use crate::compat::rand::{distributions::Standard, prelude::Distribution, random, Rng};
use crate::compat::{
    string::{String, ToString},
    vec::Vec,
};
use crate::{AddressParseError, AddressParseErrorKind, Result, TransportType, LOCAL};
use core::fmt::{self, Debug, Display};
use core::ops::Deref;
use core::str::from_utf8;
use minicbor::{Decode, Encode};
use serde::{Deserialize, Serialize};

/// A generic address type.
///
/// The address type is parsed by routers to determine the next local
/// hop in the router chain to resolve a route to a remote connection.
///
/// ## Parsing addresses
///
/// While addresses are concrete types, creating them from strings is
/// possible for ergonomic reasons.
///
/// When parsing an address from a string, the first `#` symbol is
/// used to separate the transport type from the rest of the address.
/// If no `#` symbol is found, the address is assumed to be of `transport =
/// 0`, the Local Worker transport type.
///
/// For example:
/// * `"0#alice"` represents a local worker with the address: `alice`.
/// * `"1#carol"` represents a remote worker with the address `carol`, reachable over TCP transport.
///
#[derive(Serialize, Deserialize, Decode, Encode, Clone, Hash, Ord, PartialOrd, Eq, PartialEq)]
#[rustfmt::skip]
#[cbor(map)] // TODO: Switch to an array eventually
pub struct Address {
    #[n(1)] tt: TransportType,
    // It's binary but in most cases we assume it to be an UTF-8 string
    #[n(2)] inner: Vec<u8>,
}

impl Address {
    /// Creates a new address from separate transport type and data parts.
    ///
    /// # Examples
    ///
    /// ```
    /// # use ockam_core::{Address, TransportType};
    /// # pub const TCP: TransportType = TransportType::new(1);
    /// // create a new remote worker address from a transport type and data
    /// let tcp_worker: Address = Address::new(TCP, "carol");
    /// ```
    pub fn new<S: Into<String>>(tt: TransportType, data: S) -> Self {
        Self {
            tt,
            inner: data.into().as_bytes().to_vec(),
        }
    }

    /// Parses an address from a string.
    ///
    /// # Panics
    ///
    /// This function will panic if passed an invalid address string.
    ///
    /// # Examples
    ///
    /// ```
    /// # use ockam_core::Address;
    /// // parse a local worker address
    /// let local_worker: Address = Address::from_string("alice");
    ///
    /// // parse a remote worker address reachable over tcp transport
    /// let tcp_worker: Address = Address::from_string("1#carol");
    /// ```
    pub fn from_string<S: Into<String>>(s: S) -> Self {
        match s.into().parse::<Address>() {
            Ok(a) => a,
            Err(e) => {
                panic!("Invalid address string {}", e)
            }
        }
    }

    /// Get the string value of this address without the address type
    #[doc(hidden)]
    pub fn without_type(&self) -> &str {
        from_utf8(&self.inner).unwrap_or("<unprintable>")
    }

    /// Generate a random address with the given transport type.
    ///
    /// # Examples
    ///
    /// ```
    /// # use ockam_core::{Address, LOCAL};
    /// // generate a random local address
    /// let local_worker: Address = Address::random(LOCAL);
    /// ```
    pub fn random(tt: TransportType) -> Self {
        Self { tt, ..random() }
    }

    /// Generate a random address with transport type [`LOCAL`].
    pub fn random_local() -> Self {
        Self {
            tt: LOCAL,
            ..random()
        }
    }

    // TODO: Replace with macro to take less space when "debugger" feature is disabled?
    /// Generate a random address with a debug tag and transport type [`LOCAL`].
    pub fn random_tagged(_tag: &str) -> Self {
        #[cfg(feature = "debugger")]
        {
            use core::sync::atomic::{AtomicU32, Ordering};
            static COUNTER: AtomicU32 = AtomicU32::new(0);
            let address = format!("{}_{}", _tag, COUNTER.fetch_add(1, Ordering::Relaxed),).into();
            let address = Self {
                tt: LOCAL,
                ..address
            };
            tracing::trace!("random_tagged => {}", address);
            address
        }

        #[cfg(not(feature = "debugger"))]
        Self::random_local()
    }

    /// Get transport type of this address.
    pub fn transport_type(&self) -> TransportType {
        self.tt
    }

    /// Get address portion of this address
    pub fn address(&self) -> &str {
        from_utf8(self.inner.as_slice()).unwrap_or("Invalid UTF-8")
    }

    /// Check if address is local
    pub fn is_local(&self) -> bool {
        self.tt == LOCAL
    }
}

impl core::str::FromStr for Address {
    type Err = AddressParseError;
    /// Parse an address from a string.
    ///
    /// See type documentation for more detail.
    fn from_str(s: &str) -> Result<Address, Self::Err> {
        let buf: String = s.into();
        let mut vec: Vec<_> = buf.split('#').collect();

        // If after the split we only have one element, there was no
        // `#` separator, so the type needs to be implicitly `= 0`
        if vec.len() == 1 {
            Ok(Address {
                tt: LOCAL,
                inner: vec.remove(0).as_bytes().to_vec(),
            })
        }
        // If after the split we have 2 elements, we extract the type
        // value from the string, and use the rest as the address
        else if vec.len() == 2 {
            match str::parse(vec.remove(0)) {
                Ok(tt) => Ok(Address {
                    tt: TransportType::new(tt),
                    inner: vec.remove(0).as_bytes().to_vec(),
                }),
                Err(e) => Err(AddressParseError::new(AddressParseErrorKind::InvalidType(
                    e,
                ))),
            }
        } else {
            Err(AddressParseError::new(AddressParseErrorKind::MultipleSep))
        }
    }
}

impl Display for Address {
    fn fmt<'a>(&'a self, f: &mut fmt::Formatter) -> fmt::Result {
        let inner: &'a str = from_utf8(self.inner.as_slice()).unwrap_or("Invalid UTF-8");
        write!(f, "{}#{}", self.tt, inner)
    }
}

impl Debug for Address {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        <Self as Display>::fmt(self, f)
    }
}

impl Deref for Address {
    type Target = Vec<u8>;
    fn deref(&self) -> &Self::Target {
        &self.inner
    }
}

impl From<String> for Address {
    fn from(s: String) -> Self {
        Self::from_string(s)
    }
}

impl From<&String> for Address {
    fn from(s: &String) -> Self {
        Self::from_string(s.as_str())
    }
}

impl<'a> From<&'a str> for Address {
    fn from(s: &'a str) -> Self {
        Self::from_string(s)
    }
}

impl From<Vec<u8>> for Address {
    fn from(data: Vec<u8>) -> Self {
        Self {
            tt: LOCAL,
            inner: data,
        }
    }
}

impl From<(TransportType, Vec<u8>)> for Address {
    fn from((tt, data): (TransportType, Vec<u8>)) -> Self {
        Self { tt, inner: data }
    }
}

impl<'a> From<(TransportType, &'a str)> for Address {
    fn from((tt, data): (TransportType, &'a str)) -> Self {
        Self {
            tt,
            inner: data.as_bytes().to_vec(),
        }
    }
}

impl<'a> From<(TransportType, &'a String)> for Address {
    fn from((tt, inner): (TransportType, &'a String)) -> Self {
        Self::from((tt, inner.as_str()))
    }
}

impl From<(TransportType, String)> for Address {
    fn from((transport, data): (TransportType, String)) -> Self {
        Self::from((transport, data.as_str()))
    }
}

impl<'a> From<&'a [u8]> for Address {
    fn from(data: &'a [u8]) -> Self {
        Self {
            tt: LOCAL,
            inner: data.to_vec(),
        }
    }
}

impl<'a> From<&'a [&u8]> for Address {
    fn from(data: &'a [&u8]) -> Self {
        Self {
            tt: LOCAL,
            inner: data.iter().map(|x| **x).collect(),
        }
    }
}

impl From<Address> for String {
    fn from(address: Address) -> Self {
        address.to_string()
    }
}

impl Distribution<Address> for Standard {
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Address {
        let address: [u8; 16] = rng.gen();
        hex::encode(address).as_bytes().into()
    }
}

impl Address {
    pub(crate) fn manual_encode(&self, buffer: &mut Vec<u8>) {
        buffer.push(self.tt.into());
        crate::bare::write_slice(buffer, &self.inner);
    }

    pub(crate) fn encoded_size(&self) -> usize {
        1 + crate::bare::size_of_slice(&self.inner)
    }
    pub(crate) fn manually_decode(slice: &[u8], index: &mut usize) -> Option<Address> {
        if slice.len() - *index < 2 {
            return None;
        }
        let tt = slice[*index];
        *index += 1;

        let inner = crate::bare::read_slice(slice, index)?;
        Some(Address {
            tt: TransportType::new(tt),
            inner: inner.to_vec(),
        })
    }
}

#[cfg(test)]
mod test {
    use super::*;
    use crate::Encodable;

    #[test]
    fn encode_and_manually_decode_address() {
        let super_long_string = "a".repeat(250);
        let address = Address::from_string("42#".to_string() + &super_long_string);
        assert_eq!(address.address(), super_long_string.as_str());

        let encoded = address.clone().encode().unwrap();
        let decoded = Address::manually_decode(&encoded, &mut 0).unwrap();
        assert_eq!(address, decoded);
    }

    #[test]
    fn parse_addr_simple() {
        let addr = Address::from_string("local_friend");
        assert_eq!(
            addr,
            Address {
                tt: LOCAL,
                inner: "local_friend".as_bytes().to_vec(),
            }
        );
    }

    #[test]
    fn parse_addr_with_type() {
        let addr = Address::from_string("1#remote_friend");
        assert_eq!(
            addr,
            Address {
                tt: TransportType::new(1),
                inner: "remote_friend".as_bytes().to_vec(),
            }
        );
    }

    #[test]
    #[should_panic(expected = "Failed to parse address type:")]
    fn parse_addr_invalid() {
        Address::from_string("#,my_friend");
    }

    #[test]
    #[should_panic(expected = "Invalid address string:")]
    fn parse_addr_invalid_multiple_separators() {
        let _ = Address::from_string("1#invalid#");
    }
}