auths-core 0.1.3

//! Configuration types.

use crate::crypto::EncryptionAlgorithm;
use crate::paths::auths_home;
use once_cell::sync::Lazy;
use serde::{Deserialize, Serialize};
use std::fmt;
use std::path::PathBuf;
use std::sync::RwLock;

/// Globally selected encryption algorithm (defaults to AES-GCM).
static ENCRYPTION_ALGO: Lazy<RwLock<EncryptionAlgorithm>> =
    Lazy::new(|| RwLock::new(EncryptionAlgorithm::AesGcm256));

/// Returns the currently selected encryption algorithm.
#[allow(clippy::unwrap_used)] // RwLock poisoning is fatal by design
pub fn current_algorithm() -> EncryptionAlgorithm {
    *ENCRYPTION_ALGO.read().unwrap()
}

/// Sets the encryption algorithm to use globally.
#[allow(clippy::unwrap_used)] // RwLock poisoning is fatal by design
pub fn set_encryption_algorithm(algo: EncryptionAlgorithm) {
    *ENCRYPTION_ALGO.write().unwrap() = algo;
}

/// PKCS#11 HSM configuration, sourced from `AUTHS_PKCS11_*` environment variables.
///
/// Args:
/// * `library_path`: Path to the PKCS#11 shared library (e.g. `libsofthsm2.so`).
/// * `slot_id`: Numeric slot identifier (mutually exclusive with `token_label`).
/// * `token_label`: Token label for slot lookup (mutually exclusive with `slot_id`).
/// * `pin`: User PIN for the HSM token.
/// * `key_label`: PKCS#11 object label for the Ed25519 key.
///
/// Usage:
/// ```ignore
/// let config = Pkcs11Config::from_env();
/// ```
#[derive(Debug, Clone, Default)]
pub struct Pkcs11Config {
    /// Path to the PKCS#11 shared library (e.g. `libsofthsm2.so`).
    pub library_path: Option<PathBuf>,
    /// Numeric slot identifier; mutually exclusive with `token_label`.
    pub slot_id: Option<u64>,
    /// Human-readable token label used to locate the slot.
    pub token_label: Option<String>,
    /// User PIN for the token session.
    pub pin: Option<String>,
    /// Default key label for signing operations.
    pub key_label: Option<String>,
}

impl Pkcs11Config {
    /// Build a `Pkcs11Config` from `AUTHS_PKCS11_*` environment variables.
    #[allow(clippy::disallowed_methods)]
    pub fn from_env() -> Self {
        Self {
            library_path: std::env::var("AUTHS_PKCS11_LIBRARY")
                .ok()
                .map(PathBuf::from),
            slot_id: std::env::var("AUTHS_PKCS11_SLOT")
                .ok()
                .and_then(|s| s.parse().ok()),
            token_label: std::env::var("AUTHS_PKCS11_TOKEN_LABEL").ok(),
            pin: std::env::var("AUTHS_PKCS11_PIN").ok(),
            key_label: std::env::var("AUTHS_PKCS11_KEY_LABEL").ok(),
        }
    }
}

/// Keychain backend configuration, typically sourced from environment variables.
///
/// Use `KeychainConfig::from_env()` at process boundaries (CLI entry point, FFI
/// call sites) and then thread the value through the call graph.
///
/// `Debug` output redacts the `passphrase` field to prevent accidental log leakage.
#[derive(Clone, Default)]
pub struct KeychainConfig {
    /// Override for the keychain backend (`AUTHS_KEYCHAIN_BACKEND`).
    /// Supported values: `"file"`, `"memory"`.
    pub backend: Option<String>,
    /// Override for the encrypted-file storage path (`AUTHS_KEYCHAIN_FILE`).
    pub file_path: Option<PathBuf>,
    /// Passphrase for the encrypted-file backend (`AUTHS_PASSPHRASE`).
    pub passphrase: Option<String>,
}

impl fmt::Debug for KeychainConfig {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("KeychainConfig")
            .field("backend", &self.backend)
            .field("file_path", &self.file_path)
            .field(
                "passphrase",
                &self.passphrase.as_ref().map(|_| "[REDACTED]"),
            )
            .finish()
    }
}

impl KeychainConfig {
    /// Build a `KeychainConfig` from the process environment.
    ///
    /// Reads `AUTHS_KEYCHAIN_BACKEND`, `AUTHS_KEYCHAIN_FILE`, and `AUTHS_PASSPHRASE`.
    /// Call once at the process/FFI boundary; pass the result into subsystems.
    ///
    /// Usage:
    /// ```ignore
    /// let config = KeychainConfig::from_env();
    /// let keychain = get_platform_keychain_with_config(&EnvironmentConfig { keychain: config, ..Default::default() })?;
    /// ```
    #[allow(clippy::disallowed_methods)] // Designated env-var reading boundary
    pub fn from_env() -> Self {
        Self {
            backend: std::env::var("AUTHS_KEYCHAIN_BACKEND").ok(),
            file_path: std::env::var("AUTHS_KEYCHAIN_FILE").ok().map(PathBuf::from),
            passphrase: std::env::var("AUTHS_PASSPHRASE").ok(),
        }
    }
}

/// Full environment configuration for an Auths process.
///
/// Collect all environment-variable inputs at the process boundary (main, FFI entry)
/// and thread this struct through the call graph. Subsystems accept `&EnvironmentConfig`
/// instead of reading env vars directly.
///
/// Usage:
/// ```ignore
/// let env = EnvironmentConfig::from_env();
/// let home = auths_home_with_config(&env)?;
/// let keychain = get_platform_keychain_with_config(&env)?;
/// ```
#[derive(Debug, Clone, Default)]
pub struct EnvironmentConfig {
    /// Override for the Auths home directory (`AUTHS_HOME`).
    /// `None` falls back to `~/.auths`.
    pub auths_home: Option<PathBuf>,
    /// Keychain backend settings.
    pub keychain: KeychainConfig,
    /// Path to the SSH agent socket (`SSH_AUTH_SOCK`).
    pub ssh_agent_socket: Option<PathBuf>,
    /// PKCS#11 HSM configuration.
    #[cfg(feature = "keychain-pkcs11")]
    pub pkcs11: Option<Pkcs11Config>,
}

impl EnvironmentConfig {
    /// Build an `EnvironmentConfig` from the process environment.
    ///
    /// Reads `AUTHS_HOME`, `AUTHS_KEYCHAIN_BACKEND`, `AUTHS_KEYCHAIN_FILE`,
    /// `AUTHS_PASSPHRASE`, and `SSH_AUTH_SOCK`.
    ///
    /// Usage:
    /// ```ignore
    /// let env = EnvironmentConfig::from_env();
    /// ```
    #[allow(clippy::disallowed_methods)] // Designated env-var reading boundary
    pub fn from_env() -> Self {
        Self {
            auths_home: std::env::var("AUTHS_HOME")
                .ok()
                .filter(|s| !s.is_empty())
                .map(PathBuf::from),
            keychain: KeychainConfig::from_env(),
            ssh_agent_socket: std::env::var("SSH_AUTH_SOCK").ok().map(PathBuf::from),
            #[cfg(feature = "keychain-pkcs11")]
            pkcs11: {
                let cfg = Pkcs11Config::from_env();
                if cfg.library_path.is_some() {
                    Some(cfg)
                } else {
                    None
                }
            },
        }
    }

    /// Returns a builder for constructing test configurations without env vars.
    ///
    /// Usage:
    /// ```ignore
    /// let env = EnvironmentConfig::builder()
    ///     .auths_home(temp_dir.path().to_path_buf())
    ///     .build();
    /// ```
    pub fn builder() -> EnvironmentConfigBuilder {
        EnvironmentConfigBuilder::default()
    }
}

/// Builder for `EnvironmentConfig` — use in tests to avoid env var manipulation.
///
/// Usage:
/// ```ignore
/// let env = EnvironmentConfig::builder()
///     .auths_home(PathBuf::from("/tmp/test-auths"))
///     .build();
/// ```
#[derive(Default)]
pub struct EnvironmentConfigBuilder {
    auths_home: Option<PathBuf>,
    keychain: Option<KeychainConfig>,
    ssh_agent_socket: Option<PathBuf>,
    #[cfg(feature = "keychain-pkcs11")]
    pkcs11: Option<Pkcs11Config>,
}

impl EnvironmentConfigBuilder {
    /// Set the Auths home directory override.
    pub fn auths_home(mut self, home: PathBuf) -> Self {
        self.auths_home = Some(home);
        self
    }

    /// Set the keychain configuration.
    pub fn keychain(mut self, keychain: KeychainConfig) -> Self {
        self.keychain = Some(keychain);
        self
    }

    /// Set the SSH agent socket path.
    pub fn ssh_agent_socket(mut self, path: PathBuf) -> Self {
        self.ssh_agent_socket = Some(path);
        self
    }

    /// Set the PKCS#11 configuration.
    #[cfg(feature = "keychain-pkcs11")]
    pub fn pkcs11(mut self, config: Pkcs11Config) -> Self {
        self.pkcs11 = Some(config);
        self
    }

    /// Consume the builder and produce an `EnvironmentConfig`.
    pub fn build(self) -> EnvironmentConfig {
        EnvironmentConfig {
            auths_home: self.auths_home,
            keychain: self.keychain.unwrap_or_default(),
            ssh_agent_socket: self.ssh_agent_socket,
            #[cfg(feature = "keychain-pkcs11")]
            pkcs11: self.pkcs11,
        }
    }
}

/// Passphrase caching policy.
///
/// Controls how `auths-sign` caches the passphrase between invocations:
/// - `always`: Store in OS keychain permanently until explicitly cleared.
/// - `session`: Rely on the in-memory agent (Tier 1/2) — prompt once per agent lifetime.
/// - `duration`: Store in OS keychain with a TTL (see [`PassphraseConfig::duration`]).
/// - `never`: Always prompt interactively.
#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum PassphraseCachePolicy {
    /// Store passphrase in OS keychain permanently.
    Always,
    /// Cache passphrase in the running agent's memory — prompt once per
    /// agent lifetime.
    Session,
    /// Store passphrase in OS keychain with a configurable TTL (default).
    ///
    /// Chosen as the default so unconfigured users get macOS Keychain +
    /// Touch ID caching out of the box, matching the UX of other
    /// keychain-backed developer tools. `impl Default for PassphraseConfig`
    /// supplies the complementary defaults (`duration = "1h"`,
    /// `biometric = true` on macOS). Users who explicitly opt into
    /// `Session` via `~/.auths/config.toml` retain the previous
    /// prompt-each-time behavior.
    #[default]
    Duration,
    /// Never cache — always prompt.
    Never,
}

/// Passphrase section of `~/.auths/config.toml`.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PassphraseConfig {
    /// Caching policy.
    #[serde(default)]
    pub cache: PassphraseCachePolicy,
    /// Duration string (e.g. `"7d"`, `"24h"`, `"30m"`). Only used when `cache = "duration"`.
    pub duration: Option<String>,
    /// Use Touch ID (biometric) to protect cached passphrases on macOS.
    /// Defaults to `true` on macOS, ignored on other platforms.
    #[serde(default = "default_biometric")]
    pub biometric: bool,
}

fn default_biometric() -> bool {
    cfg!(target_os = "macos")
}

impl Default for PassphraseConfig {
    fn default() -> Self {
        Self {
            cache: PassphraseCachePolicy::Duration,
            duration: Some("1h".to_string()),
            biometric: default_biometric(),
        }
    }
}

/// Top-level `~/.auths/config.toml` structure.
#[derive(Debug, Clone, Serialize, Deserialize, Default)]
pub struct AuthsConfig {
    /// Passphrase caching settings.
    #[serde(default)]
    pub passphrase: PassphraseConfig,
}

/// Loads `~/.auths/config.toml`, returning defaults on any error.
///
/// Args:
/// * `store`: The config store implementation for file I/O.
///
/// Usage:
/// ```ignore
/// let config = auths_core::config::load_config(&file_store);
/// match config.passphrase.cache {
///     PassphraseCachePolicy::Always => { /* ... */ }
///     _ => {}
/// }
/// ```
pub fn load_config(store: &dyn crate::ports::config_store::ConfigStore) -> AuthsConfig {
    let home = match auths_home() {
        Ok(h) => h,
        Err(_) => return AuthsConfig::default(),
    };
    let path = home.join("config.toml");
    match store.read(&path) {
        Ok(Some(contents)) => toml::from_str(&contents).unwrap_or_default(),
        _ => AuthsConfig::default(),
    }
}

/// Writes `~/.auths/config.toml`.
///
/// Args:
/// * `config`: The configuration to persist.
/// * `store`: The config store implementation for file I/O.
///
/// Usage:
/// ```ignore
/// let mut config = load_config(&file_store);
/// config.passphrase.cache = PassphraseCachePolicy::Always;
/// save_config(&config, &file_store)?;
/// ```
pub fn save_config(
    config: &AuthsConfig,
    store: &dyn crate::ports::config_store::ConfigStore,
) -> Result<(), crate::ports::config_store::ConfigStoreError> {
    let home = auths_home().map_err(|e| crate::ports::config_store::ConfigStoreError::Write {
        path: PathBuf::from("~/.auths"),
        source: std::io::Error::other(e.to_string()),
    })?;
    let path = home.join("config.toml");
    let contents = toml::to_string_pretty(config).map_err(|e| {
        crate::ports::config_store::ConfigStoreError::Write {
            path: path.clone(),
            source: std::io::Error::other(e.to_string()),
        }
    })?;
    store.write(&path, &contents)
}