poexam 0.0.10

// SPDX-FileCopyrightText: 2026 Sébastien Helleu <flashcode@flashtux.org>
//
// SPDX-License-Identifier: GPL-3.0-or-later

//! Implementation of the `escapes` rule: check missing/extra escape characters.

use crate::checker::Checker;
use crate::diagnostic::{Diagnostic, Severity};
use crate::po::entry::Entry;
use crate::po::message::Message;
use crate::rules::rule::RuleChecker;

pub struct EscapesRule;

impl RuleChecker for EscapesRule {
    fn name(&self) -> &'static str {
        "escapes"
    }

    fn description(&self) -> &'static str {
        "Check for missing or extra escape characters in translation."
    }

    fn is_default(&self) -> bool {
        true
    }

    fn is_check(&self) -> bool {
        true
    }

    /// Check for missing or extra escape characters (`\\` and `\`) in the translation.
    ///
    /// Wrong entry:
    /// ```text
    /// msgid "this is a \"test\""
    /// msgstr "ceci est un \\\"test\\\""
    /// ```
    ///
    /// Correct entry:
    /// ```text
    /// msgid "this is a \"test\""
    /// msgstr "ceci est un \"test\""
    /// ```
    ///
    /// Diagnostics reported:
    /// - [`error`](Severity::Error): `missing escaped escape characters '\\' (# / #)`
    /// - [`error`](Severity::Error): `extra escaped escape characters '\\' (# / #)`
    /// - [`error`](Severity::Error): `missing escaped escape characters '\' (# / #)`
    /// - [`error`](Severity::Error): `extra escaped escape characters '\' (# / #)`
    fn check_msg(
        &self,
        checker: &Checker,
        _entry: &Entry,
        msgid: &Message,
        msgstr: &Message,
    ) -> Vec<Diagnostic> {
        // First check escaped escape characters: "\\".
        let id_count = msgid.value.matches("\\\\").count();
        let str_count = msgstr.value.matches("\\\\").count();
        let msg = match id_count.cmp(&str_count) {
            std::cmp::Ordering::Greater => Some(format!(
                "missing escaped escape characters '\\\\' ({id_count} / {str_count})"
            )),
            std::cmp::Ordering::Less => Some(format!(
                "extra escaped escape characters '\\\\' ({id_count} / {str_count})"
            )),
            std::cmp::Ordering::Equal => None,
        };
        if let Some(msg) = msg {
            return self
                .new_diag(checker, Severity::Error, msg)
                .map(|d| {
                    d.with_msgs_hl(
                        msgid,
                        msgid
                            .value
                            .match_indices("\\\\")
                            .map(|(idx, value)| (idx, idx + value.len())),
                        msgstr,
                        msgstr
                            .value
                            .match_indices("\\\\")
                            .map(|(idx, value)| (idx, idx + value.len())),
                    )
                })
                .into_iter()
                .collect();
        }
        // Equal counts of "\\": now check single escape character: "\".
        let id_count = msgid.value.matches('\\').count();
        let str_count = msgstr.value.matches('\\').count();
        let msg = match id_count.cmp(&str_count) {
            std::cmp::Ordering::Equal => return vec![],
            std::cmp::Ordering::Greater => {
                format!("missing escape characters '\\' ({id_count} / {str_count})")
            }
            std::cmp::Ordering::Less => {
                format!("extra escape characters '\\' ({id_count} / {str_count})")
            }
        };
        self.new_diag(checker, Severity::Error, msg)
            .map(|d| {
                d.with_msgs_hl(
                    msgid,
                    msgid
                        .value
                        .match_indices('\\')
                        .map(|(idx, value)| (idx, idx + value.len())),
                    msgstr,
                    msgstr
                        .value
                        .match_indices('\\')
                        .map(|(idx, value)| (idx, idx + value.len())),
                )
            })
            .into_iter()
            .collect()
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::{diagnostic::Diagnostic, rules::rule::Rules};

    fn check_escapes(content: &str) -> Vec<Diagnostic> {
        let mut checker = Checker::new(content.as_bytes());
        let rules = Rules::new(vec![Box::new(EscapesRule {})]);
        checker.do_all_checks(&rules);
        checker.diagnostics
    }

    #[test]
    fn test_no_escapes() {
        let diags = check_escapes(
            r#"
msgid "tested"
msgstr "testé"
"#,
        );
        assert!(diags.is_empty());
    }

    #[test]
    fn test_escapes_ok() {
        let diags = check_escapes(
            r#"
msgid "tested: \ \n "
msgstr "testé : \ \n "
"#,
        );
        assert!(diags.is_empty());
    }

    #[test]
    fn test_escaped_escape_char_error() {
        let diags = check_escapes(
            r#"
msgid "tested\\\\"
msgstr "testé"

msgid "tested"
msgstr "testé\\\\"
"#,
        );
        assert_eq!(diags.len(), 2);
        let diag = &diags[0];
        assert_eq!(diag.severity, Severity::Error);
        assert_eq!(
            diag.message,
            "missing escaped escape characters '\\\\' (1 / 0)"
        );
        let diag = &diags[1];
        assert_eq!(diag.severity, Severity::Error);
        assert_eq!(
            diag.message,
            "extra escaped escape characters '\\\\' (0 / 1)"
        );
    }

    #[test]
    fn test_escaped_char_error_noqa() {
        let diags = check_escapes(
            r#"
#, noqa:escapes
msgid "tested\\"
msgstr "testé"
"#,
        );
        assert!(diags.is_empty());
    }

    #[test]
    fn test_escaped_char_error() {
        let diags = check_escapes(
            r#"
msgid "tested\\"
msgstr "testé"

msgid "tested"
msgstr "testé\\"
"#,
        );
        assert_eq!(diags.len(), 2);
        let diag = &diags[0];
        assert_eq!(diag.severity, Severity::Error);
        assert_eq!(diag.message, "missing escape characters '\\' (1 / 0)");
        let diag = &diags[1];
        assert_eq!(diag.severity, Severity::Error);
        assert_eq!(diag.message, "extra escape characters '\\' (0 / 1)");
    }
}