tuitube 0.4.0

//! The sidebar, in a box with the logo in its border: Home, Shorts
//! (unless turned off), Search, Jukebox, Watch later, History, then under a rule
//! your subscriptions by name (dimmed, and marked, if YouTube says one is
//! gone).

use ratatui::Frame;
use ratatui::layout::Rect;
use ratatui::style::{Color, Modifier, Style};
use ratatui::text::{Line, Span};
use ratatui::widgets::Paragraph;
use unicode_width::UnicodeWidthStr;

use super::fit;
use crate::app::{App, Entry, Focus};
use crate::icons::Icons;

fn label(entry: Entry, icons: &Icons) -> (&'static str, &'static str) {
    match entry {
        Entry::Home => (icons.home, "Home"),
        Entry::Shorts => (icons.shorts, "Shorts"),
        Entry::Search => (icons.search, "Search"),
        Entry::Jukebox => (icons.jukebox, "Jukebox"),
        Entry::WatchLater => (icons.watch_later, "Watch later"),
        Entry::History => (icons.history, "History"),
        Entry::Channel(_) => ("", ""),
    }
}

pub fn draw(frame: &mut Frame, app: &mut App, area: Rect) {
    let c = app.colors.clone();
    let focused = app.focus == Focus::Sidebar && app.prompt.is_none();
    let line = super::border(focused, &c);
    let logo = Line::from(vec![
        Span::raw(" "),
        Span::styled(" ▶ ", Style::new().fg(Color::White).bg(c.red)),
        Span::styled(
            " tuitube ",
            Style::new().fg(c.text).add_modifier(Modifier::BOLD),
        ),
    ]);
    let block = super::bordered().border_style(line).title(logo);
    let inner = block.inner(area);
    frame.render_widget(block, area);
    let width = inner.width as usize;

    // Every row, with the sidebar entry it selects, if any.
    let mut rows: Vec<(Option<usize>, Line)> = Vec::new();
    let menu = app.menu();
    for (i, entry) in menu.iter().enumerate() {
        let (icon, name) = label(*entry, &app.icons);
        let mut line = Line::from(format!("  {icon}  {name}"));
        // How many videos are waiting in the Jukebox.
        if *entry == Entry::Jukebox && !app.jukebox.is_empty() {
            line.push_span(Span::styled(
                format!("  {}", app.jukebox.len()),
                Style::new().fg(c.dim),
            ));
        }
        rows.push((Some(i), line));
    }
    // Across the box, meeting its border on both sides, as tuigram's.
    let rule = rows.len();
    let heading = fit(
        &format!(" Subscriptions ({}) ", app.subscriptions.len()),
        usize::from(area.width).saturating_sub(4),
    );
    let fill = usize::from(area.width).saturating_sub(3 + heading.width());
    rows.push((
        None,
        Line::from(vec![
            Span::styled("├─", line),
            Span::styled(heading, Style::new().fg(c.dim)),
            Span::styled(format!("{}┤", "─".repeat(fill)), line),
        ]),
    ));
    if app.subscriptions.is_empty() {
        for hint in [
            "  None yet: press I to",
            "  import them from",
            "  Google Takeout",
        ] {
            rows.push((None, Line::from(Span::styled(hint, Style::new().fg(c.dim)))));
        }
    }
    for (i, channel) in app.subscriptions.iter().enumerate() {
        let name = if channel.title.is_empty() {
            channel.id.as_str()
        } else {
            &channel.title
        };
        let line = if channel.gone {
            let mark = " removed";
            Line::from(vec![
                Span::raw("  "),
                Span::styled(
                    fit(name, width.saturating_sub(3 + mark.len())),
                    Style::new().fg(c.dim).add_modifier(Modifier::CROSSED_OUT),
                ),
                Span::styled(mark, Style::new().fg(c.red)),
            ])
        } else {
            Line::from(format!("  {}", fit(name, width.saturating_sub(3))))
        };
        rows.push((Some(menu.len() + i), line));
    }

    // Keep the selected row on screen.
    let height = inner.height as usize;
    let selected_row = rows
        .iter()
        .position(|(entry, _)| *entry == Some(app.sidebar_selected))
        .unwrap_or(0);
    let mut scroll = app.sidebar_scroll.get();
    if selected_row < scroll {
        scroll = selected_row.saturating_sub(1);
    } else if selected_row >= scroll + height {
        scroll = selected_row + 1 - height;
    }
    app.sidebar_scroll.set(scroll);

    for (y, (i, (entry, line))) in rows
        .into_iter()
        .enumerate()
        .skip(scroll)
        .take(height)
        .enumerate()
    {
        let row = Rect {
            y: inner.y + y as u16,
            height: 1,
            ..inner
        };
        if i == rule {
            frame.render_widget(
                Paragraph::new(line),
                Rect {
                    x: area.x,
                    width: area.width,
                    ..row
                },
            );
            continue;
        }
        let selected = entry == Some(app.sidebar_selected);
        let style = if selected && focused {
            Style::new()
                .bg(c.selected)
                .fg(c.accent)
                .add_modifier(Modifier::BOLD)
        } else if selected {
            Style::new().bg(c.selected).fg(c.text)
        } else {
            Style::new().fg(c.text)
        };
        frame.render_widget(Paragraph::new(line).style(style), row);
        if selected && focused {
            frame.render_widget(
                Paragraph::new(Span::styled("▌", Style::new().fg(c.accent))),
                Rect { width: 1, ..row },
            );
        }
    }
}