using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
using Azure.Storage.Blobs;
using Azure.Storage.Blobs.Models;
using Azure.Storage.Sas;
using Bit.Core.Entities;
using Bit.Core.Enums;
using Bit.Core.Settings;

namespace Bit.Core.Services
{
    public class AzureSendFileStorageService : ISendFileStorageService
    {
        public const string FilesContainerName = "sendfiles";
        private static readonly TimeSpan _downloadLinkLiveTime = TimeSpan.FromMinutes(1);
        private readonly BlobServiceClient _blobServiceClient;
        private BlobContainerClient _sendFilesContainerClient;

        public FileUploadType FileUploadType => FileUploadType.Azure;

        public static string SendIdFromBlobName(string blobName) => blobName.Split('/')[0];
        public static string BlobName(Send send, string fileId) => $"{send.Id}/{fileId}";

        public AzureSendFileStorageService(
            GlobalSettings globalSettings)
        {
            _blobServiceClient = new BlobServiceClient(globalSettings.Send.ConnectionString);
        }

        public async Task UploadNewFileAsync(Stream stream, Send send, string fileId)
        {
            await InitAsync();

            var blobClient = _sendFilesContainerClient.GetBlobClient(BlobName(send, fileId));

            var metadata = new Dictionary<string, string>();
            if (send.UserId.HasValue)
            {
                metadata.Add("userId", send.UserId.Value.ToString());
            }
            else
            {
                metadata.Add("organizationId", send.OrganizationId.Value.ToString());
            }

            var headers = new BlobHttpHeaders
            {
                ContentDisposition = $"attachment; filename=\"{fileId}\""
            };

            await blobClient.UploadAsync(stream, new BlobUploadOptions { Metadata = metadata, HttpHeaders = headers });
        }

        public async Task DeleteFileAsync(Send send, string fileId) => await DeleteBlobAsync(BlobName(send, fileId));

        public async Task DeleteBlobAsync(string blobName)
        {
            await InitAsync();
            var blobClient = _sendFilesContainerClient.GetBlobClient(blobName);
            await blobClient.DeleteIfExistsAsync();
        }

        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();
            var blobClient = _sendFilesContainerClient.GetBlobClient(BlobName(send, fileId));
            var sasUri = blobClient.GenerateSasUri(BlobSasPermissions.Read, DateTime.UtcNow.Add(_downloadLinkLiveTime));
            return sasUri.ToString();
        }

        public async Task<string> GetSendFileUploadUrlAsync(Send send, string fileId)
        {
            await InitAsync();
            var blobClient = _sendFilesContainerClient.GetBlobClient(BlobName(send, fileId));
            var sasUri = blobClient.GenerateSasUri(BlobSasPermissions.Create | BlobSasPermissions.Write, DateTime.UtcNow.Add(_downloadLinkLiveTime));
            return sasUri.ToString();
        }

        public async Task<(bool, long?)> ValidateFileAsync(Send send, string fileId, long expectedFileSize, long leeway)
        {
            await InitAsync();

            var blobClient = _sendFilesContainerClient.GetBlobClient(BlobName(send, fileId));

            try
            {
                var blobProperties = await blobClient.GetPropertiesAsync();
                var metadata = blobProperties.Value.Metadata;

                if (send.UserId.HasValue)
                {
                    metadata["userId"] = send.UserId.Value.ToString();
                }
                else
                {
                    metadata["organizationId"] = send.OrganizationId.Value.ToString();
                }
                await blobClient.SetMetadataAsync(metadata);

                var headers = new BlobHttpHeaders
                {
                    ContentDisposition = $"attachment; filename=\"{fileId}\""
                };
                await blobClient.SetHttpHeadersAsync(headers);

                var length = blobProperties.Value.ContentLength;
                if (length < expectedFileSize - leeway || length > expectedFileSize + leeway)
                {
                    return (false, length);
                }

                return (true, length);
            }
            catch (Exception ex)
            {
                return (false, null);
            }
        }

        private async Task InitAsync()
        {
            if (_sendFilesContainerClient == null)
            {
                _sendFilesContainerClient = _blobServiceClient.GetBlobContainerClient(FilesContainerName);
                await _sendFilesContainerClient.CreateIfNotExistsAsync(PublicAccessType.None, null, null);
            }
        }
    }
}