use std::path::Path;

use crate::error::AgentError;

/// Ensure the SSH key pair exists at the given path, generating it if missing.
/// Returns the public key contents.
pub fn ensure_ssh_key(key_path: &str) -> Result<String, AgentError> {
    let private_path = Path::new(key_path);
    let public_path = private_path.with_extension("pub");

    if private_path.exists() && public_path.exists() {
        return std::fs::read_to_string(&public_path)
            .map_err(|e| AgentError::Config(format!("Failed to read SSH public key: {e}")));
    }

    // Create parent directory
    if let Some(parent) = private_path.parent() {
        std::fs::create_dir_all(parent)?;
    }

    // Generate ed25519 key pair using ssh-keygen
    let output = std::process::Command::new("ssh-keygen")
        .args([
            "-t",
            "ed25519",
            "-f",
            key_path,
            "-N",
            "", // no passphrase
            "-C",
            "compliance-scanner-agent",
        ])
        .output()
        .map_err(|e| AgentError::Config(format!("Failed to run ssh-keygen: {e}")))?;

    if !output.status.success() {
        let stderr = String::from_utf8_lossy(&output.stderr);
        return Err(AgentError::Config(format!("ssh-keygen failed: {stderr}")));
    }

    // Set correct permissions
    #[cfg(unix)]
    {
        use std::os::unix::fs::PermissionsExt;
        std::fs::set_permissions(private_path, std::fs::Permissions::from_mode(0o600))?;
    }

    let public_key = std::fs::read_to_string(&public_path)
        .map_err(|e| AgentError::Config(format!("Failed to read generated SSH public key: {e}")))?;

    tracing::info!("Generated new SSH key pair at {key_path}");
    Ok(public_key)
}