tix/ui/

filter_modal.rs

//! Filter modal widget (FR-014, T012 / WP02).
//!
//! The Tab-navigated filter editor: a `FilterModal` wraps a
//! [`StructuredFilter`](crate::search::StructuredFilter) in progress plus a
//! cursor over the field rows (mirrors `FormFocus` cycle in `src/ui/form.rs`
//! at 8–34). The widget is a **pure view + model**: it does not read keys at all.
//! [`App`](crate::app::App) routes them — `enter`/`l`/`right` open the focused row's
//! value picker (or the calendar on a date row), `ctrl+enter` commits, `esc` reverts
//! — and owns the transient picker. Criterion rows hold no typed text; a row's value
//! always comes from its picker. "Clear all" (FR-014) empties every criterion but
//! never fights the `/` text filter — the `/` query layer is reset by its own path.

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

use crate::search::{FilterField, StructuredFilter};
use crate::ui::pickers::DropdownState;
use crate::views::divergence::ActiveViewMarker;
use crate::views::plan::ViewPlan;
use crate::views::registry::ViewId;

use super::modal::modal_rect;
use super::views::ViewFeedback;

/// Where an open criterion picker draws inside `area` (the filter modal's own rect)
/// and the rect of each visible option row, or `None` when there is nothing to show.
///
/// Mirrors [`crate::ui::triage::dropdown_layout`]: one clamp rule, so the list never
/// overflows the surface that owns it — a box too short or too narrow to hold a
/// title and one row simply does not draw.
pub fn picker_layout(area: Rect, state: &DropdownState) -> Option<(Rect, Vec<Rect>)> {
    let visible = state.visible_indices();
    if visible.is_empty() {
        return None;
    }
    let inner = Block::default().borders(Borders::ALL).inner(area);
    let widest = visible
        .iter()
        .map(|index| state.options[*index].label.chars().count() as u16 + 2)
        .max()
        .unwrap_or(0);
    let width = (widest + 4).clamp(6, inner.width.max(6));
    let height = (visible.len() as u16 + 2).min(inner.height.max(3));
    if height < 3 || inner.width == 0 {
        return None;
    }
    let rect = Rect::new(inner.x, inner.y, width, height);
    let rows = (0..visible.len() as u16)
        .take(height as usize - 2)
        .map(|row| Rect::new(rect.x, rect.y + 1 + row, rect.width, 1))
        .collect();
    Some((rect, rows))
}

/// The Tab-navigated structured-filter editor (T012).
///
/// WP05 adds one thing to it: the **active saved view** (T024). The modal holds
/// the marker — the stable id and the normalized plan that was applied — plus the
/// already-rendered indicator/feedback the app derived (T026). It is deliberately
/// *not* live filter state: `clear()` empties the criteria and leaves the marker
/// alone, because "the view the board is associated with" and "the criteria in
/// force" are two different facts (C-006), and only the second is editable here.
pub struct FilterModal {
    /// The StructuredFilter being edited.
    filter: StructuredFilter,
    /// Field row the cursor is on (Assignee → Label → Status → Priority).
    focus: FilterField,
    /// The saved view the live board is associated with, if any (T024).
    active: Option<ActiveViewMarker>,
    /// The rendered indicator and detail lines for `active`, refreshed by the app
    /// (T026). The widget owns no comparison and no diagnostics text.
    feedback: Option<ViewFeedback>,
}

impl Default for FilterModal {
    fn default() -> Self {
        Self::new()
    }
}

impl FilterModal {
    pub fn new() -> Self {
        Self {
            filter: StructuredFilter::default(),
            focus: FilterField::Assignee,
            active: None,
            feedback: None,
        }
    }

    /// Seed the modal with an existing filter (used when re-opening the modal
    /// for an already-applied filter).
    pub fn with_filter(filter: StructuredFilter) -> Self {
        Self {
            filter,
            focus: FilterField::Assignee,
            active: None,
            feedback: None,
        }
    }

    /// Install the active saved-view marker and its rendered feedback (T024).
    ///
    /// Informational: this changes what the modal *shows*, never the criteria it
    /// edits. The app calls it when the modal opens and after every live change
    /// while it is open, so the indicator cannot describe a state the board is no
    /// longer in.
    pub fn set_active(&mut self, active: Option<ActiveViewMarker>, feedback: Option<ViewFeedback>) {
        self.active = active;
        self.feedback = feedback;
    }

    /// The active saved-view marker, when the board is associated with one.
    pub fn active(&self) -> Option<&ActiveViewMarker> {
        self.active.as_ref()
    }

    /// The stable id of the active view — the identity, never the name (C-002).
    pub fn view_id(&self) -> Option<&ViewId> {
        self.active.as_ref().map(ActiveViewMarker::view_id)
    }

    /// The normalized plan that was applied when the marker was set.
    pub fn applied_plan(&self) -> Option<&ViewPlan> {
        self.active.as_ref().map(ActiveViewMarker::applied_plan)
    }

    /// Replace the rendered feedback (T026), which the app recomputes on every
    /// live change.
    pub fn set_feedback(&mut self, feedback: Option<ViewFeedback>) {
        self.feedback = feedback;
    }

    /// The indicator and detail lines currently rendered, when there are any.
    pub fn feedback(&self) -> Option<&ViewFeedback> {
        self.feedback.as_ref()
    }

    /// The one-line indicator, when the board is associated with a saved view.
    pub fn indicator_line(&self) -> Option<String> {
        self.feedback
            .as_ref()
            .map(|feedback| feedback.indicator.clone())
    }

    /// The rows the active-view feedback occupies above the criteria — one for
    /// the indicator, one blank, one per detail line (0 without a view).
    ///
    /// Public because the app places the criterion rows' click targets from the
    /// same arithmetic the widget draws with (D6): a hit region that ignored the
    /// feedback block would jump focus to the wrong criterion.
    pub fn header_height(&self) -> u16 {
        match &self.feedback {
            Some(feedback) => u16::try_from(feedback.lines.len())
                .unwrap_or(u16::MAX)
                .saturating_add(2),
            None => 0,
        }
    }

    /// Read the in-progress criteria for editing (App writes a picker's choice
    /// into it) and for the commit that closes the modal.
    pub fn active_filter(&self) -> &StructuredFilter {
        &self.filter
    }

    pub fn active_filter_mut(&mut self) -> &mut StructuredFilter {
        &mut self.filter
    }

    /// Clear/reset **all** criteria (FR-014). Never touches the `/` text
    /// filter layer (reset is a pure structured-filter op, mirrored by the
    /// query layer's own reset).
    ///
    /// The active-view marker is untouched: emptying the criteria is a live
    /// change, and a live change is exactly what the marker's divergence report
    /// exists to name (C-006). Clearing the marker here would hide the divergence
    /// the user just created.
    pub fn clear(&mut self) {
        self.filter = StructuredFilter::default();
        self.focus = FilterField::Assignee;
    }

    /// Move focus to the next criterion row (Tab).
    pub fn focus_next(&mut self) {
        self.focus = self.focus.next();
    }

    /// Move focus to the previous criterion row (Shift+Tab).
    pub fn focus_prev(&mut self) {
        self.focus = self.focus.prev();
    }

    /// Jump focus directly to a specific criterion row (a row click, D6) —
    /// the same focus state the Tab/arrow cycling produces, chosen directly.
    pub fn focus_field(&mut self, field: FilterField) {
        if FilterField::ALL.contains(&field) {
            self.focus = field;
        }
    }

    /// The currently-focused criterion row.
    pub fn focus(&self) -> FilterField {
        self.focus
    }

    /// Whether the focused criterion is a picker-only date field.
    pub fn is_date_focus(&self) -> bool {
        self.focus.is_date()
    }

    /// The focused criterion's value, or `""` when unset.
    pub fn focused_value(&self) -> String {
        self.focus.value(&self.filter).unwrap_or("").to_string()
    }

    /// Overwrite the focused date criterion (no-op when it isn't a date field).
    /// An empty value clears the criterion.
    pub fn set_focused_date(&mut self, value: &str) {
        if !self.focus.is_date() {
            return;
        }
        if value.is_empty() {
            self.focus.unset(&mut self.filter);
        } else {
            *self.focus.value_mut(&mut self.filter) = value.to_string();
        }
    }

    /// Render the filter modal: a bordered, centered box (via
    /// [`modal_rect`]) listing each criterion row (label + value)
    /// with the focused row highlighted; unset criteria show a placeholder.
    pub fn render(&self, f: &mut Frame, area: Rect) {
        let bindings =
            crate::keybindings::KeyBindings::resolve(&crate::keybindings::KeyBindings::default())
                .expect("built-in bindings are valid");
        self.render_with_bindings(
            f,
            area,
            &bindings,
            crate::keybindings::InputContext::FilterModal,
        );
    }

    pub fn render_with_bindings(
        &self,
        f: &mut Frame,
        area: Rect,
        bindings: &crate::keybindings::EffectiveBindings,
        context: crate::keybindings::InputContext,
    ) {
        let rect = modal_rect(area);
        let mut rows: Vec<Line> = Vec::new();

        // The active saved view renders **above** the criteria (T024/T026): the
        // indicator is the same line the board's own row shows, and the lines
        // under it are the divergence/diagnostics the app computed. Nothing here
        // is edited by this modal.
        if let Some(feedback) = &self.feedback {
            rows.push(Line::from(Span::styled(
                feedback.indicator.clone(),
                Style::default()
                    .fg(Color::Green)
                    .add_modifier(Modifier::BOLD),
            )));
            for line in &feedback.lines {
                rows.push(Line::from(Span::styled(
                    line.clone(),
                    Style::default().fg(Color::DarkGray),
                )));
            }
            rows.push(Line::from(""));
        }

        for field in FilterField::ALL {
            let (label, value) = (field.label(), field.value(&self.filter));
            let is_focus = field == self.focus;
            let value_text = value.unwrap_or("(unset)");
            let style = if is_focus {
                Style::default()
                    .fg(Color::Yellow)
                    .add_modifier(Modifier::BOLD)
            } else {
                Style::default().fg(Color::White)
            };
            let label_style = if is_focus {
                Style::default()
                    .fg(Color::Cyan)
                    .add_modifier(Modifier::BOLD)
            } else {
                Style::default().fg(Color::DarkGray)
            };
            let prefix = if is_focus { "> " } else { "  " };
            rows.push(Line::from(vec![
                ratatui::text::Span::styled(format!("{prefix}{label}:"), label_style),
                ratatui::text::Span::styled(format!(" {value_text}"), style),
            ]));
        }

        // The separator is cosmetic: keep it only while the three hint lines below
        // still fit, so a criterion list that grew (WP06's `Epic` row) cannot push
        // the last hint — the one that says how to apply and close — out of the
        // modal's fixed 75%-height rect.
        let inner_h = rect.height.saturating_sub(2) as usize;
        if rows.len() + 3 < inner_h {
            rows.push(Line::from(""));
        }
        rows.push(Line::from(Span::styled(
            format!(
                "{}/{}: navigate",
                bindings.label(context, crate::keybindings::TuiAction::Next),
                bindings.label(context, crate::keybindings::TuiAction::Previous),
            ),
            Style::default().fg(Color::DarkGray),
        )));
        // Two lines rather than one: the modal is 75% of the terminal, so at 80
        // columns the interior is 58 wide and a single hint line carrying four
        // bindings would be silently truncated.
        rows.push(Line::from(Span::styled(
            format!(
                "{}: open \u{b7} {}: reset",
                bindings.label(context, crate::keybindings::TuiAction::OpenPicker),
                bindings.label(context, crate::keybindings::TuiAction::Reset),
            ),
            Style::default().fg(Color::DarkGray),
        )));
        // One wording for both exits: the modal applies ad-hoc, so closing keeps the
        // criteria and neither key is a discard.
        rows.push(Line::from(Span::styled(
            format!(
                "{} / {}: apply & close",
                bindings.label(context, crate::keybindings::TuiAction::Submit),
                bindings.label(context, crate::keybindings::TuiAction::Cancel),
            ),
            Style::default().fg(Color::DarkGray),
        )));

        let block = Block::default()
            .borders(Borders::ALL)
            .title(" Filter ")
            .style(Style::default().fg(Color::Cyan));
        let para = Paragraph::new(rows).block(block).style(Style::default());
        f.render_widget(Clear, rect);
        f.render_widget(para, rect);
    }
}

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

    fn smoke(w: u16, h: u16, title_focus: bool) {
        let backend = TestBackend::new(w, h);
        let mut terminal = Terminal::new(backend).unwrap();
        terminal
            .draw(|f| {
                let area = f.area();
                let mut modal = FilterModal::new();
                if title_focus {
                    modal.focus_next();
                }
                modal.render(f, area);
            })
            .unwrap();
    }

    #[test]
    fn renders_at_120x40() {
        smoke(120, 40, false);
    }

    #[test]
    fn renders_at_80x24() {
        smoke(80, 24, false);
    }

    #[test]
    fn renders_at_tiny_20x5() {
        smoke(20, 5, true);
    }

    fn buffer_text(w: u16, h: u16) -> String {
        let backend = TestBackend::new(w, h);
        let mut terminal = Terminal::new(backend).unwrap();
        terminal
            .draw(|f| {
                let modal = FilterModal::new();
                modal.render(f, f.area());
            })
            .unwrap();
        let buffer = terminal.backend().buffer();
        let mut text = String::new();
        for y in 0..h {
            for x in 0..w {
                for ch in buffer[(x, y)].symbol().chars() {
                    text.push(ch);
                }
            }
            text.push('\n');
        }
        text
    }

    #[test]
    fn footer_hint_present_at_normal_size() {
        let text = buffer_text(80, 24);
        assert!(
            text.contains("Tab / Down/Shift+Tab / Up: navigate"),
            "footer must advertise field navigation, got:\n{text}"
        );
        assert!(
            text.contains("F2 / Enter / l / Right: open"),
            "footer must advertise the row picker on enter/l/right, got:\n{text}"
        );
        assert!(
            text.contains("r / Shift+R: reset"),
            "footer must advertise the reset key, got:\n{text}"
        );
        assert!(
            text.contains("a / Esc: apply & close"),
            "footer must advertise that closing applies the filter, got:\n{text}"
        );
    }

    #[test]
    fn footer_render_does_not_panic_on_tiny_terminal() {
        let text = buffer_text(20, 5);
        assert_ne!(text, "");
    }

    #[test]
    fn focus_cycles_forward() {
        let mut modal = FilterModal::new();
        assert_eq!(modal.focus(), FilterField::Assignee);
        modal.focus_next();
        assert_eq!(modal.focus(), FilterField::Label);
        modal.focus_next();
        modal.focus_next();
        assert_eq!(modal.focus(), FilterField::Priority);
        modal.focus_next();
        assert_eq!(modal.focus(), FilterField::Cycle);
    }

    #[test]
    fn focus_cycles_backward() {
        let mut modal = FilterModal::new();
        // The backward wrap lands on the **last** row, whatever that is — and the
        // last row has changed four times. `Parent` was appended as the tenth (T024
        // step 2), `Category` as the eleventh (WP08 T034 step 2), `Project` as the
        // twelfth (WP06 T026) and `Epic` as the thirteenth (WP06 T028), all appended
        // rather than interleaved. This is the one place the appending decision is
        // visible, and it is visible on purpose: a user pressing Up from the first
        // row should reach the last row, not a row chosen by history.
        modal.focus_prev();
        assert_eq!(modal.focus(), FilterField::Epic);
        modal.focus_prev();
        assert_eq!(modal.focus(), FilterField::Project);
        modal.focus_prev();
        assert_eq!(modal.focus(), FilterField::Category);
        modal.focus_prev();
        assert_eq!(modal.focus(), FilterField::Parent);
        modal.focus_prev();
        assert_eq!(modal.focus(), FilterField::DueDate);
        modal.focus_prev();
        assert_eq!(modal.focus(), FilterField::StartDate);
    }

    #[test]
    fn clear_resets_all_criteria_and_focus() {
        let mut modal = FilterModal::with_filter(StructuredFilter {
            assignee: Some("alice".to_string()),
            label: Some("urgent".to_string()),
            status: Some("todo".to_string()),
            priority: Some("high".to_string()),
            cycle: None,
            milestone: None,
            reviewer: None,
            start_date: None,
            due_date: None,
            overdue: None,
            parent: None,
            category: None,
            scope: None,
            archived: None,
            project: None,
            epic: None,
        });
        modal.clear();
        assert_eq!(modal.active_filter(), &StructuredFilter::default());
        assert_eq!(modal.focus(), FilterField::Assignee);
    }
}