openlatch-client 0.0.0

/// Configuration loading for OpenLatch daemon.
///
/// Implements the full precedence chain per CONF-03:
/// CLI flags > env vars (`OPENLATCH_*`) > `~/.openlatch/config.toml` > defaults
///
/// The default config file uses a commented-template style (D-10) with only the
/// pinned port written as an active value (D-11).
use std::path::{Path, PathBuf};

use serde::Deserialize;

use crate::error::{OlError, ERR_INVALID_CONFIG, ERR_PORT_IN_USE};

// ---------------------------------------------------------------------------
// Update check configuration
// ---------------------------------------------------------------------------

/// Configuration for the version update check performed at daemon startup.
///
/// Override via env var: `OPENLATCH_UPDATE_CHECK=false` disables the check.
#[derive(Debug, Clone)]
pub struct UpdateConfig {
    /// Whether to check for a newer version on daemon start. Default: true.
    pub check: bool,
}

impl Default for UpdateConfig {
    fn default() -> Self {
        Self { check: true }
    }
}

// ---------------------------------------------------------------------------
// Platform-aware home directory
// ---------------------------------------------------------------------------

/// Returns the platform-appropriate openlatch data directory.
///
/// - Unix/macOS: `~/.openlatch`
/// - Windows: `%APPDATA%\openlatch` (falls back to `~\openlatch` if %APPDATA% unavailable)
pub fn openlatch_dir() -> PathBuf {
    #[cfg(windows)]
    {
        dirs::data_dir()
            .unwrap_or_else(|| dirs::home_dir().expect("home directory must exist"))
            .join("openlatch")
    }
    #[cfg(not(windows))]
    {
        dirs::home_dir()
            .expect("home directory must exist")
            .join(".openlatch")
    }
}

// ---------------------------------------------------------------------------
// Config struct (public, runtime-resolved)
// ---------------------------------------------------------------------------

/// Resolved runtime configuration for the OpenLatch daemon.
///
/// This struct is constructed by [`Config::load`] from the full precedence chain:
/// CLI flags > env vars > config.toml > defaults.
#[derive(Debug, Clone)]
pub struct Config {
    /// TCP port for the local daemon (default: 7443).
    pub port: u16,
    /// Directory for audit and daemon logs.
    pub log_dir: PathBuf,
    /// Tracing log level (default: "info").
    pub log_level: String,
    /// Audit log retention in days (default: 30).
    pub retention_days: u32,
    /// Additional regex patterns for secret masking (additive to built-ins, per D-03).
    pub extra_patterns: Vec<String>,
    /// When true, daemon runs in foreground without forking.
    pub foreground: bool,
    /// Update check configuration (UPDT-01 through UPDT-04).
    pub update: UpdateConfig,
}

impl Config {
    /// Return sensible defaults for all config fields.
    pub fn defaults() -> Self {
        Self {
            port: 7443,
            log_dir: openlatch_dir().join("logs"),
            log_level: "info".into(),
            retention_days: 30,
            extra_patterns: vec![],
            foreground: false,
            update: UpdateConfig::default(),
        }
    }

    /// Load configuration from the full precedence chain.
    ///
    /// Precedence order (highest to lowest):
    /// 1. CLI flags (`cli_*` parameters — `Some(value)` overrides)
    /// 2. Environment variables (`OPENLATCH_PORT`, `OPENLATCH_HOST`, `OPENLATCH_LOG_DIR`,
    ///    `OPENLATCH_LOG`, `OPENLATCH_RETENTION_DAYS`)
    /// 3. `~/.openlatch/config.toml` (parsed, partial overrides)
    /// 4. Compile-time defaults
    ///
    /// # Errors
    ///
    /// Returns [`OlError`] if the config file exists but cannot be parsed as valid TOML.
    pub fn load(
        cli_port: Option<u16>,
        cli_log_level: Option<String>,
        cli_foreground: bool,
    ) -> Result<Self, OlError> {
        let mut cfg = Self::defaults();

        // Layer 3: config.toml
        let config_path = openlatch_dir().join("config.toml");
        if config_path.exists() {
            let raw = std::fs::read_to_string(&config_path).map_err(|e| {
                OlError::new(ERR_INVALID_CONFIG, format!("Cannot read config file: {e}"))
                    .with_suggestion("Check that the file is readable and not corrupted.")
            })?;
            let toml_cfg: TomlConfig = toml::from_str(&raw).map_err(|e| {
                OlError::new(
                    ERR_INVALID_CONFIG,
                    format!("Invalid TOML in config file: {e}"),
                )
                .with_suggestion("Check your config.toml for syntax errors.")
                .with_docs("https://docs.openlatch.ai/configuration")
            })?;
            if let Some(daemon) = toml_cfg.daemon {
                if let Some(port) = daemon.port {
                    cfg.port = port;
                }
            }
            if let Some(logging) = toml_cfg.logging {
                if let Some(level) = logging.level {
                    cfg.log_level = level;
                }
                if let Some(dir) = logging.dir {
                    cfg.log_dir = PathBuf::from(dir);
                }
                if let Some(days) = logging.retention_days {
                    cfg.retention_days = days;
                }
            }
            if let Some(privacy) = toml_cfg.privacy {
                if let Some(patterns) = privacy.extra_patterns {
                    cfg.extra_patterns = patterns;
                }
            }
            if let Some(update) = toml_cfg.update {
                if let Some(check) = update.check {
                    cfg.update.check = check;
                }
            }
        }

        // Layer 2: env vars
        if let Ok(val) = std::env::var("OPENLATCH_PORT") {
            cfg.port = val.parse::<u16>().map_err(|_| {
                OlError::new(
                    ERR_INVALID_CONFIG,
                    format!("OPENLATCH_PORT is not a valid port number: '{val}'"),
                )
                .with_suggestion("Set OPENLATCH_PORT to an integer between 1024 and 65535.")
            })?;
        }
        if let Ok(val) = std::env::var("OPENLATCH_LOG_DIR") {
            cfg.log_dir = PathBuf::from(val);
        }
        if let Ok(val) = std::env::var("OPENLATCH_LOG") {
            cfg.log_level = val;
        }
        if let Ok(val) = std::env::var("OPENLATCH_RETENTION_DAYS") {
            cfg.retention_days = val.parse::<u32>().map_err(|_| {
                OlError::new(
                    ERR_INVALID_CONFIG,
                    format!("OPENLATCH_RETENTION_DAYS is not a valid integer: '{val}'"),
                )
                .with_suggestion("Set OPENLATCH_RETENTION_DAYS to a positive integer.")
            })?;
        }
        // UPDT-04: env var override for update check
        if let Ok(val) = std::env::var("OPENLATCH_UPDATE_CHECK") {
            if val == "false" || val == "0" {
                cfg.update.check = false;
            }
        }

        // Layer 1: CLI flags (highest priority)
        if let Some(port) = cli_port {
            cfg.port = port;
        }
        if let Some(level) = cli_log_level {
            cfg.log_level = level;
        }
        if cli_foreground {
            cfg.foreground = true;
        }

        Ok(cfg)
    }
}

// ---------------------------------------------------------------------------
// TOML intermediate structs (all fields optional — partial overrides)
// ---------------------------------------------------------------------------

#[derive(Debug, Deserialize)]
struct TomlConfig {
    #[serde(default)]
    daemon: Option<DaemonToml>,
    #[serde(default)]
    logging: Option<LoggingToml>,
    #[serde(default)]
    privacy: Option<PrivacyToml>,
    #[serde(default)]
    update: Option<UpdateToml>,
}

#[derive(Debug, Deserialize)]
struct DaemonToml {
    port: Option<u16>,
}

#[derive(Debug, Deserialize)]
struct LoggingToml {
    level: Option<String>,
    dir: Option<String>,
    retention_days: Option<u32>,
}

#[derive(Debug, Deserialize)]
struct PrivacyToml {
    extra_patterns: Option<Vec<String>>,
}

#[derive(Debug, Deserialize)]
struct UpdateToml {
    check: Option<bool>,
}

// ---------------------------------------------------------------------------
// Default config template (D-10 / D-11)
// ---------------------------------------------------------------------------

/// Generate the default config.toml content.
///
/// Per D-10: commented template style — all sections present, every field commented.
/// Per D-11: only the pinned `port` value is written as an active (uncommented) line.
pub fn generate_default_config_toml(port: u16) -> String {
    format!(
        r#"# OpenLatch Configuration
# Uncomment and modify values to customize behavior.

[daemon]
port = {port}
# SECURITY: bind address is always 127.0.0.1 — not configurable

[logging]
# level = "info"
# dir = "~/.openlatch/logs"
# retention_days = 30

[privacy]
# Extra regex patterns for secret masking (additive to built-ins).
# Each entry is a regex string applied to JSON string values.
# extra_patterns = ["CUSTOM_SECRET_[A-Z0-9]{{32}}"]

# [update]
# check = true  # Set to false to disable update checks on daemon start
"#
    )
}

/// Ensure the openlatch config directory and config.toml exist.
///
/// Creates `~/.openlatch/` if missing, writes `config.toml` with the default
/// template if missing, then returns the path to `config.toml`.
///
/// # Errors
///
/// Returns [`OlError`] if the directory or file cannot be created.
pub fn ensure_config(port: u16) -> Result<PathBuf, OlError> {
    let dir = openlatch_dir();
    std::fs::create_dir_all(&dir).map_err(|e| {
        OlError::new(
            ERR_INVALID_CONFIG,
            format!("Cannot create config directory '{}': {e}", dir.display()),
        )
        .with_suggestion("Check that you have write permission to your home directory.")
    })?;

    let config_path = dir.join("config.toml");
    if !config_path.exists() {
        let content = generate_default_config_toml(port);
        std::fs::write(&config_path, content).map_err(|e| {
            OlError::new(
                ERR_INVALID_CONFIG,
                format!("Cannot write config file '{}': {e}", config_path.display()),
            )
            .with_suggestion("Check that you have write permission to ~/.openlatch/.")
        })?;
    }

    Ok(config_path)
}

// ---------------------------------------------------------------------------
// Token generation and management (SEC-01)
// ---------------------------------------------------------------------------

/// Generate a cryptographically random 64-character hex token.
///
/// Uses two UUIDv4 values (each 16 bytes of OS CSPRNG entropy via `getrandom`)
/// concatenated to produce 32 bytes = 64 hex characters. No additional
/// dependencies are needed since `uuid` with the `v4` feature already pulls
/// in `getrandom` which maps to the OS CSPRNG on all platforms.
///
/// # Security
///
/// The resulting string is suitable as a bearer token for daemon authentication.
/// The `uuid` crate uses `getrandom` internally, which calls `BCryptGenRandom`
/// on Windows and `getrandom(2)` / `/dev/urandom` on Unix.
pub fn generate_token() -> String {
    let a = uuid::Uuid::new_v4();
    let b = uuid::Uuid::new_v4();
    format!("{}{}", a.simple(), b.simple())
}

/// Ensure a daemon bearer token exists at `{dir}/daemon.token`.
///
/// If the token file already exists, reads and returns the existing token.
/// If it does not exist, generates a new token, writes it to the file with
/// restricted permissions (mode 0600 on Unix), and returns the new token.
///
/// # Errors
///
/// Returns [`OlError`] if the token file cannot be read or written.
///
/// # Security (SEC-01)
///
/// The token file is set to mode 0600 on Unix (user read/write only).
/// On Windows, the file is written to the user's AppData directory which is
/// already restricted to the current user by default ACLs.
pub fn ensure_token(dir: &Path) -> Result<String, OlError> {
    let token_path = dir.join("daemon.token");

    if token_path.exists() {
        // Read existing token
        let token = std::fs::read_to_string(&token_path).map_err(|e| {
            OlError::new(
                crate::error::ERR_INVALID_CONFIG,
                format!("Cannot read token file '{}': {e}", token_path.display()),
            )
            .with_suggestion("Check that the file exists and is readable.")
        })?;
        return Ok(token.trim().to_string());
    }

    // Generate and write new token — ensure parent directory exists first
    let token = generate_token();
    if let Some(parent) = token_path.parent() {
        std::fs::create_dir_all(parent).map_err(|e| {
            OlError::new(
                crate::error::ERR_INVALID_CONFIG,
                format!("Cannot create directory '{}': {e}", parent.display()),
            )
            .with_suggestion("Check that you have write permission to the parent directory.")
        })?;
    }
    std::fs::write(&token_path, &token).map_err(|e| {
        OlError::new(
            crate::error::ERR_INVALID_CONFIG,
            format!("Cannot write token file '{}': {e}", token_path.display()),
        )
        .with_suggestion("Check that you have write permission to the openlatch directory.")
    })?;

    // SECURITY: Restrict token file to owner only (mode 0600) on Unix.
    // Windows does not need this because AppData is already restricted by ACLs.
    #[cfg(unix)]
    {
        use std::os::unix::fs::PermissionsExt;
        let perms = std::fs::Permissions::from_mode(0o600);
        std::fs::set_permissions(&token_path, perms).map_err(|e| {
            OlError::new(
                crate::error::ERR_INVALID_CONFIG,
                format!("Cannot set permissions on token file: {e}"),
            )
            .with_suggestion("Check that you have permission to modify file attributes.")
        })?;
    }

    Ok(token)
}

// ---------------------------------------------------------------------------
// Port probing and port file (PRD: probe 7443-7543 on first init)
// ---------------------------------------------------------------------------

/// Default port range start for probing.
pub const PORT_RANGE_START: u16 = 7443;
/// Default port range end for probing (inclusive).
pub const PORT_RANGE_END: u16 = 7543;

/// Probe ports in the given range, returning the first available port.
///
/// Uses a sync `std::net::TcpListener` bind-and-drop to test availability.
/// Safe to call before any async runtime is started.
///
/// # Errors
///
/// Returns `OL-1500` if no port in the range is free.
pub fn probe_free_port(start: u16, end: u16) -> Result<u16, OlError> {
    for port in start..=end {
        if std::net::TcpListener::bind(("127.0.0.1", port)).is_ok() {
            return Ok(port);
        }
    }
    Err(OlError::new(
        ERR_PORT_IN_USE,
        format!("No free port found in range {start}-{end}"),
    )
    .with_suggestion(format!(
        "Free a port in the {start}-{end} range, or set OPENLATCH_PORT to a specific port."
    ))
    .with_docs("https://docs.openlatch.ai/errors/OL-1500"))
}

/// Write the daemon's port number to `~/.openlatch/daemon.port`.
///
/// Plain text file containing just the port number. Readable by the hook binary
/// without TOML parsing.
pub fn write_port_file(port: u16) -> Result<(), OlError> {
    let path = openlatch_dir().join("daemon.port");
    std::fs::write(&path, port.to_string()).map_err(|e| {
        OlError::new(
            ERR_INVALID_CONFIG,
            format!("Cannot write port file '{}': {e}", path.display()),
        )
    })?;
    Ok(())
}

/// Read the daemon's port from `~/.openlatch/daemon.port`.
///
/// Returns `None` if the file doesn't exist or can't be parsed.
pub fn read_port_file() -> Option<u16> {
    let path = openlatch_dir().join("daemon.port");
    std::fs::read_to_string(path)
        .ok()?
        .trim()
        .parse::<u16>()
        .ok()
}

// ---------------------------------------------------------------------------
// Tests
// ---------------------------------------------------------------------------

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

    #[test]
    fn test_config_defaults_values() {
        // Test 1: Config::defaults() returns expected values
        let cfg = Config::defaults();
        assert_eq!(cfg.port, 7443, "Default port must be 7443");
        assert_eq!(cfg.log_level, "info", "Default log level must be info");
        assert_eq!(cfg.retention_days, 30, "Default retention must be 30 days");
    }

    #[test]
    fn test_config_loads_from_toml_file() {
        // Test 2: Config loads from a TOML file in a temp directory
        let tmp = TempDir::new().unwrap();
        let config_path = tmp.path().join("config.toml");
        std::fs::write(
            &config_path,
            r#"
[daemon]
port = 8080
"#,
        )
        .unwrap();

        // Write a minimal config to the openlatch dir location by overriding
        // via env var (since Config::load reads from openlatch_dir())
        // We'll test the TOML parsing logic directly via env override
        // and by placing the file at the expected path.

        // Directly test the TOML parse path:
        let raw = std::fs::read_to_string(&config_path).unwrap();
        let toml_cfg: TomlConfig = toml::from_str(&raw).unwrap();
        let daemon = toml_cfg.daemon.unwrap();
        assert_eq!(daemon.port, Some(8080));
    }

    #[test]
    fn test_config_cli_port_overrides_default() {
        // Test 3: CLI port flag overrides default (avoids thread-unsafe env::set_var)
        let cfg = Config::load(Some(9000), None, false)
            .expect("Config::load should succeed with valid CLI port");
        assert_eq!(cfg.port, 9000, "CLI port should override default");
    }

    #[test]
    fn test_generate_token_produces_64_char_hex() {
        // Test 4: generate_token() produces a 32-byte hex string (64 chars)
        let token = generate_token();
        assert_eq!(
            token.len(),
            64,
            "Token must be 64 characters (32 bytes hex-encoded), got: {token}"
        );
        assert!(
            token.chars().all(|c| c.is_ascii_hexdigit()),
            "Token must be hex-encoded, got: {token}"
        );
    }

    #[test]
    fn test_ensure_token_creates_and_returns_token() {
        // Test 5: ensure_token() creates token file and returns token; second call reads existing
        let tmp = TempDir::new().unwrap();

        // First call: creates the file
        let token1 = ensure_token(tmp.path()).expect("First ensure_token call should succeed");
        assert_eq!(token1.len(), 64, "Generated token must be 64 chars");
        assert!(
            tmp.path().join("daemon.token").exists(),
            "Token file must be created"
        );

        // Second call: reads the existing file
        let token2 = ensure_token(tmp.path()).expect("Second ensure_token call should succeed");
        assert_eq!(token1, token2, "Second call must return the same token");
    }

    #[cfg(unix)]
    #[test]
    fn test_ensure_token_file_has_mode_0600() {
        // Test 6: On Unix, token file has mode 0o600
        use std::os::unix::fs::PermissionsExt;

        let tmp = TempDir::new().unwrap();
        ensure_token(tmp.path()).expect("ensure_token should succeed");

        let token_path = tmp.path().join("daemon.token");
        let metadata = std::fs::metadata(&token_path).unwrap();
        let mode = metadata.permissions().mode() & 0o777;
        assert_eq!(mode, 0o600, "Token file must have mode 0600, got: {mode:o}");
    }

    #[test]
    fn test_generate_default_config_toml_format() {
        // Test 7: generate_default_config_toml() contains "# [daemon]" (commented sections)
        // and "port = 7443" as the only uncommented value
        let content = generate_default_config_toml(7443);

        assert!(
            content.contains("port = 7443"),
            "Must contain active port line: {content}"
        );
        // The [daemon] section header is present (active)
        assert!(
            content.contains("[daemon]"),
            "Must contain [daemon] section: {content}"
        );
        // All other fields are commented
        assert!(
            content.contains("# level ="),
            "level must be commented out: {content}"
        );
        assert!(
            content.contains("# retention_days ="),
            "retention_days must be commented: {content}"
        );
    }

    #[test]
    fn test_config_extra_patterns_defaults_empty() {
        // Test 8: Config::extra_patterns field exists and defaults to empty vec
        let cfg = Config::defaults();
        assert!(
            cfg.extra_patterns.is_empty(),
            "Default extra_patterns must be empty"
        );
    }

    #[test]
    fn test_probe_free_port_finds_available_port() {
        // Probe a range — at least one port should be free on any test machine
        let port = probe_free_port(PORT_RANGE_START, PORT_RANGE_END)
            .expect("should find at least one free port");
        assert!((PORT_RANGE_START..=PORT_RANGE_END).contains(&port));
    }

    #[test]
    fn test_probe_free_port_skips_occupied_port() {
        // Bind a port, then probe a range starting at that port — should skip it
        let listener =
            std::net::TcpListener::bind(("127.0.0.1", 0)).expect("should bind to random port");
        let occupied = listener.local_addr().unwrap().port();

        // Probe a 1-port range with the occupied port — must fail
        let result = probe_free_port(occupied, occupied);
        assert!(
            result.is_err(),
            "must fail when only port in range is occupied"
        );

        // Probe a 2-port range — should find the next one
        if occupied < 65535 {
            let result = probe_free_port(occupied, occupied + 1);
            assert!(result.is_ok(), "should find next port after occupied one");
            assert_eq!(result.unwrap(), occupied + 1);
        }
    }

    #[test]
    fn test_write_and_read_port_file_round_trip() {
        let tmp = TempDir::new().unwrap();
        let port_path = tmp.path().join("daemon.port");

        // Write port file to temp location (test the format, not the path logic)
        std::fs::write(&port_path, "8080").unwrap();
        let content = std::fs::read_to_string(&port_path).unwrap();
        assert_eq!(content.trim().parse::<u16>().unwrap(), 8080);
    }
}