using System;
using System.IO;
using System.Text.Json;
using System.Windows;
using System.Windows.Controls;
using MembranePoreTester.Models;

namespace MembranePoreTester.Views
{
    public partial class LoginWindow : Window
    {
        private const string PasswordFile = "passwords.json";

        public LoginWindow()
        {
            InitializeComponent();
            EnsurePasswordFile();
        }

        private void EnsurePasswordFile()
        {
            if (!File.Exists(PasswordFile))
            {
                var defaultPasswords = new
                {
                    AdminPassword = "admin123",
                    OperatorPassword = "oper123"
                };
                string json = JsonSerializer.Serialize(defaultPasswords, new JsonSerializerOptions { WriteIndented = true });
                File.WriteAllText(PasswordFile, json);
            }
        }

        private void BtnLogin_Click(object sender, RoutedEventArgs e)
        {
            string role = ((ComboBoxItem)cmbRole.SelectedItem).Tag.ToString();
            string password = txtPassword.Password;

            string expectedPassword = GetPassword(role);
            if (password == expectedPassword)
            {
                App.CurrentUserRole = role == "Admin" ? UserRole.Admin : UserRole.Operator;
                DialogResult = true;
                Close();
            }
            else
            {
                MessageBox.Show("密码错误", "登录失败", MessageBoxButton.OK, MessageBoxImage.Error);
            }
        }

        private void BtnChangePwd_Click(object sender, RoutedEventArgs e)
        {
            string role = ((ComboBoxItem)cmbRole.SelectedItem).Tag.ToString();
            string title = role == "Admin" ? "修改管理员密码" : "修改操作员密码";

            var dialog = new Window
            {
                Title = title,
                Width = 350,
                Height = 250,
                WindowStartupLocation = WindowStartupLocation.CenterOwner,
                Owner = this,
                ResizeMode = ResizeMode.NoResize,
                Content = new StackPanel
                {
                    Margin = new Thickness(20),
                    Children =
                    {
                        new StackPanel { Orientation = Orientation.Horizontal, Margin = new Thickness(0,10,0,10),
                            Children = { new Label { Width = 80, Content = "新密码:" }, new PasswordBox { Name = "newPwd", Width = 180 } } },
                        new StackPanel { Orientation = Orientation.Horizontal, Margin = new Thickness(0,10,0,10),
                            Children = { new Label { Width = 80, Content = "确认密码:" }, new PasswordBox { Name = "confirmPwd", Width = 180 } } },
                        new StackPanel { Orientation = Orientation.Horizontal, HorizontalAlignment = HorizontalAlignment.Center, Margin = new Thickness(0,20,0,0),
                            Children = { new Button { Content = "确定", Width = 80, Margin = new Thickness {Left= 5} }, new Button { Content = "取消", Width = 80, Margin = new Thickness {Left= 5} } } }
                    }
                }
            };

            var confirmBtn = ((StackPanel)((StackPanel)dialog.Content).Children[2]).Children[0] as Button;
            var cancelBtn = ((StackPanel)((StackPanel)dialog.Content).Children[2]).Children[1] as Button;
            var newPwdBox = ((StackPanel)((StackPanel)dialog.Content).Children[0]).Children[1] as PasswordBox;
            var confirmPwdBox = ((StackPanel)((StackPanel)dialog.Content).Children[1]).Children[1] as PasswordBox;

            confirmBtn.Click += (s, ev) =>
            {
                string newPwd = newPwdBox.Password;
                string confirmPwd = confirmPwdBox.Password;
                if (string.IsNullOrEmpty(newPwd))
                {
                    MessageBox.Show("密码不能为空", "错误", MessageBoxButton.OK, MessageBoxImage.Warning);
                    return;
                }
                if (newPwd != confirmPwd)
                {
                    MessageBox.Show("两次输入的密码不一致", "错误", MessageBoxButton.OK, MessageBoxImage.Warning);
                    return;
                }

                if (UpdatePassword(role, newPwd))
                {
                    MessageBox.Show("密码修改成功，下次登录生效", "提示", MessageBoxButton.OK, MessageBoxImage.Information);
                    dialog.Close();
                }
                else
                {
                    MessageBox.Show("密码修改失败，请检查文件权限", "错误", MessageBoxButton.OK, MessageBoxImage.Error);
                }
            };

            cancelBtn.Click += (s, ev) => dialog.Close();
            dialog.ShowDialog();
        }

        private void BtnExit_Click(object sender, RoutedEventArgs e)
        {
            DialogResult = false;
            Close();
        }

        private string GetPassword(string role)
        {
            if (!File.Exists(PasswordFile)) return role == "Admin" ? "admin123" : "oper123";
            try
            {
                string json = File.ReadAllText(PasswordFile);
                using JsonDocument doc = JsonDocument.Parse(json);
                string key = role == "Admin" ? "AdminPassword" : "OperatorPassword";
                if (doc.RootElement.TryGetProperty(key, out JsonElement value))
                    return value.GetString();
                return role == "Admin" ? "admin123" : "oper123";
            }
            catch
            {
                return role == "Admin" ? "admin123" : "oper123";
            }
        }

        private bool UpdatePassword(string role, string newPassword)
        {
            try
            {
                Dictionary<string, string> passwords;
                if (File.Exists(PasswordFile))
                {
                    string json = File.ReadAllText(PasswordFile);
                    passwords = JsonSerializer.Deserialize<Dictionary<string, string>>(json);
                }
                else
                {
                    passwords = new Dictionary<string, string>();
                }

                string key = role == "Admin" ? "AdminPassword" : "OperatorPassword";
                passwords[key] = newPassword;

                string newJson = JsonSerializer.Serialize(passwords, new JsonSerializerOptions { WriteIndented = true });
                File.WriteAllText(PasswordFile, newJson);
                return true;
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine($"修改密码失败: {ex.Message}");
                return false;
            }
        }
    }
}