using System;
using System.Collections.Generic;
using System.IO;
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 sessionId = body.SessionId;
        if (string.IsNullOrEmpty(sessionId))
        {
            res.StatusCode = 400;
            await res.WriteAsJsonAsync(new { error = "sessionId required" });
            return;
        }

        // Agent aus Session auflösen
        var session = await db.GetSession(sessionId);
        if (session == null || string.IsNullOrEmpty(session.AgentId))
        {
            res.StatusCode = 400;
            await res.WriteAsJsonAsync(new { error = "Kein Agent ausgewählt" });
            return;
        }

        var agent = await db.GetAgent(session.AgentId);
        if (agent == null)
        {
            res.StatusCode = 400;
            await res.WriteAsJsonAsync(new { error = "Agent nicht gefunden" });
            return;
        }

        var modelId = agent.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 promptParts = new List<string>();
        promptParts.Add($"Du bist {agent.Name}.");
        if (!string.IsNullOrWhiteSpace(agent.Persona))
            promptParts.Add($"## Persona\n{agent.Persona}");
        if (!string.IsNullOrWhiteSpace(agent.Instructions))
            promptParts.Add($"## Instructions\n{agent.Instructions}");

        if (!string.IsNullOrWhiteSpace(session.Context))
            promptParts.Add($"## Kontext\n{session.Context}");

        var systemPromptText = string.Join("\n\n", promptParts);

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

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

        // 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 = systemPromptText }
        };

        var workspace = session.Workspace;
        if (!string.IsNullOrEmpty(workspace))
            Directory.CreateDirectory(workspace);

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