using DigitalData.Core.Exceptions;
using EnvelopeGenerator.Application.Common.Dto;
using EnvelopeGenerator.Domain.Interfaces;

namespace EnvelopeGenerator.Application.Common.Interfaces.Doc;

/// <summary>
/// 
/// </summary>
public interface IPdfPageImageRenderer
{
    /// <summary>
    /// 
    /// </summary>
    /// <param name="pdfBytes"></param>
    /// <param name="cancellationToken"></param>
    /// <returns></returns>
    Task<IReadOnlyList<PdfPageImageDto>> RenderPagesAsImagesAsync(byte[] pdfBytes, CancellationToken cancellationToken = default);

    /// <summary>
    /// 
    /// </summary>
    /// <param name="element"></param>
    /// <returns></returns>
    Stream ComposeSignaturePreviewPng(ISignatureInkPayload element);

    /// <summary>
    /// 
    /// </summary>
    /// <param name="bytes"></param>
    /// <returns></returns>
    public bool IsSupportedImageFormat(byte[] bytes);
}

/// <summary>
/// 
/// </summary>
public static class PdfPageImageRendererExtensions
{
    /// <summary>
    /// 
    /// </summary>
    /// <param name="renderer"></param>
    /// <param name="inkBytes"></param>
    /// <returns></returns>
    /// <exception cref="BadRequestException"></exception>
    public static byte[] EnsureSupportedImageBytes(this IPdfPageImageRenderer renderer, byte[] inkBytes)
    {
        if (!renderer.IsSupportedImageFormat(inkBytes))
            throw new BadRequestException("Only PNG and JPEG signature formats are supported.");

        return inkBytes;
    }

    public static byte[] ComposeSignaturePreviewPngBytes(this IPdfPageImageRenderer renderer, ISignatureInkPayload element)
    {
        using var stream = renderer.ComposeSignaturePreviewPng(element);

        if (stream is MemoryStream memoryStream)
            return memoryStream.ToArray();

        using var copy = new MemoryStream();
        stream.CopyTo(copy);
        return copy.ToArray();
    }
}