1use crate::Anchor;
 2use crate::{rope::TextDimension, BufferSnapshot};
 3use std::cmp::Ordering;
 4
 5#[derive(Copy, Clone, Debug, Eq, PartialEq)]
 6pub enum SelectionGoal {
 7    None,
 8    Column(u32),
 9    ColumnRange { start: u32, end: u32 },
10}
11
12#[derive(Clone, Debug, Eq, PartialEq)]
13pub struct Selection<T> {
14    pub id: usize,
15    pub start: T,
16    pub end: T,
17    pub reversed: bool,
18    pub goal: SelectionGoal,
19}
20
21impl Default for SelectionGoal {
22    fn default() -> Self {
23        Self::None
24    }
25}
26
27impl<T: Clone> Selection<T> {
28    pub fn head(&self) -> T {
29        if self.reversed {
30            self.start.clone()
31        } else {
32            self.end.clone()
33        }
34    }
35
36    pub fn tail(&self) -> T {
37        if self.reversed {
38            self.end.clone()
39        } else {
40            self.start.clone()
41        }
42    }
43}
44
45impl<T: Copy + Ord> Selection<T> {
46    pub fn is_empty(&self) -> bool {
47        self.start == self.end
48    }
49
50    pub fn set_head(&mut self, head: T, new_goal: SelectionGoal) {
51        if head.cmp(&self.tail()) < Ordering::Equal {
52            if !self.reversed {
53                self.end = self.start;
54                self.reversed = true;
55            }
56            self.start = head;
57        } else {
58            if self.reversed {
59                self.start = self.end;
60                self.reversed = false;
61            }
62            self.end = head;
63        }
64        self.goal = new_goal;
65    }
66
67    pub fn collapse_to(&mut self, point: T, new_goal: SelectionGoal) {
68        self.start = point;
69        self.end = point;
70        self.goal = new_goal;
71        self.reversed = false;
72    }
73}
74
75impl Selection<Anchor> {
76    pub fn resolve<'a, D: 'a + TextDimension>(
77        &'a self,
78        snapshot: &'a BufferSnapshot,
79    ) -> Selection<D> {
80        Selection {
81            id: self.id,
82            start: snapshot.summary_for_anchor(&self.start),
83            end: snapshot.summary_for_anchor(&self.end),
84            reversed: self.reversed,
85            goal: self.goal,
86        }
87    }
88}