using System.Threading.Tasks;
using System.IO;
using System;
using Bit.Core.Models.Table;
using Bit.Core.Settings;
using System.Linq;
using Bit.Core.Enums;

namespace Bit.Core.Services
{
    public class LocalSendStorageService : ISendFileStorageService
    {
        private readonly string _baseDirPath;
        private readonly string _baseSendUrl;

        private string RelativeFilePath(Send send, string fileID) => $"{send.Id}/{fileID}";
        private string FilePath(Send send, string fileID) => $"{_baseDirPath}/{RelativeFilePath(send, fileID)}";
        public FileUploadType FileUploadType => FileUploadType.Direct;

        public LocalSendStorageService(
            GlobalSettings globalSettings)
        {
            _baseDirPath = globalSettings.Send.BaseDirectory;
            _baseSendUrl = globalSettings.Send.BaseUrl;
        }

        public async Task UploadNewFileAsync(Stream stream, Send send, string fileId)
        {
            await InitAsync();
            var path = FilePath(send, fileId);
            Directory.CreateDirectory(Path.GetDirectoryName(path));
            using (var fs = File.Create(path))
            {
                stream.Seek(0, SeekOrigin.Begin);
                await stream.CopyToAsync(fs);
            }
        }

        public async Task DeleteFileAsync(Send send, string fileId)
        {
            await InitAsync();
            var path = FilePath(send, fileId);
            DeleteFileIfExists(path);
            DeleteDirectoryIfExistsAndEmpty(Path.GetDirectoryName(path));
        }

        public async Task DeleteFilesForOrganizationAsync(Guid organizationId)
        {
            await InitAsync();
        }

        public async Task DeleteFilesForUserAsync(Guid userId)
        {
            await InitAsync();
        }

        public async Task<string> GetSendFileDownloadUrlAsync(Send send, string fileId)
        {
            await InitAsync();
            return $"{_baseSendUrl}/{RelativeFilePath(send, fileId)}";
        }

        private void DeleteFileIfExists(string path)
        {
            if (File.Exists(path))
            {
                File.Delete(path);
            }
        }

        private void DeleteDirectoryIfExistsAndEmpty(string path)
        {
            if (Directory.Exists(path) && !Directory.EnumerateFiles(path).Any())
            {
                Directory.Delete(path);
            }
        }

        private Task InitAsync()
        {
            if (!Directory.Exists(_baseDirPath))
            {
                Directory.CreateDirectory(_baseDirPath);
            }

            return Task.FromResult(0);
        }

        public Task<string> GetSendFileUploadUrlAsync(Send send, string fileId)
            => Task.FromResult($"/sends/{send.Id}/file/{fileId}");

        public Task<(bool, long?)> ValidateFileAsync(Send send, string fileId, long expectedFileSize, long leeway)
        {
            long? length = null;
            var path = FilePath(send, fileId);
            if (!File.Exists(path))
            {
                return Task.FromResult((false, length));
            }

            length = new FileInfo(path).Length;
            if (expectedFileSize < length - leeway || expectedFileSize > length + leeway)
            {
                return Task.FromResult((false, length));
            }

            return Task.FromResult((true, length));
        }
    }
}