quadraui 0.6.1

//! Backend-agnostic app code for the Board (kanban) example
//! ([`tui_board`] / [`gtk_board`]).
//!
//! [`BoardApp`] demonstrates a three-column kanban board with cards in
//! each column, badge icons showing CI / review status, and a decision
//! hint on the selected card. It uses [`BoardModel`] for state and
//! [`Backend::draw_board`] for rendering.
//!
//! Controls:
//! - j / ↓  — move selection down
//! - k / ↑  — move selection up
//! - h / ←  — jump to previous column
//! - l / →  — jump to next column
//! - g       — jump to first card
//! - G       — jump to last card
//! - q / Esc — quit

use std::cell::RefCell;

use quadraui::{
    AppLogic, Backend, BadgeStatus, BoardAction, BoardCard, BoardColumn, BoardLayout, BoardModel,
    CardBadge, InteractionState, Key, MoveDir, NamedKey, Reaction, Rect, StatusBar,
    StatusBarSegment, UiEvent, WidgetId,
};

pub struct BoardApp {
    model: BoardModel,
    last_message: String,
    /// Cached board layout from the last render pass, used for click dispatch.
    ///
    /// Wrapped in `RefCell` so that `render(&self, …)` can update it while
    /// keeping the `AppLogic` signature immutable.  The `BoardLayout` is set
    /// every frame by `render` and read in `handle` for mouse hit-testing —
    /// avoids calling `backend.draw_board` outside an `enter_frame_scope`.
    last_layout: RefCell<Option<BoardLayout>>,
}

impl BoardApp {
    pub fn new() -> Self {
        Self {
            model: demo_board(),
            last_message: "j/k=move  h/l=col  g/G=top/bottom  q=quit".into(),
            last_layout: RefCell::new(None),
        }
    }

    fn status_bar(&self) -> StatusBar {
        let selected_title = self
            .model
            .selected_card_id
            .as_ref()
            .and_then(|id| {
                self.model.columns.iter().find_map(|col| {
                    col.cards
                        .iter()
                        .find(|c| &c.id == id)
                        .map(|c| c.title.clone())
                })
            })
            .unwrap_or_default();

        let right_text = if selected_title.is_empty() {
            " q=quit ".into()
        } else {
            format!(" {} │ q=quit ", selected_title)
        };

        StatusBar {
            id: WidgetId::new("status"),
            left_segments: vec![quadraui::StatusBarSegment {
                text: format!("  {} ", self.last_message),
                fg: quadraui::Color::rgb(255, 255, 255),
                bg: quadraui::Color::rgb(40, 80, 120),
                bold: false,
                action_id: None,
            }],
            right_segments: vec![StatusBarSegment {
                text: right_text,
                fg: quadraui::Color::rgb(200, 200, 200),
                bg: quadraui::Color::rgb(40, 80, 120),
                bold: false,
                action_id: None,
            }],
        }
    }
}

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

impl AppLogic for BoardApp {
    type AreaId = ();

    fn render(&self, backend: &mut dyn Backend, _area: ()) {
        let viewport = backend.viewport();
        let lh = backend.line_height();

        // Status bar at bottom.
        let status_h = lh;
        let status_rect = Rect::new(0.0, viewport.height - status_h, viewport.width, status_h);
        let _ = backend.draw_status_bar_interactive(
            status_rect,
            &self.status_bar(),
            &InteractionState::new(),
        );

        // Board fills the rest of the screen.
        let board_rect = Rect::new(0.0, 0.0, viewport.width, viewport.height - status_h);
        let layout = backend.draw_board(board_rect, &self.model);

        // Cache the layout so `handle` can hit-test mouse events without
        // calling `draw_board` outside a frame scope.
        *self.last_layout.borrow_mut() = Some(layout);
    }

    fn handle(&mut self, event: UiEvent, _backend: &mut dyn Backend) -> Reaction {
        match event {
            UiEvent::KeyPressed {
                key: Key::Char('q'),
                ..
            }
            | UiEvent::KeyPressed {
                key: Key::Named(NamedKey::Escape),
                ..
            } => Reaction::Exit,

            UiEvent::KeyPressed { key, .. } => {
                let action = key_to_board_action(&key);
                if let Some(act) = action {
                    self.apply_board_action(act);
                    Reaction::Redraw
                } else {
                    Reaction::Continue
                }
            }

            UiEvent::MouseDown { position, .. } => {
                use quadraui::BoardHit;
                // Use the layout cached by the last `render` call. If no render
                // has run yet (first event before first frame), skip hit-testing.
                let hit = self
                    .last_layout
                    .borrow()
                    .as_ref()
                    .map(|l| l.hit_test(position.x, position.y))
                    .unwrap_or(BoardHit::Empty);
                match hit {
                    BoardHit::Card(id) => {
                        self.model.selected_card_id = Some(id);
                        let title = self
                            .model
                            .columns
                            .iter()
                            .find_map(|col| {
                                col.cards
                                    .iter()
                                    .find(|c| c.id == id)
                                    .map(|c| c.title.clone())
                            })
                            .unwrap_or_default();
                        self.last_message = format!("Selected: {}", title);
                        Reaction::Redraw
                    }
                    BoardHit::ColumnHeader(_) | BoardHit::Empty => Reaction::Continue,
                }
            }

            UiEvent::WindowResized { .. } => Reaction::Redraw,
            _ => Reaction::Continue,
        }
    }
}

impl BoardApp {
    fn apply_board_action(&mut self, action: BoardAction) {
        match action {
            BoardAction::MoveSelection(dir) => {
                self.model.move_selection(dir);
                // After a horizontal column move, ensure the newly-selected
                // column is scrolled into view.
                if matches!(dir, MoveDir::Left | MoveDir::Right) {
                    self.clamp_col_scroll();
                }
            }
            BoardAction::JumpToTop => {
                self.model.jump_to_top();
            }
            BoardAction::JumpToBottom => {
                self.model.jump_to_bottom();
            }
            _ => {}
        }
    }

    /// Adjust `col_scroll_offset` so the currently-selected column is visible.
    ///
    /// Uses the layout cached by the last `render` call to know how many
    /// columns are visible. A no-op when no layout is cached yet.
    fn clamp_col_scroll(&mut self) {
        let Some(col_idx) = self.model.selected_col_index() else {
            return;
        };
        // Read visible column count from the cached layout, then drop the borrow
        // before mutating `self.model`.
        let visible = {
            let borrowed = self.last_layout.borrow();
            match borrowed.as_ref() {
                Some(l) => l.columns.len(),
                None => return,
            }
        };
        let offset = &mut self.model.col_scroll_offset;
        if col_idx < *offset {
            *offset = col_idx;
        } else if visible > 0 && col_idx >= *offset + visible {
            *offset = col_idx + 1 - visible;
        }
    }
}

fn key_to_board_action(key: &Key) -> Option<BoardAction> {
    match key {
        Key::Char('j') | Key::Named(NamedKey::Down) => {
            Some(BoardAction::MoveSelection(MoveDir::Down))
        }
        Key::Char('k') | Key::Named(NamedKey::Up) => Some(BoardAction::MoveSelection(MoveDir::Up)),
        Key::Char('h') | Key::Named(NamedKey::Left) => {
            Some(BoardAction::MoveSelection(MoveDir::Left))
        }
        Key::Char('l') | Key::Named(NamedKey::Right) => {
            Some(BoardAction::MoveSelection(MoveDir::Right))
        }
        Key::Char('g') => Some(BoardAction::JumpToTop),
        Key::Char('G') => Some(BoardAction::JumpToBottom),
        _ => None,
    }
}

// ── Demo data ───────────────────────────────────────────────────────────────

/// Shorthand for building a [`CardBadge`] in the demo data below. The
/// board primitive doesn't assign meaning to `label` or badge order —
/// this demo happens to use single-letter workflow-step labels.
fn badge(label: &str, status: BadgeStatus) -> CardBadge {
    CardBadge {
        label: label.into(),
        status,
    }
}

fn demo_board() -> BoardModel {
    let backlog = BoardColumn {
        id: WidgetId::new("col:backlog"),
        title: "Backlog".into(),
        cards: vec![
            BoardCard {
                id: WidgetId::new("card:1"),
                title: "Improve search indexing perf".into(),
                labels: vec!["perf".into()],
                badges: vec![
                    badge("P", BadgeStatus::Passed),
                    badge("W", BadgeStatus::Pending),
                ],
                hint: None,
            },
            BoardCard {
                id: WidgetId::new("card:2"),
                title: "Add dark-mode toggle".into(),
                labels: vec!["ui".into()],
                badges: vec![badge("P", BadgeStatus::Running)],
                hint: Some("Waiting for design sign-off".into()),
            },
            BoardCard {
                id: WidgetId::new("card:3"),
                title: "Fix memory leak in parser".into(),
                labels: vec!["bug".into()],
                badges: vec![],
                hint: None,
            },
        ],
        scroll_offset: 0,
    };

    let in_progress = BoardColumn {
        id: WidgetId::new("col:in-progress"),
        title: "In Progress".into(),
        cards: vec![
            BoardCard {
                id: WidgetId::new("card:4"),
                title: "Refactor auth middleware".into(),
                labels: vec!["refactor".into(), "security".into()],
                badges: vec![
                    badge("P", BadgeStatus::Passed),
                    badge("W", BadgeStatus::Running),
                    badge("T", BadgeStatus::Pending),
                ],
                hint: None,
            },
            BoardCard {
                id: WidgetId::new("card:5"),
                title: "Upgrade dependency stack".into(),
                labels: vec!["deps".into()],
                badges: vec![
                    badge("P", BadgeStatus::Passed),
                    badge("W", BadgeStatus::Passed),
                    badge("T", BadgeStatus::Blocked),
                ],
                hint: Some("blocked: upstream async-std 2.0 compat".into()),
            },
        ],
        scroll_offset: 0,
    };

    let review = BoardColumn {
        id: WidgetId::new("col:review"),
        title: "Review".into(),
        cards: vec![
            BoardCard {
                id: WidgetId::new("card:6"),
                title: "Paginate API list endpoints".into(),
                labels: vec!["api".into()],
                badges: vec![
                    badge("P", BadgeStatus::Passed),
                    badge("W", BadgeStatus::Passed),
                    badge("T", BadgeStatus::Passed),
                    badge("R", BadgeStatus::Warning),
                ],
                hint: Some("reviewer: needs integration test".into()),
            },
            BoardCard {
                id: WidgetId::new("card:7"),
                title: "Export CSV for analytics".into(),
                labels: vec!["feature".into()],
                badges: vec![
                    badge("P", BadgeStatus::Passed),
                    badge("W", BadgeStatus::Passed),
                    badge("T", BadgeStatus::Passed),
                    badge("R", BadgeStatus::Running),
                ],
                hint: None,
            },
        ],
        scroll_offset: 0,
    };

    BoardModel {
        id: WidgetId::new("board:main"),
        columns: vec![backlog, in_progress, review],
        selected_card_id: Some(WidgetId::new("card:4")),
        col_scroll_offset: 0,
    }
}