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

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

        [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;

        [JsonPropertyName("model")]
        public string Model { get; set; } = "google/gemini-3.8-flash";
    }

    public class ChatFunction
    {
        private readonly ILogger _logger;
        private readonly IHttpClientFactory _httpClientFactory;

        public ChatFunction(ILoggerFactory loggerFactory, IHttpClientFactory httpClientFactory)
        {
            _logger = loggerFactory.CreateLogger<ChatFunction>();
            _httpClientFactory = httpClientFactory;
        }

        [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 via OpenRouter.");

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

            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.";

            var messages = new List<object>
            {
                new { role = "system", content = roleplaySystemInstruction }
            };

            foreach (var msg in data.History)
            {
                messages.Add(new
                {
                    role = msg.Role == "model" ? "assistant" : msg.Role,
                    content = msg.Text
                });
            }

            var payload = new
            {
                model = string.IsNullOrEmpty(data.Model) ? "google/gemini-3.8-flash" : data.Model,
                messages = messages,
                temperature = 0.7,
                max_tokens = 1000
            };

            try
            {
                var client = _httpClientFactory.CreateClient();
                client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", apiKey);
                client.DefaultRequestHeaders.Add("HTTP-Referer", "https://cognitive-clarity.app");
                client.DefaultRequestHeaders.Add("X-Title", "Cognitive Clarity");

                var content = new StringContent(JsonSerializer.Serialize(payload), Encoding.UTF8, "application/json");
                var response = await client.PostAsync("https://openrouter.ai/api/v1/chat/completions", content);

                if (!response.IsSuccessStatusCode)
                {
                    var errText = await response.Content.ReadAsStringAsync();
                    _logger.LogError("OpenRouter returned error {Status}: {Error}", response.StatusCode, errText);
                    var errResponse = req.CreateResponse(response.StatusCode);
                    await errResponse.WriteStringAsync(errText);
                    return errResponse;
                }

                var resJson = await response.Content.ReadAsStringAsync();
                using var doc = JsonDocument.Parse(resJson);
                var botText = doc.RootElement
                    .GetProperty("choices")[0]
                    .GetProperty("message")
                    .GetProperty("content")
                    .GetString() ?? string.Empty;

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