llmx/codex-rs/tui/src/transcript_app.rs

use std::io::Result;

use crate::insert_history;
use crate::tui;
use crate::tui::TuiEvent;
use crossterm::event::KeyCode;
use crossterm::event::KeyEvent;
use crossterm::event::KeyEventKind;
use ratatui::buffer::Buffer;
use ratatui::layout::Rect;
use ratatui::style::Color;
use ratatui::style::Style;
use ratatui::style::Styled;
use ratatui::style::Stylize;
use ratatui::text::Line;
use ratatui::text::Span;
use ratatui::widgets::Paragraph;
use ratatui::widgets::WidgetRef;

pub(crate) struct TranscriptApp {
    pub(crate) transcript_lines: Vec<Line<'static>>,
    pub(crate) scroll_offset: usize,
    pub(crate) is_done: bool,
    title: String,
}

impl TranscriptApp {
    pub(crate) fn new(transcript_lines: Vec<Line<'static>>) -> Self {
        Self {
            transcript_lines,
            scroll_offset: 0,
            is_done: false,
            title: "T R A N S C R I P T".to_string(),
        }
    }

    pub(crate) fn with_title(transcript_lines: Vec<Line<'static>>, title: String) -> Self {
        Self {
            transcript_lines,
            scroll_offset: 0,
            is_done: false,
            title,
        }
    }

    pub(crate) fn handle_event(&mut self, tui: &mut tui::Tui, event: TuiEvent) -> Result<()> {
        match event {
            TuiEvent::Key(key_event) => self.handle_key_event(tui, key_event),
            TuiEvent::Draw => {
                tui.draw(u16::MAX, |frame| {
                    self.render(frame.area(), frame.buffer);
                })?;
            }
            _ => {}
        }
        Ok(())
    }

    pub(crate) fn insert_lines(&mut self, lines: Vec<Line<'static>>) {
        self.transcript_lines.extend(lines);
    }

    fn handle_key_event(&mut self, tui: &mut tui::Tui, key_event: KeyEvent) {
        match key_event {
            KeyEvent {
                code: KeyCode::Char('q'),
                kind: KeyEventKind::Press,
                ..
            }
            | KeyEvent {
                code: KeyCode::Char('t'),
                modifiers: crossterm::event::KeyModifiers::CONTROL,
                kind: KeyEventKind::Press,
                ..
            }
            | KeyEvent {
                code: KeyCode::Char('c'),
                modifiers: crossterm::event::KeyModifiers::CONTROL,
                kind: KeyEventKind::Press,
                ..
            } => {
                self.is_done = true;
            }
            KeyEvent {
                code: KeyCode::Up,
                kind: KeyEventKind::Press | KeyEventKind::Repeat,
                ..
            } => {
                self.scroll_offset = self.scroll_offset.saturating_sub(1);
            }
            KeyEvent {
                code: KeyCode::Down,
                kind: KeyEventKind::Press | KeyEventKind::Repeat,
                ..
            } => {
                self.scroll_offset = self.scroll_offset.saturating_add(1);
            }
            KeyEvent {
                code: KeyCode::PageUp,
                kind: KeyEventKind::Press | KeyEventKind::Repeat,
                ..
            } => {
                let area = self.scroll_area(tui.terminal.viewport_area);
                self.scroll_offset = self.scroll_offset.saturating_sub(area.height as usize);
            }
            KeyEvent {
                code: KeyCode::PageDown,
                kind: KeyEventKind::Press | KeyEventKind::Repeat,
                ..
            } => {
                let area = self.scroll_area(tui.terminal.viewport_area);
                self.scroll_offset = self.scroll_offset.saturating_add(area.height as usize);
            }
            KeyEvent {
                code: KeyCode::Home,
                kind: KeyEventKind::Press | KeyEventKind::Repeat,
                ..
            } => {
                self.scroll_offset = 0;
            }
            KeyEvent {
                code: KeyCode::End,
                kind: KeyEventKind::Press | KeyEventKind::Repeat,
                ..
            } => {
                self.scroll_offset = usize::MAX;
            }
            _ => {
                return;
            }
        }
        tui.frame_requester().schedule_frame();
    }

    fn scroll_area(&self, area: Rect) -> Rect {
        let mut area = area;
        // Reserve 1 line for the header and 4 lines for the bottom status section. This matches the chat composer.
        area.y = area.y.saturating_add(1);
        area.height = area.height.saturating_sub(5);
        area
    }

    fn render(&mut self, area: Rect, buf: &mut Buffer) {
        Span::from("/ ".repeat(area.width as usize / 2))
            .dim()
            .render_ref(area, buf);
        let header = format!("/ {}", self.title);
        Span::from(header).dim().render_ref(area, buf);

        // Main content area (excludes header and bottom status section)
        let content_area = self.scroll_area(area);
        let wrapped = insert_history::word_wrap_lines(&self.transcript_lines, content_area.width);

        // Clamp scroll offset to valid range
        self.scroll_offset = self
            .scroll_offset
            .min(wrapped.len().saturating_sub(content_area.height as usize));
        let start = self.scroll_offset;
        let end = (start + content_area.height as usize).min(wrapped.len());
        let page = &wrapped[start..end];
        Paragraph::new(page.to_vec()).render_ref(content_area, buf);

        // Fill remaining visible lines (if any) with a leading '~' in the first column.
        let visible = (end - start) as u16;
        if content_area.height > visible {
            let extra = content_area.height - visible;
            for i in 0..extra {
                let y = content_area.y.saturating_add(visible + i);
                Span::from("~")
                    .dim()
                    .render_ref(Rect::new(content_area.x, y, 1, 1), buf);
            }
        }

        // Bottom status section (4 lines): separator with % scrolled, then key hints (styled like chat composer)
        let sep_y = content_area.bottom();
        let sep_rect = Rect::new(area.x, sep_y, area.width, 1);
        let hints_rect = Rect::new(area.x, sep_y + 1, area.width, 2);

        // Separator line (dim)
        Span::from("─".repeat(sep_rect.width as usize))
            .dim()
            .render_ref(sep_rect, buf);

        // Scroll percentage (0-100%) aligned near the right edge
        let max_scroll = wrapped.len().saturating_sub(content_area.height as usize);
        let percent: u8 = if max_scroll == 0 {
            100
        } else {
            (((self.scroll_offset.min(max_scroll)) as f32 / max_scroll as f32) * 100.0).round()
                as u8
        };
        let pct_text = format!(" {percent}% ");
        let pct_w = pct_text.chars().count() as u16;
        let pct_x = sep_rect.x + sep_rect.width - pct_w - 1;
        Span::from(pct_text)
            .dim()
            .render_ref(Rect::new(pct_x, sep_rect.y, pct_w, 1), buf);

        let key_hint_style = Style::default().fg(Color::Cyan);

        let hints1 = vec![
            " ".into(),
            "↑".set_style(key_hint_style),
            "/".into(),
            "↓".set_style(key_hint_style),
            " scroll   ".into(),
            "PgUp".set_style(key_hint_style),
            "/".into(),
            "PgDn".set_style(key_hint_style),
            " page   ".into(),
            "Home".set_style(key_hint_style),
            "/".into(),
            "End".set_style(key_hint_style),
            " jump".into(),
        ];

        let hints2 = vec![" ".into(), "q".set_style(key_hint_style), " quit".into()];
        Paragraph::new(vec![Line::from(hints1).dim(), Line::from(hints2).dim()])
            .render_ref(hints_rect, buf);
    }
}