// Copyright 2019-2024 ChainSafe Systems
// SPDX-License-Identifier: Apache-2.0, MIT

use std::{
    fmt::Display,
    ops::{Deref, DerefMut},
    str::FromStr,
};

use data_encoding::Encoding;
use data_encoding_macro::new_encoding;
use fvm_shared2::address::Address as Address_v2;
use fvm_shared3::address::Address as Address_v3;
use fvm_shared4::address::Address as Address_v4;
use fvm_shared4::address::Address as Address_latest;
pub use fvm_shared4::address::{Error, Network, Payload, Protocol, PAYLOAD_HASH_LEN};
use integer_encoding::VarInt;
use num_traits::FromPrimitive;
use once_cell::sync::Lazy;
use serde::{Deserialize, Serialize};
use std::sync::atomic::{AtomicU8, Ordering};

/// Zero address used to avoid allowing it to be used for verification.
/// This is intentionally disallowed because it is an edge case with Filecoin's BLS
/// signature verification.
// Copied from ref-fvm due to a bug in their definition.
pub static ZERO_ADDRESS: Lazy<Address> = Lazy::new(|| {
    Network::Mainnet
        .parse_address(
            "f3yaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaby2smx7a",
        )
        .unwrap()
        .into()
});

static GLOBAL_NETWORK: AtomicU8 = AtomicU8::new(Network::Mainnet as u8);

thread_local! {
    // Thread local network identifier. Defaults to value in GLOBAL_NETWORK.
    static LOCAL_NETWORK: AtomicU8 = AtomicU8::new(GLOBAL_NETWORK.load(Ordering::Acquire));
}

/// For user safety, Filecoin has different addresses for its mainnet and test networks: Mainnet
/// and testnet addresses are prefixed with `f` and `t`, respectively.
///
/// We use a thread-local variable to determine which format to use when parsing and pretty-printing
/// addresses. Note that the [`Address`] structure will parse both forms, while [`StrictAddress`]
/// will only succeed if the address has the correct network prefix.
///
/// The thread-local network variable is initialized to the value of the global network. This global
/// network variable is set once when Forest has figured out which network it is using.
pub struct CurrentNetwork();
impl CurrentNetwork {
    pub fn get() -> Network {
        FromPrimitive::from_u8(LOCAL_NETWORK.with(|ident| ident.load(Ordering::Acquire)))
            .unwrap_or(Network::Mainnet)
    }

    pub fn set(network: Network) {
        LOCAL_NETWORK.with(|ident| ident.store(network as u8, Ordering::Release));
    }

    pub fn set_global(network: Network) {
        GLOBAL_NETWORK.store(network as u8, Ordering::Release);
        CurrentNetwork::set(network);
    }

    #[cfg(test)]
    pub fn with<X>(network: Network, cb: impl FnOnce() -> X) -> X {
        let guard = NetworkGuard::new(network);
        let result = cb();
        drop(guard);
        result
    }

    #[cfg(test)]
    fn get_global() -> Network {
        FromPrimitive::from_u8(GLOBAL_NETWORK.load(Ordering::Acquire)).unwrap_or(Network::Mainnet)
    }
}

#[cfg(test)]
struct NetworkGuard(Network);
#[cfg(test)]
mod network_guard_impl {
    use super::*;

    impl NetworkGuard {
        pub fn new(new_network: Network) -> Self {
            let previous_network = CurrentNetwork::get();
            CurrentNetwork::set(new_network);
            NetworkGuard(previous_network)
        }
    }

    impl Drop for NetworkGuard {
        fn drop(&mut self) {
            CurrentNetwork::set(self.0);
        }
    }
}

/// A Filecoin address is an identifier that refers to an actor in the Filecoin state. All actors
/// (miner actors, the storage market actor, account actors) have an address. This address encodes
/// information about the network to which an actor belongs, the specific type of address encoding,
/// the address payload itself, and a checksum. The goal of this format is to provide a robust
/// address format that is both easy to use and resistant to errors.
///
/// Addresses are prefixed with either a mainnet tag or a testnet tag. The [`Address`] type will
/// parse both versions and discard the prefix. See also [`StrictAddress`].
///
/// For more information, see: <https://spec.filecoin.io/appendix/address/>
#[derive(
    Copy, Clone, Debug, Default, Hash, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize,
)]
#[serde(transparent)]
#[cfg_attr(test, derive(derive_quickcheck_arbitrary::Arbitrary))]
pub struct Address(Address_latest);

impl Address {
    pub const SYSTEM_ACTOR: Address = Address::new_id(0);
    pub const INIT_ACTOR: Address = Address::new_id(1);
    pub const REWARD_ACTOR: Address = Address::new_id(2);
    pub const CRON_ACTOR: Address = Address::new_id(3);
    pub const POWER_ACTOR: Address = Address::new_id(4);
    pub const MARKET_ACTOR: Address = Address::new_id(5);
    pub const VERIFIED_REGISTRY_ACTOR: Address = Address::new_id(6);
    pub const DATACAP_TOKEN_ACTOR: Address = Address::new_id(7);
    pub const ETHEREUM_ACCOUNT_MANAGER_ACTOR: Address = Address::new_id(10);
    pub const SAFT_ACTOR: Address = Address::new_id(122);
    pub const RESERVE_ACTOR: Address = Address::new_id(90);
    pub const CHAOS_ACTOR: Address = Address::new_id(98);
    pub const BURNT_FUNDS_ACTOR: Address = Address::new_id(99);

    pub const fn new_id(id: u64) -> Self {
        Address(Address_latest::new_id(id))
    }

    pub fn new_actor(data: &[u8]) -> Self {
        Address(Address_latest::new_actor(data))
    }

    pub fn new_bls(pubkey: &[u8]) -> Result<Self, Error> {
        Address_latest::new_bls(pubkey).map(Address::from)
    }

    pub fn new_secp256k1(pubkey: &[u8]) -> Result<Self, Error> {
        Address_latest::new_secp256k1(pubkey).map(Address::from)
    }

    pub fn new_delegated(ns: u64, subaddress: &[u8]) -> Result<Self, Error> {
        Ok(Self(Address_latest::new_delegated(ns, subaddress)?))
    }

    pub fn protocol(&self) -> Protocol {
        self.0.protocol()
    }

    pub fn into_payload(self) -> Payload {
        self.0.into_payload()
    }

    pub fn from_bytes(bz: &[u8]) -> Result<Self, Error> {
        Address_latest::from_bytes(bz).map(Address)
    }
}

impl FromStr for Address {
    type Err = <Address_latest as FromStr>::Err;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        Network::Testnet
            .parse_address(s)
            .or_else(|_| Network::Mainnet.parse_address(s))
            .map(Address::from)
    }
}

/// defines the encoder for `base32` encoding with the provided string with no padding
const ADDRESS_ENCODER: Encoding = new_encoding! {
    symbols: "abcdefghijklmnopqrstuvwxyz234567",
    padding: None,
};

impl Display for Address {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        use fvm_shared4::address::CHECKSUM_HASH_LEN;
        const MAINNET_PREFIX: &str = "f";
        const TESTNET_PREFIX: &str = "t";

        let protocol = self.protocol();

        let prefix = if matches!(CurrentNetwork::get(), Network::Mainnet) {
            MAINNET_PREFIX
        } else {
            TESTNET_PREFIX
        };

        // write `fP` where P is the protocol number.
        write!(f, "{}{}", prefix, protocol)?;

        fn write_payload(
            f: &mut std::fmt::Formatter<'_>,
            protocol: Protocol,
            prefix: Option<&[u8]>,
            data: &[u8],
        ) -> std::fmt::Result {
            let mut hasher = blake2b_simd::Params::new()
                .hash_length(CHECKSUM_HASH_LEN)
                .to_state();
            hasher.update(&[protocol as u8]);
            if let Some(prefix) = prefix {
                hasher.update(prefix);
            }
            hasher.update(data);

            let mut buf = Vec::with_capacity(data.len() + CHECKSUM_HASH_LEN);
            buf.extend(data);
            buf.extend(hasher.finalize().as_bytes());

            f.write_str(&ADDRESS_ENCODER.encode(&buf))
        }

        match self.payload() {
            Payload::ID(id) => write!(f, "{}", id),
            Payload::Secp256k1(data) | Payload::Actor(data) => {
                write_payload(f, protocol, None, data)
            }
            Payload::BLS(data) => write_payload(f, protocol, None, data),
            Payload::Delegated(addr) => {
                write!(f, "{}f", addr.namespace())?;
                write_payload(
                    f,
                    protocol,
                    Some(&addr.namespace().encode_var_vec()),
                    addr.subaddress(),
                )
            }
        }
    }
}

impl Deref for Address {
    type Target = Address_latest;
    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

impl DerefMut for Address {
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.0
    }
}

/// A Filecoin address is an identifier that refers to an actor in the Filecoin state. All actors
/// (miner actors, the storage market actor, account actors) have an address. This address encodes
/// information about the network to which an actor belongs, the specific type of address encoding,
/// the address payload itself, and a checksum. The goal of this format is to provide a robust
/// address format that is both easy to use and resistant to errors.
///
/// Addresses are prefixed with either a mainnet tag or a testnet tag. The [`StrictAddress`] type
/// will fail to parse addresses unless they have the correct tag indicated by [`CurrentNetwork`].
///
/// For more information, see: <https://spec.filecoin.io/appendix/address/>
#[derive(
    Copy,
    Clone,
    Debug,
    Hash,
    PartialEq,
    Eq,
    PartialOrd,
    Ord,
    Serialize,
    Deserialize,
    displaydoc::Display,
)]
#[serde(transparent)]
#[displaydoc("{0}")]
pub struct StrictAddress(pub Address);

impl FromStr for StrictAddress {
    type Err = <Address_latest as FromStr>::Err;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let fvm_addr = CurrentNetwork::get().parse_address(s)?;
        Ok(StrictAddress(fvm_addr.into()))
    }
}

// Conversion implementations.
// Note for `::from_bytes`. Both FVM2 and FVM3 addresses values as bytes must be
// identical and able to do a conversion, otherwise it is a logic error and
// Forest should not continue so there is no point in `TryFrom`.

impl From<Address> for StrictAddress {
    fn from(other: Address) -> Self {
        StrictAddress(other)
    }
}

impl From<StrictAddress> for Address {
    fn from(other: StrictAddress) -> Self {
        other.0
    }
}

impl From<StrictAddress> for Address_v3 {
    fn from(other: StrictAddress) -> Self {
        other.0.into()
    }
}

impl From<StrictAddress> for Address_v4 {
    fn from(other: StrictAddress) -> Self {
        other.0.into()
    }
}

impl From<Address_v4> for Address {
    fn from(other: Address_v4) -> Self {
        Address(other)
    }
}

impl From<&Address_v4> for Address {
    fn from(other: &Address_v4) -> Self {
        Address(*other)
    }
}

impl From<&Address_v3> for Address {
    fn from(other: &Address_v3) -> Self {
        Address::from(
            Address_v4::from_bytes(&other.to_bytes()).unwrap_or_else(|e| {
                panic!("Couldn't convert from FVM3 address to FVM4 address: {other}, {e}")
            }),
        )
    }
}

impl From<Address_v3> for Address {
    fn from(other: Address_v3) -> Self {
        (&other).into()
    }
}

impl From<&Address_v2> for Address {
    fn from(other: &Address_v2) -> Self {
        Address::from(
            Address_v4::from_bytes(&other.to_bytes()).unwrap_or_else(|e| {
                panic!("Couldn't convert from FVM2 address to FVM4 address: {other}, {e}")
            }),
        )
    }
}

impl From<Address_v2> for Address {
    fn from(other: Address_v2) -> Self {
        (&other).into()
    }
}

impl From<Address> for Address_v4 {
    fn from(other: Address) -> Address_v4 {
        other.0
    }
}

impl From<&Address> for Address_v4 {
    fn from(other: &Address) -> Self {
        other.0
    }
}

impl From<&Address> for Address_v3 {
    fn from(other: &Address) -> Self {
        Address_v3::from_bytes(&other.to_bytes()).unwrap_or_else(|e| {
            panic!("Couldn't convert from FVM4 address to FVM3 address: {other}, {e}")
        })
    }
}

impl From<Address> for Address_v3 {
    fn from(other: Address) -> Self {
        (&other).into()
    }
}

impl From<&Address> for Address_v2 {
    fn from(other: &Address) -> Self {
        Address_v2::from_bytes(&other.to_bytes()).unwrap_or_else(|e| {
            panic!("Couldn't convert from FVM4 address to FVM2 address: {other}, {e}")
        })
    }
}

impl From<Address> for Address_v2 {
    fn from(other: Address) -> Address_v2 {
        (&other).into()
    }
}

#[cfg(test)]
fn flip_network(input: Network) -> Network {
    match input {
        Network::Mainnet => Network::Testnet,
        Network::Testnet => Network::Mainnet,
    }
}

#[test]
fn relaxed_address_parsing() {
    assert!(Address::from_str("t01234").is_ok());
    assert!(Address::from_str("f01234").is_ok());
}

#[test]
fn strict_address_parsing() {
    CurrentNetwork::with(Network::Mainnet, || {
        assert!(StrictAddress::from_str("f01234").is_ok());
        assert!(StrictAddress::from_str("t01234").is_err());
    });
    CurrentNetwork::with(Network::Testnet, || {
        assert!(StrictAddress::from_str("f01234").is_err());
        assert!(StrictAddress::from_str("t01234").is_ok());
    });
}

#[test]
fn set_with_network() {
    let outer_network = CurrentNetwork::get();
    let inner_network = flip_network(outer_network);
    CurrentNetwork::with(inner_network, || {
        assert_eq!(CurrentNetwork::get(), inner_network);
    });
    assert_eq!(outer_network, CurrentNetwork::get());
}

#[test]
fn unwind_current_network_on_panic() {
    let outer_network = CurrentNetwork::get();
    let inner_network = flip_network(outer_network);
    assert!(std::panic::catch_unwind(|| {
        CurrentNetwork::with(inner_network, || {
            panic!("unwinding stack");
        })
    })
    .is_err());
    let new_outer_network = CurrentNetwork::get();
    assert_eq!(outer_network, new_outer_network);
}

#[test]
fn inherit_global_network() {
    let outer_network = CurrentNetwork::get_global();
    let inner_network = flip_network(outer_network);
    CurrentNetwork::set_global(inner_network);
    std::thread::spawn(move || {
        assert_eq!(CurrentNetwork::get(), inner_network);
    })
    .join()
    .unwrap();
    CurrentNetwork::set_global(outer_network);
}