using System.Net.WebSockets;
using HSchool.Server.Api;
using HSchool.Server.Game;
using HSchool.Server.Net;
using HSchool.Simulation;
using Microsoft.Extensions.Configuration;

var builder = WebApplication.CreateBuilder(args);

builder.AddServiceDefaults();
builder.Services.AddProblemDetails();
builder.Services.AddOpenApi();

builder.Services
    .AddOptions<SimulationOptions>()
    .Bind(builder.Configuration.GetSection(SimulationOptions.SectionName))
    .Validate(options => options.TickRate is > 0 and <= 120, "Simulation:TickRate must be between 1 and 120.")
    .Validate(options => options.MaxSchools is > 0 and <= 255, "Simulation:MaxSchools must be between 1 and 255.")
    .Validate(options => options.GameMinutesPerRealSecond > 0, "Simulation:GameMinutesPerRealSecond must be positive.")
    .Validate(options => GameClock.IsValidStartDate(options.DefaultStartDate), "Simulation:DefaultStartDate is out of range.")
    .Validate(options => !string.IsNullOrWhiteSpace(options.SavesDirectory), "Simulation:SavesDirectory must be set.")
    .Validate(options => !string.IsNullOrWhiteSpace(options.ModsDirectory), "Simulation:ModsDirectory must be set.")
    .Validate(options => options.SaveIntervalSeconds is > 0 and <= 3600, "Simulation:SaveIntervalSeconds must be between 1 and 3600.")
    .Validate(options => options.MonthlyPayrollCap > 0, "Simulation:MonthlyPayrollCap must be positive.")
    .Validate(options => options.SchoolWeekDays is >= 5 and <= 7, "Simulation:SchoolWeekDays must be between 5 and 7.")
    .Validate(options => options.MaxDecisionsPerTick is > 0 and <= 10_000, "Simulation:MaxDecisionsPerTick must be between 1 and 10000.")
    .ValidateOnStart();

builder.Services.AddSingleton<GameCommandQueue>();
builder.Services.AddSingleton<ClientRegistry>();
builder.Services.AddSingleton<GameMetrics>();
builder.Services.AddSingleton<SchoolStore>();
builder.Services.AddSingleton<ModContent>();
builder.Services.AddSingleton<GameSocketHandler>();
builder.Services.AddSingleton<GameLoopService>();
builder.Services.AddHostedService(sp => sp.GetRequiredService<GameLoopService>());

builder.Services.AddOpenTelemetry().WithMetrics(metrics => metrics.AddMeter(GameMetrics.MeterName));

var app = builder.Build();

app.UseExceptionHandler();

if (app.Environment.IsDevelopment())
{
    app.MapOpenApi();
}

app.UseWebSockets(new WebSocketOptions
{
    KeepAliveInterval = TimeSpan.FromSeconds(30),
});

app.MapSchoolEndpoints();
app.MapTimetableEndpoints();
app.MapModEndpoints();

app.MapGet("/api/status", (GameLoopService loop, ClientRegistry clients) =>
{
    var state = loop.SchoolsState;
    return new GameStatusResponse(loop.CurrentTick, loop.Options.TickRate, state.Schools.Count, state.MaxSchools, clients.Count);
})
.WithName("GetGameStatus");

if (app.Configuration.GetValue("HSchool:AllowSaveReload", false))
{
    app.MapPost("/api/dev/reload-schools", async (GameLoopService loop, CancellationToken cancellationToken) =>
    {
        await loop.ReloadFromDiskAsync(cancellationToken);
        return Results.NoContent();
    })
    .WithName("ReloadSchoolsFromDisk");

    app.MapGet("/api/dev/saves-directory", (SchoolStore store) => Results.Json(new { path = store.DirectoryPath }))
        .WithName("GetSavesDirectory");

    app.MapGet("/api/dev/mods-directory", (ModContent mods) => Results.Json(new { path = mods.Root }))
        .WithName("GetModsDirectory");

    app.MapDevEndpoints();
}

// The realtime channel: one binary frame per protocol message, see docs/protocol.md.
app.Map("/ws/game", async (HttpContext context, GameSocketHandler handler) =>
{
    if (!context.WebSockets.IsWebSocketRequest)
    {
        context.Response.StatusCode = StatusCodes.Status400BadRequest;
        await context.Response.WriteAsync("This endpoint expects a WebSocket upgrade.");
        return;
    }

    using WebSocket socket = await context.WebSockets.AcceptWebSocketAsync();
    await handler.HandleAsync(socket, context.RequestAborted);
});

app.MapDefaultEndpoints();

// In a published container the built client lands in wwwroot next to the server.
app.UseFileServer();

app.Run();

/// <summary>Loop health for dashboards and integration tests.</summary>
internal sealed record GameStatusResponse(uint Tick, int TickRate, int Schools, int MaxSchools, int Connections);

/// <summary>Exposed so <c>WebApplicationFactory</c>-style tests can reference the entry point.</summary>
public partial class Program;