//! Parses `packages.d/*.toml` into typed, in-memory `Package` records.
//! The only module that knows the TOML shape — everything downstream
//! works with `Package`/`Verification`/`SanityCheck`, never raw TOML.

use anyhow::{Context, Result};
use serde::Deserialize;
use std::collections::{BTreeMap, HashMap};
use std::path::Path;

#[derive(Debug, Deserialize)]
struct PackageFile {
    package: HashMap<String, Package>,
}

#[derive(Debug, Deserialize, Clone)]
pub struct Package {
    pub repo: String,
    /// Exact GitHub release asset name (still not a glob — see
    /// docs/SPEC.md > Architecture > Fetcher), optionally containing a
    /// `{version}` placeholder for projects whose asset names embed the
    /// version (e.g. `scaleway-cli_{version}_linux_amd64`). Substituted via
    /// `checker::version_from_tag` before matching.
    pub asset_pattern: String,
    pub verification: Verification,
    /// Name of the executable inside the built package, if it differs from
    /// the package name itself — e.g. scaleway-cli's pacman package is
    /// named `scaleway-cli` but its real binary is `scw` (discovered by
    /// checking the currently-installed extra package, not guessable from
    /// the repo name). Defaults to the package name when omitted.
    pub binary_name: Option<String>,
    /// Explicit path to the binary inside the extracted archive, relative
    /// to `srcdir`, for archive layouts that don't match the "extracts into
    /// a directory named after the archive stem" convention `builder.rs`
    /// otherwise assumes (e.g. claude-code's tarball extracts a bare
    /// `claude` file with no wrapping directory, and that inner filename
    /// doesn't match the package name either). Only meaningful when
    /// `asset_pattern` names an archive; ignored for bare-binary downloads,
    /// where the downloaded file *is* the source path already. Defaults to
    /// the stem/`binary_name` convention when omitted.
    pub archive_binary_path: Option<String>,
    /// Environment variables to export before the real binary runs, when
    /// the vendor's own install ships them via a wrapper script that
    /// `builder.rs` would otherwise not replicate — e.g. claude-code's
    /// prior AUR package sets `DISABLE_UPDATES=1`/
    /// `DISABLE_INSTALLATION_CHECKS=1` specifically so its self-updater
    /// doesn't fight with a package manager already managing it, which
    /// applies just as much to pkgwatch-managed installs. `BTreeMap` for
    /// deterministic (sorted) ordering in the generated PKGBUILD. When
    /// present and non-empty, the real binary installs to
    /// `/usr/lib/<pkgname>/<binary_name>` instead of `/usr/bin` directly,
    /// and a generated `/usr/bin/<binary_name>` wrapper sets these vars
    /// before `exec`-ing it. Omitted or empty: no wrapper, same single-file
    /// install as before.
    pub env: Option<BTreeMap<String, String>>,
    /// Post-build correctness check (not a security control — see
    /// docs/SPEC.md > Verification trust tiers). Runs `command` against the
    /// freshly built binary and confirms `version_regex`'s capture group
    /// matches the version pkgwatch believes it just built.
    pub sanity_check: Option<SanityCheck>,
}

impl Package {
    /// The name of the executable inside the built package: `binary_name`
    /// if the package declares one, else `pkg_name` itself.
    pub fn binary_name<'a>(&'a self, pkg_name: &'a str) -> &'a str {
        self.binary_name.as_deref().unwrap_or(pkg_name)
    }
}

#[derive(Debug, Deserialize, Clone)]
pub struct SanityCheck {
    pub command: String,
    pub version_regex: String,
}

#[derive(Debug, Deserialize, Clone)]
#[serde(tag = "method", rename_all = "kebab-case")]
pub enum Verification {
    /// Tier 4: proves transport integrity only, not authorship. See
    /// docs/SPEC.md > Verification trust tiers. `checksum_asset_pattern` may
    /// also contain a `{version}` placeholder, same as `asset_pattern`.
    SameOriginSha256 { checksum_asset_pattern: String },
    /// Tier 2: GitHub build-provenance attestation, verified via `gh
    /// attestation verify` rather than reimplementing sigstore in Rust.
    GithubAttestation,
}

impl Verification {
    pub fn tier(&self) -> u8 {
        match self {
            Verification::SameOriginSha256 { .. } => 4,
            Verification::GithubAttestation => 2,
        }
    }
}

/// Loads every `*.toml` file in `dir` (the `packages.d/` layout from
/// docs/SPEC.md > Scaling to many packages), keyed by package name.
pub fn load_packages_dir(dir: &Path) -> Result<Vec<(String, Package)>> {
    let mut out = Vec::new();
    for entry in std::fs::read_dir(dir).with_context(|| format!("reading {}", dir.display()))? {
        let path = entry?.path();
        if path.extension().and_then(|e| e.to_str()) != Some("toml") {
            continue;
        }
        let text = std::fs::read_to_string(&path)
            .with_context(|| format!("reading {}", path.display()))?;
        let file: PackageFile =
            toml::from_str(&text).with_context(|| format!("parsing {}", path.display()))?;
        out.extend(file.package);
    }
    Ok(out)
}

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

    fn write(dir: &Path, name: &str, contents: &str) {
        std::fs::write(dir.join(name), contents).unwrap();
    }

    #[test]
    fn tier_matches_verification_method() {
        assert_eq!(
            Verification::SameOriginSha256 {
                checksum_asset_pattern: "x".to_string()
            }
            .tier(),
            4
        );
        assert_eq!(Verification::GithubAttestation.tier(), 2);
    }

    #[test]
    fn loads_same_origin_sha256_package() {
        let dir = tempfile::tempdir().unwrap();
        write(
            dir.path(),
            "pkg.toml",
            r#"
            [package.pkg]
            repo = "o/r"
            asset_pattern = "pkg_{version}_linux_amd64"

            [package.pkg.verification]
            method = "same-origin-sha256"
            checksum_asset_pattern = "SHA256SUMS"
            "#,
        );

        let packages = load_packages_dir(dir.path()).unwrap();
        assert_eq!(packages.len(), 1);
        let (name, pkg) = &packages[0];
        assert_eq!(name, "pkg");
        assert_eq!(pkg.repo, "o/r");
        assert_eq!(pkg.asset_pattern, "pkg_{version}_linux_amd64");
        assert_eq!(pkg.verification.tier(), 4);
    }

    #[test]
    fn loads_github_attestation_package() {
        let dir = tempfile::tempdir().unwrap();
        write(
            dir.path(),
            "pkg.toml",
            r#"
            [package.pkg]
            repo = "o/r"
            asset_pattern = "pkg-x86_64.tar.gz"

            [package.pkg.verification]
            method = "github-attestation"
            "#,
        );

        let packages = load_packages_dir(dir.path()).unwrap();
        assert_eq!(packages[0].1.verification.tier(), 2);
    }

    #[test]
    fn loads_env_table_as_sorted_map() {
        let dir = tempfile::tempdir().unwrap();
        write(
            dir.path(),
            "pkg.toml",
            r#"
            [package.pkg]
            repo = "o/r"
            asset_pattern = "pkg.tar.gz"

            [package.pkg.verification]
            method = "github-attestation"

            [package.pkg.env]
            DISABLE_UPDATES = "1"
            DISABLE_INSTALLATION_CHECKS = "1"
            "#,
        );

        let packages = load_packages_dir(dir.path()).unwrap();
        let env = packages[0].1.env.as_ref().unwrap();
        let entries: Vec<(&String, &String)> = env.iter().collect();
        assert_eq!(
            entries,
            vec![
                (&"DISABLE_INSTALLATION_CHECKS".to_string(), &"1".to_string()),
                (&"DISABLE_UPDATES".to_string(), &"1".to_string()),
            ]
        );
    }

    #[test]
    fn loads_multiple_files_and_ignores_non_toml() {
        let dir = tempfile::tempdir().unwrap();
        write(
            dir.path(),
            "a.toml",
            r#"
            [package.a]
            repo = "o/a"
            asset_pattern = "a.tar.gz"
            [package.a.verification]
            method = "github-attestation"
            "#,
        );
        write(
            dir.path(),
            "b.toml",
            r#"
            [package.b]
            repo = "o/b"
            asset_pattern = "b.tar.gz"
            [package.b.verification]
            method = "github-attestation"
            "#,
        );
        write(dir.path(), "README.md", "not a package file");

        let mut names: Vec<String> = load_packages_dir(dir.path())
            .unwrap()
            .into_iter()
            .map(|(name, _)| name)
            .collect();
        names.sort();
        assert_eq!(names, vec!["a", "b"]);
    }

    #[test]
    fn errors_on_invalid_toml() {
        let dir = tempfile::tempdir().unwrap();
        write(dir.path(), "bad.toml", "not valid toml [[[");
        assert!(load_packages_dir(dir.path()).is_err());
    }

    #[test]
    fn empty_dir_yields_empty_list() {
        let dir = tempfile::tempdir().unwrap();
        assert!(load_packages_dir(dir.path()).unwrap().is_empty());
    }
}