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

use kwap_macros::rfc_7252_doc;
#[cfg(feature = "alloc")]
use std_alloc::string::{String, ToString};

#[doc = rfc_7252_doc!("12.1")]
/// <details><summary><b>RFC7252 Section 12.1.1 Method Codes</b></summary>
#[doc = concat!("\n#", rfc_7252_doc!("12.1.1"))]
/// </details>
/// <details><summary><b>RFC7252 Section 12.1.2 Response Codes</b></summary>
#[doc = concat!("\n#", rfc_7252_doc!("12.1.2"))]
/// </details>
///
/// # Examples
/// ```
/// use kwap_msg::Code;
///
/// assert_eq!(Code { class: 2, detail: 5 }.to_string(), "2.05".to_string());
/// ```
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
pub struct Code {
  /// The "class" of message codes identify it as a request or response, and provides the class of response status:
  ///
  /// |class|meaning|
  /// |---|---|
  /// |`0`|Message is a request|
  /// |`2`|Message is a success response|
  /// |`4`|Message is a client error response|
  /// |`5`|Message is a server error response|
  pub class: u8,

  /// 2-digit integer (range `[0, 32)`) that provides granular information about the response status.
  ///
  /// Will always be `0` for requests.
  pub detail: u8,
}

/// Whether a code is for a request, response, or empty message
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum CodeKind {
  /// A request code (0.xx)
  Request,
  /// A response code ([2-5].xx)
  Response,
  /// EMPTY (0.00)
  Empty,
}

impl Code {
  /// Create a new Code
  ///
  /// ```
  /// use kwap_msg::Code;
  ///
  /// let content = Code::new(2, 05);
  /// ```
  pub const fn new(class: u8, detail: u8) -> Self {
    Self { class, detail }
  }

  /// Get the human string representation of a message code
  ///
  /// # Returns
  /// A `char` array
  ///
  /// This is to avoid unnecessary heap allocation,
  /// you can create a `String` with `FromIterator::<String>::from_iter`,
  /// or if the `alloc` feature of `kwap` is enabled there is a `ToString` implementation provided for Code.
  /// ```
  /// use kwap_msg::Code;
  ///
  /// let code = Code { class: 2, detail: 5 };
  /// let chars = code.to_human();
  /// let string = String::from_iter(chars);
  /// assert_eq!(string, "2.05".to_string());
  /// ```
  pub fn to_human(&self) -> [char; 4] {
    let to_char = |d: u8| char::from_digit(d.into(), 10).unwrap();
    [to_char(self.class),
     '.',
     to_char(self.detail / 10),
     to_char(self.detail % 10)]
  }

  /// Get whether this code is for a request, response, or empty message
  ///
  /// ```
  /// use kwap_msg::{Code, CodeKind};
  ///
  /// let empty: Code = Code::new(0, 0);
  /// assert_eq!(empty.kind(), CodeKind::Empty);
  ///
  /// let req = Code::new(1, 1); // GET
  /// assert_eq!(req.kind(), CodeKind::Request);
  ///
  /// let resp = Code::new(2, 5); // OK CONTENT
  /// assert_eq!(resp.kind(), CodeKind::Response);
  /// ```
  pub fn kind(&self) -> CodeKind {
    match self.class {
      | 0 => CodeKind::Empty,
      | 1 => CodeKind::Request,
      | _ => CodeKind::Response,
    }
  }
}

#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
impl ToString for Code {
  fn to_string(&self) -> String {
    String::from_iter(self.to_human())
  }
}

impl From<u8> for Code {
  fn from(b: u8) -> Self {
    let class = b >> 5;
    let detail = b & 0b0011111;

    Code { class, detail }
  }
}

impl From<Code> for u8 {
  fn from(code: Code) -> u8 {
    let class = code.class << 5;
    let detail = code.detail;

    class | detail
  }
}

#[cfg(test)]
mod tests {
  use super::*;
  use crate::assert_eqb;

  #[test]
  fn parse_code() {
    let byte = 0b0100_0101_u8;
    let code = Code::from(byte);
    assert_eq!(code, Code { class: 2, detail: 5 })
  }

  #[test]
  fn serialize_code() {
    let code = Code { class: 2, detail: 5 };
    let actual: u8 = code.into();
    let expected = 0b0100_0101_u8;
    assert_eqb!(actual, expected)
  }
}