using DocumentOperator.Application.ConvertFromPdfA;
using DocumentOperator.Application.ConvertToPdfA;
using DocumentOperator.Domain.Common.Exceptions;
using MediatR;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

namespace DocumentOperator.API.Controllers;

/// <summary>
/// Controller for PDF conversion operations (PDF ? PDF/A)
/// </summary>
[ApiController]
[Route("api/pdf/conversion")]
[Obsolete("This endpoint is not implemented yet.")]
public class PdfConversionController(IMediator mediator) : ControllerBase
{
    /// <summary>
    /// Converts a standard PDF to PDF/A format.
    /// Supports multipart/form-data file upload.
    /// </summary>
    /// <param name="file">The PDF file to convert</param>
    /// <param name="pdfALevel">Target PDF/A level (e.g., "PDF/A-1b", "PDF/A-2b", "PDF/A-3b")</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>PDF/A compliant document</returns>
    /// <response code="200">PDF converted to PDF/A successfully</response>
    /// <response code="400">Invalid input (file missing, not a PDF, or invalid PDF/A level)</response>
    /// <response code="500">Internal server error during PDF processing</response>
    [Obsolete("This endpoint is not implemented yet.")]
    [HttpPost("to-pdfa")]
    [Consumes("multipart/form-data")]
    [ProducesResponseType(typeof(FileContentResult), StatusCodes.Status200OK)]
    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status400BadRequest)]
    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status500InternalServerError)]
    public async Task<IActionResult> ConvertToPdfAFromFile(
        IFormFile file,
        [FromQuery] string pdfALevel = "PDF/A-3b",
        CancellationToken cancellationToken = default)
    {
        if (file == null || file.Length == 0)
        {
            throw new BadRequestException("PDF file is required");
        }

        // Use IFormFile stream directly (no intermediate byte[] conversion)
        using var pdfStream = file.OpenReadStream();

        // Send command to MediatR
        var command = new ConvertToPdfACommand 
        { 
            PdfStream = pdfStream,
            PdfALevel = pdfALevel
        };
        byte[] resultPdf = await mediator.Send(command, cancellationToken);

        // Return PDF/A file
        return File(resultPdf, "application/pdf", "converted-pdfa.pdf");
    }

    /// <summary>
    /// Converts a standard PDF to PDF/A format.
    /// Supports Base64-encoded PDF via JSON payload.
    /// </summary>
    /// <param name="request">Request containing Base64-encoded PDF and PDF/A level</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>PDF/A compliant document</returns>
    /// <response code="200">PDF converted to PDF/A successfully</response>
    /// <response code="400">Invalid input (Base64 format error, not a PDF, or invalid PDF/A level)</response>
    /// <response code="500">Internal server error during PDF processing</response>
    [Obsolete("This endpoint is not implemented yet.")]
    [HttpPost("to-pdfa")]
    [Consumes("application/json")]
    [ProducesResponseType(typeof(FileContentResult), StatusCodes.Status200OK)]
    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status400BadRequest)]
    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status500InternalServerError)]
    public async Task<IActionResult> ConvertToPdfAFromBase64(
        [FromBody] ConvertToPdfARequest request,
        CancellationToken cancellationToken = default)
    {
        // Convert Base64 PDF to stream
        byte[] pdfBytes;
        try
        {
            pdfBytes = Convert.FromBase64String(request.Base64Pdf);
        }
        catch (FormatException ex)
        {
            throw new BadRequestException("Invalid Base64 PDF format: " + ex.Message);
        }
        
        using var pdfStream = new MemoryStream(pdfBytes);

        // Send command to MediatR
        var command = new ConvertToPdfACommand 
        { 
            PdfStream = pdfStream,
            PdfALevel = request.PdfALevel ?? "PDF/A-3b"
        };
        byte[] resultPdf = await mediator.Send(command, cancellationToken);

        // Return PDF/A file
        return File(resultPdf, "application/pdf", "converted-pdfa.pdf");
    }

    /// <summary>
    /// Converts a PDF/A document to a standard PDF (removes PDF/A restrictions).
    /// Supports multipart/form-data file upload.
    /// </summary>
    /// <param name="file">The PDF/A file to convert</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>Standard PDF document</returns>
    /// <response code="200">PDF/A converted to standard PDF successfully</response>
    /// <response code="400">Invalid input (file missing, not a PDF)</response>
    /// <response code="500">Internal server error during PDF processing</response>
    [Obsolete("This endpoint is not implemented yet.")]
    [HttpPost("from-pdfa")]
    [Consumes("multipart/form-data")]
    [ProducesResponseType(typeof(FileContentResult), StatusCodes.Status200OK)]
    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status400BadRequest)]
    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status500InternalServerError)]
    public async Task<IActionResult> ConvertFromPdfAFromFile(
        IFormFile file,
        CancellationToken cancellationToken = default)
    {
        if (file == null || file.Length == 0)
        {
            throw new BadRequestException("PDF/A file is required");
        }

        // Use IFormFile stream directly (no intermediate byte[] conversion)
        using var pdfStream = file.OpenReadStream();

        // Send command to MediatR
        var command = new ConvertFromPdfACommand { PdfStream = pdfStream };
        byte[] resultPdf = await mediator.Send(command, cancellationToken);

        // Return standard PDF file
        return File(resultPdf, "application/pdf", "converted-pdf.pdf");
    }

    /// <summary>
    /// Converts a PDF/A document to a standard PDF (removes PDF/A restrictions).
    /// Supports Base64-encoded PDF via JSON payload.
    /// </summary>
    /// <param name="request">Request containing Base64-encoded PDF/A</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>Standard PDF document</returns>
    /// <response code="200">PDF/A converted to standard PDF successfully</response>
    /// <response code="400">Invalid input (Base64 format error, not a PDF)</response>
    /// <response code="500">Internal server error during PDF processing</response>
    [Obsolete("This endpoint is not implemented yet.")]
    [HttpPost("from-pdfa")]
    [Consumes("application/json")]
    [ProducesResponseType(typeof(FileContentResult), StatusCodes.Status200OK)]
    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status400BadRequest)]
    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status500InternalServerError)]
    public async Task<IActionResult> ConvertFromPdfAFromBase64(
        [FromBody] ConvertFromPdfARequest request,
        CancellationToken cancellationToken = default)
    {
        // Convert Base64 PDF to stream
        byte[] pdfBytes;
        try
        {
            pdfBytes = Convert.FromBase64String(request.Base64Pdf);
        }
        catch (FormatException ex)
        {
            throw new BadRequestException("Invalid Base64 PDF format: " + ex.Message);
        }
        
        using var pdfStream = new MemoryStream(pdfBytes);

        // Send command to MediatR
        var command = new ConvertFromPdfACommand { PdfStream = pdfStream };
        byte[] resultPdf = await mediator.Send(command, cancellationToken);

        // Return standard PDF file
        return File(resultPdf, "application/pdf", "converted-pdf.pdf");
    }
}

/// <summary>
/// Request DTO for converting PDF to PDF/A
/// </summary>
public record ConvertToPdfARequest
{
    /// <summary>
    /// PDF document encoded as Base64 string
    /// </summary>
    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
    public required string Base64Pdf { get; init; }

    /// <summary>
    /// Target PDF/A level (default: "PDF/A-3b")
    /// </summary>
    /// <example>PDF/A-3b</example>
    public string? PdfALevel { get; init; }
}

/// <summary>
/// Request DTO for converting PDF/A to PDF
/// </summary>
public record ConvertFromPdfARequest
{
    /// <summary>
    /// PDF/A document encoded as Base64 string
    /// </summary>
    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
    public required string Base64Pdf { get; init; }
}