> ValidatePdfAAsync(byte[] pdfBytes, CancellationToken cancellationToken = default);
}

/// <summary>
/// DTO for PDF validation result
/// </summary>
public record PdfValidationResult
{
    /// <summary>Total number of pages in the document.</summary>
    public int PageCount { get; init; }
    /// <summary>File size in bytes.</summary>
    public long FileSizeBytes { get; init; }
    /// <summary>PDF specification version (e.g. "1.7").</summary>
    public string PdfVersion { get; init; } = string.Empty;
    /// <summary>Whether the document is password-protected.</summary>
    public bool IsEncrypted { get; init; }
    /// <summary>Whether the document contains embedded file attachments.</summary>
    public bool HasAttachments { get; init; }
    /// <summary>Number of embedded file attachments.</summary>
    public int AttachmentCount { get; init; }
}

/// <summary>
/// DTO for PDF/A validation result
/// </summary>
public record PdfAValidationResult
{
    /// <summary>Whether the document is fully PDF/A conformant.</summary>
    public bool IsValid { get; init; }
    /// <summary>Detected PDF/A conformance level (e.g. "PDF/A-3b"), or <c>null</c> if not a PDF/A document.</summary>
    public string? PdfAVersion { get; init; }
    /// <summary>Total number of pages in the document.</summary>
    public int PageCount { get; init; }
    /// <summary>List of conformance errors found during validation.</summary>
    public List<string> Errors { get; init; } = new();
    /// <summary>List of conformance warnings found during validation.</summary>
    public List<string> Warnings { get; init; } = new();
}