using System.Net;
using Amazon.S3;
using Amazon.S3.Model;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using mws.backend.dotnet.application.Common;
using mws.backend.dotnet.application.Documents;

namespace mws.backend.dotnet.infrastructure.Storage;

public class S3DocumentContentStore(
    IAmazonS3 s3,
    IOptions<MinioOptions> opt,
    ILogger<S3DocumentContentStore> log) : IDocumentContentStore
{
    private string Bucket => opt.Value.Bucket;

    public static string FileNameNow(string name)
    {
        var slug = new string(name.Trim().ToLowerInvariant()
            .Select(c => char.IsLetterOrDigit(c) ? c : '-')
            .ToArray()).Trim('-');
        if (slug.Length == 0)
        {
            slug = "document";
        }
        return $"{slug}_{DateTime.UtcNow:yyyyMMddHHmmss}";
    }

    public async Task<string> UploadAsync(Guid projectId, string fileName, string contentType, Stream body, CancellationToken ct)
    {
        var key = $"{projectId:N}/{FileNameNow(fileName)}.html";
        try
        {
            await s3.PutObjectAsync(new PutObjectRequest
            {
                BucketName = Bucket,
                Key = key,
                InputStream = body,
                ContentType = contentType,
                AutoCloseStream = false,
            }, ct);
            return key;
        }
        catch (AmazonS3Exception ex)
        {
            log.LogError(ex, "MinIO upload failed for {Key}", key);
            throw new StorageUnavailableException("Document upload failed", ex);
        }
    }

    public async Task<Stream> DownloadAsync(string storageKey, CancellationToken ct)
    {
        try
        {
            var response = await s3.GetObjectAsync(Bucket, storageKey, ct);
            return response.ResponseStream;
        }
        catch (AmazonS3Exception ex) when (ex.StatusCode == HttpStatusCode.NotFound)
        {
            return Stream.Null;
        }
        catch (AmazonS3Exception ex)
        {
            log.LogError(ex, "MinIO download failed for {Key}", storageKey);
            throw new StorageUnavailableException("Document download failed", ex);
        }
    }

    public async Task DeleteAsync(string storageKey, CancellationToken ct)
    {
        try
        {
            await s3.DeleteObjectAsync(Bucket, storageKey, ct);
        }
        catch (AmazonS3Exception ex)
        {
            log.LogWarning(ex, "MinIO delete failed for {Key}", storageKey);
        }
    }
}