using System;
using System.Drawing;
using System.Windows.Forms;

namespace UserPermissionTest_CS_WinForms
{
    public partial class MainForm : Form
    {
        public MainForm()
        {
            InitializeComponent();
        }

        private void MainForm_Load(object sender, EventArgs e)
        {
            // Subscribe to session state change notifications
            SessionManager.SessionStateChanged += UpdateSessionUi;
            
            // Trigger initial UI update
            UpdateSessionUi();
        }

        private void UpdateSessionUi()
        {
            if (this.InvokeRequired)
            {
                this.Invoke(new Action(UpdateSessionUi));
                return;
            }

            var user = SessionManager.CurrentUser;

            if (user == null)
            {
                // Signed Out State
                lblStatusBadge.Text = "SIGNED OUT";
                lblStatusBadge.BackColor = Color.FromArgb(239, 68, 68); // Red
                lblUsernameValue.Text = "Not Logged In";
                lblUsernameValue.ForeColor = Color.FromArgb(100, 116, 139); // Slate-400
                lblFullNameValue.Text = "-";
                
                lstUserPermissions.Items.Clear();
                lstUserPermissions.Items.Add("(Sign in to view permissions)");

                btnLogin.Enabled = true;
                btnLogout.Enabled = false;
                
                // Authorization: Lock directory when not logged in
                btnUsers.Enabled = false;
                btnUsers.Text = "🔒 Manage Users";
                btnUsers.BackColor = Color.FromArgb(241, 245, 249);
            }
            else
            {
                // Signed In State
                lblStatusBadge.Text = "SIGNED IN";
                lblStatusBadge.BackColor = Color.FromArgb(16, 185, 129); // Green
                lblUsernameValue.Text = user.Username;
                lblUsernameValue.ForeColor = Color.FromArgb(15, 23, 42); // Navy-900
                lblFullNameValue.Text = user.FullName;

                lstUserPermissions.Items.Clear();
                if (user.Permissions.Count == 0)
                {
                    lstUserPermissions.Items.Add("(No permissions assigned)");
                }
                else
                {
                    foreach (var permissionId in user.Permissions)
                    {
                        var permObj = SessionManager.AvailablePermissions.FirstOrDefault(p => p.Id == permissionId);
                        string permName = permObj != null ? permObj.Name : $"Unknown (ID: {permissionId})";
                        lstUserPermissions.Items.Add("✓ " + permName);
                    }
                }

                btnLogin.Enabled = false;
                btnLogout.Enabled = true;

                // Authorization: Check if user has 'Manage Users' or 'Full Control'
                var manageUsersPerm = SessionManager.AvailablePermissions.FirstOrDefault(p => p.Name.Equals("Manage Users", StringComparison.OrdinalIgnoreCase));
                var fullControlPerm = SessionManager.AvailablePermissions.FirstOrDefault(p => p.Name.Equals("Full Control", StringComparison.OrdinalIgnoreCase));

                bool hasAccess = (manageUsersPerm != null && user.Permissions.Contains(manageUsersPerm.Id)) || 
                                 (fullControlPerm != null && user.Permissions.Contains(fullControlPerm.Id));
                if (hasAccess)
                {
                    btnUsers.Enabled = true;
                    btnUsers.Text = "👥 Manage Users";
                    btnUsers.BackColor = Color.FromArgb(241, 245, 249);
                }
                else
                {
                    btnUsers.Enabled = false;
                    btnUsers.Text = "🔒 Manage Users (Locked)";
                    btnUsers.BackColor = Color.FromArgb(241, 245, 249);
                }
            }
        }

        private void btnLogin_Click(object sender, EventArgs e)
        {
            using (var loginDialog = new LoginDialog())
            {
                if (loginDialog.ShowDialog(this) == DialogResult.OK)
                {
                    MessageBox.Show(
                        $"Welcome back, {SessionManager.CurrentUser?.FullName}!", 
                        "Sign In Successful", 
                        MessageBoxButtons.OK, 
                        MessageBoxIcon.Information);
                }
            }
        }

        private void btnLogout_Click(object sender, EventArgs e)
        {
            if (SessionManager.CurrentUser != null)
            {
                string username = SessionManager.CurrentUser.Username;
                SessionManager.Logout();
                MessageBox.Show(
                    $"User '{username}' has been successfully logged out.", 
                    "Signed Out", 
                    MessageBoxButtons.OK, 
                    MessageBoxIcon.Information);
            }
        }

        private void btnUsers_Click(object sender, EventArgs e)
        {
            var user = SessionManager.CurrentUser;
            var manageUsersPerm = SessionManager.AvailablePermissions.FirstOrDefault(p => p.Name.Equals("Manage Users", StringComparison.OrdinalIgnoreCase));
            var fullControlPerm = SessionManager.AvailablePermissions.FirstOrDefault(p => p.Name.Equals("Full Control", StringComparison.OrdinalIgnoreCase));

            bool hasAccess = user != null && (
                             (manageUsersPerm != null && user.Permissions.Contains(manageUsersPerm.Id)) || 
                             (fullControlPerm != null && user.Permissions.Contains(fullControlPerm.Id))
                             );

            if (!hasAccess)
            {
                MessageBox.Show(
                    "Security Exception: You do not possess the required credentials ('Manage Users' or 'Full Control') to access directory configuration.", 
                    "Access Denied", 
                    MessageBoxButtons.OK, 
                    MessageBoxIcon.Stop);
                return;
            }

            using (var userSettings = new UserSettings())
            {
                userSettings.ShowDialog(this);
            }
            
            // After closing settings, refresh the session UI (in case the current user's profile was changed)
            UpdateSessionUi();
        }

        protected override void OnFormClosing(FormClosingEventArgs e)
        {
            // Unsubscribe to prevent reference leaks
            SessionManager.SessionStateChanged -= UpdateSessionUi;
            base.OnFormClosing(e);
        }
    }
}