using Microsoft.AspNetCore.Cors;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using RadicadeServer.Auth;
using RadicadeServer.DB;
using RadicadeServer.Utils;

namespace RadicadeServer.Admin;

[Route("admin/auth")]
[EnableCors("AdminPanel")]
public class AdminAuthAPI(RecDBContext db) : Controller
{
	private CookieOptions SessionCookieOptions => new()
	{
		HttpOnly = true,
		Secure = true,
		SameSite = SameSiteMode.Strict,
		MaxAge = AdminSession.Lifetime,
		Path = "/"
	};

	public record LoginRequest(string? Username, string? Password);

	[HttpPost("login")]
	public async Task<IActionResult> Login([FromBody] LoginRequest request)
	{
		var username = request.Username?.Trim() ?? "";
		var ip = Request.GetClientIp();

		if (AdminLoginThrottle.IsLocked(username, ip, out var remaining))
			return LockoutResponse(remaining);

		if (string.IsNullOrWhiteSpace(username) || string.IsNullOrWhiteSpace(request.Password))
			return Unauthorized(new { error = "invalid_credentials", message = "Invalid username or password." });

		var user = await db.AdminUsers.FirstOrDefaultAsync(x => x.Username == username);

		if (user == null || !AdminSecurity.VerifyPassword(user.PasswordHash, request.Password))
		{
			await Task.Delay(350);
			AdminLoginThrottle.RecordFailure(username, ip);
			if (AdminLoginThrottle.IsLocked(username, ip, out remaining))
				return LockoutResponse(remaining);
			return Unauthorized(new { error = "invalid_credentials", message = "Invalid username or password." });
		}

		if (AdminSecurity.NeedsRehash(user.PasswordHash))
		{
			user.PasswordHash = AdminSecurity.HashPassword(request.Password);
			await db.SaveChangesAsync();
		}

		AdminLoginThrottle.Clear(username, ip);
		await AdminSession.PruneAsync(db);
		return await CompleteLoginAsync(user);
	}

	private async Task<IActionResult> CompleteLoginAsync(AdminUser user)
	{
		var token = await AdminSession.CreateAsync(db, user.Id);
		user.LastLoginAt = DateTime.UtcNow;
		await db.SaveChangesAsync();

		Response.Cookies.Append(AdminSession.CookieName, token, SessionCookieOptions);
		return Ok(new { ok = true, user = Identity(user) });
	}

	[HttpGet("session")]
	public async Task<IActionResult> Session()
	{
		var user = await RequireSessionAsync();
		if (user == null) return Unauthorized(new { error = "not_authenticated" });

		var (rotated, didRotate) = AdminSession.TryRotate(db, CurrentToken());
		if (didRotate && !string.IsNullOrEmpty(rotated))
			Response.Cookies.Append(AdminSession.CookieName, rotated, SessionCookieOptions);

		return Ok(new { user = Identity(user) });
	}

	[HttpGet("me")]
	public async Task<IActionResult> Me()
	{
		var user = await RequireSessionAsync();
		if (user == null) return Unauthorized(new { error = "not_authenticated" });
		return Ok(new { user = Identity(user) });
	}

	[HttpPost("logout")]
	public async Task<IActionResult> Logout()
	{
		await AdminSession.RevokeAsync(db, CurrentToken());
		Response.Cookies.Delete(AdminSession.CookieName, new CookieOptions { Path = "/" });
		return Ok(new { ok = true });
	}

	private string? CurrentToken() =>
		Request.Cookies.TryGetValue(AdminSession.CookieName, out var token) ? token : null;

	private async Task<AdminUser?> RequireSessionAsync()
	{
		var (ok, userId) = await AdminSession.ValidateAsync(db, CurrentToken());
		if (!ok) return null;

		return await db.AdminUsers.FirstOrDefaultAsync(x => x.Id == userId);
	}

	private static object Identity(AdminUser user) => new
	{
		id = user.Id,
		username = user.Username
	};

	private static string Display(string ip) => string.IsNullOrWhiteSpace(ip) ? "an unknown address" : ip;

	private IActionResult LockoutResponse(TimeSpan remaining)
	{
		var seconds = (int)Math.Ceiling(remaining.TotalSeconds);
		Response.Headers["Retry-After"] = seconds.ToString();

		var message = seconds > 60
			? $"Too many failed sign-in attempts. Try again in {(int)Math.Ceiling(remaining.TotalMinutes)} minutes."
			: $"Too many failed sign-in attempts. Try again in {seconds} seconds.";
		return StatusCode(429, new { error = "locked_out", message, retry_after_seconds = seconds });
	}
}