using BudgetApp.PublicModels;
using BudgetApp.Services;
using Microsoft.AspNetCore.Mvc;

namespace BudgetApp.Api.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class UploadController(IUploadService uploadService) : ControllerBase
    {

        private readonly IUploadService _uploadService = uploadService ?? throw new ArgumentNullException(nameof(uploadService));

        // Adjust as needed (e.g., 50 MB)
        private const long MaxFileSizeBytes = 50 * 1024 * 1024;

        /// <summary>
        /// Receives a CSV file via multipart/form-data.
        /// </summary>
        [HttpPost("csv")]
        [RequestSizeLimit(MaxFileSizeBytes)]
        [Consumes("multipart/form-data")]
        public async Task<ActionResult<BaseResponse>> UploadCsv([FromForm] IFormFile file, CancellationToken ct)
        {
            if (file is null)
                return BadRequest("Missing 'file' form field.");

            if (file.Length == 0)
                return BadRequest("The uploaded file is empty.");

            if (file.Length > MaxFileSizeBytes)
                return BadRequest($"File too large. Limit is {MaxFileSizeBytes} bytes.");

            // Light validation – content types for CSV vary by client/OS
            var allowedContentTypes = new[]
            {
            "text/csv",
            "application/csv",
            "text/plain",
            "application/vnd.ms-excel"
        };
            var hasCsvLikeContentType = allowedContentTypes.Contains(file.ContentType, StringComparer.OrdinalIgnoreCase);
            var hasCsvExtension = Path.GetExtension(file.FileName).Equals(".csv", StringComparison.OrdinalIgnoreCase);

            if (!hasCsvLikeContentType && !hasCsvExtension)
                return BadRequest("Only CSV files are accepted.");

            var response = await _uploadService.UploadCsv(file, ct);

            // Return whatever metadata/result you need
            return Ok(response);
        }
    }
}