tix-tracker 0.12.0

//! The F3 Cycle mode: cycles grouped chronologically with their statistics.
//!
//! The mode is a pure view + a cursor (`CycleState`): the app builds the
//! [`CycleEntry`] list through [`crate::planning::Planner`] and the cycle store
//! and the widget only groups, renders, and reports the row rectangles it drew
//! so a click selects a cycle.
//!
//! Grouping is chronological and absolute-date based — a cycle is *current*
//! when today sits inside its window (or it has no end date at all), *future*
//! when its start date is still ahead, and *archived* once its due date has
//! passed. It is derived, never stored: the same cycle moves between groups as
//! the clock advances, which is exactly what "current" has to mean.

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

use crate::app::{Action, App};
use crate::keybindings::{InputContext, TuiAction};

pub use crate::planning::Progress;

/// Where a cycle sits relative to today.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum CycleGroup {
    /// Today is inside the cycle's window, or the cycle has no end date.
    Current,
    /// The cycle's start date is still ahead.
    Future,
    /// The cycle's due date has passed.
    Archived,
}

impl CycleGroup {
    /// The three groups, in the order the mode lists them.
    pub const ALL: [Self; 3] = [Self::Current, Self::Future, Self::Archived];

    /// The heading shown above the group.
    pub const fn label(self) -> &'static str {
        match self {
            Self::Current => "Current",
            Self::Future => "Future",
            Self::Archived => "Archived",
        }
    }
}

/// One cycle as the mode lists it: identity, dates, and its issue statistics.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct CycleEntry {
    pub name: String,
    pub description: String,
    pub start_date: Option<String>,
    pub due_date: Option<String>,
    pub progress: Progress,
}

impl CycleEntry {
    /// Which chronological group this cycle belongs to on `today`.
    ///
    /// A passed due date wins outright (a cycle is archived the day after it
    /// ends, even if its start is somehow in the future); otherwise a start
    /// date still ahead makes it future; everything else — including the
    /// implicit `Default` with no dates — is current.
    pub fn group(&self, today: &str) -> CycleGroup {
        if self.due_date.as_deref().is_some_and(|due| due < today) {
            CycleGroup::Archived
        } else if self
            .start_date
            .as_deref()
            .is_some_and(|start| start > today)
        {
            CycleGroup::Future
        } else {
            CycleGroup::Current
        }
    }

    /// The mode's one-line row: name, start date, due date. A missing date
    /// renders as `—`, never as an empty column that looks like a rendering
    /// glitch.
    pub fn row_line(&self) -> String {
        let date = |value: &Option<String>| value.clone().unwrap_or_else(|| "—".to_string());
        format!(
            "{}   {} → {}",
            self.name,
            date(&self.start_date),
            date(&self.due_date)
        )
    }
}

/// The mode's cursor state. Session-only; the selected index is over the
/// **entries** (never a group heading), so `j`/`k` walk cycles and nothing
/// else.
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
pub struct CycleState {
    pub selected: usize,
}

impl CycleState {
    /// Move the cursor, clamped to `len` entries.
    pub fn move_selected(&mut self, delta: isize, len: usize) {
        if len == 0 {
            self.selected = 0;
            return;
        }
        let next = self.selected as isize + delta;
        self.selected = next.clamp(0, len as isize - 1) as usize;
    }

    /// Jump to the first entry of the group `delta` groups away, clamped at the
    /// ends: `h` in the first section and `l` in the last stay in that section
    /// rather than wrapping (tui-cycle-mode).
    ///
    /// Only groups that actually have entries are landing sites. An empty
    /// section renders nothing, so jumping to it would be a keystroke with no
    /// visible effect; skipping it is what "the rendered groups" means.
    pub fn move_group(&mut self, groups: &[CycleGrouping], delta: isize) {
        let starts = group_starts(groups);
        if starts.is_empty() {
            self.selected = 0;
            return;
        }
        // The group holding the cursor: the last one that starts at or before
        // it. A stale index past the end belongs to the last group rather than
        // to a nonexistent one.
        let current = starts
            .iter()
            .rposition(|start| *start <= self.selected)
            .unwrap_or(0);
        let last = starts.len() as isize - 1;
        self.selected = starts[(current as isize + delta).clamp(0, last) as usize];
    }
}

/// The flat index of each non-empty group's first entry, in listing order.
fn group_starts(groups: &[CycleGrouping]) -> Vec<usize> {
    let mut starts = Vec::new();
    let mut offset = 0usize;
    for grouping in groups {
        if grouping.entries.is_empty() {
            continue;
        }
        starts.push(offset);
        offset += grouping.entries.len();
    }
    starts
}

/// One chronological section of the listing.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct CycleGrouping {
    pub group: CycleGroup,
    pub entries: Vec<CycleEntry>,
}

/// Group `entries` into current/future/archived, each section ordered oldest
/// first (start date, then due date, then name) so the listing reads
/// chronologically top to bottom.
///
/// Empty sections are kept (they carry a count of zero and render as nothing),
/// so the caller can reason about all three without re-deriving them.
pub fn group_entries(entries: Vec<CycleEntry>, today: &str) -> Vec<CycleGrouping> {
    let mut groups: Vec<CycleGrouping> = CycleGroup::ALL
        .iter()
        .map(|group| CycleGrouping {
            group: *group,
            entries: Vec::new(),
        })
        .collect();
    for entry in entries {
        let group = entry.group(today);
        let slot = groups
            .iter_mut()
            .find(|slot| slot.group == group)
            .expect("all three groups exist");
        slot.entries.push(entry);
    }
    for slot in &mut groups {
        slot.entries.sort_by_key(|entry| {
            (
                entry.start_date.clone().unwrap_or_default(),
                entry.due_date.clone().unwrap_or_default(),
                entry.name.clone(),
            )
        });
    }
    groups
}

/// The flat, order-preserving list of entries across the groups — the order
/// the cursor indexes into.
pub fn flat_entries(groups: &[CycleGrouping]) -> Vec<&CycleEntry> {
    groups
        .iter()
        .flat_map(|group| group.entries.iter())
        .collect()
}

fn percent(progress: &Progress) -> usize {
    (progress.done * 100)
        .checked_div(progress.total)
        .unwrap_or(0)
}

/// Draw the Cycle mode into `area` and record one click region per visible row.
#[allow(clippy::too_many_lines)]
pub fn render(app: &App, f: &mut Frame, area: Rect, state: &CycleState, groups: &[CycleGrouping]) {
    let block = Block::default()
        .borders(Borders::ALL)
        .title(" cycles ")
        .border_style(Style::default().fg(Color::Cyan));
    let inner = block.inner(area);
    f.render_widget(block, area);

    let chunks = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Min(3),
            Constraint::Length(2),
            // The focused cycle's flat issue table (shared with the Milestones
            // mode) sits below the listing and its statistics.
            Constraint::Min(4),
            Constraint::Length(1),
        ])
        .split(inner);

    let entries = flat_entries(groups);
    let selected = entries
        .len()
        .checked_sub(1)
        .map_or(0, |last| usize::min(state.selected, last));

    // The list: group headings interleaved with their rows, cursor-highlighted.
    let mut lines: Vec<Line> = Vec::new();
    let mut rows: Vec<(usize, u16)> = Vec::new();
    let mut ordinal = 0usize;
    if entries.is_empty() {
        lines.push(Line::from(Span::styled(
            "No cycles yet — press m to manage cycles and milestones.",
            Style::default().fg(Color::DarkGray),
        )));
    }
    for grouping in groups {
        if grouping.entries.is_empty() {
            continue;
        }
        lines.push(Line::from(Span::styled(
            format!("{} ({})", grouping.group.label(), grouping.entries.len()),
            Style::default()
                .fg(Color::Cyan)
                .add_modifier(Modifier::BOLD),
        )));
        for entry in &grouping.entries {
            let cursor = if ordinal == selected { "> " } else { "  " };
            let style = if ordinal == selected {
                Style::default()
                    .fg(Color::Yellow)
                    .add_modifier(Modifier::BOLD)
            } else {
                Style::default().fg(Color::White)
            };
            lines.push(Line::from(vec![
                Span::styled(cursor, style),
                Span::styled(entry.row_line(), style),
            ]));
            rows.push((ordinal, (lines.len() - 1) as u16));
            ordinal += 1;
        }
    }

    let view_h = chunks[0].height;
    let selected_line = rows
        .iter()
        .find(|(index, _)| *index == selected)
        .map_or(0, |(_, line)| *line);
    let top = selected_line.saturating_sub(view_h.saturating_sub(1));
    let list = Paragraph::new(lines).scroll((top, 0));
    f.render_widget(list, chunks[0]);

    // One click target per entry, computed from the scroll actually applied so a
    // click maps to the row that was painted (the triage/tab pattern).
    for (index, line) in &rows {
        if *line < top || *line - top >= view_h {
            continue;
        }
        let rect = Rect {
            x: chunks[0].x,
            y: chunks[0].y + (*line - top),
            width: chunks[0].width,
            height: 1,
        };
        app.record_region(rect, Action::CycleSelect(*index));
    }

    // Statistics for the selected cycle. An empty cycle is `0/0 (0%)`, never an
    // error and never a division by zero.
    let stats = match entries.get(selected) {
        Some(entry) => vec![
            Line::from(Span::styled(
                format!(" {} ", entry.name),
                Style::default()
                    .fg(Color::Yellow)
                    .add_modifier(Modifier::BOLD),
            )),
            Line::from(format!(
                " Issues: {}   Completed: {}/{} ({}%)",
                entry.progress.total,
                entry.progress.done,
                entry.progress.total,
                percent(&entry.progress),
            )),
        ],
        None => vec![
            Line::from(Span::styled(
                " Statistics ",
                Style::default().fg(Color::DarkGray),
            )),
            Line::from(" Issues: 0   Completed: 0/0 (0%)"),
        ],
    };
    f.render_widget(Paragraph::new(stats), chunks[1]);

    // The focused cycle's issues, as a flat table: membership is exact string
    // matching on `cycles`, the same rule the statistics above are counted
    // with, and the same table the Milestones mode draws.
    let (issues_title, issues) = match entries.get(selected) {
        Some(entry) => (
            format!("issues — {}", entry.name),
            crate::ui::issue_table::cycle_rows(&app.store, &entry.name),
        ),
        None => ("issues".to_string(), Vec::new()),
    };
    crate::ui::issue_table::render(app, f, chunks[2], &issues_title, &issues);

    let hints = format!(
        "{}: move · {}: group · {}: manage cycles/milestones · {}: close",
        app.bindings.label(InputContext::Cycle, TuiAction::MoveDown),
        app.bindings
            .label(InputContext::Cycle, TuiAction::MoveRight),
        app.bindings.label(InputContext::Cycle, TuiAction::Planning),
        app.bindings.label(InputContext::Cycle, TuiAction::Close),
    );
    f.render_widget(
        Paragraph::new(Line::from(Span::styled(
            hints,
            Style::default().fg(Color::DarkGray),
        ))),
        chunks[3],
    );
}

#[cfg(test)]
mod tests {
    #[allow(clippy::wildcard_imports)]
    use super::*;

    fn entry(name: &str, start: Option<&str>, due: Option<&str>) -> CycleEntry {
        CycleEntry {
            name: name.to_string(),
            description: String::new(),
            start_date: start.map(str::to_string),
            due_date: due.map(str::to_string),
            progress: Progress { done: 0, total: 0 },
        }
    }

    const TODAY: &str = "2026-10-02";

    #[test]
    fn classifies_current_future_and_archived() {
        let past = entry("Past", Some("2026-01-01"), Some("2026-03-01"));
        let current = entry("Current", Some("2026-09-01"), Some("2026-11-01"));
        let future = entry("Future", Some("2027-01-01"), Some("2027-02-01"));
        assert_eq!(past.group(TODAY), CycleGroup::Archived);
        assert_eq!(current.group(TODAY), CycleGroup::Current);
        assert_eq!(future.group(TODAY), CycleGroup::Future);
    }

    #[test]
    fn a_cycle_with_no_end_date_is_current() {
        let open = entry("Open", Some("2026-01-01"), None);
        assert_eq!(open.group(TODAY), CycleGroup::Current);
        // ...and so is the implicit `Default`, which has no dates at all.
        let default = entry("Default", None, None);
        assert_eq!(default.group(TODAY), CycleGroup::Current);
    }

    #[test]
    fn groups_are_ordered_current_future_archived_and_chronological() {
        let entries = vec![
            entry("Archived B", Some("2025-02-01"), Some("2025-03-01")),
            entry("Future", Some("2027-01-01"), Some("2027-02-01")),
            entry("Current", Some("2026-09-01"), Some("2026-11-01")),
            entry("Archived A", Some("2025-01-01"), Some("2025-01-20")),
        ];
        let groups = group_entries(entries, TODAY);
        let names: Vec<&str> = flat_entries(&groups)
            .into_iter()
            .map(|e| e.name.as_str())
            .collect();
        assert_eq!(
            names,
            vec!["Current", "Future", "Archived A", "Archived B"],
            "current first, then future, then archived oldest-first"
        );
        assert_eq!(groups[0].group, CycleGroup::Current);
        assert_eq!(groups[1].group, CycleGroup::Future);
        assert_eq!(groups[2].group, CycleGroup::Archived);
    }

    #[test]
    fn row_line_shows_name_start_and_due_with_a_dash_for_missing_dates() {
        assert_eq!(
            entry("Sprint", Some("2026-09-01"), Some("2026-09-14")).row_line(),
            "Sprint   2026-09-01 → 2026-09-14"
        );
        assert_eq!(entry("Default", None, None).row_line(), "Default   — → —");
    }

    #[test]
    fn cursor_moves_and_clamps_and_empty_is_zero() {
        let mut state = CycleState::default();
        state.move_selected(1, 2);
        assert_eq!(state.selected, 1);
        state.move_selected(1, 2);
        assert_eq!(state.selected, 1, "clamped at the last entry");
        state.move_selected(-1, 2);
        assert_eq!(state.selected, 0);
        state.move_selected(-1, 2);
        assert_eq!(state.selected, 0, "clamped at the first entry");
        state.move_selected(1, 0);
        assert_eq!(state.selected, 0, "an empty list keeps the cursor at zero");
    }

    #[test]
    fn percent_is_zero_for_an_empty_cycle() {
        assert_eq!(percent(&Progress { done: 0, total: 0 }), 0);
        assert_eq!(percent(&Progress { done: 1, total: 4 }), 25);
        assert_eq!(percent(&Progress { done: 4, total: 4 }), 100);
    }

    #[test]
    fn a_group_jump_lands_on_the_first_entry_of_the_next_rendered_group() {
        let entries = vec![
            entry("Current A", Some("2026-09-01"), Some("2026-11-01")),
            entry("Current B", Some("2026-09-02"), Some("2026-11-02")),
            entry("Future", Some("2027-01-01"), Some("2027-02-01")),
            entry("Archived A", Some("2025-01-01"), Some("2025-02-01")),
            entry("Archived B", Some("2025-02-01"), Some("2025-03-01")),
        ];
        let groups = group_entries(entries, TODAY);
        let mut state = CycleState::default();

        state.move_group(&groups, 1);
        assert_eq!(state.selected, 2, "the first Future entry");
        state.move_group(&groups, 1);
        assert_eq!(state.selected, 3, "the first Archived entry");
        state.move_group(&groups, 1);
        assert_eq!(state.selected, 3, "the last group clamps");
        state.move_group(&groups, -1);
        assert_eq!(state.selected, 2);
        state.move_group(&groups, -1);
        assert_eq!(state.selected, 0, "back to the first Current entry");
        state.move_group(&groups, -1);
        assert_eq!(state.selected, 0, "the first group clamps");
    }

    #[test]
    fn a_group_jump_from_inside_a_group_lands_on_that_groups_first_entry() {
        let entries = vec![
            entry("Current A", Some("2026-09-01"), Some("2026-11-01")),
            entry("Current B", Some("2026-09-02"), Some("2026-11-02")),
            entry("Future", Some("2027-01-01"), Some("2027-02-01")),
        ];
        let groups = group_entries(entries, TODAY);
        let mut state = CycleState { selected: 1 };
        state.move_group(&groups, -1);
        assert_eq!(state.selected, 0, "clamped, and still the first entry");
    }

    #[test]
    fn a_group_jump_skips_an_empty_section_and_survives_an_empty_list() {
        // Current has two entries, Future none, Archived one: the empty one
        // renders nothing, so it is not a landing site.
        let entries = vec![
            entry("Current A", Some("2026-09-01"), Some("2026-11-01")),
            entry("Current B", Some("2026-09-02"), Some("2026-11-02")),
            entry("Archived", Some("2025-01-01"), Some("2025-02-01")),
        ];
        let groups = group_entries(entries, TODAY);
        assert!(groups[1].entries.is_empty(), "Future really is empty");
        let mut state = CycleState::default();
        state.move_group(&groups, 1);
        assert_eq!(
            state.selected, 2,
            "the Archived entry, not the empty Future"
        );

        let mut empty = CycleState { selected: 4 };
        empty.move_group(&[], 1);
        assert_eq!(
            empty.selected, 0,
            "an empty listing keeps the cursor at zero"
        );
    }
}