// This file is part of Deja-vu.
//
// Deja-vu is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Deja-vu is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Deja-vu. If not, see <https://www.gnu.org/licenses/>.
//
use crate::app::App;
use ratatui::{
    layout::{Constraint, Direction, Layout, Rect},
    style::{Color, Style, Stylize},
    text::{Line, Span},
    widgets::{Block, Borders, Clear, HighlightSpacing, List, ListItem, Padding, Paragraph, Wrap},
    Frame,
};

/// Renders the user interface widgets.
pub fn render(app: &mut App, frame: &mut Frame) {
    let chunks = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Length(3),
            Constraint::Min(1),
            Constraint::Length(3),
        ])
        .split(frame.size());

    // Title Block
    let title_text = Span::styled("Deja-vu: PE Menu", Style::default().fg(Color::LightCyan));
    let title = Paragraph::new(Line::from(title_text).centered())
        .block(Block::default().borders(Borders::ALL));
    frame.render_widget(title, chunks[0]);

    // Main Block
    let main_chunk = centered_rect(65, 90, chunks[1]);
    render_main_pane(frame, app, main_chunk);

    // Bottom Block
    let footer_text = Span::styled(
        "(Enter) to select / (p) to poweroff / (r) to restart / (t) for terminal",
        Style::default().fg(Color::DarkGray),
    );
    let footer = Paragraph::new(Line::from(footer_text).centered())
        .block(Block::default().borders(Borders::ALL));
    frame.render_widget(footer, chunks[2]);

    // Popup blocks
    if app.popup.is_some() {
        render_popup_pane(frame, app);
    }
}

fn centered_rect(percent_x: u16, percent_y: u16, r: Rect) -> Rect {
    // Cut the given rectangle into three vertical pieces
    let popup_layout = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Percentage((100 - percent_y) / 2),
            Constraint::Percentage(percent_y),
            Constraint::Percentage((100 - percent_y) / 2),
        ])
        .split(r);

    // Then cut the middle vertical piece into three width-wise pieces
    Layout::default()
        .direction(Direction::Horizontal)
        .constraints([
            Constraint::Percentage((100 - percent_x) / 2),
            Constraint::Percentage(percent_x),
            Constraint::Percentage((100 - percent_x) / 2),
        ])
        .split(popup_layout[1])[1] // Return the middle chunk
}

fn render_main_pane(frame: &mut Frame, app: &mut App, chunk: Rect) {
    let mut list_items = Vec::<ListItem>::new();
    for entry in &app.main_menu.items {
        let text = if entry.separator {
            if entry.name.is_empty() {
                String::from("....................")
            } else {
                entry.name.clone()
            }
        } else {
            entry.name.clone()
        };
        list_items.push(ListItem::new(format!("    {text}\n\n\n")));
    }
    let list = List::new(list_items)
        .block(
            Block::default()
                .borders(Borders::ALL)
                .padding(Padding::new(20, 20, 5, 5)),
        )
        .highlight_spacing(HighlightSpacing::Always)
        .highlight_style(Style::new().green().bold())
        .highlight_symbol(" --> ")
        .repeat_highlight_symbol(false);
    frame.render_stateful_widget(list, chunk, &mut app.main_menu.state);
}

fn render_popup_pane(frame: &mut Frame, app: &mut App) {
    let popup_block = Block::default()
        .borders(Borders::ALL)
        .style(Style::default().red().bold());
    if let Some(popup) = &app.popup {
        let scan_paragraph = Paragraph::new(vec![
            Line::from(Span::raw(&popup.title)),
            Line::default(),
            Line::from(Span::raw(&popup.body)),
        ])
        .block(popup_block)
        .centered()
        .wrap(Wrap { trim: false });
        let area = centered_rect(60, 25, frame.size());
        frame.render_widget(Clear, area);
        frame.render_widget(scan_paragraph, area);
    }
}