using MediatR;
using Microsoft.EntityFrameworkCore;
using MinAttest.Contracts.Attests;
using MinAttest.Application.Abstractions;
using MinAttest.Domain.Entities;

namespace MinAttest.Application.Features.Attests.Commands;

public record CompleteUploadCommand(Guid UploadId, CompleteUploadRequest Request) : IRequest<Guid?>;

public class CompleteUploadCommandHandler(IAppDbContext db) : IRequestHandler<CompleteUploadCommand, Guid?>
{
    public async Task<Guid?> Handle(CompleteUploadCommand request, CancellationToken cancellationToken)
    {
        var r = request.Request;
        var personExists = await db.Persons.AnyAsync(p => p.Id == r.PersonId, cancellationToken);
        if (!personExists) return null;

        if (r.EmployerId is Guid eid)
        {
            var exists = await db.Employers.AnyAsync(e => e.Id == eid, cancellationToken);
            if (!exists) return null;
        }

        byte[]? content = null;
        long? length = null;
        if (!string.IsNullOrWhiteSpace(r.ContentBase64))
        {
            try
            {
                content = Convert.FromBase64String(r.ContentBase64);
                length = content.LongLength;
            }
            catch (FormatException)
            {
                // invalid base64 -> treat as bad request
                return null;
            }
        }

        var a = new Attest
        {
            Id = Guid.NewGuid(),
            PersonId = r.PersonId,
            EmployerId = r.EmployerId,
            Title = r.Title,
            From = r.From,
            To = r.To,
            Summary = r.Summary,
            BlobPath = r.BlobPath,
            BlobHash = r.BlobHash,
            Content = content,
            ContentType = r.ContentType,
            ContentLength = length,
            IssuedAt = DateTimeOffset.UtcNow
        };

        db.Attests.Add(a);
        await db.SaveChangesAsync(cancellationToken);
        return a.Id;
    }
}