using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Amazon.S3;
using Amazon.S3.Model;
using Amazon.S3.Transfer;

namespace Sony.Filtr.AppleMusic.Streams
{
    public class AppleMusicStreamingReportApi
    {
        private readonly AmazonS3Client _s3Client;
        private const string _Bucket = "filtr-apple-music-reports";

        public AppleMusicStreamingReportApi(AmazonS3Client s3Client)
        {
            _s3Client = s3Client;
        }

        public async Task<List<string>> GetFilePaths(DateTime date)
        {
            var dateString = date.ToString("yyyyMMdd", CultureInfo.InvariantCulture);
            var streamObjects = await _s3Client.ListObjectsAsync(new ListObjectsRequest()
            {
                BucketName = _Bucket,
                Prefix = $"{dateString}/AppleMusic_Streams_"
            });
            var fileNames = streamObjects.S3Objects.Select(p => p.Key).ToList();
            return fileNames;
        }

        private async Task<List<S3Object>> ListContentFilesAsync(DateTime date)
        {
            var dateString = date.ToString("yyyyMMdd", CultureInfo.InvariantCulture);

            var contentObjects = await _s3Client.ListObjectsAsync(new ListObjectsRequest()
            {
                BucketName = _Bucket,
                Prefix = $"{dateString}/AppleMusic_Content_"
            });
            return contentObjects.S3Objects;
        }

        private async Task<List<string>> DownloadContentFilesAsync(List<S3Object> files, string destinationFolder)
        {
            List<string> filePaths = new List<string>();
            foreach (var contentObject in files)
            {
                var originalFilename = Path.GetFileName(contentObject.Key);
                var destinationPath = Path.Combine(destinationFolder, originalFilename);

                filePaths.Add(destinationPath);
                if (!File.Exists(destinationPath))
                {
                    await DownloadToFileAsync(destinationPath,  contentObject.Key);
                }

            }
            return filePaths;
        }

        public async Task DownloadToFileAsync(string destinationFilepath, string fileKey)
        {
            using (var downloadStream = await DownloadS3FileAsync(_Bucket, fileKey))
            {
                using (var fileStream = File.Open(destinationFilepath, FileMode.OpenOrCreate))
                {
                    await downloadStream.CopyToAsync(fileStream);
                }
            }
        }

        private async Task<Stream> DownloadS3FileAsync(string bucket, string key)
        {
            var transferUtility = new TransferUtility(_s3Client);

            var contentStream = await transferUtility.OpenStreamAsync(new TransferUtilityOpenStreamRequest()
            {
                BucketName = bucket,
                Key = key,

            });
            return contentStream;
        }
    }
}