Toak/Api/OpenAiCompatibleClient.cs

using System.Net.Http.Headers;
using System.Text.Json;
using Toak.Api.Models;
using Toak.Serialization;
using Toak.Core;
using Toak.Core.Interfaces;

namespace Toak.Api;

public class OpenAiCompatibleClient : ISpeechClient, ILlmClient
{
    private readonly HttpClient _httpClient;
    private readonly string? _reasoningEffort;

    public OpenAiCompatibleClient(string apiKey, string baseUrl = "https://api.groq.com/openai/v1/", string? reasoningEffort = null)
    {
        _httpClient = new HttpClient();
        _httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", apiKey);
        _httpClient.BaseAddress = new Uri(baseUrl);
        _reasoningEffort = reasoningEffort == "none" ? null : reasoningEffort;
    }

    public async Task<string> TranscribeAsync(string filePath, string language = "", string model = Constants.Defaults.WhisperModel)
    {
        // ... (TranscribeAsync content remains same except maybe some internal comments or contexts)
        using var content = new MultipartFormDataContent();
        await using var fileStream = File.OpenRead(filePath);
        using var streamContent = new StreamContent(fileStream);

        streamContent.Headers.ContentType = new MediaTypeHeaderValue("audio/wav"); // or mpeg
        content.Add(streamContent, "file", Path.GetFileName(filePath));

        var modelToUse = string.IsNullOrWhiteSpace(model) ? Constants.Defaults.WhisperModel : model;

        content.Add(new StringContent(modelToUse), "model");

        if (!string.IsNullOrWhiteSpace(language))
        {
            var firstLang = language.Split(',')[0].Trim();
            content.Add(new StringContent(firstLang), "language");
        }

        Logger.LogDebug($"Sending Whisper API request ({modelToUse})...");
        var response = await _httpClient.PostAsync("audio/transcriptions", content);
        Logger.LogDebug($"Whisper API response status: {response.StatusCode}");

        if (!response.IsSuccessStatusCode)
        {
            var error = await response.Content.ReadAsStringAsync();
            throw new Exception($"Whisper API Error: {response.StatusCode} - {error}");
        }

        var json = await response.Content.ReadAsStringAsync();
        var result = JsonSerializer.Deserialize(json, AppJsonSerializerContext.Default.WhisperResponse);
        return result?.Text ?? string.Empty;
    }

    public async Task<string> RefineTextAsync(string rawTranscript, string systemPrompt, string model = Constants.Defaults.LlmModel)
    {
        var requestBody = new OpenAiRequest
        {
            Model = string.IsNullOrWhiteSpace(model) ? Constants.Defaults.LlmModel : model,
            Temperature = 0.0,
            ReasoningEffort = _reasoningEffort,
            Messages =
            [
                new OpenAiRequestMessage { Role = "system", Content = systemPrompt },
                new OpenAiRequestMessage { Role = "user", Content = $"<transcript>{rawTranscript}</transcript>" }
            ]
        };

        var jsonContent = new StringContent(JsonSerializer.Serialize(requestBody, AppJsonSerializerContext.Default.OpenAiRequest), System.Text.Encoding.UTF8, "application/json");

        Logger.LogDebug($"Sending OpenAi API request (model: {requestBody.Model})...");
        var response = await _httpClient.PostAsync("chat/completions", jsonContent);
        Logger.LogDebug($"OpenAi API response status: {response.StatusCode}");

        if (!response.IsSuccessStatusCode)
        {
            var error = await response.Content.ReadAsStringAsync();
            throw new Exception($"OpenAi API Error: {response.StatusCode} - {error}");
        }

        var json = await response.Content.ReadAsStringAsync();
        var result = JsonSerializer.Deserialize(json, AppJsonSerializerContext.Default.OpenAiResponse);

        return result?.Choices?.FirstOrDefault()?.Message?.Content ?? string.Empty;
    }

    public async IAsyncEnumerable<string> RefineTextStreamAsync(string rawTranscript, string systemPrompt, string model = Constants.Defaults.LlmModel)
    {
        var requestBody = new OpenAiRequest
        {
            Model = string.IsNullOrWhiteSpace(model) ? Constants.Defaults.LlmModel : model,
            Temperature = 0.0,
            Stream = true,
            ReasoningEffort = _reasoningEffort,
            Messages =
            [
                new OpenAiRequestMessage { Role = "system", Content = systemPrompt },
                new OpenAiRequestMessage { Role = "user", Content = $"<transcript>{rawTranscript}</transcript>" }
            ]
        };

        var jsonContent = new StringContent(JsonSerializer.Serialize(requestBody, AppJsonSerializerContext.Default.OpenAiRequest), System.Text.Encoding.UTF8, "application/json");

        using var request = new HttpRequestMessage(HttpMethod.Post, "chat/completions");
        request.Content = jsonContent;
        request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("text/event-stream"));

        Logger.LogDebug($"Sending OpenAi Steam API request (model: {requestBody.Model})...");
        using var response = await _httpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead);
        Logger.LogDebug($"OpenAi Stream API response status: {response.StatusCode}");

        if (!response.IsSuccessStatusCode)
        {
            var error = await response.Content.ReadAsStringAsync();
            throw new Exception($"OpenAi API Error: {response.StatusCode} - {error}");
        }

        await using var stream = await response.Content.ReadAsStreamAsync();
        using var reader = new StreamReader(stream);

        string? line;
        while ((line = await reader.ReadLineAsync()) != null)
        {
            if (string.IsNullOrWhiteSpace(line)) continue;
            if (line.StartsWith("data: "))
            {
                var data = line.Substring("data: ".Length).Trim();
                if (data == "[DONE]") break;

                var chunk = JsonSerializer.Deserialize(data, AppJsonSerializerContext.Default.OpenAiStreamResponse);
                var content = chunk?.Choices?.FirstOrDefault()?.Delta?.Content;
                if (!string.IsNullOrEmpty(content))
                {
                    yield return content;
                }
            }
        }
    }
}