// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of OpenEthereum.

// OpenEthereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// OpenEthereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with OpenEthereum.  If not, see <http://www.gnu.org/licenses/>.

#![warn(missing_docs)]

//! Account management.

extern crate parity_crypto as crypto;

mod account_data;
mod error;
mod stores;

use self::{
    account_data::{AccountData, Unlock},
    stores::AddressBook,
};

use std::{
    collections::HashMap,
    time::{Duration, Instant},
};

use crypto::publickey::{Address, Generator, Message, Public, Random, Secret};
use ethkey::Password;
use ethstore::{
    accounts_dir::MemoryDirectory, random_string, EthMultiStore, EthStore, OpaqueSecret,
    SecretStore, SecretVaultRef, SimpleSecretStore, StoreAccountRef,
};
use log::*;
use parking_lot::RwLock;

pub use crypto::publickey::Signature;
pub use ethstore::{Derivation, Error, IndexDerivation, KeyFile};

pub use self::{account_data::AccountMeta, error::SignError};

type AccountToken = Password;

/// Account management settings.
#[derive(Debug, Default)]
pub struct AccountProviderSettings {
    /// Store raw account secret when unlocking the account permanently.
    pub unlock_keep_secret: bool,
    /// Disallowed accounts.
    pub blacklisted_accounts: Vec<Address>,
}

/// Account management.
/// Responsible for unlocking accounts.
pub struct AccountProvider {
    /// For performance reasons some methods can re-use unlocked secrets.
    unlocked_secrets: RwLock<HashMap<StoreAccountRef, OpaqueSecret>>,
    /// Unlocked account data.
    unlocked: RwLock<HashMap<StoreAccountRef, AccountData>>,
    /// Address book.
    address_book: RwLock<AddressBook>,
    /// Accounts on disk
    sstore: Box<dyn SecretStore>,
    /// Accounts unlocked with rolling tokens
    transient_sstore: EthMultiStore,
    /// When unlocking account permanently we additionally keep a raw secret in memory
    /// to increase the performance of transaction signing.
    unlock_keep_secret: bool,
    /// Disallowed accounts.
    blacklisted_accounts: Vec<Address>,
}

fn transient_sstore() -> EthMultiStore {
    EthMultiStore::open(Box::new(MemoryDirectory::default()))
        .expect("MemoryDirectory load always succeeds; qed")
}

impl AccountProvider {
    /// Creates new account provider.
    pub fn new(sstore: Box<dyn SecretStore>, settings: AccountProviderSettings) -> Self {
        if let Ok(accounts) = sstore.accounts() {
            for account in accounts
                .into_iter()
                .filter(|a| settings.blacklisted_accounts.contains(&a.address))
            {
                warn!("Local Account {} has a blacklisted (known to be weak) address and will be ignored",
					account.address);
            }
        }

        // Remove blacklisted accounts from address book.
        let mut address_book = AddressBook::new(&sstore.local_path());
        for addr in &settings.blacklisted_accounts {
            address_book.remove(*addr);
        }

        AccountProvider {
            unlocked_secrets: RwLock::new(HashMap::new()),
            unlocked: RwLock::new(HashMap::new()),
            address_book: RwLock::new(address_book),
            sstore: sstore,
            transient_sstore: transient_sstore(),
            unlock_keep_secret: settings.unlock_keep_secret,
            blacklisted_accounts: settings.blacklisted_accounts,
        }
    }

    /// Creates not disk backed provider.
    pub fn transient_provider() -> Self {
        AccountProvider {
            unlocked_secrets: RwLock::new(HashMap::new()),
            unlocked: RwLock::new(HashMap::new()),
            address_book: RwLock::new(AddressBook::transient()),
            sstore: Box::new(
                EthStore::open(Box::new(MemoryDirectory::default()))
                    .expect("MemoryDirectory load always succeeds; qed"),
            ),
            transient_sstore: transient_sstore(),
            unlock_keep_secret: false,
            blacklisted_accounts: vec![],
        }
    }

    /// Creates new random account.
    pub fn new_account(&self, password: &Password) -> Result<Address, Error> {
        self.new_account_and_public(password).map(|d| d.0)
    }

    /// Creates new random account and returns address and public key
    pub fn new_account_and_public(&self, password: &Password) -> Result<(Address, Public), Error> {
        let acc = Random.generate();
        let public = acc.public().clone();
        let secret = acc.secret().clone();
        let account = self
            .sstore
            .insert_account(SecretVaultRef::Root, secret, password)?;
        Ok((account.address, public))
    }

    /// Inserts new account into underlying store.
    /// Does not unlock account!
    pub fn insert_account(&self, secret: Secret, password: &Password) -> Result<Address, Error> {
        let account = self
            .sstore
            .insert_account(SecretVaultRef::Root, secret, password)?;
        if self.blacklisted_accounts.contains(&account.address) {
            self.sstore.remove_account(&account, password)?;
            return Err(Error::InvalidAccount.into());
        }
        Ok(account.address)
    }

    /// Generates new derived account based on the existing one
    /// If password is not provided, account must be unlocked
    /// New account will be created with the same password (if save: true)
    pub fn derive_account(
        &self,
        address: &Address,
        password: Option<Password>,
        derivation: Derivation,
        save: bool,
    ) -> Result<Address, SignError> {
        let account = self.sstore.account_ref(&address)?;
        let password = password
            .map(Ok)
            .unwrap_or_else(|| self.password(&account))?;
        Ok(if save {
            self.sstore
                .insert_derived(SecretVaultRef::Root, &account, &password, derivation)?
                .address
        } else {
            self.sstore
                .generate_derived(&account, &password, derivation)?
        })
    }

    /// Import a new presale wallet.
    pub fn import_presale(
        &self,
        presale_json: &[u8],
        password: &Password,
    ) -> Result<Address, Error> {
        let account = self
            .sstore
            .import_presale(SecretVaultRef::Root, presale_json, password)?;
        Ok(Address::from(account.address).into())
    }

    /// Import a new wallet.
    pub fn import_wallet(
        &self,
        json: &[u8],
        password: &Password,
        gen_id: bool,
    ) -> Result<Address, Error> {
        let account = self
            .sstore
            .import_wallet(SecretVaultRef::Root, json, password, gen_id)?;
        if self.blacklisted_accounts.contains(&account.address) {
            self.sstore.remove_account(&account, password)?;
            return Err(Error::InvalidAccount.into());
        }
        Ok(Address::from(account.address).into())
    }

    /// Checks whether an account with a given address is present.
    pub fn has_account(&self, address: Address) -> bool {
        self.sstore.account_ref(&address).is_ok() && !self.blacklisted_accounts.contains(&address)
    }

    /// Returns addresses of all accounts.
    pub fn accounts(&self) -> Result<Vec<Address>, Error> {
        let accounts = self.sstore.accounts()?;
        Ok(accounts
            .into_iter()
            .map(|a| a.address)
            .filter(|address| !self.blacklisted_accounts.contains(address))
            .collect())
    }

    /// Returns the address of default account.
    pub fn default_account(&self) -> Result<Address, Error> {
        Ok(self.accounts()?.first().cloned().unwrap_or_default())
    }

    /// Returns each address along with metadata.
    pub fn addresses_info(&self) -> HashMap<Address, AccountMeta> {
        self.address_book.read().get()
    }

    /// Returns each address along with metadata.
    pub fn set_address_name(&self, account: Address, name: String) {
        self.address_book.write().set_name(account, name)
    }

    /// Returns each address along with metadata.
    pub fn set_address_meta(&self, account: Address, meta: String) {
        self.address_book.write().set_meta(account, meta)
    }

    /// Removes and address from the address book
    pub fn remove_address(&self, addr: Address) {
        self.address_book.write().remove(addr)
    }

    /// Returns each account along with name and meta.
    pub fn accounts_info(&self) -> Result<HashMap<Address, AccountMeta>, Error> {
        let r = self
            .sstore
            .accounts()?
            .into_iter()
            .filter(|a| !self.blacklisted_accounts.contains(&a.address))
            .map(|a| {
                (
                    a.address.clone(),
                    self.account_meta(a.address).ok().unwrap_or_default(),
                )
            })
            .collect();
        Ok(r)
    }

    /// Returns each account along with name and meta.
    pub fn account_meta(&self, address: Address) -> Result<AccountMeta, Error> {
        let account = self.sstore.account_ref(&address)?;
        Ok(AccountMeta {
            name: self.sstore.name(&account)?,
            meta: self.sstore.meta(&account)?,
            uuid: self.sstore.uuid(&account).ok().map(Into::into), // allowed to not have a Uuid
        })
    }

    /// Returns account public key.
    pub fn account_public(&self, address: Address, password: &Password) -> Result<Public, Error> {
        self.sstore
            .public(&self.sstore.account_ref(&address)?, password)
    }

    /// Returns each account along with name and meta.
    pub fn set_account_name(&self, address: Address, name: String) -> Result<(), Error> {
        self.sstore
            .set_name(&self.sstore.account_ref(&address)?, name)?;
        Ok(())
    }

    /// Returns each account along with name and meta.
    pub fn set_account_meta(&self, address: Address, meta: String) -> Result<(), Error> {
        self.sstore
            .set_meta(&self.sstore.account_ref(&address)?, meta)?;
        Ok(())
    }

    /// Returns `true` if the password for `account` is `password`. `false` if not.
    pub fn test_password(&self, address: &Address, password: &Password) -> Result<bool, Error> {
        self.sstore
            .test_password(&self.sstore.account_ref(&address)?, password)
            .map_err(Into::into)
    }

    /// Permanently removes an account.
    pub fn kill_account(&self, address: &Address, password: &Password) -> Result<(), Error> {
        self.sstore
            .remove_account(&self.sstore.account_ref(&address)?, &password)?;
        Ok(())
    }

    /// Changes the password of `account` from `password` to `new_password`. Fails if incorrect `password` given.
    pub fn change_password(
        &self,
        address: &Address,
        password: Password,
        new_password: Password,
    ) -> Result<(), Error> {
        self.sstore
            .change_password(&self.sstore.account_ref(address)?, &password, &new_password)
    }

    /// Exports an account for given address.
    pub fn export_account(&self, address: &Address, password: Password) -> Result<KeyFile, Error> {
        self.sstore
            .export_account(&self.sstore.account_ref(address)?, &password)
    }

    /// Helper method used for unlocking accounts.
    fn unlock_account(
        &self,
        address: Address,
        password: Password,
        unlock: Unlock,
    ) -> Result<(), Error> {
        let account = self.sstore.account_ref(&address)?;

        // check if account is already unlocked permanently, if it is, do nothing
        let mut unlocked = self.unlocked.write();
        if let Some(data) = unlocked.get(&account) {
            if let Unlock::Perm = data.unlock {
                return Ok(());
            }
        }

        if self.unlock_keep_secret && unlock == Unlock::Perm {
            // verify password and get the secret
            let secret = self.sstore.raw_secret(&account, &password)?;
            self.unlocked_secrets
                .write()
                .insert(account.clone(), secret);
        } else {
            // verify password by signing dump message
            // result may be discarded
            let dummy_msg = [1u8; 32].into();
            let _ = self.sstore.sign(&account, &password, &dummy_msg)?;
        }

        let data = AccountData {
            unlock: unlock,
            password: password,
        };

        unlocked.insert(account, data);
        Ok(())
    }

    fn password(&self, account: &StoreAccountRef) -> Result<Password, SignError> {
        let mut unlocked = self.unlocked.write();
        let data = unlocked.get(account).ok_or(SignError::NotUnlocked)?.clone();
        if let Unlock::OneTime = data.unlock {
            unlocked
                .remove(account)
                .expect("data exists: so key must exist: qed");
        }
        if let Unlock::Timed(ref end) = data.unlock {
            if Instant::now() > *end {
                unlocked
                    .remove(account)
                    .expect("data exists: so key must exist: qed");
                return Err(SignError::NotUnlocked);
            }
        }
        Ok(data.password)
    }

    /// Unlocks account permanently.
    pub fn unlock_account_permanently(
        &self,
        account: Address,
        password: Password,
    ) -> Result<(), Error> {
        self.unlock_account(account, password, Unlock::Perm)
    }

    /// Unlocks account temporarily (for one signing).
    pub fn unlock_account_temporarily(
        &self,
        account: Address,
        password: Password,
    ) -> Result<(), Error> {
        self.unlock_account(account, password, Unlock::OneTime)
    }

    /// Unlocks account temporarily with a timeout.
    pub fn unlock_account_timed(
        &self,
        account: Address,
        password: Password,
        duration: Duration,
    ) -> Result<(), Error> {
        self.unlock_account(account, password, Unlock::Timed(Instant::now() + duration))
    }

    /// Checks if given account is unlocked
    pub fn is_unlocked(&self, address: &Address) -> bool {
        let unlocked = self.unlocked.read();
        let unlocked_secrets = self.unlocked_secrets.read();
        self.sstore
            .account_ref(address)
            .map(|r| unlocked.get(&r).is_some() || unlocked_secrets.get(&r).is_some())
            .unwrap_or(false)
    }

    /// Checks if given account is unlocked permanently
    pub fn is_unlocked_permanently(&self, address: &Address) -> bool {
        let unlocked = self.unlocked.read();
        self.sstore
            .account_ref(address)
            .map(|r| {
                unlocked
                    .get(&r)
                    .map_or(false, |account| account.unlock == Unlock::Perm)
            })
            .unwrap_or(false)
    }

    /// Signs the message. If password is not provided the account must be unlocked.
    pub fn sign(
        &self,
        address: Address,
        password: Option<Password>,
        message: Message,
    ) -> Result<Signature, SignError> {
        let account = self.sstore.account_ref(&address)?;
        match self.unlocked_secrets.read().get(&account) {
            Some(secret) => Ok(self.sstore.sign_with_secret(&secret, &message)?),
            None => {
                let password = password
                    .map(Ok)
                    .unwrap_or_else(|| self.password(&account))?;
                Ok(self.sstore.sign(&account, &password, &message)?)
            }
        }
    }

    /// Signs message using the derived secret. If password is not provided the account must be unlocked.
    pub fn sign_derived(
        &self,
        address: &Address,
        password: Option<Password>,
        derivation: Derivation,
        message: Message,
    ) -> Result<Signature, SignError> {
        let account = self.sstore.account_ref(address)?;
        let password = password
            .map(Ok)
            .unwrap_or_else(|| self.password(&account))?;
        Ok(self
            .sstore
            .sign_derived(&account, &password, derivation, &message)?)
    }

    /// Signs given message with supplied token. Returns a token to use in next signing within this session.
    pub fn sign_with_token(
        &self,
        address: Address,
        token: AccountToken,
        message: Message,
    ) -> Result<(Signature, AccountToken), SignError> {
        let account = self.sstore.account_ref(&address)?;
        let is_std_password = self.sstore.test_password(&account, &token)?;

        let new_token = Password::from(random_string(16));
        let signature = if is_std_password {
            // Insert to transient store
            self.sstore.copy_account(
                &self.transient_sstore,
                SecretVaultRef::Root,
                &account,
                &token,
                &new_token,
            )?;
            // sign
            self.sstore.sign(&account, &token, &message)?
        } else {
            // check transient store
            self.transient_sstore
                .change_password(&account, &token, &new_token)?;
            // and sign
            self.transient_sstore.sign(&account, &new_token, &message)?
        };

        Ok((signature, new_token))
    }

    /// Decrypts a message with given token. Returns a token to use in next operation for this account.
    pub fn decrypt_with_token(
        &self,
        address: Address,
        token: AccountToken,
        shared_mac: &[u8],
        message: &[u8],
    ) -> Result<(Vec<u8>, AccountToken), SignError> {
        let account = self.sstore.account_ref(&address)?;
        let is_std_password = self.sstore.test_password(&account, &token)?;

        let new_token = Password::from(random_string(16));
        let message = if is_std_password {
            // Insert to transient store
            self.sstore.copy_account(
                &self.transient_sstore,
                SecretVaultRef::Root,
                &account,
                &token,
                &new_token,
            )?;
            // decrypt
            self.sstore.decrypt(&account, &token, shared_mac, message)?
        } else {
            // check transient store
            self.transient_sstore
                .change_password(&account, &token, &new_token)?;
            // and decrypt
            self.transient_sstore
                .decrypt(&account, &token, shared_mac, message)?
        };

        Ok((message, new_token))
    }

    /// Decrypts a message. If password is not provided the account must be unlocked.
    pub fn decrypt(
        &self,
        address: Address,
        password: Option<Password>,
        shared_mac: &[u8],
        message: &[u8],
    ) -> Result<Vec<u8>, SignError> {
        let account = self.sstore.account_ref(&address)?;
        let password = password
            .map(Ok)
            .unwrap_or_else(|| self.password(&account))?;
        Ok(self
            .sstore
            .decrypt(&account, &password, shared_mac, message)?)
    }

    /// Agree on shared key.
    pub fn agree(
        &self,
        address: Address,
        password: Option<Password>,
        other_public: &Public,
    ) -> Result<Secret, SignError> {
        let account = self.sstore.account_ref(&address)?;
        let password = password
            .map(Ok)
            .unwrap_or_else(|| self.password(&account))?;
        Ok(self.sstore.agree(&account, &password, other_public)?)
    }

    /// Create new vault.
    pub fn create_vault(&self, name: &str, password: &Password) -> Result<(), Error> {
        self.sstore.create_vault(name, password).map_err(Into::into)
    }

    /// Open existing vault.
    pub fn open_vault(&self, name: &str, password: &Password) -> Result<(), Error> {
        self.sstore.open_vault(name, password).map_err(Into::into)
    }

    /// Close previously opened vault.
    pub fn close_vault(&self, name: &str) -> Result<(), Error> {
        self.sstore.close_vault(name).map_err(Into::into)
    }

    /// List all vaults
    pub fn list_vaults(&self) -> Result<Vec<String>, Error> {
        self.sstore.list_vaults().map_err(Into::into)
    }

    /// List all currently opened vaults
    pub fn list_opened_vaults(&self) -> Result<Vec<String>, Error> {
        self.sstore.list_opened_vaults().map_err(Into::into)
    }

    /// Change vault password.
    pub fn change_vault_password(&self, name: &str, new_password: &Password) -> Result<(), Error> {
        self.sstore
            .change_vault_password(name, new_password)
            .map_err(Into::into)
    }

    /// Change vault of the given address.
    pub fn change_vault(&self, address: Address, new_vault: &str) -> Result<(), Error> {
        let new_vault_ref = if new_vault.is_empty() {
            SecretVaultRef::Root
        } else {
            SecretVaultRef::Vault(new_vault.to_owned())
        };
        let old_account_ref = self.sstore.account_ref(&address)?;
        self.sstore
            .change_account_vault(new_vault_ref, old_account_ref)
            .map_err(Into::into)
            .map(|_| ())
    }

    /// Get vault metadata string.
    pub fn get_vault_meta(&self, name: &str) -> Result<String, Error> {
        self.sstore.get_vault_meta(name).map_err(Into::into)
    }

    /// Set vault metadata string.
    pub fn set_vault_meta(&self, name: &str, meta: &str) -> Result<(), Error> {
        self.sstore.set_vault_meta(name, meta).map_err(Into::into)
    }
}

#[cfg(test)]
mod tests {
    use super::{AccountProvider, Unlock};
    use crypto::publickey::{Address, Generator, Random};
    use ethereum_types::H256;
    use ethstore::{Derivation, StoreAccountRef};
    use std::time::{Duration, Instant};

    #[test]
    fn unlock_account_temp() {
        let kp = Random.generate();
        let ap = AccountProvider::transient_provider();
        let dummy_msg = [1u8; 32].into();
        assert!(ap
            .insert_account(kp.secret().clone(), &"test".into())
            .is_ok());
        assert!(ap
            .unlock_account_temporarily(kp.address(), "test1".into())
            .is_err());
        assert!(ap
            .unlock_account_temporarily(kp.address(), "test".into())
            .is_ok());
        assert!(ap.sign(kp.address(), None, dummy_msg).is_ok());
        assert!(ap.sign(kp.address(), None, dummy_msg).is_err());
    }

    #[test]
    fn derived_account_nosave() {
        let kp = Random.generate();
        let ap = AccountProvider::transient_provider();
        assert!(ap
            .insert_account(kp.secret().clone(), &"base".into())
            .is_ok());
        assert!(ap
            .unlock_account_permanently(kp.address(), "base".into())
            .is_ok());

        let derived_addr = ap
            .derive_account(
                &kp.address(),
                None,
                Derivation::SoftHash(H256::from_low_u64_be(999)),
                false,
            )
            .expect("Derivation should not fail");

        assert!(
            ap.unlock_account_permanently(derived_addr, "base".into())
                .is_err(),
            "There should be an error because account is not supposed to be saved"
        );
    }

    #[test]
    fn derived_account_save() {
        let kp = Random.generate();
        let ap = AccountProvider::transient_provider();
        assert!(ap
            .insert_account(kp.secret().clone(), &"base".into())
            .is_ok());
        assert!(ap
            .unlock_account_permanently(kp.address(), "base".into())
            .is_ok());

        let derived_addr = ap
            .derive_account(
                &kp.address(),
                None,
                Derivation::SoftHash(H256::from_low_u64_be(999)),
                true,
            )
            .expect("Derivation should not fail");

        assert!(
            ap.unlock_account_permanently(derived_addr, "base_wrong".into())
                .is_err(),
            "There should be an error because password is invalid"
        );

        assert!(
            ap.unlock_account_permanently(derived_addr, "base".into())
                .is_ok(),
            "Should be ok because account is saved and password is valid"
        );
    }

    #[test]
    fn derived_account_sign() {
        let kp = Random.generate();
        let ap = AccountProvider::transient_provider();
        assert!(ap
            .insert_account(kp.secret().clone(), &"base".into())
            .is_ok());
        assert!(ap
            .unlock_account_permanently(kp.address(), "base".into())
            .is_ok());

        let derived_addr = ap
            .derive_account(
                &kp.address(),
                None,
                Derivation::SoftHash(H256::from_low_u64_be(1999)),
                true,
            )
            .expect("Derivation should not fail");
        ap.unlock_account_permanently(derived_addr, "base".into())
            .expect("Should be ok because account is saved and password is valid");

        let msg = [2u8; 32].into();
        let signed_msg1 = ap
            .sign(derived_addr, None, msg)
            .expect("Signing with existing unlocked account should not fail");
        let signed_msg2 = ap
            .sign_derived(
                &kp.address(),
                None,
                Derivation::SoftHash(H256::from_low_u64_be(1999)),
                msg,
            )
            .expect("Derived signing with existing unlocked account should not fail");

        assert_eq!(signed_msg1, signed_msg2, "Signed messages should match");
    }

    #[test]
    fn unlock_account_perm() {
        let kp = Random.generate();
        let ap = AccountProvider::transient_provider();
        let dummy_msg = [1u8; 32].into();
        assert!(ap
            .insert_account(kp.secret().clone(), &"test".into())
            .is_ok());
        assert!(ap
            .unlock_account_permanently(kp.address(), "test1".into())
            .is_err());
        assert!(ap
            .unlock_account_permanently(kp.address(), "test".into())
            .is_ok());
        assert!(ap.sign(kp.address(), None, dummy_msg).is_ok());
        assert!(ap.sign(kp.address(), None, dummy_msg).is_ok());
        assert!(ap
            .unlock_account_temporarily(kp.address(), "test".into())
            .is_ok());
        assert!(ap.sign(kp.address(), None, dummy_msg).is_ok());
        assert!(ap.sign(kp.address(), None, dummy_msg).is_ok());
    }

    #[test]
    fn unlock_account_timer() {
        let kp = Random.generate();
        let ap = AccountProvider::transient_provider();
        let dummy_msg = [1u8; 32].into();
        assert!(ap
            .insert_account(kp.secret().clone(), &"test".into())
            .is_ok());
        assert!(ap
            .unlock_account_timed(kp.address(), "test1".into(), Duration::from_secs(60))
            .is_err());
        assert!(ap
            .unlock_account_timed(kp.address(), "test".into(), Duration::from_secs(60))
            .is_ok());
        assert!(ap.sign(kp.address(), None, dummy_msg).is_ok());
        ap.unlocked
            .write()
            .get_mut(&StoreAccountRef::root(kp.address()))
            .unwrap()
            .unlock = Unlock::Timed(Instant::now());
        assert!(ap.sign(kp.address(), None, dummy_msg).is_err());
    }

    #[test]
    fn should_sign_and_return_token() {
        // given
        let kp = Random.generate();
        let ap = AccountProvider::transient_provider();
        let dummy_msg = [1u8; 32].into();
        assert!(ap
            .insert_account(kp.secret().clone(), &"test".into())
            .is_ok());

        // when
        let (_signature, token) = ap
            .sign_with_token(kp.address(), "test".into(), dummy_msg)
            .unwrap();

        // then
        ap.sign_with_token(kp.address(), token.clone(), dummy_msg)
            .expect("First usage of token should be correct.");
        assert!(
            ap.sign_with_token(kp.address(), token, dummy_msg).is_err(),
            "Second usage of the same token should fail."
        );
    }

    #[test]
    fn should_not_return_blacklisted_account() {
        // given
        let mut ap = AccountProvider::transient_provider();
        let acc = ap.new_account(&"test".into()).unwrap();
        ap.blacklisted_accounts = vec![acc];

        // then
        assert_eq!(
            ap.accounts_info()
                .unwrap()
                .keys()
                .cloned()
                .collect::<Vec<Address>>(),
            vec![]
        );
        assert_eq!(ap.accounts().unwrap(), vec![]);
    }
}