use crate::{
    LayerId, Len, MaskIdx, MoveIdx, PrimitiveHandle, Size, TextureHandle, UiRegion, WidgetId,
    util::Vec2,
};

/// important non rendering data for retained drawing
#[derive(Debug)]
pub struct ActiveData {
    pub id: WidgetId,
    pub region: UiRegion,
    /// What the widget said it used of `region`, the last time it drew.
    pub size: Size,
    /// The pixel size of the box it drew against. `region` alone cannot say:
    /// it is a fraction of a slot's box, and the same fraction of a box that
    /// has since changed is a different number of pixels.
    pub px: Vec2,
    /// The pixel size of the box its parent first asked about it in, before
    /// knowing what it came to. `px` may be a box derived from that answer,
    /// and a size measured there is only the same answer asked again.
    pub offered_px: Vec2,
    pub parent: Option<WidgetId>,
    /// How far down the tree it was drawn, the root being 1. Carried down a
    /// draw rather than worked out by walking up, so it is right for every
    /// widget a frame visits and cannot drift while one is being drawn.
    pub depth: usize,
    pub textures: Vec<TextureHandle>,
    pub primitives: Vec<PrimitiveHandle>,
    pub children: Vec<WidgetId>,
    /// The children whose size this widget read while drawing.
    pub size_deps: Vec<WidgetId>,
    /// Offered pixel axes which flowed into this widget's reported size,
    /// directly or through a child size it read.
    pub size_box_inputs: [bool; 2],
    /// Output axes read while producing `size`, distinct from the widget's
    /// own box when that box has a fixed pixel length.
    pub size_output_inputs: [bool; 2],
    /// The output dimensions against which those dependencies were observed.
    pub output_px: Vec2,
    /// The slot its primitives are positioned through: its own if its parent
    /// placed it, otherwise the nearest ancestor that has one.
    pub move_idx: MoveIdx,
    /// The declared lengths whoever drew this widget resolved into its box.
    /// A change to one moves a box this widget cannot fix by drawing again,
    /// and comparing them is what says so.
    pub declared: [Option<Len>; 2],
    /// The slot `region` is given in, which is whatever its parent drew in.
    pub parent_move: MoveIdx,
    pub mask: MaskIdx,
    pub layer: LayerId,
}