use std::{fmt, io, net};

use crate::crypto;
use crate::git;
use crate::identity::Id;
use crate::service::filter::Filter;
use crate::service::{NodeId, Timestamp, PROTOCOL_VERSION};
use crate::storage::refs::Refs;
use crate::wire;

/// Message envelope. All messages sent over the network are wrapped in this type.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Envelope {
    /// Network magic constant. Used to differentiate networks.
    pub magic: u32,
    /// The message payload.
    pub msg: Message,
}

/// Advertized node feature. Signals what services the node supports.
pub type NodeFeatures = [u8; 32];

#[derive(Debug, Clone, PartialEq, Eq)]
// TODO: We should check the length and charset when deserializing.
pub struct Hostname(String);

/// Peer public protocol address.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum Address {
    Ipv4 {
        ip: net::Ipv4Addr,
        port: u16,
    },
    Ipv6 {
        ip: net::Ipv6Addr,
        port: u16,
    },
    Hostname {
        host: Hostname,
        port: u16,
    },
    /// Tor V3 onion address.
    Onion {
        key: crypto::PublicKey,
        port: u16,
        checksum: u16,
        version: u8,
    },
}

impl From<net::SocketAddr> for Address {
    fn from(other: net::SocketAddr) -> Self {
        let port = other.port();

        match other.ip() {
            net::IpAddr::V4(ip) => Self::Ipv4 { ip, port },
            net::IpAddr::V6(ip) => Self::Ipv6 { ip, port },
        }
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Subscribe {
    /// Subscribe to events matching this filter.
    pub filter: Filter,
    /// Request messages since this time.
    pub since: Timestamp,
    /// Request messages until this time.
    pub until: Timestamp,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct NodeAnnouncement {
    /// Advertized features.
    pub features: NodeFeatures,
    /// Monotonic timestamp.
    pub timestamp: Timestamp,
    /// Non-unique alias. Must be valid UTF-8.
    pub alias: [u8; 32],
    /// Announced addresses.
    pub addresses: Vec<Address>,
}

impl NodeAnnouncement {
    /// Verify a signature on this message.
    pub fn verify(&self, signer: &NodeId, signature: &crypto::Signature) -> bool {
        let msg = wire::serialize(self);
        signer.verify(signature, &msg).is_ok()
    }
}

impl wire::Encode for NodeAnnouncement {
    fn encode<W: io::Write + ?Sized>(&self, writer: &mut W) -> Result<usize, io::Error> {
        let mut n = 0;

        n += self.features.encode(writer)?;
        n += self.timestamp.encode(writer)?;
        n += self.alias.encode(writer)?;
        n += self.addresses.as_slice().encode(writer)?;

        Ok(n)
    }
}

impl wire::Decode for NodeAnnouncement {
    fn decode<R: std::io::Read + ?Sized>(reader: &mut R) -> Result<Self, wire::Error> {
        let features = NodeFeatures::decode(reader)?;
        let timestamp = Timestamp::decode(reader)?;
        let alias = wire::Decode::decode(reader)?;
        let addresses = Vec::<Address>::decode(reader)?;

        Ok(Self {
            features,
            timestamp,
            alias,
            addresses,
        })
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct RefsAnnouncement {
    /// Repository identifier.
    pub id: Id,
    /// Updated refs.
    pub refs: Refs,
}

impl RefsAnnouncement {
    /// Verify a signature on this message.
    pub fn verify(&self, signer: &NodeId, signature: &crypto::Signature) -> bool {
        let msg = wire::serialize(self);
        signer.verify(signature, &msg).is_ok()
    }

    /// Sign this announcement.
    pub fn sign<S: crypto::Signer>(&self, signer: S) -> crypto::Signature {
        let msg = wire::serialize(self);
        signer.sign(&msg)
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct InventoryAnnouncement {
    pub inventory: Vec<Id>,
    pub timestamp: Timestamp,
}

impl InventoryAnnouncement {
    /// Verify a signature on this message.
    pub fn verify(&self, signer: NodeId, signature: &crypto::Signature) -> bool {
        let msg = wire::serialize(self);
        signer.verify(signature, &msg).is_ok()
    }
}

/// Message payload.
/// These are the messages peers send to each other.
#[derive(Clone, PartialEq, Eq)]
pub enum Message {
    /// The first message sent to a peer after connection.
    Initialize {
        // TODO: This is currently untrusted.
        id: NodeId,
        timestamp: Timestamp,
        version: u32,
        addrs: Vec<Address>,
        git: git::Url,
    },

    /// Subscribe to gossip messages matching the filter and time range.
    /// timestamp.
    Subscribe(Subscribe),

    /// Node announcing its inventory to the network.
    /// This should be the whole inventory every time.
    InventoryAnnouncement {
        /// Node identifier.
        node: NodeId,
        /// Unsigned node inventory.
        message: InventoryAnnouncement,
        /// Signature over the announcement.
        signature: crypto::Signature,
    },

    /// Node announcing itself to the network.
    NodeAnnouncement {
        /// Node identifier.
        node: NodeId,
        /// Unsigned node announcement.
        message: NodeAnnouncement,
        /// Signature over the announcement, by the node being announced.
        signature: crypto::Signature,
    },

    /// Node announcing project refs being created or updated.
    RefsAnnouncement {
        /// Node identifier.
        node: NodeId,
        /// Unsigned refs announcement.
        message: RefsAnnouncement,
        /// Signature over the announcement, by the node that updated the refs.
        signature: crypto::Signature,
    },
}

impl Message {
    pub fn init(id: NodeId, timestamp: Timestamp, addrs: Vec<Address>, git: git::Url) -> Self {
        Self::Initialize {
            id,
            timestamp,
            version: PROTOCOL_VERSION,
            addrs,
            git,
        }
    }

    pub fn node<S: crypto::Signer>(message: NodeAnnouncement, signer: S) -> Self {
        let msg = wire::serialize(&message);
        let signature = signer.sign(&msg);
        let node = *signer.public_key();

        Self::NodeAnnouncement {
            node,
            signature,
            message,
        }
    }

    pub fn inventory<S: crypto::Signer>(message: InventoryAnnouncement, signer: S) -> Self {
        let msg = wire::serialize(&message);
        let signature = signer.sign(&msg);
        let node = *signer.public_key();

        Self::InventoryAnnouncement {
            node,
            signature,
            message,
        }
    }

    pub fn subscribe(filter: Filter, since: Timestamp, until: Timestamp) -> Self {
        Self::Subscribe(Subscribe {
            filter,
            since,
            until,
        })
    }
}

impl fmt::Debug for Message {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Initialize { id, .. } => write!(f, "Initialize({})", id),
            Self::Subscribe(Subscribe { since, until, .. }) => {
                write!(f, "Subscribe({}..{})", since, until)
            }

            Self::NodeAnnouncement { node, .. } => write!(f, "NodeAnnouncement({})", node),
            Self::InventoryAnnouncement { node, message, .. } => {
                write!(
                    f,
                    "InventoryAnnouncement({}, [{}], {})",
                    node,
                    message
                        .inventory
                        .iter()
                        .map(|i| i.to_string())
                        .collect::<Vec<String>>()
                        .join(", "),
                    message.timestamp
                )
            }
            Self::RefsAnnouncement { node, message, .. } => {
                write!(
                    f,
                    "RefsAnnouncement({}, {}, {:?})",
                    node, message.id, message.refs
                )
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use quickcheck_macros::quickcheck;

    use crate::crypto::Signer;
    use crate::test::crypto::MockSigner;

    #[quickcheck]
    fn prop_refs_announcement_signing(id: Id, refs: Refs) {
        let signer = MockSigner::new(&mut fastrand::Rng::new());
        let message = RefsAnnouncement { id, refs };
        let signature = message.sign(&signer);

        assert!(message.verify(signer.public_key(), &signature));
    }
}