using System.Collections.Generic;
using System.Linq;
using System.Text.Json;
using System.Threading.Tasks;
using Gott.Services;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;

namespace Gott.Endpoints;

public static class SessionEndpoint
{
    public static void MapSessionEndpoints(this IEndpointRouteBuilder app)
    {
        app.MapGet("/api/sessions", HandleList);
        app.MapGet("/api/sessions/{sessionId}", HandleGet);
        app.MapPost("/api/sessions", HandleCreate);
        app.MapPut("/api/sessions/{sessionId}", HandleUpdate);
        app.MapDelete("/api/sessions/{sessionId}", HandleDelete);
        app.MapGet("/api/sessions/{sessionId}/system-prompt", HandleSystemPrompt);
    }

    private static async Task HandleList(HttpContext ctx, DatabaseService db)
    {
        var sessions = await db.GetSessions();
        await ctx.Response.WriteAsJsonAsync(sessions);
    }

    private static async Task HandleGet(HttpContext ctx, DatabaseService db)
    {
        var sessionId = ctx.Request.RouteValues["sessionId"]?.ToString();
        if (string.IsNullOrEmpty(sessionId))
        {
            ctx.Response.StatusCode = 400;
            return;
        }
        var session = await db.GetSession(sessionId);
        if (session == null)
        {
            ctx.Response.StatusCode = 404;
            return;
        }
        await ctx.Response.WriteAsJsonAsync(session);
    }

    private static async Task HandleCreate(HttpContext ctx, DatabaseService db)
    {
        var body = await JsonSerializer.DeserializeAsync<JsonElement>(ctx.Request.Body);

        var name = body.TryGetProperty("name", out var n) ? n.GetString() : "Neue Session";
        var description = body.TryGetProperty("description", out var d) ? d.GetString() : null;
        var image = body.TryGetProperty("image", out var img) ? img.GetString() : null;
        var agentId = body.TryGetProperty("agentId", out var a) ? a.GetString() : null;
        var workspace = body.TryGetProperty("workspace", out var w) ? w.GetString() : null;
        var context = body.TryGetProperty("context", out var ctxEl) ? ctxEl.GetString() : null;

        var session = await db.CreateSession(name, description, image, agentId, workspace, context);
        await ctx.Response.WriteAsJsonAsync(session);
    }

    private static async Task HandleUpdate(HttpContext ctx, DatabaseService db)
    {
        var sessionId = ctx.Request.RouteValues["sessionId"]?.ToString();
        if (string.IsNullOrEmpty(sessionId))
        {
            ctx.Response.StatusCode = 400;
            return;
        }

        var body = await JsonSerializer.DeserializeAsync<JsonElement>(ctx.Request.Body);
        await db.UpdateSession(sessionId, body);

        var session = await db.GetSession(sessionId);
        await ctx.Response.WriteAsJsonAsync(session);
    }

    private static async Task HandleDelete(HttpContext ctx, DatabaseService db)
    {
        var sessionId = ctx.Request.RouteValues["sessionId"]?.ToString();
        if (string.IsNullOrEmpty(sessionId)) { ctx.Response.StatusCode = 400; return; }

        await db.DeleteSession(sessionId);
        ctx.Response.StatusCode = 204;
    }

    private static async Task HandleSystemPrompt(HttpContext ctx, DatabaseService db)
    {
        var sessionId = ctx.Request.RouteValues["sessionId"]?.ToString();
        if (string.IsNullOrEmpty(sessionId))
        {
            ctx.Response.StatusCode = 400;
            return;
        }

        var session = await db.GetSession(sessionId);
        if (session == null)
        {
            ctx.Response.StatusCode = 404;
            return;
        }

        if (string.IsNullOrEmpty(session.AgentId))
        {
            ctx.Response.StatusCode = 400;
            await ctx.Response.WriteAsJsonAsync(new { error = "Kein Agent ausgewählt" });
            return;
        }

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

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

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

        ctx.Response.ContentType = "text/plain; charset=utf-8";
        await ctx.Response.WriteAsync(systemPrompt);
    }
}