matrix_sdk_ui/timeline/
item.rs

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
// Copyright 2023 The Matrix.org Foundation C.I.C.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::{ops::Deref, sync::Arc};

use as_variant::as_variant;

use super::{EventTimelineItem, VirtualTimelineItem};

/// Opaque unique identifier for a timeline item.
///
/// It is transferred whenever a timeline item is updated. This can be used as a
/// stable identifier for UI purposes, as well as operations on the event
/// represented by the item.
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct TimelineUniqueId(pub String);

/// The type of timeline item.
#[derive(Clone, Debug)]
#[allow(clippy::large_enum_variant)]
pub enum TimelineItemKind {
    /// An event or aggregation of multiple events.
    Event(EventTimelineItem),
    /// An item that doesn't correspond to an event, for example the user's
    /// own read marker, or a date divider.
    Virtual(VirtualTimelineItem),
}

/// A single entry in timeline.
#[derive(Clone, Debug)]
pub struct TimelineItem {
    pub(crate) kind: TimelineItemKind,
    pub(crate) internal_id: TimelineUniqueId,
}

impl TimelineItem {
    /// Create a new `TimelineItem` with the given kind and internal id.
    pub(crate) fn new(
        kind: impl Into<TimelineItemKind>,
        internal_id: TimelineUniqueId,
    ) -> Arc<Self> {
        Arc::new(TimelineItem { kind: kind.into(), internal_id })
    }

    /// Create a clone of the current `TimelineItem` with the given kind.
    pub(crate) fn with_kind(&self, kind: impl Into<TimelineItemKind>) -> Arc<Self> {
        Arc::new(Self { kind: kind.into(), internal_id: self.internal_id.clone() })
    }

    /// Get the [`TimelineItemKind`] of this item.
    pub fn kind(&self) -> &TimelineItemKind {
        &self.kind
    }

    /// Get the inner `EventTimelineItem`, if this is a
    /// [`TimelineItemKind::Event`].
    pub fn as_event(&self) -> Option<&EventTimelineItem> {
        as_variant!(&self.kind, TimelineItemKind::Event)
    }

    /// Get the inner `VirtualTimelineItem`, if this is a
    /// [`TimelineItemKind::Virtual`].
    pub fn as_virtual(&self) -> Option<&VirtualTimelineItem> {
        as_variant!(&self.kind, TimelineItemKind::Virtual)
    }

    /// Get a unique ID for this timeline item.
    ///
    /// It identifies the item on a best-effort basis. For instance, edits
    /// to an [`EventTimelineItem`] will not change the ID of the
    /// enclosing `TimelineItem`. For some virtual items like date
    /// dividers, identity isn't easy to define though and you might
    /// see a new ID getting generated for a date divider that you
    /// perceive to be "the same" as a previous one.
    pub fn unique_id(&self) -> &TimelineUniqueId {
        &self.internal_id
    }

    pub(crate) fn read_marker() -> Arc<TimelineItem> {
        Arc::new(Self {
            kind: TimelineItemKind::Virtual(VirtualTimelineItem::ReadMarker),
            internal_id: TimelineUniqueId("__read_marker".to_owned()),
        })
    }

    pub(crate) fn is_local_echo(&self) -> bool {
        matches!(&self.kind, TimelineItemKind::Event(ev) if ev.is_local_echo())
    }

    pub(crate) fn is_remote_event(&self) -> bool {
        matches!(&self.kind, TimelineItemKind::Event(ev) if ev.is_remote_event())
    }

    pub(crate) fn is_event(&self) -> bool {
        matches!(&self.kind, TimelineItemKind::Event(_))
    }

    /// Check whether this item is a date divider.
    #[must_use]
    pub fn is_date_divider(&self) -> bool {
        matches!(self.kind, TimelineItemKind::Virtual(VirtualTimelineItem::DateDivider(_)))
    }

    pub(crate) fn is_read_marker(&self) -> bool {
        matches!(self.kind, TimelineItemKind::Virtual(VirtualTimelineItem::ReadMarker))
    }
}

impl Deref for TimelineItem {
    type Target = TimelineItemKind;

    fn deref(&self) -> &Self::Target {
        &self.kind
    }
}

impl From<EventTimelineItem> for TimelineItemKind {
    fn from(item: EventTimelineItem) -> Self {
        Self::Event(item)
    }
}

impl From<VirtualTimelineItem> for TimelineItemKind {
    fn from(item: VirtualTimelineItem) -> Self {
        Self::Virtual(item)
    }
}