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
144
145
146
147
148
149
150
151

// 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::collections::HashMap;

use serde_json::Value;

/// A list of arguments that can be accessed by index or name.
#[derive(Debug, Clone, Default)]
pub struct List {
    arguments: Vec<Value>,
    name_index: HashMap<String, usize>,
}

impl List {
    /// Get an argument by its index.
    #[must_use]
    pub fn get_by_index(&self, index: usize) -> Option<&Value> {
        self.arguments.get(index)
    }

    /// Get an argument by its name.
    #[must_use]
    pub fn get_by_name(&self, name: &str) -> Option<&Value> {
        self.name_index
            .get(name)
            .and_then(|index| self.get_by_index(*index))
    }
}

impl<A: Into<Argument>> FromIterator<A> for List {
    fn from_iter<T: IntoIterator<Item = A>>(iter: T) -> Self {
        let mut arguments = Vec::new();
        let mut name_index = HashMap::new();

        for (index, argument) in iter.into_iter().enumerate() {
            let argument = argument.into();
            if let Some(name) = argument.name {
                name_index.insert(name.clone(), index);
            }

            arguments.push(argument.value);
        }

        Self {
            arguments,
            name_index,
        }
    }
}

/// A single argument value.
pub struct Argument {
    name: Option<String>,
    value: Value,
}

impl From<Value> for Argument {
    fn from(value: Value) -> Self {
        Self { name: None, value }
    }
}

impl From<(&str, Value)> for Argument {
    fn from((name, value): (&str, Value)) -> Self {
        Self {
            name: Some(name.to_owned()),
            value,
        }
    }
}

impl From<(String, Value)> for Argument {
    fn from((name, value): (String, Value)) -> Self {
        Self {
            name: Some(name),
            value,
        }
    }
}

impl Argument {
    /// Create a new argument with the given name and value.
    #[must_use]
    pub fn named(name: String, value: Value) -> Self {
        Self {
            name: Some(name),
            value,
        }
    }

    /// Set the name of the argument.
    #[must_use]
    pub fn with_name(mut self, name: String) -> Self {
        self.name = Some(name);
        self
    }
}

#[cfg(test)]
mod tests {
    use serde_json::json;

    use super::*;

    #[test]
    fn test_argument_list() {
        let list = List::from_iter([
            ("hello", json!("world")),
            ("alice", json!(null)),
            ("bob", json!(42)),
        ]);

        assert_eq!(list.get_by_index(0), Some(&json!("world")));
        assert_eq!(list.get_by_index(1), Some(&json!(null)));
        assert_eq!(list.get_by_index(2), Some(&json!(42)));
        assert_eq!(list.get_by_index(3), None);

        assert_eq!(list.get_by_name("hello"), Some(&json!("world")));
        assert_eq!(list.get_by_name("alice"), Some(&json!(null)));
        assert_eq!(list.get_by_name("bob"), Some(&json!(42)));
        assert_eq!(list.get_by_name("charlie"), None);

        let list = List::from_iter([
            Argument::from(json!("hello")),
            Argument::named("alice".to_owned(), json!(null)),
            Argument::named("bob".to_owned(), json!(42)),
        ]);

        assert_eq!(list.get_by_index(0), Some(&json!("hello")));
        assert_eq!(list.get_by_index(1), Some(&json!(null)));
        assert_eq!(list.get_by_index(2), Some(&json!(42)));
        assert_eq!(list.get_by_index(3), None);

        assert_eq!(list.get_by_name("hello"), None);
        assert_eq!(list.get_by_name("alice"), Some(&json!(null)));
        assert_eq!(list.get_by_name("bob"), Some(&json!(42)));
        assert_eq!(list.get_by_name("charlie"), None);
    }
}