using Amazon.S3;
using Amazon.S3.Model;
using Pldpro.Web.Services.Models;

namespace Pldpro.Web.Services;

public sealed class S3StorageService(IAmazonS3 s3) : IStorageService
{
    private readonly IAmazonS3 _s3 = s3;

    public async Task<IEnumerable<BucketItem>> ListBucketsAsync(CancellationToken ct = default)
    {
        var resp = await _s3.ListBucketsAsync(ct);
        return resp.Buckets.Select(b => new BucketItem(b.BucketName, b.CreationDate));
    }

    public async Task CreateBucketAsync(string bucketName, CancellationToken ct = default)
    {
        // Für S3-kompatible Endpoints reicht häufig nur der Name
        var req = new PutBucketRequest { BucketName = bucketName };
        await _s3.PutBucketAsync(req, ct);
    }

    public async Task<IEnumerable<ObjectItem>> ListObjectsAsync(string bucket, CancellationToken ct = default)
    {
        var items = new List<ObjectItem>();
        string? token = null;
        do
        {
            var resp = await _s3.ListObjectsV2Async(new ListObjectsV2Request
            {
                BucketName = bucket,
                ContinuationToken = token
            }, ct);
            if (resp.S3Objects != null)
            {
                items.AddRange(resp.S3Objects.Select(o => new ObjectItem(o.Key, o.Size, o.LastModified)));
                token = (bool)resp.IsTruncated ? resp.NextContinuationToken : null;
            }
        } while (token is not null);

        return items;
    }

    public async Task UploadObjectAsync(string bucket, string key, Stream content, string contentType, CancellationToken ct = default)
    {
        var req = new PutObjectRequest
        {
            BucketName = bucket,
            Key = key,
            InputStream = content,
            ContentType = contentType
        };
        await _s3.PutObjectAsync(req, ct);
    }


    public async Task<(Stream Stream, string ContentType, long? ContentLength)> GetObjectAsync(
        string bucket, string key, CancellationToken ct = default)
    {
        var resp = await _s3.GetObjectAsync(new GetObjectRequest
        {
            BucketName = bucket,
            Key = key
        }, ct);

        // ResponseStream NICHT kopieren, sondern direkt zurückgeben (Server streamt es weiter)
        var contentType = string.IsNullOrWhiteSpace(resp.Headers.ContentType)
            ? "application/octet-stream"
            : resp.Headers.ContentType;

        long? len = resp.Headers.ContentLength >= 0 ? resp.Headers.ContentLength : null;
        return (resp.ResponseStream, contentType, len);
    }


    public async Task DeleteObjectAsync(string bucket, string key)
    {
        // S3-Delete ist idempotent: 204 auch wenn das Objekt nicht existiert.
        await _s3.DeleteObjectAsync(new Amazon.S3.Model.DeleteObjectRequest
        {
            BucketName = bucket,
            Key = key
        });
    }

}