using System;
using System.IO;
using UnityEngine;

public static class SettingsPasswordStore
{
    private const string FileName = "settings-password.txt";
    private const int PasswordLength = 6;

    public static string PasswordFilePath => Path.Combine(Application.persistentDataPath, FileName);

    public static bool HasPassword => TryGetPassword(out _);

    public static bool Save(string combination)
    {
        string normalizedCombination = Normalize(combination);

        if (IsValid(normalizedCombination) == false)
            return false;

        try
        {
            File.WriteAllText(PasswordFilePath, normalizedCombination);
            return true;
        }
        catch (Exception exception)
        {
            Debug.LogError($"Не удалось сохранить пароль настроек: {exception.Message}");
            return false;
        }
    }

    public static bool Validate(string combination)
    {
        if (TryGetPassword(out string savedPassword) == false)
            return false;

        return string.Equals(savedPassword, Normalize(combination), StringComparison.Ordinal);
    }

    public static bool Reset()
    {
        try
        {
            if (File.Exists(PasswordFilePath))
                File.Delete(PasswordFilePath);

            return true;
        }
        catch (Exception exception)
        {
            Debug.LogError($"Не удалось сбросить пароль настроек: {exception.Message}");
            return false;
        }
    }

    private static bool TryGetPassword(out string password)
    {
        password = null;

        try
        {
            if (File.Exists(PasswordFilePath) == false)
                return false;

            string savedPassword = Normalize(File.ReadAllText(PasswordFilePath));

            if (IsValid(savedPassword) == false)
                return false;

            password = savedPassword;
            return true;
        }
        catch (Exception exception)
        {
            Debug.LogError($"Не удалось прочитать пароль настроек: {exception.Message}");
            return false;
        }
    }

    private static string Normalize(string combination)
        => string.IsNullOrWhiteSpace(combination) ? string.Empty : combination.Trim().ToUpperInvariant();

    private static bool IsValid(string combination)
    {
        if (combination.Length != PasswordLength)
            return false;

        for (int i = 0; i < combination.Length; i++)
        {
            char symbol = combination[i];

            if (symbol != 'U' && symbol != 'D' && symbol != 'L' && symbol != 'R')
                return false;
        }

        return true;
    }
}