1use crate::{BufferSnapshot, Point, PointUtf16, TextDimension, ToOffset, ToPoint, ToPointUtf16};
  2use anyhow::Result;
  3use std::{cmp::Ordering, fmt::Debug, ops::Range};
  4use sum_tree::Bias;
  5
  6#[derive(Copy, Clone, Eq, PartialEq, Debug, Hash, Default)]
  7pub struct Anchor {
  8    pub timestamp: clock::Local,
  9    pub offset: usize,
 10    pub bias: Bias,
 11    pub buffer_id: Option<u64>,
 12}
 13
 14impl Anchor {
 15    pub const MIN: Self = Self {
 16        timestamp: clock::Local::MIN,
 17        offset: usize::MIN,
 18        bias: Bias::Left,
 19        buffer_id: None,
 20    };
 21
 22    pub const MAX: Self = Self {
 23        timestamp: clock::Local::MAX,
 24        offset: usize::MAX,
 25        bias: Bias::Right,
 26        buffer_id: None,
 27    };
 28
 29    pub fn cmp(&self, other: &Anchor, buffer: &BufferSnapshot) -> Ordering {
 30        let fragment_id_comparison = if self.timestamp == other.timestamp {
 31            Ordering::Equal
 32        } else {
 33            buffer
 34                .fragment_id_for_anchor(self)
 35                .cmp(buffer.fragment_id_for_anchor(other))
 36        };
 37
 38        fragment_id_comparison
 39            .then_with(|| self.offset.cmp(&other.offset))
 40            .then_with(|| self.bias.cmp(&other.bias))
 41    }
 42
 43    pub fn min(&self, other: &Self, buffer: &BufferSnapshot) -> Self {
 44        if self.cmp(other, buffer).is_le() {
 45            *self
 46        } else {
 47            *other
 48        }
 49    }
 50
 51    pub fn max(&self, other: &Self, buffer: &BufferSnapshot) -> Self {
 52        if self.cmp(other, buffer).is_ge() {
 53            *self
 54        } else {
 55            *other
 56        }
 57    }
 58
 59    pub fn bias(&self, bias: Bias, buffer: &BufferSnapshot) -> Anchor {
 60        if bias == Bias::Left {
 61            self.bias_left(buffer)
 62        } else {
 63            self.bias_right(buffer)
 64        }
 65    }
 66
 67    pub fn bias_left(&self, buffer: &BufferSnapshot) -> Anchor {
 68        if self.bias == Bias::Left {
 69            *self
 70        } else {
 71            buffer.anchor_before(self)
 72        }
 73    }
 74
 75    pub fn bias_right(&self, buffer: &BufferSnapshot) -> Anchor {
 76        if self.bias == Bias::Right {
 77            *self
 78        } else {
 79            buffer.anchor_after(self)
 80        }
 81    }
 82
 83    pub fn summary<D>(&self, content: &BufferSnapshot) -> D
 84    where
 85        D: TextDimension,
 86    {
 87        content.summary_for_anchor(self)
 88    }
 89}
 90
 91pub trait OffsetRangeExt {
 92    fn to_offset(&self, snapshot: &BufferSnapshot) -> Range<usize>;
 93    fn to_point(&self, snapshot: &BufferSnapshot) -> Range<Point>;
 94    fn to_point_utf16(&self, snapshot: &BufferSnapshot) -> Range<PointUtf16>;
 95}
 96
 97impl<T> OffsetRangeExt for Range<T>
 98where
 99    T: ToOffset,
100{
101    fn to_offset(&self, snapshot: &BufferSnapshot) -> Range<usize> {
102        self.start.to_offset(snapshot)..self.end.to_offset(snapshot)
103    }
104
105    fn to_point(&self, snapshot: &BufferSnapshot) -> Range<Point> {
106        self.start.to_offset(snapshot).to_point(snapshot)
107            ..self.end.to_offset(snapshot).to_point(snapshot)
108    }
109
110    fn to_point_utf16(&self, snapshot: &BufferSnapshot) -> Range<PointUtf16> {
111        self.start.to_offset(snapshot).to_point_utf16(snapshot)
112            ..self.end.to_offset(snapshot).to_point_utf16(snapshot)
113    }
114}
115
116pub trait AnchorRangeExt {
117    fn cmp(&self, b: &Range<Anchor>, buffer: &BufferSnapshot) -> Result<Ordering>;
118}
119
120impl AnchorRangeExt for Range<Anchor> {
121    fn cmp(&self, other: &Range<Anchor>, buffer: &BufferSnapshot) -> Result<Ordering> {
122        Ok(match self.start.cmp(&other.start, buffer) {
123            Ordering::Equal => other.end.cmp(&self.end, buffer),
124            ord => ord,
125        })
126    }
127}