// Copyright 2019-2021 Parity Technologies (UK) Ltd.
// This file is part of subxt.
//
// subxt 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.
//
// subxt 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 subxt.  If not, see <http://www.gnu.org/licenses/>.

//! RPC types and client for interacting with a substrate node.

// jsonrpsee subscriptions are interminable.
// Allows `while let status = subscription.next().await {}`
// Related: https://github.com/paritytech/subxt/issues/66
#![allow(irrefutable_let_patterns)]

use std::sync::Arc;

use codec::{
    Decode,
    Encode,
    Error as CodecError,
};
use core::{
    convert::TryInto,
    marker::PhantomData,
};
use frame_metadata::RuntimeMetadataPrefixed;
pub use jsonrpsee::{
    client_transport::ws::{
        Receiver as WsReceiver,
        Sender as WsSender,
        Uri,
        WsTransportClientBuilder,
    },
    core_client::{
        Client as RpcClient,
        ClientBuilder as RpcClientBuilder,
    },
    rpc_params,
    types::{
        to_json_value,
        traits::{
            Client,
            SubscriptionClient,
        },
        DeserializeOwned,
        Error as RpcError,
        JsonValue,
        Subscription,
    },
};
use serde::{
    Deserialize,
    Serialize,
};
use sp_core::{
    storage::{
        StorageChangeSet,
        StorageData,
        StorageKey,
    },
    Bytes,
    U256,
};
use sp_runtime::{
    generic::{
        Block,
        SignedBlock,
    },
    traits::Hash,
};
use sp_version::RuntimeVersion;

use crate::{
    error::Error,
    events::{
        EventsDecoder,
        RawEvent,
    },
    storage::StorageKeyPrefix,
    subscription::{
        EventStorageSubscription,
        EventSubscription,
        FinalizedEventStorageSubscription,
        SystemEvents,
    },
    Config,
    Event,
    Metadata,
};

/// A number type that can be serialized both as a number or a string that encodes a number in a
/// string.
///
/// We allow two representations of the block number as input. Either we deserialize to the type
/// that is specified in the block type or we attempt to parse given hex value.
///
/// The primary motivation for having this type is to avoid overflows when using big integers in
/// JavaScript (which we consider as an important RPC API consumer).
#[derive(Copy, Clone, Serialize, Deserialize, Debug, PartialEq)]
#[serde(untagged)]
pub enum NumberOrHex {
    /// The number represented directly.
    Number(u64),
    /// Hex representation of the number.
    Hex(U256),
}

/// RPC list or value wrapper.
#[derive(Serialize, Deserialize, Debug, PartialEq)]
#[serde(untagged)]
pub enum ListOrValue<T> {
    /// A list of values of given type.
    List(Vec<T>),
    /// A single value of given type.
    Value(T),
}

/// Alias for the type of a block returned by `chain_getBlock`
pub type ChainBlock<T> =
    SignedBlock<Block<<T as Config>::Header, <T as Config>::Extrinsic>>;

/// Wrapper for NumberOrHex to allow custom From impls
#[derive(Serialize)]
pub struct BlockNumber(NumberOrHex);

impl From<NumberOrHex> for BlockNumber {
    fn from(x: NumberOrHex) -> Self {
        BlockNumber(x)
    }
}

impl From<u32> for BlockNumber {
    fn from(x: u32) -> Self {
        NumberOrHex::Number(x.into()).into()
    }
}

/// System properties for a Substrate-based runtime
#[derive(serde::Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Default)]
#[serde(rename_all = "camelCase")]
pub struct SystemProperties {
    /// The address format
    pub ss58_format: u8,
    /// The number of digits after the decimal point in the native token
    pub token_decimals: u8,
    /// The symbol of the native token
    pub token_symbol: String,
}

/// Possible transaction status events.
///
/// # Note
///
/// This is copied from `sp-transaction-pool` to avoid a dependency on that crate. Therefore it
/// must be kept compatible with that type from the target substrate version.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub enum TransactionStatus<Hash, BlockHash> {
    /// Transaction is part of the future queue.
    Future,
    /// Transaction is part of the ready queue.
    Ready,
    /// The transaction has been broadcast to the given peers.
    Broadcast(Vec<String>),
    /// Transaction has been included in block with given hash.
    InBlock(BlockHash),
    /// The block this transaction was included in has been retracted.
    Retracted(BlockHash),
    /// Maximum number of finality watchers has been reached,
    /// old watchers are being removed.
    FinalityTimeout(BlockHash),
    /// Transaction has been finalized by a finality-gadget, e.g GRANDPA
    Finalized(BlockHash),
    /// Transaction has been replaced in the pool, by another transaction
    /// that provides the same tags. (e.g. same (sender, nonce)).
    Usurped(Hash),
    /// Transaction has been dropped from the pool because of the limit.
    Dropped,
    /// Transaction is no longer valid in the current state.
    Invalid,
}

/// ReadProof struct returned by the RPC
///
/// # Note
///
/// This is copied from `sc-rpc-api` to avoid a dependency on that crate. Therefore it
/// must be kept compatible with that type from the target substrate version.
#[derive(Debug, PartialEq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ReadProof<Hash> {
    /// Block hash used to generate the proof
    pub at: Hash,
    /// A proof used to prove that storage entries are included in the storage trie
    pub proof: Vec<Bytes>,
}

/// Client for substrate rpc interfaces
pub struct Rpc<T: Config> {
    /// Rpc client for sending requests.
    pub client: Arc<RpcClient>,
    marker: PhantomData<T>,
    accept_weak_inclusion: bool,
}

impl<T: Config> Clone for Rpc<T> {
    fn clone(&self) -> Self {
        Self {
            client: self.client.clone(),
            marker: PhantomData,
            accept_weak_inclusion: self.accept_weak_inclusion,
        }
    }
}

impl<T: Config> Rpc<T> {
    /// Create a new [`Rpc`]
    pub fn new(client: RpcClient) -> Self {
        Self {
            client: Arc::new(client),
            marker: PhantomData,
            accept_weak_inclusion: false,
        }
    }

    /// Configure the Rpc to accept non-finalized blocks
    /// in `submit_and_watch_extrinsic`
    pub fn accept_weak_inclusion(&mut self) {
        self.accept_weak_inclusion = true;
    }

    /// Fetch a storage key
    pub async fn storage(
        &self,
        key: &StorageKey,
        hash: Option<T::Hash>,
    ) -> Result<Option<StorageData>, Error> {
        let params = rpc_params![key, hash];
        let data = self.client.request("state_getStorage", params).await?;
        Ok(data)
    }

    /// Returns the keys with prefix with pagination support.
    /// Up to `count` keys will be returned.
    /// If `start_key` is passed, return next keys in storage in lexicographic order.
    pub async fn storage_keys_paged(
        &self,
        prefix: Option<StorageKeyPrefix>,
        count: u32,
        start_key: Option<StorageKey>,
        hash: Option<T::Hash>,
    ) -> Result<Vec<StorageKey>, Error> {
        let prefix = prefix.map(|p| p.to_storage_key());
        let params = rpc_params![prefix, count, start_key, hash];
        let data = self.client.request("state_getKeysPaged", params).await?;
        Ok(data)
    }

    /// Query historical storage entries
    pub async fn query_storage(
        &self,
        keys: Vec<StorageKey>,
        from: T::Hash,
        to: Option<T::Hash>,
    ) -> Result<Vec<StorageChangeSet<T::Hash>>, Error> {
        let params = rpc_params![keys, from, to];
        self.client
            .request("state_queryStorage", params)
            .await
            .map_err(Into::into)
    }

    /// Query historical storage entries
    pub async fn query_storage_at(
        &self,
        keys: &[StorageKey],
        at: Option<T::Hash>,
    ) -> Result<Vec<StorageChangeSet<T::Hash>>, Error> {
        let params = rpc_params![keys, at];
        self.client
            .request("state_queryStorageAt", params)
            .await
            .map_err(Into::into)
    }

    /// Fetch the genesis hash
    pub async fn genesis_hash(&self) -> Result<T::Hash, Error> {
        let block_zero = Some(ListOrValue::Value(NumberOrHex::Number(0)));
        let params = rpc_params![block_zero];
        let list_or_value: ListOrValue<Option<T::Hash>> =
            self.client.request("chain_getBlockHash", params).await?;
        match list_or_value {
            ListOrValue::Value(genesis_hash) => {
                genesis_hash.ok_or_else(|| "Genesis hash not found".into())
            }
            ListOrValue::List(_) => Err("Expected a Value, got a List".into()),
        }
    }

    /// Fetch the metadata
    pub async fn metadata(&self) -> Result<Metadata, Error> {
        let bytes: Bytes = self
            .client
            .request("state_getMetadata", rpc_params![])
            .await?;
        let meta: RuntimeMetadataPrefixed = Decode::decode(&mut &bytes[..])?;
        let metadata: Metadata = meta.try_into()?;
        Ok(metadata)
    }

    /// Fetch system properties
    pub async fn system_properties(&self) -> Result<SystemProperties, Error> {
        Ok(self
            .client
            .request("system_properties", rpc_params![])
            .await?)
    }

    /// Get a header
    pub async fn header(
        &self,
        hash: Option<T::Hash>,
    ) -> Result<Option<T::Header>, Error> {
        let params = rpc_params![hash];
        let header = self.client.request("chain_getHeader", params).await?;
        Ok(header)
    }

    /// Get a block hash, returns hash of latest block by default
    pub async fn block_hash(
        &self,
        block_number: Option<BlockNumber>,
    ) -> Result<Option<T::Hash>, Error> {
        let block_number = block_number.map(ListOrValue::Value);
        let params = rpc_params![block_number];
        let list_or_value = self.client.request("chain_getBlockHash", params).await?;
        match list_or_value {
            ListOrValue::Value(hash) => Ok(hash),
            ListOrValue::List(_) => Err("Expected a Value, got a List".into()),
        }
    }

    /// Get a block hash of the latest finalized block
    pub async fn finalized_head(&self) -> Result<T::Hash, Error> {
        let hash = self
            .client
            .request("chain_getFinalizedHead", rpc_params![])
            .await?;
        Ok(hash)
    }

    /// Get a Block
    pub async fn block(
        &self,
        hash: Option<T::Hash>,
    ) -> Result<Option<ChainBlock<T>>, Error> {
        let params = rpc_params![hash];
        let block = self.client.request("chain_getBlock", params).await?;
        Ok(block)
    }

    /// Get proof of storage entries at a specific block's state.
    pub async fn read_proof(
        &self,
        keys: Vec<StorageKey>,
        hash: Option<T::Hash>,
    ) -> Result<ReadProof<T::Hash>, Error> {
        let params = rpc_params![keys, hash];
        let proof = self.client.request("state_getReadProof", params).await?;
        Ok(proof)
    }

    /// Fetch the runtime version
    pub async fn runtime_version(
        &self,
        at: Option<T::Hash>,
    ) -> Result<RuntimeVersion, Error> {
        let params = rpc_params![at];
        let version = self
            .client
            .request("state_getRuntimeVersion", params)
            .await?;
        Ok(version)
    }

    /// Subscribe to System Events that are imported into blocks.
    ///
    /// *WARNING* these may not be included in the finalized chain, use
    /// `subscribe_finalized_events` to ensure events are finalized.
    pub async fn subscribe_events(&self) -> Result<EventStorageSubscription<T>, Error> {
        let keys = Some(vec![StorageKey::from(SystemEvents::new())]);
        let params = rpc_params![keys];

        let subscription = self
            .client
            .subscribe("state_subscribeStorage", params, "state_unsubscribeStorage")
            .await?;
        Ok(EventStorageSubscription::Imported(subscription))
    }

    /// Subscribe to finalized events.
    pub async fn subscribe_finalized_events(
        &self,
    ) -> Result<EventStorageSubscription<T>, Error> {
        Ok(EventStorageSubscription::Finalized(
            FinalizedEventStorageSubscription::new(
                self.clone(),
                self.subscribe_finalized_blocks().await?,
            ),
        ))
    }

    /// Subscribe to blocks.
    pub async fn subscribe_blocks(&self) -> Result<Subscription<T::Header>, Error> {
        let subscription = self
            .client
            .subscribe(
                "chain_subscribeNewHeads",
                rpc_params![],
                "chain_unsubscribeNewHeads",
            )
            .await?;

        Ok(subscription)
    }

    /// Subscribe to finalized blocks.
    pub async fn subscribe_finalized_blocks(
        &self,
    ) -> Result<Subscription<T::Header>, Error> {
        let subscription = self
            .client
            .subscribe(
                "chain_subscribeFinalizedHeads",
                rpc_params![],
                "chain_unsubscribeFinalizedHeads",
            )
            .await?;
        Ok(subscription)
    }

    /// Create and submit an extrinsic and return corresponding Hash if successful
    pub async fn submit_extrinsic<E: Encode>(
        &self,
        extrinsic: E,
    ) -> Result<T::Hash, Error> {
        let bytes: Bytes = extrinsic.encode().into();
        let params = rpc_params![bytes];
        let xt_hash = self
            .client
            .request("author_submitExtrinsic", params)
            .await?;
        Ok(xt_hash)
    }

    /// Create and submit an extrinsic and return a subscription to the events triggered.
    pub async fn watch_extrinsic<E: Encode>(
        &self,
        extrinsic: E,
    ) -> Result<Subscription<TransactionStatus<T::Hash, T::Hash>>, Error> {
        let bytes: Bytes = extrinsic.encode().into();
        let params = rpc_params![bytes];
        let subscription = self
            .client
            .subscribe(
                "author_submitAndWatchExtrinsic",
                params,
                "author_unwatchExtrinsic",
            )
            .await?;
        Ok(subscription)
    }

    /// Create and submit an extrinsic and return corresponding Event if successful
    pub async fn submit_and_watch_extrinsic<'a, E: Encode + 'static>(
        &self,
        extrinsic: E,
        decoder: &'a EventsDecoder<T>,
    ) -> Result<ExtrinsicSuccess<T>, Error> {
        let ext_hash = T::Hashing::hash_of(&extrinsic);
        log::info!("Submitting Extrinsic `{:?}`", ext_hash);

        let events_sub = if self.accept_weak_inclusion {
            self.subscribe_events().await
        } else {
            self.subscribe_finalized_events().await
        }?;
        let mut xt_sub = self.watch_extrinsic(extrinsic).await?;

        while let Ok(Some(status)) = xt_sub.next().await {
            log::info!("Received status {:?}", status);
            match status {
                // ignore in progress extrinsic for now
                TransactionStatus::Future
                | TransactionStatus::Ready
                | TransactionStatus::Broadcast(_)
                | TransactionStatus::Retracted(_) => continue,
                TransactionStatus::InBlock(block_hash) => {
                    if self.accept_weak_inclusion {
                        return self
                            .process_block(events_sub, decoder, block_hash, ext_hash)
                            .await
                    }
                    continue
                }
                TransactionStatus::Invalid => return Err("Extrinsic Invalid".into()),
                TransactionStatus::Usurped(_) => return Err("Extrinsic Usurped".into()),
                TransactionStatus::Dropped => return Err("Extrinsic Dropped".into()),
                TransactionStatus::Finalized(block_hash) => {
                    // read finalized blocks by default
                    return self
                        .process_block(events_sub, decoder, block_hash, ext_hash)
                        .await
                }
                TransactionStatus::FinalityTimeout(_) => {
                    return Err("Extrinsic FinalityTimeout".into())
                }
            }
        }
        Err(RpcError::Custom("RPC subscription dropped".into()).into())
    }

    async fn process_block(
        &self,
        events_sub: EventStorageSubscription<T>,
        decoder: &EventsDecoder<T>,
        block_hash: T::Hash,
        ext_hash: T::Hash,
    ) -> Result<ExtrinsicSuccess<T>, Error> {
        log::info!("Fetching block {:?}", block_hash);
        if let Some(signed_block) = self.block(Some(block_hash)).await? {
            log::info!(
                "Found block {:?}, with {} extrinsics",
                block_hash,
                signed_block.block.extrinsics.len()
            );
            let ext_index = signed_block
                .block
                .extrinsics
                .iter()
                .position(|ext| {
                    let hash = T::Hashing::hash_of(ext);
                    hash == ext_hash
                })
                .ok_or_else(|| {
                    Error::Other(format!(
                        "Failed to find Extrinsic with hash {:?}",
                        ext_hash,
                    ))
                })?;
            let mut sub = EventSubscription::new(events_sub, decoder);
            sub.filter_extrinsic(block_hash, ext_index);
            let mut events = vec![];
            while let Some(event) = sub.next().await {
                events.push(event?);
            }
            Ok(ExtrinsicSuccess {
                block: block_hash,
                extrinsic: ext_hash,
                events,
            })
        } else {
            Err(format!("Failed to find block {:?}", block_hash).into())
        }
    }

    /// Insert a key into the keystore.
    pub async fn insert_key(
        &self,
        key_type: String,
        suri: String,
        public: Bytes,
    ) -> Result<(), Error> {
        let params = rpc_params![key_type, suri, public];
        self.client.request("author_insertKey", params).await?;
        Ok(())
    }

    /// Generate new session keys and returns the corresponding public keys.
    pub async fn rotate_keys(&self) -> Result<Bytes, Error> {
        Ok(self
            .client
            .request("author_rotateKeys", rpc_params![])
            .await?)
    }

    /// Checks if the keystore has private keys for the given session public keys.
    ///
    /// `session_keys` is the SCALE encoded session keys object from the runtime.
    ///
    /// Returns `true` iff all private keys could be found.
    pub async fn has_session_keys(&self, session_keys: Bytes) -> Result<bool, Error> {
        let params = rpc_params![session_keys];
        Ok(self.client.request("author_hasSessionKeys", params).await?)
    }

    /// Checks if the keystore has private keys for the given public key and key type.
    ///
    /// Returns `true` if a private key could be found.
    pub async fn has_key(
        &self,
        public_key: Bytes,
        key_type: String,
    ) -> Result<bool, Error> {
        let params = rpc_params![public_key, key_type];
        Ok(self.client.request("author_hasKey", params).await?)
    }
}

/// Captures data for when an extrinsic is successfully included in a block
#[derive(Debug)]
pub struct ExtrinsicSuccess<T: Config> {
    /// Block hash.
    pub block: T::Hash,
    /// Extrinsic hash.
    pub extrinsic: T::Hash,
    /// Raw runtime events, can be decoded by the caller.
    pub events: Vec<RawEvent>,
}

impl<T: Config> ExtrinsicSuccess<T> {
    /// Find the Event for the given module/variant, with raw encoded event data.
    /// Returns `None` if the Event is not found.
    pub fn find_event_raw(&self, module: &str, variant: &str) -> Option<&RawEvent> {
        self.events
            .iter()
            .find(|raw| raw.pallet == module && raw.variant == variant)
    }

    /// Find the Event for the given module/variant, attempting to decode the event data.
    /// Returns `None` if the Event is not found.
    /// Returns `Err` if the data fails to decode into the supplied type.
    pub fn find_event<E: Event>(&self) -> Result<Option<E>, CodecError> {
        if let Some(event) = self.find_event_raw(E::PALLET, E::EVENT) {
            Ok(Some(E::decode(&mut &event.data[..])?))
        } else {
            Ok(None)
        }
    }
}

/// Example to check that `From<(Sender, Receiver) for RpcClient` works.
pub async fn build_ws_client_default(url: &str) -> Result<RpcClient, RpcError> {
    let client = ws_transport(url).await.into();
    Ok(client)
}

/// Build WS RPC client from URL
pub async fn build_ws_client(url: &str) -> Result<RpcClient, RpcError> {
    let (sender, receiver) = ws_transport(url).await;
    Ok(RpcClientBuilder::default()
        .max_notifs_per_subscription(4096)
        .build(sender, receiver))
}

async fn ws_transport(url: &str) -> (WsSender, WsReceiver) {
    // fix unwraps because I'm lazy.
    let url: Uri = url.parse().unwrap();
    WsTransportClientBuilder::default()
        .build(url)
        .await
        .unwrap()
}