SA-29 created openai service

ShoppingAssistantApi.Application/IServices/Identity/IOpenAiService.cs

@@ -0,0 +1,10 @@
+using ShoppingAssistantApi.Application.Models.OpenAi;
+
+namespace ShoppingAssistantApi.Application.IServices;
+
+public interface IOpenAiService
+{
+    Task<OpenAiResponse?> GetChatCompletion(ChatCompletionRequest chat, CancellationToken cancellationToken);
+
+    IAsyncEnumerable<OpenAiResponse> GetChatCompletionStream(ChatCompletionRequest chat, CancellationToken cancellationToken);
+}

ShoppingAssistantApi.Application/Models/OpenAi/OpenAiChoice.cs

@@ -0,0 +1,12 @@
+namespace ShoppingAssistantApi.Application.Models.OpenAi;
+
+public class OpenAiChoice
+{
+    public OpenAiMessage Message { get; set; }
+    
+    public OpenAiDelta Delta { get; set; }
+
+    public string FinishReason { get; set; }
+    
+    public int Index { get; set; }
+}

ShoppingAssistantApi.Application/Models/OpenAi/OpenAiDelta.cs

@@ -0,0 +1,8 @@
+namespace ShoppingAssistantApi.Application.Models.OpenAi;
+
+public class OpenAiDelta
+{
+    public string Role { get; set; }
+
+    public string Content { get; set; }
+}

ShoppingAssistantApi.Application/Models/OpenAi/OpenAiResponse.cs

@@ -0,0 +1,16 @@
+namespace ShoppingAssistantApi.Application.Models.OpenAi;
+
+public class OpenAiResponse
+{
+    public string Id { get; set; }
+
+    public string Object { get; set; }
+
+    public int Created { get; set; }
+
+    public string Model { get; set; }
+
+    public OpenAiUsage Usage { get; set; }
+
+    public List<OpenAiChoice> Choices { get; set; }
+}

ShoppingAssistantApi.Application/Models/OpenAi/OpenAiUsage.cs

@@ -0,0 +1,10 @@
+namespace ShoppingAssistantApi.Application.Models.OpenAi;
+
+public class OpenAiUsage
+{
+    public int PromptTokens { get; set; }
+
+    public int CompletionTokens { get; set; }
+
+    public int TotalTokens { get; set; }
+}

ShoppingAssistantApi.Infrastructure/Services/Identity/OpenAiService.cs

@@ -0,0 +1,101 @@
+using System;
+using System.Net.Http.Headers;
+using System.Text;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Serialization;
+using ShoppingAssistantApi.Application.IServices;
+using ShoppingAssistantApi.Application.Models.OpenAi;
+
+namespace ShoppingAssistantApi.Infrastructure.Services;
+
+public class OpenaiService : IOpenAiService
+{
+    private readonly HttpClient _httpClient;
+
+    private readonly JsonSerializerSettings _jsonSettings = new JsonSerializerSettings
+    {
+        ContractResolver = new DefaultContractResolver
+        {
+            NamingStrategy = new SnakeCaseNamingStrategy()
+        },
+        NullValueHandling = NullValueHandling.Ignore,
+    };
+
+    private readonly IConfiguration _configuration;
+
+    //private readonly OpenAIClient _openAiClient;
+
+    private readonly ILogger _logger;
+
+    public OpenaiService(
+        IConfiguration configuration,
+        IHttpClientFactory httpClientFactory,
+        ILogger<OpenaiService> logger
+    )
+    {
+        _httpClient = httpClientFactory.CreateClient("OpenAiHttpClient");
+        _configuration = configuration;
+
+        //var openAIApiKey = _configuration.GetSection("OpenAi")?.GetValue<string>("ApiKey");
+        //_openAiClient = new OpenAIClient(openAIApiKey, new OpenAIClientOptions());
+
+        _logger = logger;
+    }
+
+    public async IAsyncEnumerable<OpenAiResponse> GetChatCompletionStream(ChatCompletionRequest chat, CancellationToken cancellationToken)
+    {
+        chat.Stream = true;
+        var jsonBody = JsonConvert.SerializeObject(chat, _jsonSettings);
+        _logger.LogInformation(jsonBody);
+        var body = new StringContent(jsonBody, Encoding.UTF8, "application/json");
+        var request = new HttpRequestMessage(HttpMethod.Post, "chat/completions")
+        {
+            Content = body
+        };
+        request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("text/event-stream"));
+
+        using var httpResponse = await _httpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, cancellationToken);
+
+        var allData = string.Empty;
+
+        using var streamReader = new StreamReader(await httpResponse.Content.ReadAsStringAsync(cancellationToken));
+        while(!streamReader.EndOfStream)
+        {
+            var line = await streamReader.ReadLineAsync();
+            allData += line + "\n\n";
+            if (string.IsNullOrEmpty(line)) continue;
+
+            var json = line?.Substring(6, line.Length - 6);
+            if (json == "[DONE]") yield break;
+
+            var OpenAiResponse = JsonConvert.DeserializeObject<OpenAiResponse>(json, _jsonSettings);
+            yield return OpenAiResponse;
+        }
+    }
+
+    public async Task<OpenAiResponse?> GetChatCompletion(ChatCompletionRequest chat, CancellationToken cancellationToken)
+    {
+        chat.Stream = false; 
+        var jsonBody = JsonConvert.SerializeObject(chat, _jsonSettings);
+        var body = new StringContent(jsonBody, Encoding.UTF8, "application/json");
+
+        _logger.LogInformation(jsonBody);
+        using var httpResponse = await _httpClient.PostAsync("chat/completions", body, cancellationToken);
+
+        var responseBody = await httpResponse.Content.ReadAsStringAsync(cancellationToken);
+
+        var responses = new List<OpenAiResponse>();
+        foreach (var line in responseBody.Split(new[] {"\n\n"}, StringSplitOptions.RemoveEmptyEntries))
+        {
+            if (line.Trim() == "[DONE]") break;
+
+            var json = line.Substring(6);
+            var OpenAiResponse = JsonConvert.DeserializeObject<OpenAiResponse>(json, _jsonSettings);
+            responses.Add(OpenAiResponse);
+        }
+
+        return responses.Count > 0 ? responses.Last() : null;
+    }
+}

ShoppingAssistantApi.Infrastructure/ShoppingAssistantApi.Infrastructure.csproj

@@ -11,6 +11,7 @@
     <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="7.0.0" />
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="7.0.1" />
     <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="6.32.0" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
     <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="6.32.0" />
   </ItemGroup>