mise 2026.9.12

//! Client for the formulae.brew.sh JSON API (static JSON, no auth).

use std::collections::HashMap;

use eyre::{WrapErr, bail, eyre};
use serde::Deserialize;

use crate::http::HTTP_FETCH;
use crate::result::Result;

const API_BASE: &str = "https://formulae.brew.sh/api";

#[derive(Debug, Clone, Deserialize)]
pub(super) struct Formula {
    pub name: String,
    #[serde(default)]
    pub tap: Option<String>,
    #[serde(default)]
    pub aliases: Vec<String>,
    /// names this formula had before a rename
    #[serde(default)]
    pub oldnames: Vec<String>,
    pub versions: Versions,
    #[serde(default)]
    pub revision: u32,
    #[serde(default)]
    pub keg_only: bool,
    #[serde(default)]
    pub keg_only_reason: Option<KegOnlyReason>,
    /// runtime dependencies (formula names)
    #[serde(default)]
    pub dependencies: Vec<String>,
    /// build-time-only dependencies — needed for source builds, not pours
    #[serde(default)]
    pub build_dependencies: Vec<String>,
    #[serde(default)]
    pub bottle: HashMap<String, BottleSpec>,
    /// per-bottle-tag overrides (e.g. different dependencies on some platforms)
    #[serde(default)]
    pub variations: HashMap<String, Variation>,
    /// source download specs keyed by spec name ("stable")
    #[serde(default)]
    pub urls: HashMap<String, SourceUrl>,
    /// formula .rb location in homebrew/core (e.g. "Formula/h/hello.rb")
    #[serde(default)]
    pub ruby_source_path: Option<String>,
    #[serde(default)]
    pub ruby_source_checksum: Option<RubySourceChecksum>,
    /// homebrew/core commit this API snapshot was generated from
    #[serde(default)]
    pub tap_git_head: Option<String>,
}

#[derive(Debug, Clone, Deserialize)]
pub(super) struct SourceUrl {
    pub url: String,
    /// sha256 of the source archive; absent for VCS sources
    #[serde(default)]
    pub checksum: Option<String>,
    /// non-default download strategy (":git", ":svn", ...) — unsupported
    #[serde(default)]
    pub using: Option<String>,
}

#[derive(Debug, Clone, Deserialize)]
pub(super) struct RubySourceChecksum {
    #[serde(default)]
    pub sha256: Option<String>,
}

#[derive(Debug, Clone, Deserialize)]
pub(super) struct Versions {
    pub stable: Option<String>,
}

#[derive(Debug, Clone, Deserialize)]
pub(super) struct BottleSpec {
    #[serde(default)]
    pub files: HashMap<String, BottleFile>,
}

#[derive(Debug, Clone, Deserialize)]
pub(super) struct BottleFile {
    /// ":any", ":any_skip_relocation", or a pinned cellar path
    pub cellar: String,
    pub url: String,
    pub sha256: String,
}

#[derive(Debug, Clone, Default, Deserialize)]
pub(super) struct Variation {
    #[serde(default)]
    pub dependencies: Option<Vec<String>>,
    #[serde(default)]
    pub build_dependencies: Option<Vec<String>>,
}

#[derive(Debug, Clone, Deserialize)]
pub(super) struct KegOnlyReason {
    /// ":provided_by_macos", another reason symbol, or free text
    #[serde(default)]
    pub reason: String,
}

impl Formula {
    /// every name that refers to this formula: canonical, aliases, old names
    pub(super) fn names(&self) -> impl Iterator<Item = &str> {
        std::iter::once(self.name.as_str())
            .chain(self.aliases.iter().map(String::as_str))
            .chain(self.oldnames.iter().map(String::as_str))
    }

    /// keg directory name: version plus brew's bottle revision suffix
    pub(super) fn pkg_version(&self) -> Result<String> {
        let stable = self
            .versions
            .stable
            .as_ref()
            .ok_or_else(|| eyre!("formula {} has no stable version", self.name))?;
        Ok(if self.revision > 0 {
            format!("{stable}_{}", self.revision)
        } else {
            stable.clone()
        })
    }

    /// Mirrors brew's KegOnlyReason#applicable?: keg-only reasons tied to
    /// macOS (:provided_by_macos, :shadowed_by_macos) do not apply on other
    /// OSes, where brew links these formulae normally.
    pub(super) fn keg_only_for_target(&self) -> bool {
        if !self.keg_only {
            return false;
        }
        if cfg!(target_os = "macos") {
            return true;
        }
        !matches!(
            self.keg_only_reason.as_ref().map(|r| r.reason.as_str()),
            Some(":provided_by_macos") | Some(":shadowed_by_macos")
        )
    }

    /// runtime dependencies for the given bottle tag, applying `variations`
    pub(super) fn dependencies_for(&self, tag: &str) -> &[String] {
        if let Some(v) = self.variations.get(tag)
            && let Some(deps) = &v.dependencies
        {
            return deps;
        }
        &self.dependencies
    }

    /// build-time dependencies for the given bottle tag, applying `variations`
    pub(super) fn build_dependencies_for(&self, tag: &str) -> &[String] {
        if let Some(v) = self.variations.get(tag)
            && let Some(deps) = &v.build_dependencies
        {
            return deps;
        }
        &self.build_dependencies
    }

    pub(super) fn bottle_files(&self) -> Option<&HashMap<String, BottleFile>> {
        self.bottle.get("stable").map(|b| &b.files)
    }

    /// the stable source archive spec, when present
    pub(super) fn stable_url(&self) -> Option<&SourceUrl> {
        self.urls.get("stable")
    }
}

/// Fetch homebrew/core formula metadata by name, alias, or old name.
///
/// The per-formula API serves canonical names only: an alias (`openssl`) or a
/// renamed formula's old name returns 404 rather than redirecting. When the
/// exact lookup fails, the name is resolved through the bulk formula index and
/// the canonical formula is fetched instead; if the index has no entry for it,
/// the original error is returned.
pub(super) async fn formula(name: &str) -> Result<Formula> {
    formula_from(API_BASE, &FORMULA_ALIASES, name).await
}

async fn formula_from(base: &str, aliases: &AliasIndex, name: &str) -> Result<Formula> {
    let err = match formula_exact_from(base, name).await {
        Ok(formula) => return Ok(formula),
        Err(err) => err,
    };
    match canonical_formula_name(base, aliases, name).await {
        Ok(Some(canonical)) => {
            debug!("brew: {name} resolves to {canonical}");
            formula_exact_from(base, &canonical).await
        }
        Ok(None) => Err(err),
        Err(index_err) => {
            debug!("brew: could not load the formula index to resolve {name}: {index_err:#}");
            Err(err)
        }
    }
}

/// Fetch homebrew/core formula metadata by its canonical name only.
pub(super) async fn formula_exact(name: &str) -> Result<Formula> {
    formula_exact_from(API_BASE, name).await
}

async fn formula_exact_from(base: &str, name: &str) -> Result<Formula> {
    let url = format!("{base}/formula/{name}.json");
    HTTP_FETCH
        .json_cached::<Formula, _>(url)
        .await
        .wrap_err_with(|| format!("failed to fetch Homebrew formula '{name}'"))
}

#[derive(Debug, Deserialize)]
struct FormulaIndexEntry {
    name: String,
    #[serde(default)]
    aliases: Vec<String>,
    #[serde(default)]
    oldnames: Vec<String>,
}

/// alias or old name -> canonical name, from the bulk `formula.json`, or why
/// it could not be loaded. Fetched at most once per process, and only after
/// an exact lookup has failed; a failure is kept so that every alias in a
/// dependency frontier does not retry the download.
type AliasIndex = tokio::sync::OnceCell<std::result::Result<HashMap<String, String>, String>>;

static FORMULA_ALIASES: AliasIndex = tokio::sync::OnceCell::const_new();

async fn canonical_formula_name(
    base: &str,
    aliases: &AliasIndex,
    name: &str,
) -> Result<Option<String>> {
    let aliases = aliases
        .get_or_init(|| async {
            HTTP_FETCH
                .json::<Vec<FormulaIndexEntry>, _>(format!("{base}/formula.json"))
                .await
                .map(alias_map)
                .map_err(|err| format!("{err:#}"))
        })
        .await;
    match aliases {
        Ok(aliases) => Ok(aliases.get(name).cloned()),
        Err(err) => bail!("failed to fetch the Homebrew formula index: {err}"),
    }
}

/// A name that is both an alias and an old name resolves as the alias.
fn alias_map(entries: Vec<FormulaIndexEntry>) -> HashMap<String, String> {
    let mut map = HashMap::new();
    for entry in &entries {
        for alias in &entry.aliases {
            map.insert(alias.clone(), entry.name.clone());
        }
    }
    for entry in entries {
        for oldname in entry.oldnames {
            map.entry(oldname).or_insert_with(|| entry.name.clone());
        }
    }
    map
}

pub(super) async fn formula_with_tap_name(
    name: &str,
    tap_name: Option<&str>,
    tap_url: Option<&str>,
    provision_ruby: bool,
) -> Result<Formula> {
    let Some((owner, tap, formula_name)) = split_tap_name(name).or_else(|| {
        let (owner, tap) = split_tap(tap_name?)?;
        Some((owner, tap, name))
    }) else {
        return formula(name).await;
    };
    if owner == "homebrew" && tap == "core" {
        return formula(formula_name).await;
    }
    let Some(url) = tap_formula_api_url(owner, tap, formula_name, tap_url) else {
        bail!(
            "brew: tapped formula '{name}' needs a GitHub tap URL in [bootstrap.brew.taps] \
             so mise can fetch metadata directly without the brew CLI"
        );
    };
    match HTTP_FETCH.json_cached::<Formula, _>(url).await {
        Ok(formula) => Ok(formula),
        Err(api_err) => {
            super::tap::formula_from_ruby(owner, tap, formula_name, tap_url, provision_ruby)
                .await
                .wrap_err_with(|| {
                    format!(
                        "failed to resolve Homebrew tap formula '{name}'; published API metadata \
                     was unavailable ({api_err}) and mise could not evaluate its tap definition"
                    )
                })
        }
    }
}

pub(super) fn tap_name(name: &str) -> Option<String> {
    let (owner, tap, _) = split_tap_name(name)?;
    if owner == "homebrew" && tap == "core" {
        None
    } else {
        Some(format!("{owner}/{tap}"))
    }
}

pub(super) fn tap_name_from_url(url: &str) -> Option<String> {
    let url = url.trim_end_matches('/').trim_end_matches(".git");
    let rest = url.strip_prefix("https://github.com/")?;
    let mut parts = rest.split('/');
    let owner = parts.next()?;
    let repo = parts.next()?;
    if parts.next().is_some() || owner.is_empty() || repo.is_empty() {
        return None;
    }
    Some(format!(
        "{owner}/{}",
        repo.strip_prefix("homebrew-").unwrap_or(repo)
    ))
}

fn split_tap(name: &str) -> Option<(&str, &str)> {
    let mut parts = name.split('/');
    let owner = parts.next()?;
    let tap = parts.next()?;
    if parts.next().is_some() || owner.is_empty() || tap.is_empty() {
        None
    } else {
        Some((owner, tap))
    }
}

pub(super) fn split_tap_name(name: &str) -> Option<(&str, &str, &str)> {
    let mut parts = name.split('/');
    let owner = parts.next()?;
    let tap = parts.next()?;
    let formula = parts.next()?;
    if parts.next().is_some() || owner.is_empty() || tap.is_empty() || formula.is_empty() {
        None
    } else {
        Some((owner, tap, formula))
    }
}

fn tap_formula_api_url(
    owner: &str,
    tap: &str,
    formula: &str,
    tap_url: Option<&str>,
) -> Option<String> {
    let repo = tap_raw_base(owner, tap, tap_url)?;
    Some(format!("{repo}/api/formula/{formula}.json"))
}

pub(super) fn tap_raw_base(owner: &str, tap: &str, tap_url: Option<&str>) -> Option<String> {
    match tap_url {
        Some(url) => github_raw_base(url),
        None => Some(format!(
            "https://raw.githubusercontent.com/{owner}/homebrew-{tap}/HEAD"
        )),
    }
}

pub(super) fn github_raw_base(url: &str) -> Option<String> {
    let url = url.trim_end_matches('/').trim_end_matches(".git");
    let rest = url.strip_prefix("https://github.com/")?;
    let mut parts = rest.split('/');
    let owner = parts.next()?;
    let repo = parts.next()?;
    if parts.next().is_some() || owner.is_empty() || repo.is_empty() {
        None
    } else {
        Some(format!(
            "https://raw.githubusercontent.com/{owner}/{repo}/HEAD"
        ))
    }
}

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

    fn keg_only_formula(reason: Option<&str>) -> Formula {
        let mut json = serde_json::json!({
            "name": "zip",
            "versions": {"stable": "3.0"},
            "keg_only": true,
        });
        if let Some(reason) = reason {
            json["keg_only_reason"] = serde_json::json!({"reason": reason});
        }
        serde_json::from_value(json).unwrap()
    }

    #[test]
    fn macos_keg_only_reasons_only_apply_on_macos() {
        for reason in [":provided_by_macos", ":shadowed_by_macos"] {
            let formula = keg_only_formula(Some(reason));
            assert_eq!(formula.keg_only_for_target(), cfg!(target_os = "macos"));
        }
    }

    #[test]
    fn other_keg_only_reasons_apply_everywhere() {
        assert!(keg_only_formula(Some(":versioned_formula")).keg_only_for_target());
        assert!(keg_only_formula(Some("free-text reason")).keg_only_for_target());
        assert!(keg_only_formula(None).keg_only_for_target());
    }

    #[test]
    fn alias_map_resolves_aliases_before_old_names() {
        let entries: Vec<FormulaIndexEntry> = serde_json::from_value(serde_json::json!([
            {"name": "openssl@3", "aliases": ["openssl", "openssl@3.6"], "oldnames": []},
            {"name": "gitea-runner", "aliases": [], "oldnames": ["act_runner"]},
            {"name": "shadowed", "oldnames": ["openssl"]},
            {"name": "hello"},
        ]))
        .unwrap();
        let map = alias_map(entries);
        assert_eq!(map.get("openssl").map(String::as_str), Some("openssl@3"));
        assert_eq!(
            map.get("openssl@3.6").map(String::as_str),
            Some("openssl@3")
        );
        assert_eq!(
            map.get("act_runner").map(String::as_str),
            Some("gitea-runner")
        );
        assert_eq!(map.get("hello"), None);
    }

    #[tokio::test]
    async fn failed_lookup_resolves_through_the_alias_index_once() -> Result<()> {
        let mut server = mockito::Server::new_async().await;
        let base = server.url();
        let mut not_found = Vec::new();
        for path in ["/formula/openssl.json", "/formula/missing.json"] {
            not_found.push(
                server
                    .mock("GET", path)
                    .with_status(404)
                    .expect(1)
                    .create_async()
                    .await,
            );
        }
        let index = server
            .mock("GET", "/formula.json")
            .with_body(
                serde_json::json!([{"name": "openssl@3", "aliases": ["openssl"]}]).to_string(),
            )
            .expect(1)
            .create_async()
            .await;
        let canonical = server
            .mock("GET", "/formula/openssl@3.json")
            .with_body(
                serde_json::json!({"name": "openssl@3", "versions": {"stable": "3.6.4"}})
                    .to_string(),
            )
            .expect(1)
            .create_async()
            .await;
        let aliases = AliasIndex::const_new();

        assert_eq!(
            formula_from(&base, &aliases, "openssl").await?.name,
            "openssl@3"
        );
        let err = formula_from(&base, &aliases, "missing").await.unwrap_err();
        assert!(format!("{err:#}").contains("missing.json"), "{err:#}");

        for mock in not_found.iter().chain([&index, &canonical]) {
            mock.assert_async().await;
        }
        Ok(())
    }

    #[tokio::test]
    async fn failed_alias_index_is_fetched_once() -> Result<()> {
        let mut server = mockito::Server::new_async().await;
        let base = server.url();
        server
            .mock("GET", mockito::Matcher::Regex("^/formula/".into()))
            .with_status(404)
            .create_async()
            .await;
        let index = server
            .mock("GET", "/formula.json")
            .with_status(404)
            .expect(1)
            .create_async()
            .await;
        let aliases = AliasIndex::const_new();

        for name in ["first", "second"] {
            let err = formula_from(&base, &aliases, name).await.unwrap_err();
            assert!(
                format!("{err:#}").contains(&format!("{name}.json")),
                "{err:#}"
            );
        }
        index.assert_async().await;
        Ok(())
    }

    #[test]
    fn formula_names_include_aliases_and_old_names() {
        let formula: Formula = serde_json::from_value(serde_json::json!({
            "name": "gitea-runner",
            "aliases": ["runner"],
            "oldnames": ["act_runner"],
            "versions": {"stable": "1.0"},
        }))
        .unwrap();
        assert_eq!(
            formula.names().collect::<Vec<_>>(),
            ["gitea-runner", "runner", "act_runner"]
        );
    }

    #[test]
    fn github_tap_urls_allow_trailing_slashes() {
        let url = "https://github.com/acme/homebrew-tools.git/";
        assert_eq!(tap_name_from_url(url).as_deref(), Some("acme/tools"));
        assert_eq!(
            github_raw_base(url).as_deref(),
            Some("https://raw.githubusercontent.com/acme/homebrew-tools/HEAD")
        );
    }
}