//! Support for shell expansion in [`general::SocketAddr`].

use crate::{CfgPath, CfgPathError};

use serde::{Deserialize, Serialize};

use std::{io, net, path::PathBuf, str::FromStr, sync::Arc};

use tor_general_addr::{general, unix};

/// A variation of [`general::SocketAddr`] that allows shell expansions in Unix paths.

///

/// The string representation for these addresses is the same as for [`general::SocketAddr`];

/// but the shell expansion syntax is the same as for [`CfgPath`].

///

/// Shell expansion is only supported _within_ paths: Even if the user has set `${HOME}`

/// to `127.0.0.1`, the address `inet:${HOME}:9999` is a syntax error.

///

/// In addition to the "inet:" and "unix:" schemas supported by `general::SocketAddr`,

/// This type also supports a "unix-literal" schema,

/// to indicate that no shell expansion should occur.

#[derive(Clone, Debug, Serialize, Deserialize, Eq, PartialEq)]

#[serde(into = "CfgAddrSerde", try_from = "CfgAddrSerde")]

pub struct CfgAddr(AddrInner);

/// Implementation type for `CfgAddr`.

///

/// This is a separate type because we can't define an public enum with private members.

#[derive(Clone, Debug, Eq, PartialEq)]

enum AddrInner {

    /// An internet address (which will not be expanded).

    Inet(net::SocketAddr),

    /// A unix domain socket path.

    Unix(CfgPath),

}

impl CfgAddr {

    /// Create a new [`CfgAddr`] that will produce an `AF_UNIX` address

    /// corresponding to the provided path.

    ///

    /// Note that not all platforms support AF\_UNIX addresses;

    /// on Windows, notably, expanding this path will produce an error.

    /// Return the [`general::SocketAddr`] produced by expanding this `CfgAddr`.

    #[cfg_attr(not(unix), expect(unused_variables))]

                // Easy case: This is an inet address.

            }

                #[cfg(not(unix))]

                {

                    // Give this error early on non-unix platforms, so that we don't confuse the user.

                    Err(unix::NoAfUnixSocketSupport::default().into())

                }

                #[cfg(unix)]

                {

                }

            }

        }

    /// Return true if this address is of a type to which variable substitutions will apply.

    ///

    /// Currently, substitutions apply to AF\_UNIX addresses but not to Inet addresses.

        }

    /// Helper: if possible, format this address as a String.

    ///

    /// (This will return Err(p) if this path is a literal unix domain socket path

    /// that can't be represented as a string.)

    //

    // This is a separate function so that it can form the basis of a "display_lossy"

    // implementation, assuming we need one.

        use crate::PathInner as PI;

        use AddrInner as AI;

                },

            },

        }

}

/// Error produced when trying to expand a [`CfgAddr`] into a [`general::SocketAddr`].

#[derive(Clone, Debug, thiserror::Error)]

#[non_exhaustive]

pub enum CfgAddrError {

    /// Tried to expand a `unix:` address on a platform where we don't support `AF_UNIX` addresses.

    #[error("No support for AF_UNIX addresses on this platform")]

    NoAfUnixSocketSupport(#[from] unix::NoAfUnixSocketSupport),

    /// Unable to expand the underlying `CfgPath`, likely due to syntax or missing variables.

    #[error("Could not expand path")]

    Path(#[from] CfgPathError),

    /// Unable to create an AF_UNIX address from a path.

    ///

    /// (This can happen if the path is too long, or contains internal NULs.)

    #[error("Could not construct AF_UNIX address")]

    ConstructAfUnixAddress(#[source] Arc<io::Error>),

}

impl FromStr for CfgAddr {

    type Err = general::AddrParseError;

        // NOTE: This logic is mostly duplicated from <FromStr for general::SocketAddr>;

        // I don't see an easy way to deduplicate it.

            // This looks like an inet address, and cannot be a qualified address.

                }

                }

            }

        } else {

        }

}

impl From<net::SocketAddr> for CfgAddr {

}

impl TryFrom<unix::SocketAddr> for CfgAddr {

    type Error = UnixAddrNotAPath;

        // We don't need to check `#[cfg(unix)]` here:

        // if unix::SocketAddr is inhabited, then we can construct the Unix variant.

        )))

}

// NOTE that we deliberately _don't_ implement From<Path> or From<CfgPath>;

// we want to keep open the possibility that there may be non-AF\_UNIX path-based

// addresses in the future!

/// Error returned when trying to convert a non-path `unix::SocketAddr` into a `CfgAddr` .

#[derive(Clone, Debug, Default, thiserror::Error)]

#[non_exhaustive]

#[error("Unix domain socket address was not a path.")]

pub struct UnixAddrNotAPath;

/// Serde helper: We convert CfgAddr through this format in order to serialize and deserialize it.

#[derive(Serialize, Deserialize)]

#[serde(untagged)]

enum CfgAddrSerde {

    /// We serialize most types as a string.

    Str(String),

    /// We have another format for representing AF\_UNIX address literals

    /// that can't be represented as a string.

    UnixLiteral {

        /// A path that won't be expanded.

        unix_literal: PathBuf,

    },

}

impl TryFrom<CfgAddrSerde> for CfgAddr {

    type Error = general::AddrParseError;

        use CfgAddrSerde as S;

            }

        }

}

impl From<CfgAddr> for CfgAddrSerde {

        }

}

#[cfg(test)]

mod test {

    // @@ begin test lint list maintained by maint/add_warning @@

    #![allow(clippy::bool_assert_comparison)]

    #![allow(clippy::clone_on_copy)]

    #![allow(clippy::dbg_macro)]

    #![allow(clippy::mixed_attributes_style)]

    #![allow(clippy::print_stderr)]

    #![allow(clippy::print_stdout)]

    #![allow(clippy::single_char_pattern)]

    #![allow(clippy::unwrap_used)]

    #![allow(clippy::unchecked_time_subtraction)]

    #![allow(clippy::useless_vec)]

    #![allow(clippy::needless_pass_by_value)]

    #![allow(clippy::string_slice)] // See arti#2571

    //! <!-- @@ end test lint list maintained by maint/add_warning @@ -->

    use super::*;

    use assert_matches::assert_matches;

    use std::path::PathBuf;

    use crate::{CfgPathResolver, home};

    #[test]

    fn parse_inet_ok() {

        fn check(s: &str) {

            let resolv = CfgPathResolver::from_pairs([("FOO", "foo")]);

            let a: general::SocketAddr = CfgAddr::from_str(s).unwrap().address(&resolv).unwrap();

            assert_eq!(a, general::SocketAddr::from_str(s).unwrap());

        }

        check("127.0.0.1:9999");

        check("inet:127.0.0.1:9999");

        check("[2001:db8::413]:443");

        check("inet:[2001:db8::413]:443");

    }

    #[test]

    fn parse_inet_bad() {

        assert_matches!(

            CfgAddr::from_str("612"),

            Err(general::AddrParseError::InvalidInetAddress(_))

        );

        assert_matches!(

            CfgAddr::from_str("612unix:/home"),

            Err(general::AddrParseError::InvalidInetAddress(_))

        );

        assert_matches!(

            CfgAddr::from_str("127.0.0.1.1:99"),

            Err(general::AddrParseError::InvalidInetAddress(_))

        );

        assert_matches!(

            CfgAddr::from_str("inet:6"),

            Err(general::AddrParseError::InvalidInetAddress(_))

        );

        assert_matches!(

            CfgAddr::from_str("[[[[[]]]]]"),

            Err(general::AddrParseError::InvalidInetAddress(_))

        );

    }

    #[test]

    fn parse_bad_schemas() {

        assert_matches!(

            CfgAddr::from_str("uranian:umbra"),

            Err(general::AddrParseError::UnrecognizedSchema(_))

        );

    }

    #[test]

    #[cfg_attr(not(unix), expect(unused_variables))]

    fn unix_literal() {

        let resolv = CfgPathResolver::from_pairs([("USER_HOME", home().unwrap())]);

        let pb = PathBuf::from("${USER_HOME}/.local/socket");

        let a1 = CfgAddr::new_unix(CfgPath::new_literal(&pb));

        let a2 = CfgAddr::from_str("unix-literal:${USER_HOME}/.local/socket").unwrap();

        #[cfg(unix)]

        {

            assert_eq!(a1.address(&resolv).unwrap(), a2.address(&resolv).unwrap(),);

            match a1.address(&resolv).unwrap() {

                general::SocketAddr::Unix(socket_addr) => {

                    // can't use assert_eq because these types are not Debug.

                    assert!(socket_addr.as_pathname() == Some(pb.as_ref()));

                }

                _ => panic!("Expected a unix domain socket address"),

            }

        }

        #[cfg(not(unix))]

        assert_matches!(

            a1.address(&resolv),

            Err(CfgAddrError::NoAfUnixSocketSupport(_))

        );

    }

    #[cfg_attr(not(unix), expect(unused_variables))]

    fn try_unix(addr: &str, want: &str, path_resolver: &CfgPathResolver) {

        let p = CfgPath::new(want.to_string());

        let expansion = p.path(path_resolver).unwrap();

        let cfg_addr = CfgAddr::from_str(addr).unwrap();

        assert_matches!(&cfg_addr.0, AddrInner::Unix(_));

        #[cfg(unix)]

        {

            let gen_addr = cfg_addr.address(path_resolver).unwrap();

            let expected_addr = unix::SocketAddr::from_pathname(expansion).unwrap();

            assert_eq!(gen_addr, expected_addr.into());

        }

        #[cfg(not(unix))]

        {

            assert_matches!(

                cfg_addr.address(path_resolver),

                Err(CfgAddrError::NoAfUnixSocketSupport(_))

            );

        }

    }

    #[test]

    fn unix_no_substitution() {

        let resolver = CfgPathResolver::from_pairs([("FOO", "foo")]);

        try_unix("unix:/home/mayor/.socket", "/home/mayor/.socket", &resolver);

    }

    #[test]

    #[cfg(feature = "expand-paths")]

    fn unix_substitution() {

        let resolver = CfgPathResolver::from_pairs([("FOO", "foo")]);

        try_unix("unix:${FOO}/socket", "${FOO}/socket", &resolver);

    }

    #[test]

    fn serde() {

        fn testcase_with_provided_addr(json: &str, addr: &CfgAddr) {

            let a1: CfgAddr = serde_json::from_str(json).unwrap();

            assert_eq!(&a1, addr);

            let encoded = serde_json::to_string(&a1).unwrap();

            let a2: CfgAddr = serde_json::from_str(&encoded).unwrap();

            assert_eq!(&a2, addr);

        }

        fn testcase(json: &str, addr: &str) {

            let addr = CfgAddr::from_str(addr).unwrap();

            testcase_with_provided_addr(json, &addr);

        }

        testcase(r#" "inet:127.0.0.1:443" "#, "inet:127.0.0.1:443");

        testcase(r#" "unix:${HOME}/socket" "#, "unix:${HOME}/socket");

        testcase(

            r#" "unix-literal:${HOME}/socket" "#,

            "unix-literal:${HOME}/socket",

        );

    }

}