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
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179

pub mod if_not_exists;
pub mod list_append;
pub mod math;

pub use self::if_not_exists::IfNotExists;
pub use self::list_append::ListAppend;
pub use self::math::Math;

use core::fmt;

use crate::{
    path::Path,
    value::{Value, ValueOrRef},
};

/// Represents a [`SET` statement for an update expression][1].
///
/// See also: [`Update`]
///
/// [1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.SET
/// [`Update`]: crate::update::Update
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct Set {
    pub(crate) actions: Vec<SetAction>,
}

impl Set {
    /// Add an additional action to this `SET` statement.
    pub fn and<T>(mut self, action: T) -> Self
    where
        T: Into<SetAction>,
    {
        self.actions.push(action.into());

        self
    }
}

impl fmt::Display for Set {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.write_str("SET ")?;

        let mut first = true;
        self.actions.iter().try_for_each(|action| {
            if first {
                first = false
            } else {
                f.write_str(", ")?;
            }

            action.fmt(f)
        })
    }
}

impl<T> From<T> for Set
where
    T: Into<SetAction>,
{
    fn from(value: T) -> Self {
        Self {
            actions: vec![value.into()],
        }
    }
}

impl<T> FromIterator<T> for Set
where
    T: Into<SetAction>,
{
    fn from_iter<I>(iter: I) -> Self
    where
        I: IntoIterator<Item = T>,
    {
        Self {
            actions: iter.into_iter().map(Into::into).collect(),
        }
    }
}

/// Represents an action to take in a [`SET` statement][1] for an update expression.
///
/// See also: [`Set`], [`Update`]
///
/// [1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.SET
/// [`Update`]: crate::update::Update
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub enum SetAction {
    /// Assign a value in a `SET` statement for an update expression.
    ///
    /// See also: [`Assign`]
    Assign(Assign),

    /// Perform [math against a value in a `SET` statement][1] for an update expression.
    ///
    /// See also: [`Math`]
    ///
    /// [1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.SET.IncrementAndDecrement
    Math(Math),

    /// [Add values to a list][1] in a `SET` statement for an update expression.
    ///
    /// See also: [`ListAppend`]
    ///
    /// [1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.SET.UpdatingListElements
    ListAppend(ListAppend),

    /// Assign a value [only if it doesn't exist][1].
    ///
    /// See also: [`IfNotExists`]
    ///
    /// [1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.SET.PreventingAttributeOverwrites
    IfNotExists(IfNotExists),
}

impl From<Assign> for SetAction {
    fn from(assign: Assign) -> Self {
        Self::Assign(assign)
    }
}

impl From<Math> for SetAction {
    fn from(math: Math) -> Self {
        Self::Math(math)
    }
}

impl From<ListAppend> for SetAction {
    fn from(append: ListAppend) -> Self {
        Self::ListAppend(append)
    }
}

impl From<IfNotExists> for SetAction {
    fn from(if_not_exists: IfNotExists) -> Self {
        Self::IfNotExists(if_not_exists)
    }
}

impl fmt::Display for SetAction {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            SetAction::Assign(action) => action.fmt(f),
            SetAction::Math(action) => action.fmt(f),
            SetAction::ListAppend(action) => action.fmt(f),
            SetAction::IfNotExists(action) => action.fmt(f),
        }
    }
}

/// Represents assigning a value of a [field][1], [list][2], or [map][3].
///
/// [1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.SET.ModifyingAttributes
/// [2]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.SET.AddingListElements
/// [3]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.SET.AddingNestedMapAttributes
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct Assign {
    pub(crate) path: Path,
    pub(crate) value: ValueOrRef,
}

impl Assign {
    pub fn new<P, V>(path: P, value: V) -> Self
    where
        P: Into<Path>,
        V: Into<Value>,
    {
        Self {
            path: path.into(),
            value: value.into().into(),
        }
    }
}

impl fmt::Display for Assign {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{} = {}", self.path, self.value)
    }
}