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

use serde::{Deserialize, Serialize};
use std::fmt;

#[derive(Clone, Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
pub enum StatusCode {
    Code(u16),
    Range(u16),
}

impl fmt::Display for StatusCode {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            StatusCode::Code(n) => write!(f, "{}", n),
            StatusCode::Range(n) => write!(f, "{}XX", n),
        }
    }
}

impl<'de> Deserialize<'de> for StatusCode {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: serde::Deserializer<'de>,
    {
        use serde::de::{self, Unexpected, Visitor};

        struct StatusCodeVisitor;

        impl<'de> Visitor<'de> for StatusCodeVisitor {
            type Value = StatusCode;

            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
                formatter.write_str("number between 100 and 999 (as string or integer) or a string that matches `\\dXX`")
            }

            fn visit_i64<E>(self, value: i64) -> Result<Self::Value, E>
            where
                E: de::Error,
            {
                if value >= 100 && value < 1000 {
                    Ok(StatusCode::Code(value as u16))
                } else {
                    Err(E::invalid_value(Unexpected::Signed(value), &self))
                }
            }

            fn visit_u64<E>(self, value: u64) -> Result<Self::Value, E>
            where
                E: de::Error,
            {
                if value >= 100 && value < 1000 {
                    Ok(StatusCode::Code(value as u16))
                } else {
                    Err(E::invalid_value(Unexpected::Unsigned(value), &self))
                }
            }

            fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
            where
                E: de::Error,
            {
                if value.len() != 3 {
                    return Err(E::invalid_value(Unexpected::Str(value), &"length 3"));
                }

                if let Ok(number) = value.parse::<i64>() {
                    return self.visit_i64(number);
                }

                if !value.is_ascii() {
                    return Err(E::invalid_value(
                        Unexpected::Str(value),
                        &"ascii, format `\\dXX`",
                    ));
                }

                let v = value.as_bytes().to_ascii_uppercase();

                match [v[0], v[1], v[2]] {
                    [n, b'X', b'X'] if n.is_ascii_digit() => {
                        Ok(StatusCode::Range(u16::from(n - b'0')))
                    }
                    _ => Err(E::invalid_value(Unexpected::Str(value), &"format `\\dXX`")),
                }
            }
        }

        deserializer.deserialize_any(StatusCodeVisitor)
    }
}

impl Serialize for StatusCode {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: serde::Serializer,
    {
        serializer.serialize_str(&self.to_string())
    }
}

#[cfg(test)]
mod tests {
    use super::StatusCode;
    use serde_yaml::from_str;

    #[test]
    fn deserialize_strings_and_numbers() {
        assert_eq!(StatusCode::Code(200), from_str("200").unwrap(),);
        assert_eq!(StatusCode::Code(200), from_str("'200'").unwrap(),);
    }

    #[test]
    #[should_panic = "expected length 3"]
    fn deserialize_invalid_code() {
        let _: StatusCode = from_str("'6666'").unwrap();
    }

    #[test]
    fn deserialize_ranges() {
        assert_eq!(StatusCode::Range(2), from_str("2XX").unwrap(),);
        assert_eq!(StatusCode::Range(4), from_str("'4xx'").unwrap(),);
    }

    #[test]
    #[should_panic = "invalid value"]
    fn deserialize_invalid_range() {
        let _: StatusCode = from_str("2XY").unwrap();
    }
}