auths_cli/commands/

key.rs

use anyhow::{Context, Result, anyhow};
use clap::{Parser, Subcommand};
use serde::Serialize;
use std::ffi::CString;
use std::fs;
use std::path::PathBuf;

use auths_sdk::error::AgentError;
use auths_sdk::ffi::ffi;
use auths_sdk::keychain::EncryptedFileStorage;
use auths_sdk::keychain::{IdentityDID, KeyAlias, KeyRole, KeyStorage, get_platform_keychain};
use zeroize::{Zeroize, Zeroizing};

use crate::core::types::ExportFormat;
use crate::ux::format::{JsonResponse, is_json_mode};

#[derive(Parser, Debug, Clone)]
#[command(
    name = "key",
    about = "Manage signing keys stored on this device.",
    after_help = "Examples:
  auths key list            # List all stored key aliases
  auths key import --key-alias mykey --seed-file seed.bin
                            # Import an Ed25519 key from a 32-byte seed
  auths key export --key-alias mykey --format pub --passphrase <pass>
                            # Export a public key in OpenSSH format
  auths key delete --key-alias mykey
                            # Remove a key from secure storage

Related:
  auths id     — Manage identities
  auths device — Manage linked devices
  auths sign   — Sign commits and artifacts using keys"
)]
pub struct KeyCommand {
    #[command(subcommand)]
    pub command: KeySubcommand,
}

#[derive(Subcommand, Debug, Clone)]
pub enum KeySubcommand {
    /// List aliases of all keys stored in the platform's secure storage.
    List,

    /// Export a stored key in various formats (requires passphrase for some formats).
    Export {
        /// Local alias of the key to export.
        #[arg(
            long = "key-alias",
            visible_alias = "alias",
            help = "Local alias of the key to export."
        )]
        key_alias: String,

        /// Passphrase to decrypt the key (needed for 'pem'/'pub' formats).
        /// Omit it to be prompted — passing it as an argument leaves it in
        /// shell history.
        #[arg(
            long,
            help = "Passphrase to decrypt the key (omit to be prompted securely)."
        )]
        passphrase: Option<String>,

        /// Export format: pem (OpenSSH private), pub (OpenSSH public), enc (raw encrypted bytes).
        #[arg(
            long,
            help = "Export format: pem (OpenSSH private), pub (OpenSSH public), enc (raw encrypted bytes)."
        )]
        format: ExportFormat,
    },

    /// Remove a key from the platform's secure storage by alias.
    Delete {
        /// Local alias of the key to remove.
        #[arg(
            long = "key-alias",
            visible_alias = "alias",
            help = "Local alias of the key to remove."
        )]
        key_alias: String,
    },

    /// Import an Ed25519 key from a 32-byte seed file and store it encrypted.
    Import {
        /// Local alias to assign to the imported key.
        #[arg(
            long = "key-alias",
            visible_alias = "alias",
            help = "Local alias to assign to the imported key."
        )]
        key_alias: String,

        /// Path to the file containing the raw 32-byte Ed25519 seed.
        #[arg(
            long,
            value_parser, // Add value_parser for PathBuf
            help = "Path to the file containing the raw 32-byte Ed25519 seed."
        )]
        seed_file: PathBuf,

        /// Your identity to associate with this key (e.g., did:keri:E...).
        #[arg(
            long,
            help = "Your identity to associate with this key (e.g., did:keri:E...)."
        )]
        controller_did: String,
    },

    /// Copy a key from the current keychain backend to a different backend.
    ///
    /// Useful for creating a file-based keychain for headless CI environments without
    /// exposing the raw key material. The encrypted key bytes are copied as-is; the
    /// same passphrase used to store the key in the source backend must be used when
    /// loading it from the destination.
    ///
    /// Examples:
    ///   # Copy to file keychain (passphrase from env var)
    ///   AUTHS_PASSPHRASE="$PASS" auths key copy-backend \
    ///     --alias main --dst-backend file --dst-file /tmp/keychain.enc
    ///
    ///   # Copy to file keychain (passphrase from flag)
    ///   auths key copy-backend --alias main \
    ///     --dst-backend file --dst-file /tmp/keychain.enc --dst-passphrase "$PASS"
    CopyBackend {
        /// Alias of the key to copy from the current (source) keychain.
        #[arg(long = "key-alias", visible_alias = "alias")]
        key_alias: String,

        /// Destination backend type. Currently supported: "file".
        #[arg(long)]
        dst_backend: String,

        /// Path for the destination file keychain (required when --dst-backend is "file").
        #[arg(long)]
        dst_file: Option<PathBuf>,

        /// Passphrase for the destination file keychain.
        /// If omitted, the AUTHS_PASSPHRASE environment variable is used.
        #[arg(long)]
        dst_passphrase: Option<String>,
    },
}

pub fn handle_key(cmd: KeyCommand) -> Result<()> {
    match cmd.command {
        KeySubcommand::List => key_list(),
        KeySubcommand::Export {
            key_alias,
            passphrase,
            format,
        } => {
            let passphrase = match passphrase {
                Some(p) => p,
                None => prompt_export_passphrase()?,
            };
            key_export(&key_alias, &passphrase, format)
        }
        KeySubcommand::Delete { key_alias } => key_delete(&key_alias),
        KeySubcommand::Import {
            key_alias,
            seed_file,
            controller_did,
        } => {
            #[allow(clippy::disallowed_methods)]
            // INVARIANT: controller_did from CLI arg validated by clap
            let identity_did = IdentityDID::new_unchecked(controller_did);
            key_import(&key_alias, &seed_file, &identity_did)
        }
        KeySubcommand::CopyBackend {
            key_alias,
            dst_backend,
            dst_file,
            dst_passphrase,
        } => key_copy_backend(
            &key_alias,
            &dst_backend,
            dst_file.as_ref(),
            dst_passphrase.as_deref(),
        ),
    }
}

/// JSON response for key list command.
#[derive(Debug, Serialize)]
struct KeyListResponse {
    backend: String,
    aliases: Vec<String>,
    count: usize,
}

/// Lists all key aliases stored in the platform's secure storage.
fn key_list() -> Result<()> {
    let keychain: Box<dyn KeyStorage> = get_platform_keychain()?;
    let backend_name = keychain.backend_name().to_string();

    let aliases = match keychain.list_aliases() {
        Ok(a) => a,
        Err(AgentError::SecurityError(msg))
            if cfg!(target_os = "macos") && msg.contains("-25300") =>
        {
            // Handle macOS 'item not found' gracefully
            Vec::new()
        }
        Err(e) => return Err(e.into()),
    };

    if is_json_mode() {
        let alias_strings: Vec<String> = aliases.iter().map(|a| a.to_string()).collect();
        let count = alias_strings.len();
        let response = JsonResponse::success(
            "key list",
            KeyListResponse {
                backend: backend_name,
                aliases: alias_strings,
                count,
            },
        );
        response.print()?;
    } else {
        // Use eprintln for status messages to not interfere with potential stdout parsing
        eprintln!("Using key storage: {}", backend_name);

        if aliases.is_empty() {
            println!("No keys found in keychain for this application.");
        } else {
            println!("Stored keys:");
            for alias in aliases {
                println!("- {}", alias);
            }
        }
    }

    Ok(())
}

/// Frees the wrapped FFI context on drop, covering early returns in `key_export`.
struct FfiContextGuard(*mut ffi::AuthsFfiContext);

impl Drop for FfiContextGuard {
    fn drop(&mut self) {
        unsafe { ffi::ffi_context_free(self.0) };
    }
}

/// Exports a stored key in one of several formats using FFI calls.
#[inline]
/// Prompt for the export passphrase on the terminal — never via a CLI argument
/// (which would land in shell history). Falls back to AUTHS_PASSPHRASE for
/// headless use.
fn prompt_export_passphrase() -> Result<String> {
    #[allow(clippy::disallowed_methods)] // CLI boundary: env fallback for headless export
    if let Ok(pass) = std::env::var("AUTHS_PASSPHRASE") {
        return Ok(pass);
    }
    rpassword::prompt_password("Enter passphrase: ")
        .map_err(|e| anyhow::anyhow!("Failed to read passphrase from terminal: {e}"))
}

fn key_export(alias: &str, passphrase: &str, format: ExportFormat) -> Result<()> {
    let c_alias = CString::new(alias).context("Alias contains null byte")?;
    let c_passphrase = CString::new(passphrase).context("Passphrase contains null byte")?;
    let ctx = unsafe { ffi::ffi_context_new(std::ptr::null()) };
    if ctx.is_null() {
        anyhow::bail!("Failed to initialize FFI configuration context");
    }
    let ctx_guard = FfiContextGuard(ctx);
    let ctx = ctx_guard.0.cast_const();

    match format {
        ExportFormat::Pem => {
            let ptr = unsafe {
                ffi::ffi_export_private_key_openssh(ctx, c_alias.as_ptr(), c_passphrase.as_ptr())
            };
            if ptr.is_null() {
                anyhow::bail!(
                    "Failed to export PEM private key. Check the key alias with `auths key list` or verify your passphrase."
                );
            }
            let pem_string = unsafe {
                // Safety: ptr is not null and points to a C string allocated by FFI
                let c_str = std::ffi::CStr::from_ptr(ptr);
                let rust_str = c_str
                    .to_str()
                    .context("Failed to convert PEM FFI string to UTF-8")?
                    .to_owned(); // Own the string before freeing ptr
                ffi::ffi_free_str(ptr); // Free immediately after copying
                rust_str
            };
            println!("{}", pem_string); // Print the owned Rust string
        }
        ExportFormat::Pub => {
            let ptr = unsafe {
                ffi::ffi_export_public_key_openssh(ctx, c_alias.as_ptr(), c_passphrase.as_ptr())
            };
            if ptr.is_null() {
                anyhow::bail!(
                    "Failed to export public key. Check the key alias with `auths key list` or verify your passphrase."
                );
            }
            let pub_string = unsafe {
                // Safety: ptr is not null and points to a C string allocated by FFI
                let c_str = std::ffi::CStr::from_ptr(ptr);
                let rust_str = c_str
                    .to_str()
                    .context("Failed to convert Pubkey FFI string to UTF-8")?
                    .to_owned();
                ffi::ffi_free_str(ptr);
                rust_str
            };
            println!("{}", pub_string);
        }
        ExportFormat::Enc => {
            let mut out_len: usize = 0;
            let buf_ptr =
                unsafe { ffi::ffi_export_encrypted_key(ctx, c_alias.as_ptr(), &mut out_len) };
            if buf_ptr.is_null() {
                anyhow::bail!(
                    "❌ Failed to export encrypted private key (key not found or FFI error)"
                );
            }
            let slice_data = unsafe {
                // Safety: buf_ptr is not null and out_len is set by FFI
                let slice = std::slice::from_raw_parts(buf_ptr, out_len);
                let data = slice.to_vec(); // Copy data before freeing
                ffi::ffi_free_bytes(buf_ptr, out_len); // Free immediately
                data
            };
            println!("{}", hex::encode(slice_data)); // Print hex of copied data
        }
    }

    Ok(())
}

/// Deletes a key from the platform's secure storage by its alias.
fn key_delete(alias: &str) -> Result<()> {
    let keychain: Box<dyn KeyStorage> = get_platform_keychain()?;
    eprintln!("Using key storage: {}", keychain.backend_name());

    match keychain.delete_key(&KeyAlias::new_unchecked(alias)) {
        Ok(_) => {
            println!("🗑️ Removed key alias '{}'", alias); // Print confirmation to stdout
            Ok(())
        }
        Err(AgentError::KeyNotFound) => {
            eprintln!("ℹ️ Key alias '{}' not found, nothing to remove.", alias);
            Ok(()) // Treat 'not found' as success for delete idempotency
        }
        Err(err) => {
            // Propagate other errors
            Err(anyhow!(err)).context(format!("Failed to remove key '{}'", alias))
        }
    }
}

/// Imports an Ed25519 key from a 32-byte seed file, encrypts, and stores it.
fn key_import(alias: &str, seed_file_path: &PathBuf, controller_did: &IdentityDID) -> Result<()> {
    let seed_bytes = fs::read(seed_file_path)
        .with_context(|| format!("Failed to read seed file: {:?}", seed_file_path))?;
    if seed_bytes.len() != 32 {
        return Err(anyhow!(
            "Seed file must contain exactly 32 bytes, found {}.",
            seed_bytes.len()
        ));
    }
    #[allow(clippy::expect_used)] // INVARIANT: length validated to be 32 bytes on line 309
    let seed: [u8; 32] = seed_bytes.try_into().expect("validated 32 bytes above");
    let seed = Zeroizing::new(seed);

    #[allow(clippy::disallowed_methods)] // CLI boundary: passphrase from env
    let passphrase = if let Ok(env_pass) = std::env::var("AUTHS_PASSPHRASE") {
        Zeroizing::new(env_pass)
    } else {
        Zeroizing::new(
            rpassword::prompt_password(format!(
                "Enter passphrase to encrypt the key '{}': ",
                alias
            ))
            .context("Failed to read passphrase")?,
        )
    };
    if passphrase.is_empty() {
        return Err(anyhow!("Passphrase cannot be empty."));
    }

    let keychain = get_platform_keychain()?;
    let result = auths_sdk::keys::import_seed(
        &seed,
        auths_crypto::CurveType::default(),
        &passphrase,
        alias,
        controller_did,
        keychain.as_ref(),
    )
    .with_context(|| format!("Failed to import key '{alias}'"))?;

    println!(
        "Imported key '{}' ({} public key: {})",
        result.alias,
        result.curve,
        hex::encode(&result.public_key)
    );
    Ok(())
}

/// Copies a key from the current (source) keychain to a different destination backend.
///
/// The encrypted key bytes are transferred as-is — no re-encryption occurs. The same
/// passphrase used when the key was originally stored must be used to load it later.
///
/// For the file backend, the destination file keychain is protected by an additional
/// file-level passphrase supplied via `--dst-passphrase` or `AUTHS_PASSPHRASE`.
fn key_copy_backend(
    alias: &str,
    dst_backend: &str,
    dst_file: Option<&PathBuf>,
    dst_passphrase: Option<&str>,
) -> Result<()> {
    // Load the encrypted key bytes from the source keychain (no decryption).
    let src_keychain = get_platform_keychain()?;
    eprintln!("Source backend: {}", src_keychain.backend_name());

    let key_alias = KeyAlias::new_unchecked(alias);
    let (identity_did, _role, mut encrypted_key_data) = src_keychain
        .load_key(&key_alias)
        .with_context(|| format!("Key '{}' not found in source keychain", alias))?;

    // Build destination storage.
    let dst_storage: Box<dyn KeyStorage> = match dst_backend.to_lowercase().as_str() {
        "file" => {
            let path = dst_file
                .ok_or_else(|| anyhow!("--dst-file is required when --dst-backend is 'file'"))?;
            let storage = EncryptedFileStorage::with_path(path.clone())
                .context("Failed to create destination file storage")?;
            // Passphrase priority: explicit flag > AUTHS_PASSPHRASE env var > error.
            // Wrap immediately in Zeroizing so the heap allocation is cleared on drop.
            let password: Zeroizing<String> = dst_passphrase
                .map(|s| Zeroizing::new(s.to_string()))
                .or_else(|| {
                    #[allow(clippy::disallowed_methods)] // CLI boundary: passphrase from env
                    std::env::var("AUTHS_PASSPHRASE").ok().map(Zeroizing::new)
                })
                .ok_or_else(|| {
                    anyhow!(
                        "Passphrase required for file backend. \
                        Use --dst-passphrase or set the AUTHS_PASSPHRASE env var."
                    )
                })?;
            storage.set_password(password);
            Box::new(storage)
        }
        other => {
            encrypted_key_data.zeroize();
            return Err(anyhow!(
                "Unknown destination backend '{}'. Supported values: file",
                other
            ));
        }
    };

    eprintln!("Destination backend: {}", dst_storage.backend_name());

    let result = dst_storage
        .store_key(
            &key_alias,
            &identity_did,
            KeyRole::Primary,
            &encrypted_key_data,
        )
        .with_context(|| format!("Failed to store key '{}' in destination backend", alias));

    // Zeroize the encrypted key bytes regardless of whether store succeeded.
    encrypted_key_data.zeroize();

    result?;
    eprintln!(
        "✓ Copied key '{}' ({}) to {}",
        alias, identity_did, dst_backend
    );
    Ok(())
}

use crate::commands::executable::ExecutableCommand;
use crate::config::CliConfig;

impl ExecutableCommand for KeyCommand {
    fn execute(&self, _ctx: &CliConfig) -> Result<()> {
        handle_key(self.clone())
    }
}