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

namespace Bit.Core.Services
{
    public class LocalAttachmentStorageService : IAttachmentStorageService
    {
        private readonly string _baseAttachmentUrl;
        private readonly string _baseDirPath;
        private readonly string _baseTempDirPath;

        public FileUploadType FileUploadType => FileUploadType.Direct;

        public LocalAttachmentStorageService(
            IGlobalSettings globalSettings)
        {
            _baseDirPath = globalSettings.Attachment.BaseDirectory;
            _baseTempDirPath = $"{_baseDirPath}/temp";
            _baseAttachmentUrl = globalSettings.Attachment.BaseUrl;
        }

        public async Task<string> GetAttachmentDownloadUrlAsync(Cipher cipher, CipherAttachment.MetaData attachmentData)
        {
            await InitAsync();
            return $"{_baseAttachmentUrl}/{cipher.Id}/{attachmentData.AttachmentId}";
        }

        public async Task UploadNewAttachmentAsync(Stream stream, Cipher cipher, CipherAttachment.MetaData attachmentData)
        {
            await InitAsync();
            var cipherDirPath = CipherDirectoryPath(cipher.Id, temp: false);
            CreateDirectoryIfNotExists(cipherDirPath);

            using (var fs = File.Create(AttachmentFilePath(cipherDirPath, attachmentData.AttachmentId)))
            {
                stream.Seek(0, SeekOrigin.Begin);
                await stream.CopyToAsync(fs);
            }
        }

        public async Task UploadShareAttachmentAsync(Stream stream, Guid cipherId, Guid organizationId, CipherAttachment.MetaData attachmentData)
        {
            await InitAsync();
            var tempCipherOrgDirPath = OrganizationDirectoryPath(cipherId, organizationId, temp: true);
            CreateDirectoryIfNotExists(tempCipherOrgDirPath);

            using (var fs = File.Create(AttachmentFilePath(tempCipherOrgDirPath, attachmentData.AttachmentId)))
            {
                stream.Seek(0, SeekOrigin.Begin);
                await stream.CopyToAsync(fs);
            }
        }

        public async Task StartShareAttachmentAsync(Guid cipherId, Guid organizationId, CipherAttachment.MetaData attachmentData)
        {
            await InitAsync();
            var sourceFilePath = AttachmentFilePath(attachmentData.AttachmentId, cipherId, organizationId, temp: true);
            if (!File.Exists(sourceFilePath))
            {
                return;
            }

            var destFilePath = AttachmentFilePath(attachmentData.AttachmentId, cipherId, temp: false);
            if (!File.Exists(destFilePath))
            {
                return;
            }

            var originalFilePath = AttachmentFilePath(attachmentData.AttachmentId, cipherId, temp: true);
            DeleteFileIfExists(originalFilePath);

            File.Move(destFilePath, originalFilePath);
            DeleteFileIfExists(destFilePath);

            File.Move(sourceFilePath, destFilePath);
        }

        public async Task RollbackShareAttachmentAsync(Guid cipherId, Guid organizationId, CipherAttachment.MetaData attachmentData, string originalContainer)
        {
            await InitAsync();
            DeleteFileIfExists(AttachmentFilePath(attachmentData.AttachmentId, cipherId, organizationId, temp: true));

            var originalFilePath = AttachmentFilePath(attachmentData.AttachmentId, cipherId, temp: true);
            if (!File.Exists(originalFilePath))
            {
                return;
            }

            var destFilePath = AttachmentFilePath(attachmentData.AttachmentId, cipherId, temp: false);
            DeleteFileIfExists(destFilePath);

            File.Move(originalFilePath, destFilePath);
            DeleteFileIfExists(originalFilePath);
        }

        public async Task DeleteAttachmentAsync(Guid cipherId, CipherAttachment.MetaData attachmentData)
        {
            await InitAsync();
            DeleteFileIfExists(AttachmentFilePath(attachmentData.AttachmentId, cipherId, temp: false));
        }

        public async Task CleanupAsync(Guid cipherId)
        {
            await InitAsync();
            DeleteDirectoryIfExists(CipherDirectoryPath(cipherId, temp: true));
        }

        public async Task DeleteAttachmentsForCipherAsync(Guid cipherId)
        {
            await InitAsync();
            DeleteDirectoryIfExists(CipherDirectoryPath(cipherId, temp: false));
        }

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

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

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

        private void DeleteDirectoryIfExists(string path)
        {
            if (Directory.Exists(path))
            {
                Directory.Delete(path, true);
            }
        }

        private void CreateDirectoryIfNotExists(string path)
        {
            if (!Directory.Exists(path))
            {
                Directory.CreateDirectory(path);
            }
        }

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

            if (!Directory.Exists(_baseTempDirPath))
            {
                Directory.CreateDirectory(_baseTempDirPath);
            }

            return Task.FromResult(0);
        }

        private string CipherDirectoryPath(Guid cipherId, bool temp = false) =>
            Path.Combine(temp ? _baseTempDirPath : _baseDirPath, cipherId.ToString());
        private string OrganizationDirectoryPath(Guid cipherId, Guid organizationId, bool temp = false) =>
            Path.Combine(temp ? _baseTempDirPath : _baseDirPath, cipherId.ToString(), organizationId.ToString());

        private string AttachmentFilePath(string dir, string attachmentId) => Path.Combine(dir, attachmentId);
        private string AttachmentFilePath(string attachmentId, Guid cipherId, Guid? organizationId = null,
            bool temp = false) =>
            organizationId.HasValue ?
            AttachmentFilePath(OrganizationDirectoryPath(cipherId, organizationId.Value, temp), attachmentId) :
            AttachmentFilePath(CipherDirectoryPath(cipherId, temp), attachmentId);
        public Task<string> GetAttachmentUploadUrlAsync(Cipher cipher, CipherAttachment.MetaData attachmentData)
            => Task.FromResult($"{cipher.Id}/attachment/{attachmentData.AttachmentId}");

        public Task<(bool, long?)> ValidateFileAsync(Cipher cipher, CipherAttachment.MetaData attachmentData, long leeway)
        {
            long? length = null;
            var path = AttachmentFilePath(attachmentData.AttachmentId, cipher.Id, temp: false);
            if (!File.Exists(path))
            {
                return Task.FromResult((false, length));
            }

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

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