wdl-modules 0.1.1

//! Dependency-name newtype with hyphen-to-underscore normalization.

use std::str::FromStr;

use serde::Deserialize;
use serde::Serialize;
use thiserror::Error;

/// An error parsing a [`DependencyName`].
#[derive(Debug, Error, PartialEq, Eq)]
#[error("dependency name `{0}` does not match `[A-Za-z][A-Za-z0-9_-]*`")]
pub struct DependencyNameError(String);

/// Returns `true` if `s` matches the dependency-name grammar
/// `[A-Za-z][A-Za-z0-9_-]*`.
fn is_dependency_name(s: &str) -> bool {
    let mut chars = s.chars();
    match chars.next() {
        Some(c) if c.is_ascii_alphabetic() => {}
        _ => return false,
    }
    chars.all(|c| c.is_ascii_alphanumeric() || c == '_' || c == '-')
}

/// A dependency name.
///
/// Dependency names begin with an ASCII letter and continue with ASCII
/// letters, digits, underscores, or hyphens. Following Cargo's
/// convention, hyphens and underscores are interchangeable: `spell-book`
/// and `spell_book` refer to the same dependency.
///
/// Two forms are stored: the **manifest** form preserves the exact
/// spelling from `module.json`, and the **identifier** form replaces
/// hyphens with underscores to produce a valid WDL identifier suitable
/// for use in symbolic imports. The identifier form must not be a
/// reserved keyword.
#[derive(Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd, Serialize, Deserialize)]
#[serde(into = "String", try_from = "String")]
pub struct DependencyName {
    /// The name as written in `module.json`.
    manifest: String,
    /// The WDL identifier form (hyphens replaced with underscores).
    identifier: String,
}

impl DependencyName {
    /// Returns the name as written in `module.json`.
    pub fn manifest(&self) -> &str {
        &self.manifest
    }

    /// Returns the WDL identifier form of the name (hyphens replaced
    /// with underscores).
    pub fn identifier(&self) -> &str {
        &self.identifier
    }

    /// Consumes the [`DependencyName`] and returns the manifest form.
    pub fn into_manifest(self) -> String {
        self.manifest
    }

    /// Consumes the [`DependencyName`] and returns the identifier form.
    pub fn into_identifier(self) -> String {
        self.identifier
    }
}

impl TryFrom<String> for DependencyName {
    type Error = DependencyNameError;

    fn try_from(s: String) -> Result<Self, Self::Error> {
        if !is_dependency_name(&s) {
            return Err(DependencyNameError(s));
        }
        let identifier = s.replace('-', "_");
        if !wdl_grammar::lexer::v1::is_ident(&identifier) {
            return Err(DependencyNameError(s));
        }
        Ok(Self {
            manifest: s,
            identifier,
        })
    }
}

impl FromStr for DependencyName {
    type Err = DependencyNameError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        Self::try_from(s.to_string())
    }
}

impl From<DependencyName> for String {
    fn from(name: DependencyName) -> Self {
        name.manifest
    }
}

impl AsRef<str> for DependencyName {
    fn as_ref(&self) -> &str {
        &self.manifest
    }
}

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

    #[test]
    fn accepts_valid_names() {
        for name in [
            "a",
            "spellbook",
            "spell_book",
            "spell-book",
            "Spell2",
            "X_1_2_3",
            "my-crate",
        ] {
            assert!(name.parse::<DependencyName>().is_ok(), "rejected `{name}`");
        }
    }

    #[test]
    fn normalizes_hyphens_to_underscores() {
        let hyphen: DependencyName = "spell-book".parse().unwrap();
        let underscore: DependencyName = "spell_book".parse().unwrap();
        assert_eq!(hyphen.identifier(), "spell_book");
        assert_eq!(hyphen.manifest(), "spell-book");
        assert_eq!(underscore.manifest(), "spell_book");
    }

    #[test]
    fn rejects_invalid_format() {
        for bad in [
            "",
            "1spellbook",
            "_spellbook",
            "-spellbook",
            "spell book",
            "spell.book",
            "spell/book",
        ] {
            assert!(bad.parse::<DependencyName>().is_err(), "accepted `{bad}`");
        }
    }

    #[test]
    fn rejects_reserved_keywords() {
        for bad in ["task", "workflow", "import", "if", "as"] {
            assert!(
                bad.parse::<DependencyName>().is_err(),
                "accepted reserved keyword `{bad}` as a dependency name"
            );
        }
    }

    #[test]
    fn round_trips_via_serde() {
        let name: DependencyName = "spell-book".parse().unwrap();
        let json = serde_json::to_string(&name).unwrap();
        assert_eq!(json, r#""spell-book""#);
        let parsed: DependencyName = serde_json::from_str(&json).unwrap();
        assert_eq!(parsed, name);
        assert_eq!(parsed.manifest(), "spell-book");
    }

    #[test]
    fn deserialize_rejects_invalid() {
        let err = serde_json::from_str::<DependencyName>(r#""1spellbook""#).unwrap_err();
        assert!(err.to_string().contains("does not match"));
    }
}