using Shadow.Data;
using Shadow.Entities;

namespace Shadow.Controllers;
public class Cli
{
	private readonly ApplicationDbContext db;
	private readonly GeneralUseHelpers guhf;
	private readonly string[] args;

	// TODO: Add "changeUser"

	public Cli(ApplicationDbContext _db, GeneralUseHelpers _guhf, string[] _args)
	{
		db   =   _db;
		guhf = _guhf;
		args = _args;
	}

	public async Task<bool> Parse()
	{
		// Returns true if the program can finish execution.
		bool exit = true;
		// Check if anything has been passed
		if (args.Length == 0 || args.FirstOrDefault() is null) {
			return true;
		}
		switch (args[0].ToLower())
		{
			case "adduser":
				AddUser();
				break;
			case "resetpassword":
				ResetPassword();
				break;
			case "removeuser":
				RemoveUser();
				break;
			case "help":
			case "--help":
			case "h":
			case "-h":
			case "/h":
			case "/?":
			case "?":
				ShowHelp();
				break;
			default:
				Console.WriteLine($"Unknown option: \"{args[0]}\". See \"help\" for available arguments.");
				break;
		}

		return exit;
	}

	public void ShowHelp()
	{
		// Shown when "Shadow --help"/"Shadow help"/... is ran.
		Console.WriteLine(
			$"--- Shadow commandline utility ---\n" +
			$"Shadow version: #{ThisAssembly.Git.Commit} {ThisAssembly.Git.Branch} ({ThisAssembly.Git.CommitDate})\n\n" +
			$"Available commands:\n" +
			$"- addUser [username] - create a new user,\n" +
			$"- resetPassword [username] - reset a user's password,\n" +
			$"- removeUser [username] - remove the user COMPLETELY.\n\n" +
			$"Username is optional. If not provided, user will be prompted to enter it.\n" +
			$"Running without specifying a command launches a Kestrel web server.\n\n" +
			$"License: AGPLv3+, Source code: https://gitea.7o7.cx/sherl/Shadow"
		);
	}

	public void AddUser()
	{
		// Check if any cli arguments have been passed
		// Both:
		// Shadow addUser
		// and
		// Shadow addUser username
		// are supported.

		Console.WriteLine($"[Shadow] Add a new user");
		if (args.Length == 2)
			Console.WriteLine($"         You will be promped to enter a password.");
		else
			Console.WriteLine($"         You will be promped to enter a username and password.");

		string? username = null;
		if (args.Length != 2)
		{
			while (username is null || username == String.Empty)
				username = ReadName("         Please enter a username: ");
		}
		else
			username = args[1];

		// Check if user by this name exists in DB
		User? foundUser = db.Users
							.FirstOrDefault(u => u.NormalizedName == username!.ToLower());
		if (foundUser != null) {
			Console.WriteLine("Error! User with this name already exists in the database!");
			return;
		}

		string             password = ReadPassword();
		string passwordConfirmation = ReadPassword("         Confirm password: ");
		if (!password.Equals(passwordConfirmation))
		{
			Console.WriteLine("Error! Passwords do not match. Please try again.");
			return;
		}
		bool isUserAdmin = YesNoPrompt($"         Should \"{username}\" be an administrator? [y/N]: ", false);

		User newUser = new User
		{
			Name = username!,
			NormalizedName = username!.ToLower(),
			Password = password
		};

		db.Users.Add(newUser);
		db.SaveChanges();
	}

	public void ResetPassword()
	{
		// Check if any cli arguments have been passed
		// Both:
		// Shadow resetPassword
		// and
		// Shadow resetPassword username
		// are supported.

		Console.WriteLine($"[Shadow] Reset password");
		if (args.Length == 2)
			Console.WriteLine($"         You will be promped to enter a new password.");
		else
			Console.WriteLine($"         You will be promped to enter a username and a new password.");

		string? username = null;
		if (args.Length != 2)
		{
			while (username is null || username == String.Empty)
				username = ReadName("         Please enter a username: ");
		}
		else
			username = args[1];

		// Check if user by this name exists in DB
		User? foundUser = db.Users
							.FirstOrDefault(u => u.NormalizedName == username!.ToLower());
		if (foundUser == null)
		{
			Console.WriteLine("Error! User with this name does not exist in the database!");
			return;
		}

		string password = ReadPassword();
		string passwordConfirmation = ReadPassword("         Confirm new password: ");
		if (!password.Equals(passwordConfirmation))
		{
			Console.WriteLine("Error! Passwords do not match. Please try again.");
			return;
		}

		foundUser.Password = password;
		db.SaveChanges();

	}

	public void RemoveUser()
	{
		// Check if any cli arguments have been passed
		// Both:
		// Shadow removeUser
		// and
		// Shadow removeUser username
		// are supported.

		Console.WriteLine($"[Shadow] Remove user");
		if (args.Length == 2)
			Console.WriteLine($"         You will be promped to enter the password.");
		else
			Console.WriteLine($"         You will be promped to enter the username and password.");

		string? username = null;
		if (args.Length != 2)
		{
			while (username is null || username == String.Empty)
				username = ReadName("         Please enter the username: ");
		}
		else
			username = args[1];

		// Check if user by this name exists in DB
		User? foundUser = db.Users
							.FirstOrDefault(u => u.NormalizedName == username!.ToLower());
		if (foundUser == null)
		{
			Console.WriteLine("Error! User with this name does not exist in the database!");
			return;
		}

		string password             = ReadPassword();
		string passwordConfirmation = ReadPassword("         Confirm password: ");
		if (!password.Equals(passwordConfirmation))
		{
			Console.WriteLine("Error! Passwords do not match. Please try again.");
			return;
		}
		if (foundUser.Password != password)
		{
			Console.WriteLine($"Error! Entered password does not match that of \"{username}\"!");
			return;
		}

		bool userDeletionConfirmation = YesNoPrompt($"         Do you want to remove \"{username}\" completely?\n" +
													$"         This cannot be undone! [y/N]: ", false);
		if (userDeletionConfirmation) {

			// All playlists, interactions should be deleted as well.
			List<AlbumInteraction> albumInteractions = db.AlbumInteractions
															.Where(ai => ai.User == foundUser)
															.ToList();

			List<SongInteraction> songInteractions = db.SongInteractions
														.Where(si => si.User == foundUser)
														.ToList();

			foreach(AlbumInteraction ai in albumInteractions)
				db.AlbumInteractions.Remove(ai);

			foreach (SongInteraction si in songInteractions)
				db.SongInteractions.Remove(si);

			db.Users.Remove(foundUser);
			db.SaveChanges();

			Console.WriteLine($"User \"{username}\" and all their data deleted successfully.");
		}
		else
			Console.WriteLine("User not removed.");

	}

	public string ReadPassword(string prompt = "         Enter password (will not be echoed back): ")
	{
		// https://www.silicloud.com/blog/how-to-hide-content-in-the-console-using-c/
		string password = String.Empty;
		ConsoleKeyInfo key;

		bool exit = false;
		Console.Write(prompt);
		while (!exit) {
			key = Console.ReadKey(true);

			// Exit on enter
			if (key.Key == ConsoleKey.Enter)
				exit = true;
			// Clear last character on backspace
			else if (key.Key == ConsoleKey.Backspace && password.Length > 0)
				password = password.Substring(0, (password.Length - 1));
			// Append any other character
			else
				password += key.KeyChar;
		}
		Console.WriteLine();
		return password;
	}

	public string? ReadName(string prompt = "         Enter username: ")
	{
		Console.Write(prompt);
		string? input = Console.ReadLine();
		return input;
	}

	public bool YesNoPrompt(string prompt, bool? default_value = null)
	{
		// Checks if user input starts with "y", and if it does, returns true.
		// Otherwise checks for "n". If both checks fail, and default_value is null,
		// user will be asked repeatedly.
		bool exit = false;
		bool response = false;

		Console.Write(prompt);
		string? input = Console.ReadLine();

		while (!exit)
		{
			if (input is not null && input.Length > 0)
			{
				if (input.ToLower().StartsWith("y"))
				{
					response = true;
					exit = true;
				}
				else if (input.ToLower().StartsWith("n"))
				{
					response = false;
					exit = true;
				}
			}
			else if (default_value is not null)
			{
				response = (bool)default_value;
				exit = true;
			}
		}
		return response;
	}
}