using System;
using System.Collections.Generic;
using System.IO;
using System.Text.Json;
using System.Text.Json.Nodes;
using System.Text.Json.Serialization;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.FileProviders;
using Microsoft.Extensions.Hosting;
using AISApp;

namespace AISApp
{
    internal static class ProgramEntry
    {
        // Minimal REST server + static file serving
        private sealed class ChatInput
        {
            [JsonPropertyName("message")] public string? Message { get; set; }
        }

        public static async Task Main(string[] args)
        {
            var builder = WebApplication.CreateBuilder(args);
            var app = builder.Build();

            // Prepare static directory (relative to app base)
            var staticRoot = Path.Combine(builder.Environment.ContentRootPath, "static");

            if (!Directory.Exists(staticRoot)) Directory.CreateDirectory(staticRoot);

            // Serve index.html at "/" and other assets from /static
            var fileProvider = new PhysicalFileProvider(staticRoot);

            var defaultFiles = new DefaultFilesOptions
            {
                FileProvider = fileProvider,
                RequestPath = ""
            };
            defaultFiles.DefaultFileNames.Clear();
            defaultFiles.DefaultFileNames.Add("index.html");
            app.UseDefaultFiles(defaultFiles);

            app.UseStaticFiles(new StaticFileOptions
            {
                FileProvider = fileProvider,
                RequestPath = ""
            });

            // Load system message from prompt.txt
            string systemMessage = System.IO.File.ReadAllText("prompt.txt");

            // Single AIS instance for the app
            var ai = new AIS(model: "gemma", safeMode: false, systemMessage: systemMessage);

            // Minimal chat endpoint
            app.MapPost("/api/chat", async (HttpContext ctx) =>
            {
                try
                {
                    var input = await JsonSerializer.DeserializeAsync<ChatInput>(ctx.Request.Body);
                    var prompt = input?.Message ?? string.Empty;

                    var result = await ai.ChatAsync(prompt);
                    object replyPayload = result is JsonNode jn ? jn : (object)(result?.ToString() ?? "");

                    await ctx.Response.WriteAsJsonAsync(new { ok = true, reply = replyPayload });
                }
                catch (Exception ex)
                {
                    ctx.Response.StatusCode = 400;
                    await ctx.Response.WriteAsJsonAsync(new { ok = false, error = ex.Message });
                }
            });

            await app.RunAsync();
        }
    }
}