using DocumentOperator.Application.Common.DTOs;
using DocumentOperator.Application.Features.Documents.ValidatePdf;
using DocumentOperator.Domain.Models.ValueObjects;
using MediatR;
using Microsoft.AspNetCore.Mvc;

namespace DocumentOperator.API.Endpoints.v1;

/// <summary>
/// Document endpoints (Minimal API)
/// </summary>
public static class DocumentEndpoints
{
    /// <summary>
    /// Maps all document-related endpoints
    /// </summary>
    public static void MapDocumentEndpoints(this IEndpointRouteBuilder app)
    {
        var group = app.MapGroup("/api/v1/documents")
            .WithTags("Documents");

        // POST /api/v1/documents/validate
        group.MapPost("/validate", ValidatePdf)
            .WithName("ValidatePdf")
            .WithSummary("Validates a PDF document and returns metadata")
            .WithDescription("Validates the PDF format and extracts metadata (page count, file size, PDF version, attachments)")
            .Produces<ValidatePdfResponse>(StatusCodes.Status200OK)
            .Produces<ProblemDetails>(StatusCodes.Status400BadRequest)
            .Produces<ProblemDetails>(StatusCodes.Status500InternalServerError);
    }

    /// <summary>
    /// Validates a PDF document and returns metadata
    /// </summary>
    /// <param name="request">PDF as Base64 string</param>
    /// <param name="mediator">MediatR instance</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>PDF metadata (page count, file size, etc.)</returns>
    /// <response code="200">PDF is valid, metadata returned</response>
    /// <response code="400">Invalid PDF or Base64 format</response>
    /// <response code="500">Internal server error during validation</response>
    private static async Task<IResult> ValidatePdf(
        ValidatePdfRequest request,
        IMediator mediator,
        CancellationToken cancellationToken)
    {
        // DTO → Query (Value Objects erstellen - kann DomainValidationException werfen!)
        var query = new ValidatePdfQuery(
            Base64String.Create(request.Base64Pdf)
        );

        // MediatR Handler aufrufen (ValidationBehavior → Handler)
        var metadata = await mediator.Send(query, cancellationToken);

        // PdfMetadata → Response DTO
        var response = new ValidatePdfResponse(
            metadata.PageCount,
            metadata.FileSizeBytes,
            metadata.FileSizeMB,
            metadata.PdfVersion,
            metadata.HasAttachments,
            metadata.AttachmentCount
        );

        return Results.Ok(response);
    }
}