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

use rustc_error_messages::{
    fluent_bundle::resolver::errors::{ReferenceKind, ResolverError},
    FluentArgs, FluentError,
};
use std::borrow::Cow;
use std::error::Error;
use std::fmt;

#[derive(Debug)]
pub enum TranslateError<'args> {
    One {
        id: &'args Cow<'args, str>,
        args: &'args FluentArgs<'args>,
        kind: TranslateErrorKind<'args>,
    },
    Two {
        primary: Box<TranslateError<'args>>,
        fallback: Box<TranslateError<'args>>,
    },
}

impl<'args> TranslateError<'args> {
    pub fn message(id: &'args Cow<'args, str>, args: &'args FluentArgs<'args>) -> Self {
        Self::One { id, args, kind: TranslateErrorKind::MessageMissing }
    }

    pub fn primary(id: &'args Cow<'args, str>, args: &'args FluentArgs<'args>) -> Self {
        Self::One { id, args, kind: TranslateErrorKind::PrimaryBundleMissing }
    }

    pub fn attribute(
        id: &'args Cow<'args, str>,
        args: &'args FluentArgs<'args>,
        attr: &'args str,
    ) -> Self {
        Self::One { id, args, kind: TranslateErrorKind::AttributeMissing { attr } }
    }

    pub fn value(id: &'args Cow<'args, str>, args: &'args FluentArgs<'args>) -> Self {
        Self::One { id, args, kind: TranslateErrorKind::ValueMissing }
    }

    pub fn fluent(
        id: &'args Cow<'args, str>,
        args: &'args FluentArgs<'args>,
        errs: Vec<FluentError>,
    ) -> Self {
        Self::One { id, args, kind: TranslateErrorKind::Fluent { errs } }
    }

    pub fn and(self, fallback: TranslateError<'args>) -> TranslateError<'args> {
        Self::Two { primary: Box::new(self), fallback: Box::new(fallback) }
    }
}

#[derive(Debug)]
pub enum TranslateErrorKind<'args> {
    MessageMissing,
    PrimaryBundleMissing,
    AttributeMissing { attr: &'args str },
    ValueMissing,
    Fluent { errs: Vec<FluentError> },
}

impl fmt::Display for TranslateError<'_> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        use TranslateErrorKind::*;

        match self {
            Self::One { id, args, kind } => {
                writeln!(f, "failed while formatting fluent string `{id}`: ")?;
                match kind {
                    MessageMissing => writeln!(f, "message was missing")?,
                    PrimaryBundleMissing => writeln!(f, "the primary bundle was missing")?,
                    AttributeMissing { attr } => {
                        writeln!(f, "the attribute `{attr}` was missing")?;
                        writeln!(f, "help: add `.{attr} = <message>`")?;
                    }
                    ValueMissing => writeln!(f, "the value was missing")?,
                    Fluent { errs } => {
                        for err in errs {
                            match err {
                                FluentError::ResolverError(ResolverError::Reference(
                                    ReferenceKind::Message { id, .. }
                                    | ReferenceKind::Variable { id, .. },
                                )) => {
                                    if args.iter().any(|(arg_id, _)| arg_id == id) {
                                        writeln!(
                                            f,
                                            "argument `{id}` exists but was not referenced correctly"
                                        )?;
                                        writeln!(f, "help: try using `{{${id}}}` instead")?;
                                    } else {
                                        writeln!(
                                            f,
                                            "the fluent string has an argument `{id}` that was not found."
                                        )?;
                                        let vars: Vec<&str> =
                                            args.iter().map(|(a, _v)| a).collect();
                                        match &*vars {
                                            [] => writeln!(f, "help: no arguments are available")?,
                                            [one] => writeln!(
                                                f,
                                                "help: the argument `{one}` is available"
                                            )?,
                                            [first, middle @ .., last] => {
                                                write!(f, "help: the arguments `{first}`")?;
                                                for a in middle {
                                                    write!(f, ", `{a}`")?;
                                                }
                                                writeln!(f, " and `{last}` are available")?;
                                            }
                                        }
                                    }
                                }
                                _ => writeln!(f, "{err}")?,
                            }
                        }
                    }
                }
            }
            // If someone cares about primary bundles, they'll probably notice it's missing
            // regardless or will be using `debug_assertions`
            // so we skip the arm below this one to avoid confusing the regular user.
            Self::Two { primary: box Self::One { kind: PrimaryBundleMissing, .. }, fallback } => {
                fmt::Display::fmt(fallback, f)?;
            }
            Self::Two { primary, fallback } => {
                writeln!(
                    f,
                    "first, fluent formatting using the primary bundle failed:\n {primary}\n \
                    while attempting to recover by using the fallback bundle instead, another error occurred:\n{fallback}"
                )?;
            }
        }
        Ok(())
    }
}

impl Error for TranslateError<'_> {}