// Copyright 2021 Axiom-Team
//
// This file is part of Duniter-v2S.
//
// Duniter-v2S is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, version 3 of the License.
//
// Duniter-v2S 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with Duniter-v2S. If not, see <https://www.gnu.org/licenses/>.

use sc_cli::{
    utils, with_crypto_scheme, CryptoScheme, Error, KeystoreParams, SharedParams, SubstrateCli,
};
use sc_keystore::LocalKeystore;
use sc_service::config::{BasePath, KeystoreConfig};
use sp_core::crypto::{AccountId32, KeyTypeId, SecretString};
use sp_keystore::{SyncCryptoStore, SyncCryptoStorePtr};
use std::sync::Arc;

#[derive(Debug, clap::Subcommand)]
pub enum KeySubcommand {
    /// Generate session keys and store them in the keystore
    GenerateSessionKeys(GenSessionKeysCmd),

    #[allow(missing_docs)]
    #[clap(flatten)]
    Key(sc_cli::KeySubcommand),
}

impl KeySubcommand {
    /// Run the command
    pub fn run<C: SubstrateCli>(&self, cli: &C) -> Result<(), Error> {
        match self {
            Self::GenerateSessionKeys(cmd) => cmd.run(cli),
            Self::Key(cmd) => cmd.run(cli),
        }
    }
}

#[derive(Debug, clap::Args)]
pub struct GenSessionKeysCmd {
    /// The secret key URI.
    /// If the value is a file, the file content is used as URI.
    /// If not given, you will be prompted for the URI.
    #[clap(long)]
    suri: Option<String>,

    #[allow(missing_docs)]
    #[clap(flatten)]
    pub shared_params: SharedParams,

    #[allow(missing_docs)]
    #[clap(flatten)]
    pub keystore_params: KeystoreParams,
}

const KEY_TYPES: [(KeyTypeId, CryptoScheme); 4] = [
    (KeyTypeId(*b"gran"), CryptoScheme::Ed25519),
    (KeyTypeId(*b"babe"), CryptoScheme::Sr25519),
    (KeyTypeId(*b"imon"), CryptoScheme::Sr25519),
    (KeyTypeId(*b"audi"), CryptoScheme::Sr25519),
];

impl GenSessionKeysCmd {
    /// Run the command
    pub fn run<C: SubstrateCli>(&self, cli: &C) -> Result<(), Error> {
        let suri = utils::read_uri(self.suri.as_ref())?;
        let base_path = self
            .shared_params
            .base_path()?
            .unwrap_or_else(|| BasePath::from_project("", "", &C::executable_name()));
        let chain_id = self.shared_params.chain_id(self.shared_params.is_dev());
        let chain_spec = cli.load_spec(&chain_id)?;
        let config_dir = base_path.config_dir(chain_spec.id());

        let mut public_keys_bytes = Vec::with_capacity(128);
        for (key_type_id, crypto_scheme) in KEY_TYPES {
            let (keystore, public) = match self.keystore_params.keystore_config(&config_dir)? {
                (_, KeystoreConfig::Path { path, password }) => {
                    let public =
                        with_crypto_scheme!(crypto_scheme, to_vec(&suri, password.clone()))?;
                    let keystore: SyncCryptoStorePtr =
                        Arc::new(LocalKeystore::open(path, password)?);
                    (keystore, public)
                }
                _ => unreachable!("keystore_config always returns path and password; qed"),
            };

            SyncCryptoStore::insert_unknown(&*keystore, key_type_id, &suri, &public[..])
                .map_err(|_| Error::KeyStoreOperation)?;

            public_keys_bytes.extend_from_slice(&public[..]);
        }

        let mut buffer = [0; 32];
        // grandpa
        buffer.copy_from_slice(&public_keys_bytes[..32]);
        println!("grandpa: {}", AccountId32::new(buffer));
        // babe
        buffer.copy_from_slice(&public_keys_bytes[32..64]);
        println!("babe: {}", AccountId32::new(buffer));
        // im_online
        buffer.copy_from_slice(&public_keys_bytes[64..96]);
        println!("im_online: {}", AccountId32::new(buffer));
        // authority discovery
        buffer.copy_from_slice(&public_keys_bytes[96..]);
        println!("authority_discovery: {}", AccountId32::new(buffer));

        println!("Session Keys: 0x{}", hex::encode(public_keys_bytes));
        Ok(())
    }
}

fn to_vec<P: sp_core::Pair>(uri: &str, pass: Option<SecretString>) -> Result<Vec<u8>, Error> {
    let p = utils::pair_from_suri::<P>(uri, pass)?;
    Ok(p.public().as_ref().to_vec())
}