//! Per-target spec (`targets/<name>/target.toml`). All commands and
//! paths are relative to the repository root; `{binary}` in commands is
//! substituted with the built binary path.

use serde::Deserialize;
use std::path::{Path, PathBuf};

#[derive(Debug, Deserialize)]
pub struct TargetSpec {
    pub source: Source,
    pub build: Build,
    pub gates: Gates,
    pub corpus: Corpus,
}

#[derive(Debug, Deserialize)]
pub struct Source {
    pub repo: String,
    pub commit: String,
    pub license: String,
    #[serde(default)]
    pub submodules: toml::value::Table,
}

#[derive(Debug, Deserialize)]
pub struct Build {
    /// Baseline build command, run from repo root.
    pub baseline: String,
    /// Built binary path, relative to repo root.
    pub binary: String,
}

#[derive(Debug, Deserialize)]
pub struct Gates {
    /// Upstream test suite command, run from repo root.
    pub tests: String,
    /// Golden replay command; stdout is hashed. `{binary}` substituted.
    pub golden: String,
}

#[derive(Debug, Deserialize)]
pub struct Corpus {
    /// sha256sum-format manifest of the corpus inputs.
    pub manifest: PathBuf,
    /// Directory the manifest's relative paths resolve against.
    pub root: PathBuf,
    /// File whose last whitespace-delimited-first-field line is the
    /// expected sha256 of the golden command's stdout.
    pub golden_sha256: PathBuf,
}

impl TargetSpec {
    pub fn load(repo_root: &Path, name: &str) -> anyhow::Result<Self> {
        let path = repo_root.join("targets").join(name).join("target.toml");
        let raw = std::fs::read_to_string(&path)
            .map_err(|e| anyhow::anyhow!("cannot read {}: {e}", path.display()))?;
        Ok(toml::from_str(&raw)?)
    }
}

/// Parse the expected stdout hash out of a GOLDEN.sha256 file
/// (comment lines starting with '#' ignored).
pub fn expected_golden_hash(path: &Path) -> anyhow::Result<String> {
    let raw = std::fs::read_to_string(path)?;
    raw.lines()
        .map(str::trim)
        .filter(|l| !l.is_empty() && !l.starts_with('#'))
        .filter_map(|l| l.split_whitespace().next())
        .next_back()
        .map(str::to_string)
        .ok_or_else(|| anyhow::anyhow!("no hash entry in {}", path.display()))
}