quadraui 0.2.2

//! Direct2D / DirectWrite rasteriser for [`crate::ListView`].
//!
//! Content painting (background, title, rows, h/v scrollbars) is shared via
//! [`crate::primitives::list::native_surface_paint::paint`] — see that fn's
//! module doc for what's shared and what stays per-backend. This module owns
//! the [`ListView::bordered`] frame itself: a plain (square-cornered) 1-DIP
//! rectangle border painted *after* the shared content paint. Painting the
//! border after, not before, matters: the shared `paint` unconditionally fills
//! the whole rect with `base_bg` as its first operation, which would erase a
//! border drawn beforehand.
//!
//! [`win_list_layout`] itself needs no Direct2D/DirectWrite type — it's pure
//! geometry over [`crate::primitives::layout_metrics::list_layout`], same as
//! `mac_list_layout` / `gtk_list_layout` — so only [`draw_list`] (the actual
//! Direct2D paint entry point) is `#[cfg(target_os = "windows")]`-gated;
//! `win_list_layout` compiles and runs everywhere. See `super::mod`'s `mod list;`
//! and `backend.rs`'s module docs. See `win::status_bar`'s module doc for why
//! colours come from `Theme::default()` rather than a live `WinBackend` theme field.
//!
//! # Scope for #26
//!
//! `bordered` lists get a plain (square-cornered) 1-DIP rectangle border rather
//! than GTK's rounded-rect stroke — Direct2D's rounded rectangle would need a
//! second brush/geometry path for no visual contract this issue depends on.
//! Nerd-Font icon glyphs are not distinguished from ASCII fallbacks — see
//! `win::tree`'s module doc for why.
//!
//! # H-scrollbar row reservation now shared
//!
//! [`win_list_layout`] now reserves a bottom row for an h-scrollbar by routing
//! through [`crate::primitives::layout_metrics::list_layout`] (with `border_inset`
//! derived from [`ListView::bordered`], matching [`BORDER_DIP`]), matching
//! `gtk_list_layout` / `mac_list_layout`. Windows now reserves the same row every
//! other pixel backend does, and [`draw_list`] passes `supports_hscrollbar: true`
//! to the shared paint to match.

use crate::event::Rect;
use crate::primitives::list::{ListView, ListViewLayout};

/// Border thickness (DIPs) for a `bordered` list — matches the 1-unit
/// inset [`ListView::layout`] itself bakes in for bordered lists, and
/// the `border_inset` [`win_list_layout`] passes to
/// [`crate::primitives::layout_metrics::list_layout`].
const BORDER_DIP: f32 = 1.0;

/// Compute a [`ListView`]'s layout without painting — the DirectWrite twin of
/// [`draw_list`]'s internal layout call. Pure geometry (no Direct2D/DirectWrite
/// type in its signature), so unlike [`draw_list`], this is not
/// `target_os = "windows"`-gated; see this module's doc.
///
/// `char_width` is used only for the h-scrollbar-overflow threshold check
/// (`ListView::max_content_width` is in character columns); pass a live
/// `DWrite`-measured glyph width when painting (see [`draw_list`]), or
/// [`crate::backend::Backend::char_width`]'s cached value for a no-paint layout,
/// matching every other pixel backend's `Backend::list_layout`.
/// ```text
/// $ grep -rn 'win_list_layout\|win_data_table_layout\|win_menu_bar_layout\|win_status_bar_layout\|win_spinner_layout\|win_toast_stack_layout\|win_tab_bar_layout\|win_tab_bar_layout_icons\|win_tab_bar_native_layout\|win_tab_bar_native_layout_icons' \
///     ~/src/coord-tui/src ~/src/vimcode/src
/// (no output — zero hits in both, for every symbol above)
/// ```
///
/// Both consumers reach the Win-GUI backend only through the `Backend`
/// trait (`WinBackend`) or `quadraui::win::shell_runner::run_with_shell` /
/// `quadraui::win::testing::driver_with_shell` — neither calls any raw
/// `win::*_layout` free function directly. Changing this signature is a
/// no-op for both today.
pub fn win_list_layout(
    list: &ListView,
    rect: Rect,
    line_height: f32,
    char_width: f32,
) -> ListViewLayout {
    let border_inset = if list.bordered {
        BORDER_DIP as f64
    } else {
        0.0
    };
    crate::primitives::layout_metrics::list_layout(
        list,
        rect.width as f64,
        rect.height as f64,
        line_height as f64,
        char_width as f64,
        border_inset,
    )
}

/// Draw a [`ListView`] into `rect` (DIPs) on `target`. Returns the resolved
/// [`ListViewLayout`] for host click dispatch (list-local coordinates, matching
/// every other backend's `draw_list` contract).
///
/// # Visual contract
///
/// - **Background:** `Theme::surface_bg` when `bordered`, else
///   `Theme::background`.
/// - **Selected row:** `Theme::selected_bg`.
/// - **Header-decorated row:** `Theme::header_bg` / `header_fg`.
/// - **Muted / Error / Warning rows:** `muted_fg` / `error_fg` / `warning_fg`
///   on the row's own background.
/// - **Detail span:** right-aligned in `muted_fg`, skipped when there isn't
///   room past the main text.
/// - **Vertical scrollbar:** painted via
///   [`crate::primitives::scrollbar::native_surface_paint::paint`] when
///   [`ListView::show_v_scrollbar`] calls for one.
#[cfg(target_os = "windows")]
pub fn draw_list(
    target: &windows::Win32::Graphics::Direct2D::ID2D1RenderTarget,
    dwrite: &super::text::DWrite,
    rect: Rect,
    list: &ListView,
    line_height: f32,
) -> ListViewLayout {
    use super::text::fill_rect;
    use crate::theme::Theme;

    let theme = Theme::default();
    let char_width = dwrite
        .measure_text("M")
        .map(|(w, _)| w)
        .unwrap_or(0.0)
        .max(1.0);
    let layout = win_list_layout(list, rect, line_height, char_width);

    let mut surface = super::surface::D2dSurface {
        target,
        dwrite: Some(dwrite),
    };
    crate::primitives::list::native_surface_paint::paint(
        list,
        rect,
        &layout,
        line_height,
        // Nerd-Font icon glyphs: this rasteriser has never distinguished
        // `Icon::glyph` from `Icon::fallback` (unlike `win::tree`, wired
        // in #804) — extending it is separate, unstarted scope (see this
        // module's doc). `false` preserves that exactly.
        /* nerd_fonts_enabled */
        false,
        /* supports_border */ true,
        // `win_list_layout` now reserves the h-scrollbar row via
        // the shared `layout_metrics::list_layout`, so painting one here
        // when it's needed matches the reservation instead of leaving an
        // unlabeled blank row.
        /* supports_hscrollbar */
        true,
        &mut surface,
        &theme,
    );

    // The `bordered` frame is drawn *after* the shared content paint so it
    // isn't erased by `native_surface_paint::paint`'s own initial full-`rect`
    // background fill (`surface_fill_rect(area, base_bg)`, `primitives/list.rs`).
    // This order mirrors `gtk::list::draw_list`, which strokes its border after
    // the content paint for the same reason.
    if list.bordered {
        let br = theme.border_fg;
        let _ = fill_rect(
            target,
            Rect::new(rect.x, rect.y, rect.width, BORDER_DIP),
            br,
        );
        let _ = fill_rect(
            target,
            Rect::new(
                rect.x,
                rect.y + rect.height - BORDER_DIP,
                rect.width,
                BORDER_DIP,
            ),
            br,
        );
        let _ = fill_rect(
            target,
            Rect::new(rect.x, rect.y, BORDER_DIP, rect.height),
            br,
        );
        let _ = fill_rect(
            target,
            Rect::new(
                rect.x + rect.width - BORDER_DIP,
                rect.y,
                BORDER_DIP,
                rect.height,
            ),
            br,
        );
    }

    layout
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::types::{Decoration, StyledText, WidgetId};

    const W: f32 = 200.0;
    const H: f32 = 100.0;
    const LINE_HEIGHT: f32 = 14.0;
    const CHAR_WIDTH: f32 = 8.0;

    fn item(label: &str) -> crate::primitives::list::ListItem {
        crate::primitives::list::ListItem {
            text: StyledText::plain(label.to_string()),
            icon: None,
            detail: None,
            decoration: Decoration::Normal,
        }
    }

    fn make_list(items: Vec<crate::primitives::list::ListItem>) -> ListView {
        ListView {
            id: WidgetId::new("list"),
            title: None,
            items,
            selected_idx: 0,
            scroll_offset: 0,
            has_focus: true,
            bordered: false,
            h_scroll: 0,
            max_content_width: None,
            show_v_scrollbar: false,
        }
    }

    fn make_bordered_list(items: Vec<crate::primitives::list::ListItem>) -> ListView {
        ListView {
            id: WidgetId::new("list"),
            title: None,
            items,
            selected_idx: 0,
            scroll_offset: 0,
            has_focus: true,
            bordered: true,
            h_scroll: 0,
            max_content_width: None,
            show_v_scrollbar: false,
        }
    }

    /// `win_list_layout` must apply the exact same `border_inset`
    /// [`crate::primitives::layout_metrics::list_layout`] would given
    /// [`BORDER_DIP`] — this ensures both functions agree on the bordered list's
    /// layout. Runs on Linux: no Direct2D/DirectWrite type involved.
    #[test]
    fn win_list_layout_matches_layout_metrics_list_layout_border_inset() {
        let list = make_bordered_list(vec![item("alpha"), item("beta"), item("gamma")]);
        let rect = Rect::new(0.0, 0.0, W, H);

        let via_win = win_list_layout(&list, rect, LINE_HEIGHT, CHAR_WIDTH);
        let via_shared = crate::primitives::layout_metrics::list_layout(
            &list,
            W as f64,
            H as f64,
            LINE_HEIGHT as f64,
            CHAR_WIDTH as f64,
            BORDER_DIP as f64,
        );

        assert_eq!(
            via_win, via_shared,
            "win_list_layout must delegate to layout_metrics::list_layout \
             with border_inset == BORDER_DIP for a bordered list"
        );
    }

    /// Same invariant for the unbordered case (`border_inset` must be
    /// `0.0`), and a sanity check that the two differ from each other —
    /// otherwise the assertion above could pass for the wrong reason
    /// (both layouts ignoring the inset).
    #[test]
    fn win_list_layout_unbordered_has_no_inset_and_differs_from_bordered() {
        let bordered = make_bordered_list(vec![item("alpha"), item("beta")]);
        let unbordered = make_list(vec![item("alpha"), item("beta")]);
        let rect = Rect::new(0.0, 0.0, W, H);

        let via_win_unbordered = win_list_layout(&unbordered, rect, LINE_HEIGHT, CHAR_WIDTH);
        let via_shared_unbordered = crate::primitives::layout_metrics::list_layout(
            &unbordered,
            W as f64,
            H as f64,
            LINE_HEIGHT as f64,
            CHAR_WIDTH as f64,
            0.0,
        );
        assert_eq!(via_win_unbordered, via_shared_unbordered);

        let via_win_bordered = win_list_layout(&bordered, rect, LINE_HEIGHT, CHAR_WIDTH);
        assert_ne!(
            via_win_unbordered.visible_items[0].bounds, via_win_bordered.visible_items[0].bounds,
            "a bordered list must actually inset its rows relative to an \
             unbordered one"
        );
    }

    /// An overflowing `max_content_width` must reserve the bottom row for an
    /// h-scrollbar, exactly like `mac_list_layout` / `gtk_list_layout`.
    #[test]
    fn win_list_layout_reserves_hscrollbar_row_when_content_overflows() {
        let mut list = make_list((0..12).map(|i| item(&format!("row-{i}"))).collect());
        list.max_content_width = Some(1000); // guarantees overflow at any sane char_width
        let rect = Rect::new(0.0, 0.0, W, H);

        let overflowing = win_list_layout(&list, rect, LINE_HEIGHT, CHAR_WIDTH);
        list.max_content_width = None;
        let fitting = win_list_layout(&list, rect, LINE_HEIGHT, CHAR_WIDTH);

        assert!(
            overflowing.visible_items.len() < fitting.visible_items.len(),
            "an overflowing max_content_width must reserve a row, leaving \
             fewer visible items than the non-overflowing layout"
        );
    }

    #[cfg(target_os = "windows")]
    mod windows_only {
        use super::*;
        use crate::primitives::list::ListViewHit;
        use crate::win::testing::HeadlessSurface;
        use crate::win::text::DWrite;

        /// Paint↔click round trip: the selected row's background must be
        /// painted at its own bounds, and clicking each visible row's
        /// centre must hit_test back to that row.
        #[test]
        fn paint_and_hit_test_round_trip() {
            let surface = HeadlessSurface::new(W as u32, H as u32).expect("create surface");
            let (dwrite, _, _) = DWrite::new("Segoe UI", 10.0, None).expect("create DWrite");
            let list = make_list(vec![item("alpha"), item("beta"), item("gamma")]);
            let rect = Rect::new(0.0, 0.0, W, H);

            let layout = surface
                .paint(|target| {
                    draw_list(target, &dwrite, rect, &list, LINE_HEIGHT);
                })
                .map(|_| win_list_layout(&list, rect, LINE_HEIGHT, CHAR_WIDTH))
                .expect("paint list");

            assert_eq!(layout.visible_items.len(), 3);
            for vis in &layout.visible_items {
                let hit = layout.hit_test(
                    vis.bounds.x + vis.bounds.width / 2.0,
                    vis.bounds.y + vis.bounds.height / 2.0,
                );
                assert_eq!(hit, ListViewHit::Item(vis.item_idx));
            }

            let theme = crate::theme::Theme::default();
            let sel_bounds = layout.visible_items[0].bounds;
            let px = surface.pixel_at((sel_bounds.x + 1.0) as u32, (sel_bounds.y + 1.0) as u32);
            assert_eq!(
                (px.r, px.g, px.b),
                (
                    theme.selected_bg.r,
                    theme.selected_bg.g,
                    theme.selected_bg.b
                ),
                "selected row (idx 0) should paint selected_bg at its own bounds"
            );
        }

        /// Scroll-offset round trip.
        #[test]
        fn scroll_offset_paint_and_click_agree() {
            let mut list = make_list((0..6).map(|i| item(&format!("row-{i}"))).collect());
            list.scroll_offset = 2;
            let rect = Rect::new(0.0, 0.0, W, H);
            let layout = win_list_layout(&list, rect, LINE_HEIGHT, CHAR_WIDTH);
            let first = layout.visible_items.first().expect("has items");
            assert_eq!(first.item_idx, 2);
            let hit = layout.hit_test(
                first.bounds.x + 5.0,
                first.bounds.y + first.bounds.height / 2.0,
            );
            assert_eq!(hit, ListViewHit::Item(2));
        }

        /// A click below the last item returns `Empty`.
        #[test]
        fn click_below_last_item_returns_empty() {
            let list = make_list(vec![item("a"), item("b")]);
            let rect = Rect::new(0.0, 0.0, W, H);
            let layout = win_list_layout(&list, rect, LINE_HEIGHT, CHAR_WIDTH);
            let last = layout.visible_items.last().expect("has items");
            let hit = layout.hit_test(10.0, last.bounds.y + last.bounds.height + 5.0);
            assert_eq!(hit, ListViewHit::Empty);
        }

        /// No-paint layout must agree byte-for-byte with what `draw_list`
        /// painted, including a title row.
        #[test]
        fn no_paint_layout_matches_paint_layout() {
            let mut list = make_list(vec![item("alpha"), item("beta")]);
            list.title = Some(StyledText::plain("Files"));
            let rect = Rect::new(0.0, 0.0, W, H);
            let (dwrite, _, _) = DWrite::new("Segoe UI", 10.0, None).expect("create DWrite");
            let surface = HeadlessSurface::new(W as u32, H as u32).expect("create surface");

            let painted = surface
                .paint(|target| {
                    draw_list(target, &dwrite, rect, &list, LINE_HEIGHT);
                })
                .map(|_| {
                    let char_width = dwrite
                        .measure_text("M")
                        .map(|(w, _)| w)
                        .unwrap_or(0.0)
                        .max(1.0);
                    win_list_layout(&list, rect, LINE_HEIGHT, char_width)
                })
                .expect("paint");
            let char_width = dwrite
                .measure_text("M")
                .map(|(w, _)| w)
                .unwrap_or(0.0)
                .max(1.0);
            let no_paint = win_list_layout(&list, rect, LINE_HEIGHT, char_width);
            assert_eq!(painted, no_paint);
        }

        /// The vertical scrollbar's track and thumb are painted when
        /// [`ListView::show_v_scrollbar`] is true. This probes a pixel inside the
        /// resolved track rect to verify painting occurred.
        #[test]
        fn paints_vertical_scrollbar_track_when_enabled() {
            let mut list = make_list((0..30).map(|i| item(&format!("row-{i}"))).collect());
            list.show_v_scrollbar = true;
            let rect = Rect::new(0.0, 0.0, W, H);
            let expected = list
                .vscrollbar(rect, LINE_HEIGHT)
                .expect("30 rows in a 100px / 14px viewport must need a v-scrollbar");

            let (dwrite, _, _) = DWrite::new("Segoe UI", 10.0, None).expect("create DWrite");
            let surface = HeadlessSurface::new(W as u32, H as u32).expect("create surface");
            surface
                .paint(|target| {
                    draw_list(target, &dwrite, rect, &list, LINE_HEIGHT);
                })
                .expect("paint list");

            let theme = crate::theme::Theme::default();
            let probe_x = (expected.track.x + expected.track.width / 2.0) as u32;
            let probe_y = (expected.track.y + expected.track.height / 2.0) as u32;
            let px = surface.pixel_at(probe_x.min(W as u32 - 1), probe_y.min(H as u32 - 1));
            assert_ne!(
                (px.r, px.g, px.b),
                (theme.background.r, theme.background.g, theme.background.b),
                "expected the v-scrollbar track at ({probe_x}, {probe_y}) to be painted \
                 (non-background) — the #1075 regression this test guards"
            );
        }

        /// The `ListView::bordered` frame is drawn *after* the shared content
        /// paint, which unconditionally fills the whole `rect` with `base_bg` as its
        /// first operation. This test verifies all four edges still carry
        /// `theme.border_fg` after the shared paint has run.
        #[test]
        fn bordered_frame_survives_shared_content_paint() {
            let list = make_bordered_list(vec![item("alpha"), item("beta"), item("gamma")]);
            let rect = Rect::new(0.0, 0.0, W, H);

            let (dwrite, _, _) = DWrite::new("Segoe UI", 10.0, None).expect("create DWrite");
            let surface = HeadlessSurface::new(W as u32, H as u32).expect("create surface");
            surface
                .paint(|target| {
                    draw_list(target, &dwrite, rect, &list, LINE_HEIGHT);
                })
                .expect("paint list");

            let theme = crate::theme::Theme::default();
            let border = (theme.border_fg.r, theme.border_fg.g, theme.border_fg.b);
            let mid_x = (W / 2.0) as u32;
            let mid_y = (H / 2.0) as u32;

            let top = surface.pixel_at(mid_x, 0);
            let bottom = surface.pixel_at(mid_x, H as u32 - 1);
            let left = surface.pixel_at(0, mid_y);
            let right = surface.pixel_at(W as u32 - 1, mid_y);

            for (label, px) in [
                ("top", top),
                ("bottom", bottom),
                ("left", left),
                ("right", right),
            ] {
                assert_eq!(
                    (px.r, px.g, px.b),
                    border,
                    "{label} border edge should still be theme.border_fg after the shared \
                     content paint ran (#1075 review regression: the border was being \
                     painted before, then erased by native_surface_paint::paint's initial \
                     full-rect background fill)"
                );
            }
        }
    }
}