using System.Text.Json;
using Microsoft.Extensions.Logging;
using StellaOps.Microservice;

namespace Examples.Billing.Microservice.Endpoints;

/// <summary>
/// Endpoint for uploading attachments to an invoice.
/// Demonstrates streaming upload using IRawStellaEndpoint.
/// </summary>
[StellaEndpoint("POST", "/invoices/{id}/attachments", SupportsStreaming = true, TimeoutSeconds = 300)]
public sealed class UploadAttachmentEndpoint : IRawStellaEndpoint
{
    private readonly ILogger<UploadAttachmentEndpoint> _logger;

    public UploadAttachmentEndpoint(ILogger<UploadAttachmentEndpoint> logger)
    {
        _logger = logger;
    }

    public async Task<RawResponse> HandleAsync(
        RawRequestContext context,
        CancellationToken cancellationToken)
    {
        var invoiceId = context.PathParameters.GetValueOrDefault("id") ?? "unknown";

        var contentType = context.Headers["Content-Type"] ?? "application/octet-stream";
        _logger.LogInformation(
            "Uploading attachment for invoice {InvoiceId}, Content-Type: {ContentType}",
            invoiceId,
            contentType);

        // Read the streamed body
        long totalBytes = 0;
        var buffer = new byte[8192];
        int bytesRead;

        while ((bytesRead = await context.Body.ReadAsync(buffer, cancellationToken)) > 0)
        {
            totalBytes += bytesRead;
            // In a real implementation, you would write to storage here
        }

        _logger.LogInformation(
            "Received {TotalBytes} bytes for invoice {InvoiceId}",
            totalBytes,
            invoiceId);

        // Return success response
        var response = new
        {
            invoiceId,
            attachmentId = $"ATT-{Guid.NewGuid():N}"[..16].ToUpperInvariant(),
            size = totalBytes,
            uploadedAt = DateTime.UtcNow
        };

        return RawResponse.Ok(JsonSerializer.Serialize(response));
    }
}