//! Post-build correctness check: runs the freshly built binary and
//! confirms it reports the version pkgwatch believes it just built. Not a
//! security control — see docs/SPEC.md > Verification trust tiers.

use crate::config::SanityCheck;
use anyhow::{Context, Result, bail};
use regex::Regex;
use std::path::Path;
use std::process::Command;

/// Runs `check.command` with `pkg_bin_dir` prepended to `PATH`, so it
/// exercises the binary pkgwatch just built (still sitting in makepkg's
/// package staging directory, not installed system-wide) rather than
/// whatever's already on the system. Confirms `check.version_regex`'s
/// capture group matches `expected_version`.
///
/// Correctness check only, not a security control — see docs/SPEC.md >
/// Verification trust tiers. Catches checker bugs and mangled/wrong-asset
/// downloads, not malicious releases.
pub fn run(check: &SanityCheck, pkg_bin_dir: &Path, expected_version: &str) -> Result<()> {
    let path_env = format!(
        "{}:{}",
        pkg_bin_dir.display(),
        std::env::var("PATH").unwrap_or_default()
    );
    let output = Command::new("sh")
        .arg("-c")
        .arg(&check.command)
        .env("PATH", path_env)
        .output()
        .with_context(|| format!("running sanity check command '{}'", check.command))?;
    if !output.status.success() {
        bail!(
            "sanity check command '{}' exited with {}: {}",
            check.command,
            output.status,
            String::from_utf8_lossy(&output.stderr).trim()
        );
    }

    let combined = format!(
        "{}{}",
        String::from_utf8_lossy(&output.stdout),
        String::from_utf8_lossy(&output.stderr)
    );
    let re = Regex::new(&check.version_regex)
        .with_context(|| format!("invalid version_regex '{}'", check.version_regex))?;
    let found = re
        .captures(&combined)
        .and_then(|caps| caps.get(1))
        .with_context(|| {
            format!(
                "version_regex '{}' did not match sanity check output: {combined:?}",
                check.version_regex
            )
        })?
        .as_str();

    if found != expected_version {
        bail!(
            "sanity check reported version '{found}', pkgwatch built '{expected_version}' — mismatch"
        );
    }
    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::test_support::write_executable_script as write_fake_binary;

    #[test]
    fn run_passes_when_reported_version_matches() {
        let dir = tempfile::tempdir().unwrap();
        write_fake_binary(dir.path(), "uv", "echo 'uv 0.12.15 (abc 2026-09-01)'");

        let check = SanityCheck {
            command: "uv --version".to_string(),
            version_regex: r"uv (\d+\.\d+\.\d+)".to_string(),
        };
        assert!(run(&check, dir.path(), "0.12.15").is_ok());
    }

    #[test]
    fn run_fails_when_reported_version_differs() {
        let dir = tempfile::tempdir().unwrap();
        write_fake_binary(dir.path(), "uv", "echo 'uv 0.12.14 (abc 2026-08-01)'");

        let check = SanityCheck {
            command: "uv --version".to_string(),
            version_regex: r"uv (\d+\.\d+\.\d+)".to_string(),
        };
        let err = run(&check, dir.path(), "0.12.15").unwrap_err();
        assert!(err.to_string().contains("mismatch"));
    }

    #[test]
    fn run_fails_when_command_exits_nonzero() {
        let dir = tempfile::tempdir().unwrap();
        write_fake_binary(dir.path(), "uv", "exit 1");

        let check = SanityCheck {
            command: "uv --version".to_string(),
            version_regex: r"uv (\d+\.\d+\.\d+)".to_string(),
        };
        let err = run(&check, dir.path(), "0.12.15").unwrap_err();
        assert!(err.to_string().contains("exited with"));
    }

    #[test]
    fn run_fails_when_output_does_not_match_regex() {
        let dir = tempfile::tempdir().unwrap();
        write_fake_binary(dir.path(), "uv", "echo 'not a version'");

        let check = SanityCheck {
            command: "uv --version".to_string(),
            version_regex: r"uv (\d+\.\d+\.\d+)".to_string(),
        };
        let err = run(&check, dir.path(), "0.12.15").unwrap_err();
        assert!(err.to_string().contains("did not match"));
    }
}