created initial service for local ai

Lingarr.Server/Models/Api/LocalAiResponse.cs

@@ -0,0 +1,57 @@
+using System.Text.Json.Serialization;
+
+namespace Lingarr.Server.Models.Api;
+
+public class LocalAiResponse
+{
+    [JsonPropertyName("created")]
+    public long Created { get; set; }
+
+    [JsonPropertyName("object")]
+    public string Object { get; set; }
+
+    [JsonPropertyName("id")]
+    public string Id { get; set; }
+
+    [JsonPropertyName("model")]
+    public string Model { get; set; }
+
+    [JsonPropertyName("choices")]
+    public List<Choice> Choices { get; set; }
+
+    [JsonPropertyName("usage")]
+    public Usage Usage { get; set; }
+}
+
+public class Choice
+{
+    [JsonPropertyName("index")]
+    public int Index { get; set; }
+
+    [JsonPropertyName("finish_reason")]
+    public string FinishReason { get; set; }
+
+    [JsonPropertyName("message")]
+    public Message Message { get; set; }
+}
+
+public class Message
+{
+    [JsonPropertyName("role")]
+    public string Role { get; set; }
+
+    [JsonPropertyName("content")]
+    public string Content { get; set; }
+}
+
+public class Usage
+{
+    [JsonPropertyName("prompt_tokens")]
+    public int PromptTokens { get; set; }
+
+    [JsonPropertyName("completion_tokens")]
+    public int CompletionTokens { get; set; }
+
+    [JsonPropertyName("total_tokens")]
+    public int TotalTokens { get; set; }
+}

Lingarr.Server/Services/Translation/LocalAiTranslationService.cs

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+using System.Text;
+using System.Text.Json;
+using Lingarr.Server.Exceptions;
+using Lingarr.Server.Interfaces.Services;
+using Lingarr.Server.Models.Api;
+
+namespace Lingarr.Server.Services.Translation;
+
+public class LocalAiTranslationService : TranslationServiceBase
+{
+    private readonly HttpClient _httpClient;
+
+    public LocalAiTranslationService(ISettingService settings,
+        HttpClient httpClient,
+        ILogger<LocalAiTranslationService> logger) : base(settings, logger)
+    {
+        _httpClient = httpClient;
+    }
+
+    /// <inheritdoc />
+    public override async Task<string> TranslateAsync(string text, string sourceLanguage, string targetLanguage)
+    {
+        var settings = await _settings.GetSettings(["local_ai_model", "local_ai_endpoint"]);
+        if (string.IsNullOrEmpty(settings["local_ai_model"]) || string.IsNullOrEmpty(settings["local_ai_endpoint"]))
+        {
+            throw new InvalidOperationException("Local AI API key or model is not configured.");
+        }
+        var prompt = $"Translate the following text from {sourceLanguage} to {targetLanguage}. Only provide the translation, without any additional comments or explanations: {text}";
+
+        _httpClient.DefaultRequestHeaders.Add("Accept", "application/json");
+        var content = new StringContent(JsonSerializer.Serialize(new
+        {
+            model = settings["local_ai_model"],
+            messages = new[]
+            {
+                new { role = "user", content = prompt }
+            }
+        }), Encoding.UTF8, "application/json");
+
+        var response = await _httpClient.PostAsync(settings["local_ai_endpoint"], content);
+        if (!response.IsSuccessStatusCode)
+        {
+            _logger.LogError("Response Status Code: {StatusCode}", response.StatusCode);
+            _logger.LogError("Response Content: {ResponseContent}", await response.Content.ReadAsStringAsync());
+            throw new TranslationException("Translation using Local AI failed.");
+        }
+
+        var responseBody = await response.Content.ReadAsStringAsync();
+        var jsonResponse = JsonSerializer.Deserialize<LocalAiResponse>(responseBody);
+        return jsonResponse.Choices[0].Message.Content ?? throw new InvalidOperationException();
+    }
+}