1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143

use std::sync::Arc;

pub use euclid::Rect;
use freya_native_core::SendAnyMap;

use crate::{
    geometry::{
        Area,
        Size2D,
    },
    node::Node,
    prelude::{
        AreaModel,
        Gaps,
    },
};

/// Cached layout results of a Node
#[derive(Debug, Default, Clone)]
pub struct LayoutNode {
    /// Area that ocuppies this node
    pub area: Area,

    /// Area inside this Node
    pub inner_area: Area,

    /// Ocuppied sizes from the inner children in this Node
    pub inner_sizes: Size2D,

    /// Outer margin
    pub margin: Gaps,

    /// Associated data
    pub data: Option<Arc<SendAnyMap>>,
}

impl PartialEq for LayoutNode {
    fn eq(&self, other: &Self) -> bool {
        self.area == other.area
            && self.inner_area == other.inner_area
            && self.inner_sizes == other.inner_sizes
            && self.margin == other.margin
    }
}

impl LayoutNode {
    // The area without any margin
    pub fn visible_area(&self) -> Area {
        self.area.after_gaps(&self.margin)
    }
}

pub trait NodeKey: Clone + PartialEq + Eq + std::hash::Hash + Copy + std::fmt::Debug {}

impl NodeKey for usize {}

#[cfg(feature = "dioxus")]
impl NodeKey for freya_native_core::NodeId {}

pub trait DOMAdapter<Key: NodeKey> {
    fn root_id(&self) -> Key;

    /// Get the Node size
    fn get_node(&self, node_id: &Key) -> Option<Node>;

    /// Get the height in the DOM of the given Node
    fn height(&self, node_id: &Key) -> Option<u16>;

    /// Get the parent of a Node
    fn parent_of(&self, node_id: &Key) -> Option<Key>;

    /// Get the children of a Node
    fn children_of(&mut self, node_id: &Key) -> Vec<Key>;

    /// Check whether the given Node is valid (isn't a placeholder, unconnected node..)
    fn is_node_valid(&mut self, node_id: &Key) -> bool;

    /// Get the closest common parent Node of two Nodes
    fn closest_common_parent(&self, node_a: &Key, node_b: &Key) -> Option<Key> {
        let height_a = self.height(node_a)?;
        let height_b = self.height(node_b)?;

        let (node_a, node_b) = match height_a.cmp(&height_b) {
            std::cmp::Ordering::Less => (
                *node_a,
                balance_heights(self, *node_b, *node_a).unwrap_or(*node_b),
            ),
            std::cmp::Ordering::Equal => (*node_a, *node_b),
            std::cmp::Ordering::Greater => (
                balance_heights(self, *node_a, *node_b).unwrap_or(*node_a),
                *node_b,
            ),
        };

        let mut currents = (node_a, node_b);

        loop {
            // Common parent of node_a and node_b
            if currents.0 == currents.1 {
                return Some(currents.0);
            }

            let parent_a = self.parent_of(&currents.0);
            if let Some(parent_a) = parent_a {
                currents.0 = parent_a;
            } else if self.root_id() != currents.0 {
                // Skip unconected nodes
                break;
            }

            let parent_b = self.parent_of(&currents.1);
            if let Some(parent_b) = parent_b {
                currents.1 = parent_b;
            } else if self.root_id() != currents.1 {
                // Skip unconected nodes
                break;
            }
        }

        None
    }
}

/// Walk to the ancestor of `base` with the same height of `target`
fn balance_heights<Key: NodeKey>(
    dom_adapter: &(impl DOMAdapter<Key> + ?Sized),
    base: Key,
    target: Key,
) -> Option<Key> {
    let target_height = dom_adapter.height(&target)?;
    let mut current = base;
    loop {
        if dom_adapter.height(&current)? == target_height {
            break;
        }

        let parent_current = dom_adapter.parent_of(&current);
        if let Some(parent_current) = parent_current {
            current = parent_current;
        }
    }
    Some(current)
}