using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Text.Json;
using System.Threading.Tasks;
using Gott.Models;
using Gott.Services;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace Gott.Endpoints;

public static class ChatEndpoint
{
    public static void MapChatEndpoint(this IEndpointRouteBuilder app)
    {
        app.MapPost("/api/chat", HandleChat);
    }

    private static async Task HandleChat(HttpRequest req, HttpResponse res, IHttpClientFactory httpFactory, IConfiguration config, ToolService toolService, DatabaseService db)
    {
        var body = await JsonSerializer.DeserializeAsync<ChatRequest>(req.Body);
        if (body == null || body.Messages == null || body.Messages.Count == 0)
        {
            res.StatusCode = 400;
            await res.WriteAsJsonAsync(new { error = "messages required" });
            return;
        }

        var token = config["AnthropicToken"];
        if (string.IsNullOrEmpty(token))
        {
            res.StatusCode = 500;
            await res.WriteAsJsonAsync(new { error = "AnthropicToken not configured" });
            return;
        }

        var modelId = body.Model switch
        {
            "opus" => "claude-opus-4-6",
            "sonnet" => "claude-sonnet-4-6",
            _ => "claude-sonnet-4-6"
        };

        res.Headers["Content-Type"] = "text/event-stream";
        res.Headers["Cache-Control"] = "no-cache";
        res.Headers["Connection"] = "keep-alive";

        var sessionId = body.SessionId;
        if (string.IsNullOrEmpty(sessionId))
        {
            res.StatusCode = 400;
            await res.WriteAsJsonAsync(new { error = "sessionId required" });
            return;
        }

        var chainId = Guid.NewGuid().ToString("N");

        await db.CreateChain(new ChainRecord
        {
            ChainId = chainId,
            SessionId = sessionId,
            Model = modelId,
            SystemPrompt = body.SystemPrompt
        });

        // Session-Timestamp aktualisieren
        await db.UpdateSessionTimestamp(sessionId);

        var messages = new List<object>();
        foreach (var msg in body.Messages)
            messages.Add(new { role = msg.Role, content = msg.Content });

        // Nur die letzte User-Message speichern (= die neue)
        var lastUserMsg = body.Messages.LastOrDefault(m => m.Role == "user");
        if (lastUserMsg != null)
        {
            await db.SaveMessage(new MessageRecord
            {
                ChainId = chainId,
                Iteration = 0,
                Role = "user",
                Type = "text",
                Content = lastUserMsg.Content
            });
        }

        var systemPrompt = new List<object>
        {
            new { type = "text", text = "You are Claude Code, Anthropic's official CLI for Claude." }
        };
        if (!string.IsNullOrWhiteSpace(body.SystemPrompt))
            systemPrompt.Add(new { type = "text", text = body.SystemPrompt });

        var anthropic = new AnthropicService(httpFactory, token, toolService, db);
        await anthropic.StreamChat(res, modelId, systemPrompt, messages, chainId);
    }
}