use ratatui::{
    layout::{Alignment, Constraint, Direction, Layout},
    style::{Color, Modifier, Style},
    text::{Line, Span},
    widgets::{Block, Borders, Paragraph},
    Frame,
};

use crate::tui::app::{App, LoginField};

pub fn draw(frame: &mut Frame, app: &App) {
    let area = frame.size();

    // Centre a 50×12 box on screen.
    let v = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Percentage(30),
            Constraint::Length(14),
            Constraint::Min(0),
        ])
        .split(area);

    let h = Layout::default()
        .direction(Direction::Horizontal)
        .constraints([
            Constraint::Percentage(25),
            Constraint::Percentage(50),
            Constraint::Percentage(25),
        ])
        .split(v[1]);

    let box_area = h[1];

    let mode_label = if app.login_register { "Register" } else { "Login" };

    let outer = Block::default()
        .title(format!(" BackChannel — {} ", mode_label))
        .borders(Borders::ALL)
        .style(Style::default().fg(Color::Cyan));

    frame.render_widget(outer, box_area);

    let inner = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Length(1), // padding
            Constraint::Length(3), // username
            Constraint::Length(3), // password
            Constraint::Length(1), // padding
            Constraint::Length(1), // hint
            Constraint::Length(1), // status
        ])
        .margin(1)
        .split(box_area);

    // Username field
    let username_style = if app.login_field == LoginField::Username {
        Style::default().fg(Color::Yellow).add_modifier(Modifier::BOLD)
    } else {
        Style::default()
    };
    let username_widget = Paragraph::new(app.login_username.as_str())
        .block(Block::default().borders(Borders::ALL).title(" Username "))
        .style(username_style);
    frame.render_widget(username_widget, inner[1]);

    // Password field (mask with asterisks)
    let password_style = if app.login_field == LoginField::Password {
        Style::default().fg(Color::Yellow).add_modifier(Modifier::BOLD)
    } else {
        Style::default()
    };
    let masked: String = "*".repeat(app.login_password.len());
    let password_widget = Paragraph::new(masked.as_str())
        .block(Block::default().borders(Borders::ALL).title(" Password "))
        .style(password_style);
    frame.render_widget(password_widget, inner[2]);

    // Hints
    let hint = Paragraph::new(Line::from(vec![
        Span::raw("Tab: switch field  |  Enter: submit  |  "),
        Span::styled(
            if app.login_register { "T: switch to Login" } else { "T: switch to Register" },
            Style::default().fg(Color::DarkGray),
        ),
    ]))
    .alignment(Alignment::Center);
    frame.render_widget(hint, inner[4]);

    // Status / error message
    if let Some(msg) = &app.status_msg {
        let status = Paragraph::new(msg.as_str())
            .style(Style::default().fg(Color::Red))
            .alignment(Alignment::Center);
        frame.render_widget(status, inner[5]);
    }
}