DeutschLernen/GermanApp/Presentation/Controllers/SpeechController.cs

using GermanApp.Domain.Interfaces;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

namespace GermanApp.Presentation.Controllers;

/// <summary>
/// API controller for speech recognition using Vosk.
/// This is part of the Presentation layer.
/// </summary>
[ApiController]
[Route("api/[controller]")]
[Authorize]
public class SpeechController : ControllerBase
{
    private readonly IVoskService _voskService;

    public SpeechController(IVoskService voskService)
    {
        _voskService = voskService;
    }

    /// <summary>
    /// Recognizes speech from audio bytes.
    /// </summary>
    /// <param name="request">Audio recognition request</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>Recognized text</returns>
    [HttpPost("recognize")]
    [RequestSizeLimit(10_000_000)] // 10MB limit
    [RequestFormLimits(MultipartBodyLengthLimit = 10_000_000)]
    public async Task<IActionResult> RecognizeSpeech(
        [FromForm] SpeechRecognitionRequest request,
        CancellationToken cancellationToken = default)
    {
        if (request?.Audio == null || request.Audio.Length == 0)
            return BadRequest("Audio data is required");

        try
        {
            var result = await _voskService.RecognizeSpeechAsync(
                request.Audio,
                request.SampleRate,
                request.Hint,
                cancellationToken);

            return Ok(new SpeechRecognitionResponse(result));
        }
        catch (TimeoutException ex)
        {
            return StatusCode(504, new { Error = ex.Message });
        }
        catch (Exception ex)
        {
            return StatusCode(500, new { Error = ex.Message });
        }
    }

    /// <summary>
    /// Tests the speech recognition service.
    /// </summary>
    /// <returns>Health check result</returns>
    [HttpGet("health")]
    [AllowAnonymous]
    public async Task<IActionResult> HealthCheck(CancellationToken cancellationToken = default)
    {
        try
        {
            var isHealthy = await _voskService.TestModelAsync(cancellationToken);
            return Ok(new { Healthy = isHealthy });
        }
        catch (Exception ex)
        {
            return StatusCode(500, new { Error = ex.Message });
        }
    }

    /// <summary>
    /// Gets information about the current Vosk model.
    /// </summary>
    /// <returns>Model information</returns>
    [HttpGet("model-info")]
    [AllowAnonymous]
    public async Task<IActionResult> GetModelInfo(CancellationToken cancellationToken = default)
    {
        try
        {
            var (modelName, modelPath) = await _voskService.GetModelInfoAsync();
            return Ok(new { ModelName = modelName, ModelPath = modelPath });
        }
        catch (Exception ex)
        {
            return StatusCode(500, new { Error = ex.Message });
        }
    }
}

/// <summary>
/// Request DTO for speech recognition.
/// </summary>
public record SpeechRecognitionRequest(
    byte[] Audio,
    int SampleRate = 16000,
    string? Hint = null);

/// <summary>
/// Response DTO for speech recognition.
/// </summary>
public record SpeechRecognitionResponse(string Text);