uzor 1.3.0

//! Chrome render entry point and 16-step draw pipeline.
//!
//! # API
//!
//! - `register_input_coordinator_chrome` — registers the composite + all child
//!   hit-rects with an `InputCoordinator`.  **No drawing.**
//! - `register_context_manager_chrome`   — convenience wrapper: registers and
//!   draws in one call via a `ContextManager`.
//!
//! # Draw order (non-Custom kinds)
//!
//! 1.  Background strip
//! 2.  Tab bodies (hover/active accent 2 px bottom line + label)
//! 3.  Tab close-X icons
//! 4.  New-tab "+" button
//! 5.  New-window icon button
//! 6.  Menu / gear icon button
//! 7.  Group divider (left of min/max/close)
//! 8.  Close-window icon button
//! 9.  Group divider (between close-window and minimize group)
//! 10. Minimize button
//! 11. Maximize / restore button
//! 12. Close-app button (red hover BG)
//! 13. Active tab bottom accent indicator
//! 14. Bottom separator line
//! 15. Context menu (if open)
//! 16. Tooltip overlay (if visible)

use crate::app_context::ContextManager;
use crate::input::core::coordinator::LayerId;
use crate::input::{InputCoordinator, Sense, WidgetKind};
use crate::core::render::draw_svg_icon;
use crate::render::{RenderContext, TextAlign, TextBaseline};
use crate::ui::assets::icons::ui::{ICON_CLOSE, ICON_NEW_WINDOW};
use crate::types::{Rect, WidgetId, CompositeId};

use super::settings::ChromeSettings;
use super::state::ChromeState;
use super::types::{ChromeRenderKind, ChromeTabConfig, ChromeView};

// ---------------------------------------------------------------------------
// Layout constants (mirrors chrome-deep.md §2)
// ---------------------------------------------------------------------------

const TAB_LEFT_MARGIN: f64 = 0.0;
const NEW_TAB_BTN_WIDTH: f64 = 28.0;
const BUTTON_WIDTH: f64 = 46.0;
const CLOSE_WINDOW_BTN_WIDTH: f64 = 36.0;
const MENU_BTN_WIDTH: f64 = 36.0;
const NEW_WINDOW_BTN_WIDTH: f64 = 36.0;

// ---------------------------------------------------------------------------
// ButtonPositions helper
// ---------------------------------------------------------------------------

struct ButtonPositions {
    close_x: f64,
    maximize_x: f64,
    minimize_x: f64,
    /// Pre-divider button column starts here (rightmost of the optional
    /// button group: new_window / menu / close_window).  `None` means no
    /// optional button is enabled and there is no left-group divider.
    group_right: Option<f64>,
    /// Compact left edges, `None` when the corresponding button is disabled.
    close_window_left: Option<f64>,
    menu_left:         Option<f64>,
    new_window_left:   Option<f64>,
}

impl ButtonPositions {
    /// Compute compact positions: each optional button reserves its column
    /// only when enabled.  Disabled buttons leave no gap — the next-left
    /// button slides right against the previous.
    fn compute(width: f64, view: &super::types::ChromeView<'_>) -> Self {
        let close_x    = width - BUTTON_WIDTH;
        let maximize_x = width - BUTTON_WIDTH * 2.0;
        let minimize_x = width - BUTTON_WIDTH * 3.0;

        // Walk right-to-left through the optional group, pushing each
        // enabled button against the previous one.
        let mut cursor = minimize_x;          // right edge of the group
        let mut close_window_left: Option<f64> = None;
        let mut menu_left:         Option<f64> = None;
        let mut new_window_left:   Option<f64> = None;

        // Pair rule: enabling new_window pulls in close_window so users
        // always have a way to close the spawned window even if they only
        // flipped one flag.
        let effective_close_window =
            view.show_close_window_btn || view.show_new_window_btn;
        if effective_close_window {
            cursor -= CLOSE_WINDOW_BTN_WIDTH;
            close_window_left = Some(cursor);
        }
        if view.show_menu_btn {
            cursor -= MENU_BTN_WIDTH;
            menu_left = Some(cursor);
        }
        if view.show_new_window_btn {
            cursor -= NEW_WINDOW_BTN_WIDTH;
            new_window_left = Some(cursor);
        }
        let any_enabled = close_window_left.is_some()
            || menu_left.is_some()
            || new_window_left.is_some();
        let group_right = if any_enabled { Some(minimize_x) } else { None };

        Self {
            close_x,
            maximize_x,
            minimize_x,
            group_right,
            close_window_left,
            menu_left,
            new_window_left,
        }
    }
}

// ---------------------------------------------------------------------------
// Public API — InputCoordinator
// ---------------------------------------------------------------------------

/// Register the Chrome composite and all child hit-rects with the coordinator.
///
/// **No drawing happens here.**
///
/// Returns the [`CompositeId`] assigned to the composite.
pub fn register_input_coordinator_chrome(
    coord:    &mut InputCoordinator,
    id:       impl Into<WidgetId>,
    rect:     Rect,
    state:    &ChromeState,
    view:     &ChromeView<'_>,
    settings: &ChromeSettings,
    kind:     &ChromeRenderKind,
    layer:    &LayerId,
) -> CompositeId {
    let chrome_id = coord.register_composite(
        id,
        WidgetKind::Chrome,
        rect,
        Sense::NONE,
        layer,
    );

    if matches!(kind, ChromeRenderKind::Custom(_)) {
        return chrome_id;
    }

    let style = settings.style.as_ref();
    let bp    = ButtonPositions::compute(rect.width, view);
    let h     = style.chrome_height();

    // --- Tabs ---
    let show_tabs = !matches!(kind, ChromeRenderKind::WindowControlsOnly);
    if show_tabs {
        let uniform_w = uniform_tab_width(view.tabs, style.tab_padding_h(), style.tab_close_size());
        let mut x = rect.x + TAB_LEFT_MARGIN;
        for (i, tab) in view.tabs.iter().enumerate() {
            let cached = tab_width(tab, state, i, style.tab_padding_h(), style.tab_close_size());
            let tab_w = if cached > 0.0 { cached } else { uniform_w };
            let tab_rect = Rect::new(x, rect.y, tab_w, h);

            // Tab body
            coord.register_child(
                &chrome_id,
                format!("{}:tab:{}", chrome_id.0.0, i),
                WidgetKind::Button,
                tab_rect,
                Sense::CLICK | Sense::HOVER,
            );

            // Tab close-X
            if tab.closable {
                let close_w = style.tab_close_size();
                let close_x = x + tab_w - close_w - style.tab_padding_h() / 2.0;
                let close_y = rect.y + (h - close_w) / 2.0;
                coord.register_child(
                    &chrome_id,
                    format!("{}:tab_close:{}", chrome_id.0.0, i),
                    WidgetKind::Button,
                    Rect::new(close_x, close_y, close_w, close_w),
                    Sense::CLICK | Sense::HOVER,
                );
            }

            x += tab_w + style.tab_gap();
        }

        // New-tab "+" button
        if view.show_new_tab_btn {
            coord.register_child(
                &chrome_id,
                format!("{}:new_tab", chrome_id.0.0),
                WidgetKind::Button,
                Rect::new(x, rect.y, NEW_TAB_BTN_WIDTH, h),
                Sense::CLICK | Sense::HOVER,
            );
            x += NEW_TAB_BTN_WIDTH;
        }

        // Caption / drag zone — extends up to the leftmost enabled
        // optional button (or to Min when none are enabled).
        let group_left = bp.new_window_left
            .or(bp.menu_left)
            .or(bp.close_window_left)
            .unwrap_or(bp.minimize_x);
        let drag_right = rect.x + group_left;
        let drag_w = (drag_right - x).max(0.0);
        if drag_w > 0.0 {
            coord.register_child(
                &chrome_id,
                format!("{}:drag", chrome_id.0.0),
                WidgetKind::DragHandle,
                Rect::new(x, rect.y, drag_w, h),
                Sense::DRAG,
            );
        }
    } else {
        // WindowControlsOnly: drag zone fills the full width except button column
        let drag_end = rect.x + bp.minimize_x;
        let drag_w   = drag_end - rect.x;
        if drag_w > 0.0 {
            coord.register_child(
                &chrome_id,
                format!("{}:drag", chrome_id.0.0),
                WidgetKind::DragHandle,
                Rect::new(rect.x, rect.y, drag_w, h),
                Sense::DRAG,
            );
        }
    }

    // --- Action buttons (right side) ---
    let show_window_controls = !matches!(kind, ChromeRenderKind::Minimal);

    if show_window_controls {
        let optional_visible = !matches!(kind, ChromeRenderKind::WindowControlsOnly);

        // New-window button
        if optional_visible {
            if let Some(left) = bp.new_window_left {
                coord.register_child(
                    &chrome_id,
                    format!("{}:new_win", chrome_id.0.0),
                    WidgetKind::Button,
                    Rect::new(rect.x + left, rect.y, NEW_WINDOW_BTN_WIDTH, h),
                    Sense::CLICK | Sense::HOVER,
                );
            }
            if let Some(left) = bp.menu_left {
                coord.register_child(
                    &chrome_id,
                    format!("{}:menu", chrome_id.0.0),
                    WidgetKind::Button,
                    Rect::new(rect.x + left, rect.y, MENU_BTN_WIDTH, h),
                    Sense::CLICK | Sense::HOVER,
                );
            }
            if let Some(left) = bp.close_window_left {
                coord.register_child(
                    &chrome_id,
                    format!("{}:close_win", chrome_id.0.0),
                    WidgetKind::Button,
                    Rect::new(rect.x + left, rect.y, CLOSE_WINDOW_BTN_WIDTH, h),
                    Sense::CLICK | Sense::HOVER,
                );
            }
        }

        // Minimize
        coord.register_child(
            &chrome_id,
            format!("{}:min", chrome_id.0.0),
            WidgetKind::Button,
            Rect::new(rect.x + bp.minimize_x, rect.y, BUTTON_WIDTH, h),
            Sense::CLICK | Sense::HOVER,
        );

        // Maximize / restore
        coord.register_child(
            &chrome_id,
            format!("{}:max", chrome_id.0.0),
            WidgetKind::Button,
            Rect::new(rect.x + bp.maximize_x, rect.y, BUTTON_WIDTH, h),
            Sense::CLICK | Sense::HOVER,
        );

        // Close app
        coord.register_child(
            &chrome_id,
            format!("{}:close", chrome_id.0.0),
            WidgetKind::Button,
            Rect::new(rect.x + bp.close_x, rect.y, BUTTON_WIDTH, h),
            Sense::CLICK | Sense::HOVER,
        );
    }

    chrome_id
}

// ---------------------------------------------------------------------------
// Public API — ContextManager convenience wrapper
// ---------------------------------------------------------------------------

/// Register + draw the Chrome composite in one call using a `ContextManager`.
///
/// Returns the [`CompositeId`] assigned to the composite.
pub fn register_context_manager_chrome(
    ctx_mgr:  &mut ContextManager,
    render:   &mut dyn RenderContext,
    id:       impl Into<WidgetId>,
    rect:     Rect,
    state:    &mut ChromeState,
    view:     &ChromeView<'_>,
    settings: &ChromeSettings,
    kind:     &ChromeRenderKind,
    layer:    &LayerId,
) -> CompositeId {
    let coord = &mut ctx_mgr.input;
    let chrome_id =
        register_input_coordinator_chrome(coord, id, rect, state, view, settings, kind, layer);
    draw_chrome(render, rect, state, view, settings, kind);
    chrome_id
}

// ---------------------------------------------------------------------------
// Internal draw pipeline
// ---------------------------------------------------------------------------

/// Pure paint — `uzor::l0::chrome::draw_chrome`.
///
/// Renders the entire chrome strip into `ctx` based on the given
/// state + view + settings.  Self-contained: no L1 / L2 / L3 / WM
/// dependency.  Promoted from a private `draw_chrome_internal` so
/// embedders can drive their own input pipeline without touching
/// `LayoutManager` or `InputCoordinator`.
pub fn draw_chrome(
    ctx:      &mut dyn RenderContext,
    rect:     Rect,
    state:    &ChromeState,
    view:     &ChromeView<'_>,
    settings: &ChromeSettings,
    kind:     &ChromeRenderKind,
) {
    match kind {
        ChromeRenderKind::Custom(f) => {
            f(ctx, rect, view, settings);
            return;
        }
        _ => {}
    }

    let theme = settings.theme.as_ref();
    let style = settings.style.as_ref();
    let h     = style.chrome_height();
    let w     = rect.width;
    let bp    = ButtonPositions::compute(w, view);

    // --- 1. Background strip ---
    ctx.set_fill_color(theme.background());
    ctx.fill_rect(rect.x, rect.y, w, h);

    let show_tabs     = !matches!(kind, ChromeRenderKind::WindowControlsOnly);
    let show_controls = !matches!(kind, ChromeRenderKind::Minimal);

    // --- 2–3. Tab bodies + close-X icons ---
    if show_tabs {
        let uniform_w = uniform_tab_width(view.tabs, style.tab_padding_h(), style.tab_close_size());
        let mut x = rect.x + TAB_LEFT_MARGIN;
        for (i, tab) in view.tabs.iter().enumerate() {
            let cached = tab_width(tab, state, i, style.tab_padding_h(), style.tab_close_size());
            let tw = if cached > 0.0 { cached } else { uniform_w };
            let tab_rect = Rect::new(x, rect.y, tw, h);

            let ts = state.tabs_state.get(i);
            let hovered      = ts.map(|s| s.hovered).unwrap_or(false);
            let close_hovered = ts.map(|s| s.close_hovered).unwrap_or(false);
            let active = view.active_tab_id.map(|id| id == tab.id).unwrap_or(false);

            // Tab background
            let bg_color = if active {
                theme.tab_bg_active()
            } else if hovered || close_hovered {
                theme.tab_bg_hover()
            } else {
                theme.tab_bg_normal()
            };
            if bg_color != "transparent" {
                ctx.set_fill_color(bg_color);
                ctx.fill_rect(tab_rect.x, tab_rect.y, tab_rect.width, tab_rect.height);
            }

            // Label text
            let text_color = if active {
                theme.tab_text_active()
            } else if hovered {
                theme.tab_text_hover()
            } else {
                theme.tab_text_normal()
            };
            ctx.set_fill_color(text_color);
            ctx.set_font("12px sans-serif");
            ctx.set_text_align(TextAlign::Left);
            ctx.set_text_baseline(TextBaseline::Middle);
            ctx.fill_text(
                tab.label,
                tab_rect.x + style.tab_padding_h(),
                tab_rect.y + h / 2.0,
            );

            // Tab close-X icon (step 3)
            if tab.closable {
                let icon_sz  = style.tab_close_icon_size();
                let close_bw = style.tab_close_size();
                let cx = x + tw - close_bw + (close_bw - icon_sz) / 2.0;
                let cy = rect.y + (h - icon_sz) / 2.0;
                let icon_color = if close_hovered {
                    theme.close_hover()
                } else {
                    theme.icon_normal()
                };
                draw_cross(ctx, cx, cy, icon_sz, icon_color, 1.0);
            }

            x += tw + style.tab_gap();
        }

        // --- 4. New-tab "+" button ---
        if view.show_new_tab_btn {
            let nt_x = rect.x
                + TAB_LEFT_MARGIN
                + tab_total_width(view.tabs, state, style.tab_padding_h(),
                                   style.tab_close_size(), style.tab_gap());
            // 1 px separator before "+"
            ctx.set_fill_color(theme.separator());
            ctx.fill_rect(nt_x, rect.y + 4.0, 1.0, h - 8.0);
            // Cross strokes
            let cx = nt_x + NEW_TAB_BTN_WIDTH / 2.0;
            let cy = rect.y + h / 2.0;
            let arm = 5.0_f64;
            ctx.set_stroke_color(theme.icon_normal());
            ctx.set_stroke_width(1.5);
            ctx.set_line_dash(&[]);
            // horizontal
            ctx.move_to(cx - arm, cy);
            ctx.line_to(cx + arm, cy);
            ctx.stroke();
            // vertical
            ctx.move_to(cx, cy - arm);
            ctx.line_to(cx, cy + arm);
            ctx.stroke();
        }
    }

    // --- Right-side action buttons ---
    if show_controls {
        use super::types::ChromeHit;
        let icon_sz = style.action_icon_size();
        let hover_bg     = theme.tab_bg_hover();
        let icon_normal  = theme.icon_normal();
        let icon_hover   = theme.tab_text_hover();

        // --- 5. New-window icon (uzor SVG ICON_NEW_WINDOW) ---
        if show_tabs {
            if let Some(left) = bp.new_window_left {
                let bx = rect.x + left;
                let by = rect.y;
                let hovered = state.hovered == ChromeHit::NewWindowBtn;
                if hovered {
                    ctx.set_fill_color(hover_bg);
                    ctx.fill_rect(bx, by, NEW_WINDOW_BTN_WIDTH, h);
                }
                let color = if hovered { icon_hover } else { icon_normal };
                let s = icon_sz + 2.0;
                let ix = bx + (NEW_WINDOW_BTN_WIDTH - s) / 2.0;
                let iy = by + (h - s) / 2.0;
                draw_svg_icon(ctx, ICON_NEW_WINDOW, ix, iy, s, s, color);
            }
        }

        // --- 6. Menu icon ---
        if show_tabs {
            if let Some(left) = bp.menu_left {
                let menu_cx = rect.x + left + MENU_BTN_WIDTH / 2.0;
                let menu_cy = rect.y + h / 2.0;
                let line_w  = icon_sz;
                ctx.set_fill_color(theme.icon_normal());
                for i in 0_i32..3_i32 {
                    let ly = menu_cy - 3.0 + i as f64 * 3.0;
                    ctx.fill_rect(menu_cx - line_w / 2.0, ly - 0.75, line_w, 1.5);
                }
            }
        }

        // --- 7. Divider between optional group and min/max/close ---
        if bp.group_right.is_some() {
            ctx.set_fill_color(theme.separator());
            ctx.fill_rect(rect.x + bp.minimize_x - 1.0, rect.y + 6.0, 1.0, h - 12.0);
        }

        // --- 8. Close-window icon (uzor SVG ICON_CLOSE) ---
        if show_tabs {
            if let Some(left) = bp.close_window_left {
                let bx = rect.x + left;
                let by = rect.y;
                let hovered = state.hovered == ChromeHit::CloseWindowBtn;
                if hovered {
                    ctx.set_fill_color(hover_bg);
                    ctx.fill_rect(bx, by, CLOSE_WINDOW_BTN_WIDTH, h);
                }
                let color = if hovered { icon_hover } else { icon_normal };
                let s = icon_sz;
                let ix = bx + (CLOSE_WINDOW_BTN_WIDTH - s) / 2.0;
                let iy = by + (h - s) / 2.0;
                draw_svg_icon(ctx, ICON_CLOSE, ix, iy, s, s, color);
            }
        }

        // --- 10. Minimize icon (10×1 filled rect) ---
        {
            let btn_rect = Rect::new(rect.x + bp.minimize_x, rect.y, BUTTON_WIDTH, h);
            if state.hovered == super::types::ChromeHit::MinBtn {
                ctx.set_fill_color(theme.button_hover());
                ctx.fill_rect(btn_rect.x, btn_rect.y, btn_rect.width, btn_rect.height);
            }
            let mid_x = rect.x + bp.minimize_x + BUTTON_WIDTH / 2.0;
            let mid_y = rect.y + h / 2.0;
            ctx.set_fill_color(theme.icon_normal());
            ctx.fill_rect(mid_x - 5.0, mid_y - 0.5, 10.0, 1.0);
        }

        // --- 11. Maximize / restore icon ---
        {
            let btn_rect = Rect::new(rect.x + bp.maximize_x, rect.y, BUTTON_WIDTH, h);
            if state.hovered == super::types::ChromeHit::MaxBtn {
                ctx.set_fill_color(theme.button_hover());
                ctx.fill_rect(btn_rect.x, btn_rect.y, btn_rect.width, btn_rect.height);
            }
            let mid_x = rect.x + bp.maximize_x + BUTTON_WIDTH / 2.0;
            let mid_y = rect.y + h / 2.0;
            ctx.set_stroke_color(theme.icon_normal());
            ctx.set_stroke_width(1.0);
            ctx.set_line_dash(&[]);
            if view.is_maximized {
                // Restore: two overlapping rects
                ctx.stroke_rect(mid_x - 3.0, mid_y - 5.0, 8.0, 8.0);
                ctx.stroke_rect(mid_x - 5.0, mid_y - 3.0, 8.0, 8.0);
            } else {
                ctx.stroke_rect(mid_x - 5.0, mid_y - 5.0, 10.0, 10.0);
            }
        }

        // --- 12. Close-app button (hover = red BG) ---
        {
            let close_rect = Rect::new(rect.x + bp.close_x, rect.y, BUTTON_WIDTH, h);
            // Hover background
            if state.hovered == super::types::ChromeHit::CloseBtn {
                ctx.set_fill_color(theme.close_hover());
                ctx.fill_rect(close_rect.x, close_rect.y, close_rect.width, close_rect.height);
            }
            let cx  = rect.x + bp.close_x + BUTTON_WIDTH / 2.0;
            let cy  = rect.y + h / 2.0;
            let arm = 5.0_f64;
            draw_cross(ctx, cx - arm, cy - arm, arm * 2.0, theme.icon_normal(), 1.5);
        }
    }

    // --- 13. Active tab bottom accent indicator ---
    if show_tabs {
        let uniform_w = uniform_tab_width(view.tabs, style.tab_padding_h(), style.tab_close_size());
        let mut x = rect.x + TAB_LEFT_MARGIN;
        for (i, tab) in view.tabs.iter().enumerate() {
            let cached = tab_width(tab, state, i, style.tab_padding_h(), style.tab_close_size());
            let tw = if cached > 0.0 { cached } else { uniform_w };
            let active = view.active_tab_id.map(|id| id == tab.id).unwrap_or(false);
            let ts = state.tabs_state.get(i);
            let hovered = ts.map(|s| s.hovered).unwrap_or(false);
            if active || hovered {
                let accent_color = if active {
                    theme.tab_accent()
                } else {
                    theme.button_hover()
                };
                ctx.set_fill_color(accent_color);
                ctx.fill_rect(
                    x,
                    rect.y + h - style.tab_accent_height(),
                    tw,
                    style.tab_accent_height(),
                );
            }
            x += tw + style.tab_gap();
        }
    }

    // --- 14. Bottom separator line (controlled by style.show_bottom_border) ---
    if style.show_bottom_border() {
        ctx.set_fill_color(theme.separator());
        ctx.fill_rect(rect.x, rect.y + h - 1.0, w, 1.0);
    }

    // --- 15. Context menu (if open) ---
    // Context menu rendering is delegated to the composite::context_menu widget.
    // The chrome state holds a `ContextMenuState`; callers drive rendering
    // via the context_menu composite after this call.

    // --- 16. Tooltip overlay ---
    // Tooltip rendering is also deferred to the caller via `state.tooltip`.
}

// ---------------------------------------------------------------------------
// Internal draw helpers
// ---------------------------------------------------------------------------

/// Draw an × cross centred at `(x, y)` (top-left origin) with `size` and `stroke_w`.
fn draw_cross(
    ctx:      &mut dyn RenderContext,
    x:        f64,
    y:        f64,
    size:     f64,
    color:    &str,
    stroke_w: f64,
) {
    ctx.set_stroke_color(color);
    ctx.set_stroke_width(stroke_w);
    ctx.set_line_dash(&[]);
    ctx.begin_path();
    ctx.move_to(x, y);
    ctx.line_to(x + size, y + size);
    ctx.stroke();
    ctx.begin_path();
    ctx.move_to(x + size, y);
    ctx.line_to(x, y + size);
    ctx.stroke();
}

// ---------------------------------------------------------------------------
// Tab width helpers
// ---------------------------------------------------------------------------

/// Measure natural width of the chrome bar for the given tabs and render kind.
///
/// Width = `tab_left_margin + tab_total_width + (new_tab_btn if enabled)
///         + drag_zone_min_width + window-controls width(kind, view)`.
/// Height is always `style.chrome_height()`.
///
/// Use this when you need a content-driven chrome rect instead of stretching to
/// the full viewport width.
pub fn measure(
    view:     &ChromeView<'_>,
    state:    &ChromeState,
    settings: &ChromeSettings,
    kind:     &ChromeRenderKind,
) -> (f64, f64) {
    let style = settings.style.as_ref();

    let pad_h     = style.tab_padding_h();
    let close_sz  = style.tab_close_size();
    let gap       = style.tab_gap();
    let left_mrg  = style.tab_left_margin();

    let tabs_w   = tab_total_width(view.tabs, state, pad_h, close_sz, gap);
    let new_tab  = if view.show_new_tab_btn { style.new_tab_btn_width() } else { 0.0 };
    let drag_w   = style.drag_zone_min_width();

    // Window-controls column varies per kind.
    let controls_w: f64 = match kind {
        ChromeRenderKind::Minimal => 0.0,
        ChromeRenderKind::WindowControlsOnly | ChromeRenderKind::Default | ChromeRenderKind::Custom(_) => {
            let mut w = 0.0;
            if view.show_menu_btn         { w += style.button_size_max();   }
            if view.show_new_window_btn   { w += style.button_size_max();   }
            // min/max/close-app: a standard window controls trio (3 × button_size_min).
            w += style.button_size_min() * 3.0;
            if view.show_close_window_btn || view.show_new_window_btn {
                w += style.button_size_close();
            }
            w
        }
    };

    let total_w = left_mrg + tabs_w + new_tab + drag_w + controls_w;
    let total_h = style.chrome_height();
    (total_w, total_h)
}

/// Pixel width for tab `i`, using cached `tab_widths` if available.
///
/// All tabs share a uniform width = max(label) across the tab set, so the
/// strip looks consistent (chrome-style). The cache in `ChromeState.tab_widths`
/// is honoured if populated by the caller (advanced layout overrides).
fn tab_width(
    _tab:        &ChromeTabConfig<'_>,
    state:       &ChromeState,
    i:           usize,
    _padding_h:  f64,
    _close_size: f64,
) -> f64 {
    // Cache override (caller-supplied per-tab widths).
    if let Some(&w) = state.tab_widths.get(i) {
        return w;
    }
    // Without cached widths the renderer can't know the full tab set here,
    // so fall back to a fixed sentinel — `tab_total_width` recomputes the
    // uniform width from the full slice and overrides this.
    0.0
}

/// Uniform width applied to every tab in the set: the longest label drives
/// the width so all tabs render identically.
fn uniform_tab_width(
    tabs:       &[ChromeTabConfig<'_>],
    padding_h:  f64,
    close_size: f64,
) -> f64 {
    let max_label = tabs.iter().map(|t| t.label.len()).max().unwrap_or(0) as f64;
    let text_w = max_label * 7.0;
    padding_h + text_w + close_size + padding_h
}

/// Total pixel width consumed by all tabs + gaps. Uses cached state widths
/// if every entry is populated, otherwise falls back to uniform width.
fn tab_total_width(
    tabs:       &[ChromeTabConfig<'_>],
    state:      &ChromeState,
    padding_h:  f64,
    close_size: f64,
    gap:        f64,
) -> f64 {
    if !tabs.is_empty() && state.tab_widths.len() == tabs.len() {
        // All cached — sum cached widths + gaps.
        let mut total = 0.0_f64;
        for (i, _) in tabs.iter().enumerate() {
            total += state.tab_widths[i];
            if i + 1 < tabs.len() {
                total += gap;
            }
        }
        return total;
    }
    let uw = uniform_tab_width(tabs, padding_h, close_size);
    let n = tabs.len() as f64;
    if n == 0.0 { 0.0 } else { uw * n + gap * (n - 1.0) }
}