using MongoDB.Entities;

using PrivaPub.ClientModels;
using PrivaPub.ClientModels.User;
using PrivaPub.ClientModels.User.Avatar;
using PrivaPub.Models.User;
using PrivaPub.Services;
using PrivaPub.Services.ClientToServer.Private;
using PrivaPub.StaticServices;

using System.ComponentModel.DataAnnotations;
using System.Security.Cryptography;

namespace PrivaPub.Infrastructure.Cli
{
	// `PrivaPub admin ...` runs with the whole server built but not started: no Kestrel, no hosted services.
	public static class AdminCommands
	{
		public const string SmokeLogin = "deploy-smoke";

		const string Usage = """
			usage: PrivaPub admin promote|demote <root>
			       PrivaPub admin create-root <login> [--admin]   the password is read from standard input
			       PrivaPub admin smoke <persona>                 prints "<login> <password>" for the deploy's signed-in check
			""";

		public static async Task<int> Run(string[] args, IServiceProvider services, TextReader input = default, TextWriter output = default)
		{
			input ??= Console.In;
			output ??= Console.Out;
			switch (args)
			{
				case [("promote" or "demote") and var verb, var userName]:
					return await Promote(verb == "promote", userName, output);
				case ["create-root", var login, .. var flags] when flags.All(f => f == "--admin"):
					return await CreateRoot(services, login, input.ReadLine(), flags.Contains("--admin"), output);
				case ["smoke", var persona]:
					return await Smoke(services, persona, output);
				default:
					Console.Error.WriteLine(Usage);
					return 2;
			}
		}

		static async Task<int> Promote(bool promote, string userName, TextWriter output)
		{
			userName = userName.ToLowerInvariant();
			var user = await DB.Default.Find<RootUser>().Match(u => u.UserName == userName).ExecuteFirstAsync();
			if (user == default)
			{
				Console.Error.WriteLine($"no root user '{userName}'");
				return 1;
			}

			user.Policies.RemoveAll(p => p is Policies.IsAdmin or Policies.IsModerator);
			if (promote)
				user.Policies.AddRange(new[] { Policies.IsAdmin, Policies.IsModerator });
			if (!user.Policies.Contains(Policies.IsUser))
				user.Policies.Add(Policies.IsUser);
			user.UpdatedAt = DateTime.UtcNow;
			await DB.Default.SaveAsync(user);

			output.WriteLine($"{userName}: {string.Join(", ", user.Policies)}");
			return 0;
		}

		// With sign-up closed this is how the first root is made; group invitations make the rest.
		static async Task<int> CreateRoot(IServiceProvider services, string login, string password, bool admin, TextWriter output)
		{
			var form = new LoginForm { UserName = login, Password = password?.Trim() };
			var problems = new List<ValidationResult>();
			if (!Validator.TryValidateObject(form, new ValidationContext(form), problems, validateAllProperties: true))
			{
				Console.Error.WriteLine(string.Join(Environment.NewLine, problems.Select(p => p.ErrorMessage)));
				return 1;
			}
			var created = await services.GetRequiredService<IRootUsersService>().SignUpAsync(form);
			if (!created.IsValid)
			{
				Console.Error.WriteLine(created.ErrorMessage);
				return 1;
			}
			return admin ? await Promote(true, login, output) : await Report(login, output);
		}

		static Task<int> Report(string login, TextWriter output)
		{
			output.WriteLine($"{login.ToLowerInvariant()}: created");
			return Task.FromResult(0);
		}

		// The deploy's signed-in smoke check: a root nobody signs in to by hand, owning one undiscoverable persona. Every run
		// sets a new password and prints it, so no secret is kept anywhere and nothing waits on a person.
		static async Task<int> Smoke(IServiceProvider services, string personaName, TextWriter output)
		{
			personaName = personaName.ToLowerInvariant();
			var password = "Smoke-x" + Convert.ToHexStringLower(RandomNumberGenerator.GetBytes(24));
			var root = await DB.Default.Find<RootUser>().Match(u => u.UserName == SmokeLogin).ExecuteFirstAsync();
			if (root == default)
			{
				var created = await services.GetRequiredService<IRootUsersService>().SignUpAsync(new LoginForm { UserName = SmokeLogin, Password = password });
				if (!created.IsValid)
				{
					Console.Error.WriteLine(created.ErrorMessage);
					return 1;
				}
				root = await DB.Default.Find<RootUser>().Match(u => u.UserName == SmokeLogin).ExecuteFirstAsync();
			}
			else if (root.DeletedAt.HasValue || root.IsBanned)
			{
				Console.Error.WriteLine($"the root '{SmokeLogin}' is deleted or banned");
				return 1;
			}
			else
				await DB.Default.Update<RootUser>().MatchID(root.ID)
					.Modify(u => u.HashedPassword, services.GetRequiredService<IPasswordHasher>().Hash(password))
					.Modify(u => u.UpdatedAt, DateTime.UtcNow)
					.ExecuteAsync();

			var owned = (await DB.Default.Find<RootToAvatar>().Match(ra => ra.RootId == root.ID).ExecuteAsync()).Select(ra => ra.AvatarId).ToList();
			var persona = await DB.Default.Find<Avatar>().Match(a => owned.Contains(a.ID) && a.UserName == personaName && !a.DeletionAt.HasValue).ExecuteFirstAsync();
			if (persona == default)
			{
				var inserted = await services.GetRequiredService<IPrivateAvatarUsersService>().InsertAvatar(new InsertAvatarForm
				{
					RootId = root.ID,
					UserName = personaName,
					Name = personaName,
					Biography = "The deploy signs in here to check that the Mastodon API works for a signed-in persona."
				});
				if (!inserted.IsValid)
				{
					Console.Error.WriteLine(inserted.ErrorMessage);
					return 1;
				}
				persona = await DB.Default.Find<Avatar>().MatchID(((ViewAvatar)inserted.Data).Id).ExecuteFirstAsync();
			}
			await DB.Default.Update<Avatar>().MatchID(persona.ID)
				.Modify(a => a.Settings.IsDiscoverable, false)
				.Modify(a => a.Settings.IsIndexable, false)
				.ExecuteAsync();

			output.WriteLine($"{SmokeLogin} {password}");
			return 0;
		}
	}
}