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

use core::fmt;

use crate::path::Path;

use super::set_remove::SetRemove;

/// For use an in an update expression to [remove attributes from an
/// item][1], or [elements from a list][2].
///
/// See also: [`Path::remove`], [`SetRemove`], [`Update`]
///
/// # Examples
///
/// ```
/// # fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
/// use dynamodb_expression::{Expression, Path, update::{Remove, Update}};
/// # use pretty_assertions::assert_eq;
///
/// let remove = "foo".parse::<Path>()?.remove();
/// assert_eq!("REMOVE foo", remove.to_string());
///
/// let remove = Remove::from("foo[8]".parse::<Path>()?);
/// assert_eq!("REMOVE foo[8]", remove.to_string());
///
/// let remove: Remove = ["foo", "bar", "baz"].into_iter().map(Path::new_name).collect();
/// assert_eq!("REMOVE foo, bar, baz", remove.to_string());
///
/// let remove = remove.and("quux".parse::<Path>()?.remove());
/// assert_eq!("REMOVE foo, bar, baz, quux", remove.to_string());
///
/// // Use in an update expression
/// let update = Update::from(remove.clone());
/// # _ = update;
///
/// // Use an expression builder
/// let expression = Expression::builder().with_update(remove).build();
/// # _ = expression;
/// #
/// # Ok(())
/// # }
/// ```
///
/// [1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.REMOVE
/// [2]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.REMOVE.RemovingListElements
/// [`SetRemove`]: crate::update::SetRemove
/// [`Update`]: crate::update::Update
#[must_use = "Use in an update expression with `Update::from(remove)`"]
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Remove {
    pub(crate) paths: Vec<Path>,
}

impl Remove {
    /// Add an additional [`Remove`] or [`Set`] statement to this expression.
    ///
    /// ```
    /// # fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
    /// use dynamodb_expression::Path;
    /// # use pretty_assertions::assert_eq;
    ///
    /// let remove = "foo".parse::<Path>()?.remove().and("bar".parse::<Path>()?.remove());
    /// assert_eq!("REMOVE foo, bar", remove.to_string());
    ///
    /// let set_remove = remove.and("baz".parse::<Path>()?.set("a value"));
    /// assert_eq!(r#"SET baz = "a value" REMOVE foo, bar"#, set_remove.to_string());
    /// #
    /// # Ok(())
    /// # }
    /// ```
    ///
    /// [`Set`]: crate::update::Set
    pub fn and<T>(self, other: T) -> SetRemove
    where
        T: Into<SetRemove>,
    {
        SetRemove::from(self).and(other)
    }
}

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

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

            name.fmt(f)
        })
    }
}

impl<T> From<T> for Remove
where
    T: Into<Path>,
{
    fn from(path: T) -> Self {
        Self {
            paths: vec![path.into()],
        }
    }
}

impl<T> FromIterator<T> for Remove
where
    T: Into<Path>,
{
    fn from_iter<I>(paths: I) -> Self
    where
        I: IntoIterator<Item = T>,
    {
        Self {
            paths: paths.into_iter().map(Into::into).collect(),
        }
    }
}

#[cfg(test)]
mod test {
    use pretty_assertions::assert_eq;

    use crate::Path;

    #[test]
    fn sub_attributes() {
        assert_eq!(
            "REMOVE foo.bar",
            "foo.bar".parse::<Path>().unwrap().remove().to_string()
        );
        assert_eq!(
            "REMOVE foo[3].bar",
            "foo[3].bar".parse::<Path>().unwrap().remove().to_string()
        );
        assert_eq!(
            "REMOVE foo[3][7]",
            "foo[3][7]".parse::<Path>().unwrap().remove().to_string()
        );
    }

    #[test]
    fn and() {
        let remove = "foo"
            .parse::<Path>()
            .unwrap()
            .remove()
            .and("bar".parse::<Path>().unwrap().remove());
        assert_eq!("REMOVE foo, bar", remove.to_string());
    }
}