//! Command classification against the corpus.

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

/// How a command is classified.
#[derive(Debug)]
pub enum CommandClass {
    /// In corpus directory — governed execution via org-ops wrapper.
    Governed { corpus_binary: PathBuf },
    /// Not in corpus but exists on PATH — allowed but untracked.
    Ungoverned,
    /// Was in corpus manifest but binary removed — DENIED (killswitch).
    Denied { reason: String },
    /// Shell builtins and navigation — zero governance overhead.
    Free,
}

/// Free commands: zero governance overhead.
pub const FREE_COMMANDS: &[&str] = &[
    "ls", "ll", "la", "dir", "cat", "head", "tail", "less", "more",
    "grep", "awk", "sed", "echo", "printf", "pwd", "cd", "pushd", "popd",
    "env", "export", "set", "unset", "which", "whereis", "type", "file",
    "stat", "wc", "sort", "uniq", "tr", "cut", "date", "cal", "whoami",
    "id", "hostname", "uname", "clear", "history", "alias", "true", "false",
    "test", "man", "help", "fg", "bg", "jobs", "kill", "ps", "top",
    "df", "du", "free", "uptime", "find", "xargs", "tee", "touch",
    "mkdir", "rmdir", "cp", "mv", "rm", "ln", "chmod", "chown",
    "diff", "patch", "tar", "gzip", "gunzip", "zip", "unzip",
    "ssh", "scp", "rsync", "curl", "wget", "ping", "dig", "nslookup",
    "git", "vim", "vi", "nano", "tree", "watch", "source", ".",
];

/// Classify a command against the corpus.
pub fn classify_command(
    command_line: &str,
    corpus_cid: &str,
    corpus_base: &Path,
) -> CommandClass {
    let cmd_name = command_line.split_whitespace().next().unwrap_or("");
    if cmd_name.is_empty() {
        return CommandClass::Free;
    }

    // Strip path prefix to get bare name:
    let bare_name = Path::new(cmd_name)
        .file_name()
        .map(|n| n.to_string_lossy().to_string())
        .unwrap_or_else(|| cmd_name.to_string());

    // Free commands — zero overhead:
    if FREE_COMMANDS.contains(&bare_name.as_str()) {
        return CommandClass::Free;
    }

    // Ungoverned corpus — everything is free:
    if corpus_cid == "sha256:ungoverned" {
        return CommandClass::Free;
    }

    // Check corpus directory:
    let corpus_dir = corpus_base.join(corpus_cid);
    if !corpus_dir.exists() {
        // No corpus mounted — treat as ungoverned
        return CommandClass::Ungoverned;
    }

    let binary_path = corpus_dir.join(&bare_name);
    if binary_path.exists() {
        CommandClass::Governed {
            corpus_binary: binary_path,
        }
    } else {
        // Not in corpus dir — could be a PATH binary or truly missing
        // Check if it's on PATH:
        let on_path = std::process::Command::new("which")
            .arg(&bare_name)
            .output()
            .map(|o| o.status.success())
            .unwrap_or(false);

        if on_path {
            CommandClass::Ungoverned
        } else {
            CommandClass::Denied {
                reason: format!("'{}' not found in corpus or PATH", bare_name),
            }
        }
    }
}

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

    #[test]
    fn test_free_commands() {
        let base = Path::new("/nonexistent");
        assert!(matches!(
            classify_command("ls -la", "sha256:test", base),
            CommandClass::Free
        ));
        assert!(matches!(
            classify_command("echo hello", "sha256:test", base),
            CommandClass::Free
        ));
        assert!(matches!(
            classify_command("cat /etc/hosts", "sha256:test", base),
            CommandClass::Free
        ));
    }

    #[test]
    fn test_ungoverned_corpus_is_free() {
        let base = Path::new("/nonexistent");
        assert!(matches!(
            classify_command("kubectl get pods", "sha256:ungoverned", base),
            CommandClass::Free
        ));
    }

    #[test]
    fn test_governed_binary() {
        let dir = tempfile::tempdir().unwrap();
        let cid = "sha256:test-corpus";
        let corpus_dir = dir.path().join(cid);
        std::fs::create_dir_all(&corpus_dir).unwrap();
        std::fs::write(corpus_dir.join("my-tool"), "#!/bin/bash\necho ok").unwrap();

        assert!(matches!(
            classify_command("my-tool --flag", cid, dir.path()),
            CommandClass::Governed { .. }
        ));
    }

    #[test]
    fn test_empty_command() {
        assert!(matches!(
            classify_command("", "sha256:test", Path::new("/")),
            CommandClass::Free
        ));
    }
}