void-focus 0.3.0-alpha.3

//! Statistics dashboard — heatmap, summary panel, weekly bar chart, recent sessions.

use ratatui::layout::{Alignment, Constraint, Direction, Layout, Rect};
use ratatui::style::{Modifier, Style};
use ratatui::text::{Line, Span};
use ratatui::widgets::{Cell, List, ListItem, Paragraph, Row, Table};
use ratatui::Frame;

use crate::app::{App, Theme};
use crate::ui::IconSet;

use super::heatmap;
use super::widgets::{format_minutes, section_panel, section_panel_bottom};

// ── Main entry point ─────────────────────────────────────────────────────────

pub fn draw_stats(f: &mut Frame, app: &App, area: Rect) {
    let theme = &app.theme;

    let rows = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Min(10),
            Constraint::Length(1),
            Constraint::Min(6),
        ])
        .split(area);

    draw_heatmap_section(f, app, rows[0]);
    draw_divider(f, rows[1], theme);

    let bottom_cols = Layout::default()
        .direction(Direction::Horizontal)
        .constraints([
            Constraint::Percentage(33),
            Constraint::Length(1),
            Constraint::Percentage(33),
            Constraint::Length(1),
            Constraint::Percentage(34),
        ])
        .split(rows[2]);

    draw_summary(f, app, bottom_cols[0]);
    draw_vdivider(f, bottom_cols[1], theme);
    draw_week_bars(f, app, bottom_cols[2]);
    draw_vdivider(f, bottom_cols[3], theme);
    draw_recent_sessions(f, app, bottom_cols[4]);
}

// ── Dividers ─────────────────────────────────────────────────────────────────

fn draw_divider(f: &mut Frame, area: Rect, theme: &Theme) {
    let border = Style::default().fg(theme.panel_border);
    f.render_widget(
        Paragraph::new(Span::styled("─".repeat(area.width as usize), border)),
        area,
    );
}

fn draw_vdivider(f: &mut Frame, area: Rect, theme: &Theme) {
    if area.height == 0 {
        return;
    }
    let border = Style::default().fg(theme.panel_border);
    let pipe = Span::styled("│", border);
    let lines: Vec<Line> = (0..area.height).map(|_| Line::from(pipe.clone())).collect();
    f.render_widget(Paragraph::new(lines).alignment(Alignment::Center), area);
}

// ── Heatmap section ──────────────────────────────────────────────────────────

fn draw_heatmap_section(f: &mut Frame, app: &App, area: Rect) {
    let theme = &app.theme;
    let icons = app.icons;

    let block = section_panel(
        theme,
        Line::from(Span::styled(
            format!(" {} Focus activity ", icons.calendar),
            Style::default()
                .fg(theme.accent)
                .add_modifier(Modifier::BOLD),
        )),
    );
    let inner = block.inner(area);
    f.render_widget(block, area);

    let today_mins = crate::storage::today_focus_minutes(&app.data);
    heatmap::draw_focus_heatmap(
        f,
        inner,
        theme,
        icons,
        &app.heatmap_data,
        app.data.daily_goal_minutes,
        today_mins,
    );

    render_bottom_cap(f, theme, area);
}

// ── Summary panel ────────────────────────────────────────────────────────────

fn draw_summary(f: &mut Frame, app: &App, area: Rect) {
    let theme = &app.theme;
    let icons = app.icons;
    let (focus_n, custom_n, break_n) = app.session_counts;
    let today = crate::storage::today_focus_minutes(&app.data);

    let dim_style = Style::default().fg(theme.dim);
    let val_style = Style::default().fg(theme.text).add_modifier(Modifier::BOLD);

    let summary_rows: [(&str, &str, String); 5] = [
        (
            icons.target,
            "Today",
            format!(
                "{} / {}",
                format_minutes(today),
                format_minutes(app.data.daily_goal_minutes)
            ),
        ),
        (
            icons.fire,
            "Streak",
            format!(
                "{}d / {}d goal",
                app.data.streak_days, app.data.goal_streak_days
            ),
        ),
        (
            icons.timer,
            "Sessions",
            format!("{focus_n}p · {custom_n}c · {break_n}b"),
        ),
        (
            icons.chart,
            "Total",
            format_minutes(app.data.total_focus_minutes),
        ),
        (
            icons.star,
            "Peak Time",
            crate::storage::most_productive_hour_label(&app.data),
        ),
    ];

    let block = section_panel(
        theme,
        Line::from(Span::styled(
            format!(" {} Summary ", icons.stats),
            Style::default().fg(theme.accent),
        )),
    );
    let inner = block.inner(area);
    f.render_widget(block, area);

    let table_rows: Vec<Row> = summary_rows
        .iter()
        .map(|(icon, label, value)| {
            Row::new([
                Cell::from(Span::styled(format!("{icon} {label}"), dim_style)),
                Cell::from(Span::styled(value.as_str(), val_style)),
            ])
        })
        .collect();

    let table = Table::new(table_rows, [Constraint::Length(14), Constraint::Min(6)]);
    f.render_widget(table, inner);

    render_bottom_cap(f, theme, area);
}

// ── Weekly bar chart ─────────────────────────────────────────────────────────

fn draw_week_bars(f: &mut Frame, app: &App, area: Rect) {
    let theme = &app.theme;
    let icons = app.icons;
    let data = &app.weekly_chart;

    let block = section_panel(
        theme,
        Line::from(Span::styled(
            format!(" {} This week ", icons.chart),
            Style::default()
                .fg(theme.accent)
                .add_modifier(Modifier::BOLD),
        )),
    );
    let inner = block.inner(area);
    f.render_widget(block, area);

    if data.is_empty() {
        f.render_widget(
            Paragraph::new(Span::styled(
                "No sessions this week",
                Style::default().fg(theme.dim),
            ))
            .alignment(Alignment::Center),
            inner,
        );
    } else {
        render_week_chart(f, theme, icons, data, inner);
    }

    render_bottom_cap(f, theme, area);
}

/// Core bar-chart rendering extracted for clarity.
fn render_week_chart(
    f: &mut Frame,
    theme: &Theme,
    icons: IconSet,
    data: &[(String, u32)],
    inner: Rect,
) {
    let max_mins = data.iter().map(|(_, m)| *m).max().unwrap_or(1).max(1);
    let last_idx = data.len() - 1;
    let total_mins: u32 = data.iter().map(|(_, m)| *m).sum();
    let avg_mins = total_mins / data.len() as u32;

    // Layout: "▸DAY ████████░░░░ XXm"
    const LABEL_W: usize = 4;
    const MINS_W: usize = 6;
    let bar_max = (inner.width as usize)
        .saturating_sub(LABEL_W + MINS_W + 2)
        .max(4);

    // Show the most recent days so today is always visible.
    let visible_days = (inner.height as usize)
        .saturating_sub(3)
        .min(7)
        .min(data.len());
    let start_idx = data.len() - visible_days;

    // Pre-compute shared styles.
    let today_style = Style::default()
        .fg(theme.success)
        .add_modifier(Modifier::BOLD);
    let dim_style = Style::default().fg(theme.dim);
    let text_style = Style::default().fg(theme.text);
    let track_style = Style::default().fg(theme.progress_dim);
    let hidden_marker = Style::default().fg(theme.bg);

    let mut lines = Vec::with_capacity(visible_days + 2);

    for (idx, (day_label, mins)) in data.iter().enumerate().skip(start_idx) {
        let mins = *mins;
        let is_today = idx == last_idx;

        let fill = ((mins as u64 * bar_max as u64) / max_mins as u64) as usize;
        let empty = bar_max - fill;

        let (day_style, mins_style, bar_fg, marker, marker_style) = if is_today {
            (today_style, today_style, theme.success, "▸", today_style)
        } else {
            (dim_style, text_style, theme.accent, " ", hidden_marker)
        };

        lines.push(Line::from(vec![
            Span::styled(marker, marker_style),
            Span::styled(format!("{:<3} ", day_label), day_style),
            Span::styled("█".repeat(fill), Style::default().fg(bar_fg)),
            Span::styled("░".repeat(empty), track_style),
            Span::styled(format!(" {:>4}", format_minutes(mins)), mins_style),
        ]));
    }

    // Summary footer.
    if inner.height as usize > visible_days + 1 {
        lines.push(Line::from(""));
        lines.push(Line::from(vec![
            Span::styled(
                format!(" {} ", icons.chart),
                Style::default().fg(theme.accent),
            ),
            Span::styled(
                format!("{} total", format_minutes(total_mins)),
                Style::default().fg(theme.text).add_modifier(Modifier::BOLD),
            ),
            Span::styled(
                format!("  {}  ", icons.dot),
                Style::default().fg(theme.panel_border),
            ),
            Span::styled(format!("~{} avg/day", format_minutes(avg_mins)), dim_style),
        ]));
    }

    f.render_widget(Paragraph::new(lines).alignment(Alignment::Left), inner);
}

// ── Recent sessions ──────────────────────────────────────────────────────────

fn draw_recent_sessions(f: &mut Frame, app: &App, area: Rect) {
    let theme = &app.theme;
    let icons = app.icons;

    let block = section_panel(
        theme,
        Line::from(Span::styled(
            format!(" {} Recent sessions ", icons.calendar),
            Style::default().fg(theme.accent),
        )),
    );
    let inner = block.inner(area);
    f.render_widget(block, area);

    let items: Vec<ListItem> = if app.recent_sessions.is_empty() {
        vec![ListItem::new(Span::styled(
            "No sessions yet",
            Style::default().fg(theme.dim),
        ))]
    } else {
        let dim_style = Style::default().fg(theme.dim);
        let normal_style = Style::default().fg(theme.text);
        let selected_style = Style::default()
            .fg(theme.select_fg)
            .bg(theme.select_bg)
            .add_modifier(Modifier::BOLD);
        let mins_style = Style::default().fg(theme.success);

        app.recent_sessions
            .iter()
            .take(inner.height as usize)
            .enumerate()
            .map(|(idx, s)| {
                let style = if idx == app.stats_session_selected {
                    selected_style
                } else {
                    normal_style
                };

                ListItem::new(Line::from(vec![
                    Span::styled(
                        s.record.completed_at.format("%H:%M ").to_string(),
                        dim_style,
                    ),
                    Span::styled(format!("{}m ", s.record.minutes), mins_style),
                    Span::styled(session_task_label(app, s.record.task_id), style),
                ]))
                .style(style)
            })
            .collect()
    };

    f.render_widget(List::new(items), inner);

    render_bottom_cap(f, theme, area);
}

// ── Helpers ──────────────────────────────────────────────────────────────────

/// Renders the bottom border cap shared by all panel sections.
#[inline]
fn render_bottom_cap(f: &mut Frame, theme: &Theme, area: Rect) {
    let bottom = Rect {
        x: area.x,
        y: area.y + area.height.saturating_sub(1),
        width: area.width,
        height: 1,
    };
    f.render_widget(section_panel_bottom(theme), bottom);
}

/// Resolves a task ID to a truncated display label.
fn session_task_label(app: &App, task_id: Option<u64>) -> String {
    match task_id {
        None => "general".into(),
        Some(id) => app
            .data
            .tasks
            .iter()
            .find(|t| t.id == id)
            .map(|t| super::widgets::truncate(&t.title, 16))
            .unwrap_or_else(|| "?".into()),
    }
}