using Microsoft.EntityFrameworkCore;
using Shadow.Data;
using Shadow.Entities;

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

	// TODO: Add "changeUser", "fullRescan", "destructiveRescan", "healthcheck"
	// TODO: Make this async

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

	public 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":
			case "--adduser":
			case "--add-user":
				if (!Seeder.EnsureMigrations(db)) return true;
				AddUser();
				break;
			case "resetpassword":
			case "--resetpassword":
			case "--reset-password":
				if (!Seeder.EnsureMigrations(db)) return true;
				ResetPassword();
				break;
			case "removeuser":
			case "--removeuser":
			case "--remove-user":
				if (!Seeder.EnsureMigrations(db)) return true;
				RemoveUser();
				break;
			case "help":
			case "--help":
			case "h":
			case "-h":
			case "/h":
			case "/?":
			case "?":
				// Help should be shown without forcing migrations.
				ShowHelp();
				break;
			case "setupwizard":
			case "--setupwizard":
			case "--setup-wizard":
			case "setup":
			case "--setup":
			case "configure":
			case "--configure":
				if (!Seeder.EnsureMigrations(db)) return true;
				SetupWizard();
				break;
			case "clear":
			case "cleanup":
			case "cleardb":
			case "cleanupdb":
			case "--clear":
			case "--cleanup":
				if (!Seeder.EnsureMigrations(db)) return true;
				CleanUpDb();
				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" +
			$"\n" +
			$"=== User management ===\n" +
			$"- addUser [username] - create a new user,\n" +
			$"- resetPassword [username] - reset a user's password,\n" +
			$"- removeUser [username] - remove the user COMPLETELY.\n" +
			$"\n" +
			$"=== Server maintenance ===\n" +
			$"- setupWizard - configure library and thumbnail location on disk,\n" +
			$"- cleanup - cleanup database from orphaned songs/albums/artists.\n" +
			$"\n" +
			$"[field] means the field 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,
			Role = isUserAdmin ? 0 : 1 // 0 = admin
		};

		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 prompted to enter the password.");
		else
			Console.WriteLine($"         You will be prompted 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 bool SetupWizard()
	{
		// Returns true if setup successful. Otherwise false.
		bool success = false;

		Console.WriteLine("[Shadow] Setup wizard\n" +
			"         Welcome to Shadow's setup wizard. Here, you can customize:\n" +
			"         - Shadow's music library path, used to scan for audio files,\n" +
			"         - Shadow's image thumbnails path, used to provide cover art extracted from media.\n" +
			"         Finally, you will be asked if you want your changes saved.\n");

		// TODO: do a healthcheck here

		Global? musicLibraryPath   = db.Globals.FirstOrDefault(g => g.Key == "musicLibraryPath");
		Global? musicThumbnailPath = db.Globals.FirstOrDefault(g => g.Key == "musicThumbnailPath");

		bool configurationExists = musicLibraryPath is not null || musicThumbnailPath is not null;
		if (configurationExists)
		{
			Console.WriteLine("         Found existing configuration:");
			if (musicLibraryPath is not null)
				Console.WriteLine($"         - for music library: {musicLibraryPath.Value}");
			if (musicThumbnailPath is not null)
				Console.WriteLine($"         - for image thumbnails: {musicThumbnailPath.Value}");
			Console.WriteLine("         They will be OVERWRITTEN if you'll commit your changes.\n");
		}
		else
		{
			Console.WriteLine("         No existing configuration found.\n");
		}

		string newMusicLibraryPath   = DefaultPrompt("Please enter your new music library path", musicLibraryPath?.Value).TrimEnd(['\\', '/']);
		string newMusicThumbnailPath = DefaultPrompt("Please enter your new image thumbnail path", musicThumbnailPath?.Value ?? Path.Combine(newMusicLibraryPath, ".shadow")).TrimEnd(['\\', '/']);

		bool confirmed = YesNoPrompt("Are you sure you want:\n" +
			$"- \"{newMusicLibraryPath}\" as your new music library path,\n" +
			$"- \"{newMusicThumbnailPath}\" as your new image thumbnail path?\n" +
			$"Please answer yes or no [y/N]: ", false);

		if (!confirmed)
		{
			Console.WriteLine("Changes not saved.");
			success = false;
		}
		else
		{
			Console.Write("Saving changes... ");

			musicLibraryPath   ??= new Global() { Key = "musicLibraryPath" };
			musicThumbnailPath ??= new Global() { Key = "musicThumbnailPath" };

			musicLibraryPath.Value   = newMusicLibraryPath;
			musicThumbnailPath.Value = newMusicThumbnailPath;

			System.IO.Directory.CreateDirectory(newMusicLibraryPath);
			System.IO.Directory.CreateDirectory(newMusicThumbnailPath);

			// Try to find the Assets directory automatically
			string currentPath = AppContext.BaseDirectory;
			for (int i = 0; i < 5; i++)
			{
				if (Directory.GetFiles(currentPath, "Shadow.slnx")
					.FirstOrDefault() != null)
				{
					File.Copy(
						Path.Combine(currentPath, "Assets", "vinyl.png"),
						Path.Combine(newMusicThumbnailPath, "default.png"),
						true
					);
					break;
				}

				currentPath = Path.Combine(currentPath, "..");

				if (i == 5) Console.WriteLine("\n" +
					"[Error] Could not determine content root path. \n" +
					"Please place Assets/vinyl.png in your thumbnail path directory manually\n" +
					"and rename it to default.png.");
			}

			// UpdateRange can both Add and Update rows.
			db.Globals.UpdateRange(musicLibraryPath, musicThumbnailPath);
			db.SaveChanges();

			Console.WriteLine("success!");
			success = true;

			Console.WriteLine("\n" +
				"Tip: On your next run of Shadow, a web server will start.\n" +
				"If you ever need to enter setup wizard again, use `Shadow setupWizard`.\n" +
				"For a complete list of available commands use `Shadow help`.\n");
		}

		return success;
	}

	public void CleanUpDb()
	{
		// Ask user here whether he/she wants to
		// clear the DB from dangling records (orphaned songs/albums/artists).
		int rowsAffected = 0;

		// Retrieve orphaned songs
		List<Song> orphanedSongs = db.Songs
			.Where(s => s.State == 1)
			.Include(s => s.Album)
			.ToList();

		// Ask if it's alright to remove them
		// and related listening data permanently
		if (orphanedSongs.Count != 0)
		{
			bool songConsent = false;
			songConsent = YesNoPrompt($"Found {orphanedSongs.Count} orphaned songs. Remove them? [y/N]: ", false);
			if (songConsent)
			{
				foreach (Song s in orphanedSongs)
				{
					// Remove song interactions
					List<SongInteraction> interactions = db.SongInteractions.Where(si => si.Song == s).ToList();
					db.SongInteractions.RemoveRange(interactions);

					// Remove song from playlists
					List<PlaylistSong> playlists = db.PlaylistSongs.Where(ps => ps.Song == s).ToList();
					db.PlaylistSongs.RemoveRange(playlists);

					// Remove song from albums
					Album album = s.Album;
					album.Songs.Remove(s);

					if (album.Songs.Count == 0) album.State = 1; // Set album state to orphaned.

					// TODO: Remove song images if not used by any other resource
					// ...

					db.SaveChanges();
				}

				// Perform cleanup with stored procedure
				db.Database.ExecuteSqlRaw("CALL song_cleanup()");
				rowsAffected += orphanedSongs.Count;
			}
		}
		else Console.WriteLine("No orphaned songs found.");

		// Rinse and repeat
		// Retrieve orphaned albums
		List<Album> orphanedAlbums = db.Albums.Where(a => a.State == 1).ToList();

		if (orphanedAlbums.Count != 0)
		{
			bool albumConsent = false;
			albumConsent = YesNoPrompt($"Found {orphanedAlbums.Count} orphaned albums. Remove them? [y/N]: ", false);
			if (albumConsent)
			{
				db.Albums.RemoveRange(orphanedAlbums);
				rowsAffected += orphanedAlbums.Count;
				db.SaveChanges();
			}
		}
		else Console.WriteLine("No orphaned albums found.");

		// Retrieve orphaned artists (artists with no songs AND albums)
		List<Artist> orphanedArtists = db.Artists
			.Where(a => a.Songs.Count == 0 && a.Albums.Count == 0)
			.ToList();
		Artist? unknownArtist = db.Artists
			.FirstOrDefault(a => a.NormalizedName == "[unknown artist]");

		// Account for the [Unknown Artist],
		// which is a meta-artist and shall
		// not be slated for removal.
		// Can be null only if this command
		// is ran before seeding.
		if (unknownArtist != null) orphanedArtists.Remove(unknownArtist);

		if (orphanedArtists.Count != 0)
		{
			bool artistConsent = false;
			artistConsent = YesNoPrompt($"Found {orphanedArtists.Count} orphaned artists. Remove them? [y/N]: ", false);
			if (artistConsent)
			{
				db.Artists.RemoveRange(orphanedArtists);
				rowsAffected += orphanedArtists.Count;
			}
		}
		else Console.WriteLine("No orphaned artists found.");

		Console.WriteLine($"{rowsAffected} entries affected.");
		db.SaveChanges();
	}

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

	public static 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;
		string? input = null;


		while (!exit)
		{
			Console.Write(prompt);
			input = Console.ReadLine();

			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;
	}

	public static string DefaultPrompt(string prompt, string? default_value = null)
	{
		// Prompt the user repeatedly for answer. If default value
		// is specified, an enter will be treated as if the user
		// entered the default value.
		string response = String.Empty;
		string? input;

		while (response.Trim() == String.Empty)
		{
			Console.Write($"{prompt}" + (default_value is not null ? $" [{default_value}]" : "") + ": ");
			input = Console.ReadLine();

			if (input is not null && input.Length > 0)
				response = input;
			else if (default_value is not null)
				response = default_value;
		}
		return response;
	}
}