clarity-helper/api/ChatFunction.cs

using System.Net;
using System.Text.Json;
using Microsoft.Azure.Functions.Worker;
using Microsoft.Azure.Functions.Worker.Http;
using Microsoft.Extensions.Logging;
using Google.GenAI;
using System.Text.Json.Serialization;

namespace CognitiveClarity.api
{
    public class ChatMessage
    {
        [JsonPropertyName("role")]
        public string Role { get; set; } = string.Empty; // "user" or "model"

        [JsonPropertyName("text")]
        public string Text { get; set; } = string.Empty;
    }

    public class ChatRequest
    {
        [JsonPropertyName("history")]
        public List<ChatMessage> History { get; set; } = new();

        [JsonPropertyName("systemInstruction")]
        public string SystemInstruction { get; set; } = string.Empty;
    }

    public class ChatFunction
    {
        private readonly ILogger _logger;

        public ChatFunction(ILoggerFactory loggerFactory)
        {
            _logger = loggerFactory.CreateLogger<ChatFunction>();
        }

        [Function("ChatProgression")]
        public async Task<HttpResponseData> Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = "chat")] HttpRequestData req)
        {
            _logger.LogInformation("C# HTTP trigger function processed a chat progression request.");

            var requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            var data = JsonSerializer.Deserialize<ChatRequest>(requestBody);

            if (data == null || data.History.Count == 0)
            {
                var badResponse = req.CreateResponse(HttpStatusCode.BadRequest);
                await badResponse.WriteStringAsync("Please provide chat history in the request body");
                return badResponse;
            }

            var apiKey = Environment.GetEnvironmentVariable("GEMINI_API_KEY");
            if (string.IsNullOrEmpty(apiKey))
            {
                _logger.LogError("GEMINI_API_KEY is missing from environment variables.");
                return req.CreateResponse(HttpStatusCode.InternalServerError);
            }

            // Initialize the Gemini Client
            var ai = new GeminiClient(apiKey: apiKey);

            // Construct contents from history
            var contents = new List<Content>();
            foreach (var msg in data.History)
            {
                contents.Add(new Content
                {
                    Role = msg.Role,
                    Parts = new List<Part> { new Part { Text = msg.Text } }
                });
            }

            var roleplaySystemInstruction = $@"{data.SystemInstruction}
      
      [CONTEXT]
      You are participating in a clinical CBT roleplay simulation. 
      The instructions above define your character, the scenario, and your internal CBT logic.
      
      [TASK]
      Respond to the user naturally in character to advance the roleplay scenario.
      
      [CONSTRAINTS]
      - CRITICAL: Stay strictly in character as the persona defined in the scenario.
      - CRITICAL: NEVER provide clinical feedback, advice, or meta-commentary about the user's progress.
      - CRITICAL: NEVER use phrases like ""Great job holding your boundary"" or ""Feedback:"".
      - CRITICAL: Do not congratulate the user on using CBT techniques; simply react as the character would.
      - If the user successfully concludes the scenario, end the dialogue naturally.
      
      [OUTPUT REQUIREMENTS]
      Return the character's direct dialogue response. Keep it conversational and proportional to the user's input.
            ";

            try 
            {
                var response = await ai.Models.GenerateContentAsync(
                    model: "gemini-3.0-flash", 
                    contents: contents,
                    new GenerateContentConfig 
                    {
                        SystemInstruction = new Content { Parts = new List<Part> { new Part { Text = roleplaySystemInstruction } } },
                        // Streaming isn't natively supported in standard HTTP Functions easily without Server-Sent Events (SSE).
                        // We will return a standard block response for now, which simplifies the architecture.
                    });

                var successResponse = req.CreateResponse(HttpStatusCode.OK);
                successResponse.Headers.Add("Content-Type", "application/json");
                
                // Return just the text in a JSON wrapper
                var resultObj = new { text = response.Text };
                await successResponse.WriteStringAsync(JsonSerializer.Serialize(resultObj));
                return successResponse;
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Failed to generate chat progression via Gemini API.");
                var errorResponse = req.CreateResponse(HttpStatusCode.InternalServerError);
                await errorResponse.WriteStringAsync("Error communicating with Gemini API.");
                return errorResponse;
            }
        }
    }
}