using BMA.EHR.Recruit.Service.Core;
using BMA.EHR.Recruit.Service.Data;
using Microsoft.EntityFrameworkCore;
using MongoDB.Driver.GridFS;
using MongoDB.Driver;
using BMA.EHR.Recruit.Service.Models.Documents;
using System.Net.Http.Headers;
using BMA.EHR.Recruit.Service.Responses.Document;
using MongoDB.Bson;

namespace BMA.EHR.Recruit.Service.Services
{
	public class DocumentService
	{
		private readonly ApplicationDbContext _context;
		private readonly IConfiguration _configuration;
		private readonly IWebHostEnvironment _webHostEnvironment;
		private const string MONGO_DATABASE = "bma-recruit";

		public DocumentService(ApplicationDbContext context,
							   IConfiguration configuration,
							   IWebHostEnvironment webHostEnvironment)
		{
			_context = context;
			_configuration = configuration;
			_webHostEnvironment = webHostEnvironment;
		}

		public string MongoConnectionString
		{
			get => _configuration.GetConnectionString("MongoConnection");
		}

		public async Task<Document> UploadFile(IFormFile file, string newFileName = "")
		{
			var fileName = "";
			var fileExt = Path.GetExtension(file.FileName);
			if (newFileName != "")
				fileName = $"{newFileName}";
			else
				fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');


			var tmpDir = Path.Combine(_webHostEnvironment.ContentRootPath, "tmp");
			if (!Directory.Exists(tmpDir))
				Directory.CreateDirectory(tmpDir);

			var tmpFile = Path.Combine(tmpDir, $"tmp_{DateTime.Now.ToString("ddMMyyyyHHmmss")}{fileExt}");

			try
			{
				// upload to tmp
				using (var stream = new FileStream(tmpFile, FileMode.Create))
				{
					file.CopyTo(stream);
				}

				var mongo = new MongoClient(MongoConnectionString);
				var bucket = new GridFSBucket(mongo.GetDatabase(MONGO_DATABASE));

				using (var fs = new FileStream(tmpFile, FileMode.Open, FileAccess.Read))
				{
					var fileId = bucket.UploadFromStream(fileName, fs);
					var info = new FileInfo(tmpFile);

					try
					{
						var doc = new Document()
						{
							FileName = fileName,
							FileType = file.ContentType,
							FileSize = Convert.ToInt32(file.Length),
							ObjectRefId = fileId.ToString(),
							CreatedDate = DateTime.Now
						};

						await _context.Documents.AddAsync(doc);
						await _context.SaveChangesAsync();

						return doc;
					}
					catch
					{
						bucket.Delete(fileId);
						throw new Exception(GlobalMessages.CannotInsertToDatabase);
					}
				}
			}
			catch
			{
				throw;
			}
			finally
			{
				System.IO.File.Delete(tmpFile);
			}
		}

		public async Task DeleteFile(Guid fileId)
		{
			try
			{
				var doc = await _context.Documents.AsQueryable()
									.FirstOrDefaultAsync(x => x.Id == fileId);

				if (doc == null)
					throw new Exception(GlobalMessages.FileNotFoundOnServer);

				var mongo = new MongoClient(MongoConnectionString);
				var bucket = new GridFSBucket(mongo.GetDatabase(MONGO_DATABASE));

				bucket.Delete(ObjectId.Parse(doc.ObjectRefId));

				_context.Documents.Remove(doc);
				await _context.SaveChangesAsync();
			}
			catch
			{
				throw;
			}
		}

		public async Task<FileDownloadResponse> DownloadFile(Guid fileId)
		{
			var tmpDir = Path.Combine(_webHostEnvironment.ContentRootPath, "tmp");
			if (!Directory.Exists(tmpDir))
				Directory.CreateDirectory(tmpDir);

			var tmpFile = Path.Combine(tmpDir, $"tmp_{DateTime.Now.ToString("ddMMyyyyHHmmss")}");


			try
			{
				var doc = await _context.Documents.AsQueryable()
									.FirstOrDefaultAsync(x => x.Id == fileId);

				if (doc == null)
					throw new Exception(GlobalMessages.FileNotFoundOnServer);


				var fileExt = Path.GetExtension(doc.FileName);
				tmpFile = tmpFile + fileExt;

				var mongo = new MongoClient(MongoConnectionString);
				var bucket = new GridFSBucket(mongo.GetDatabase(MONGO_DATABASE));

				var f = bucket.DownloadAsBytes(ObjectId.Parse(doc.ObjectRefId));
				return new FileDownloadResponse
				{
					FileName = doc.FileName,
					FileType = doc.FileType,
					FileContent = f
				};
			}
			catch
			{
				throw;
			}
			finally
			{
				File.Delete(tmpFile);
			}
		}
	}
}