using FastEndpoints;
using FrameworkBLL.DataSync;
using FrameworkDAL.DTO.DataSync;
using GB5Shared.DTO.Framework.Login;
using GB5Shared.FastEndPoint;
using Microsoft.AspNetCore.Http;
using static GB5Shared.GB5Constant.Constant;

namespace FrameworkSL.Endpoints.DataSync
{
    // Returns a ZIP file stream. BaseEndpoint<TReq, TRes> is not used here because the
    // response is a raw blob stream rather than ResponseStandardDTO — handled via
    // HttpContext.Response directly.
    public class ExportToFile : EndpointWithoutRequest
    {
        private readonly IDataSyncExportBLL _bll;

        public ExportToFile(IDataSyncExportBLL bll) => _bll = bll;

        public override void Configure()
        {
            Get("/DataSync/ExportToFile");
            AllowAnonymous();
        }

        public override async Task HandleAsync(CancellationToken ct)
        {
            var loginHeader = HttpContext.Request.Headers["Login"].FirstOrDefault()
                ?? throw new InvalidOperationException("Login header is missing.");
            var login = System.Text.Json.JsonSerializer.Deserialize<LoginDTO>(loginHeader)
                ?? throw new InvalidOperationException("Login header contains invalid JSON.");

            int.TryParse(Query<string>("SyncJobId"), out var syncJobId);
            var exportMode = Query<string>("ExportMode") ?? "Incremental";
            DateTime? fromDate = null;
            DateTime? toDate   = null;
            if (Query<string>("FromDate") is { } fd && DateTime.TryParse(fd, out var fdt)) fromDate = fdt;
            if (Query<string>("ToDate")   is { } td && DateTime.TryParse(td, out var tdt)) toDate   = tdt;

            var req = new SyncExportRequestDTO
            {
                SyncJobId  = syncJobId,
                ExportMode = exportMode,
                FromDate   = fromDate,
                ToDate     = toDate
            };

            try
            {
                await using var stream = await _bll.ExportToZipAsync(req, login, ct).ConfigureAwait(false);
                var ts       = DateTime.UtcNow.ToString("yyyyMMdd-HHmm");
                var fileName = $"datasync-export-{syncJobId}-{ts}.zip";

                HttpContext.Response.ContentType                = "application/zip";
                HttpContext.Response.Headers["Content-Disposition"] = $"attachment; filename=\"{fileName}\"";
                await stream.CopyToAsync(HttpContext.Response.Body, ct).ConfigureAwait(false);
            }
            catch (Exception ex)
            {
                HttpContext.Response.StatusCode = 500;
                await HttpContext.Response.WriteAsync(ex.Message, ct).ConfigureAwait(false);
            }
        }
    }
}