vrl 0.32.0

use crate::compiler::prelude::*;
use std::net::IpAddr;

fn ip_ntop(value: Value) -> Resolved {
    let value = value.try_bytes()?;

    match value.len() {
        4 => {
            let bytes: [u8; 4] = value[..].try_into().expect("invalid length");
            Ok(IpAddr::from(bytes).to_string().into())
        }
        16 => {
            let bytes: [u8; 16] = value[..].try_into().expect("invalid length");
            Ok(IpAddr::from(bytes).to_string().into())
        }
        _ => Err(r#""value" must be of length 4 or 16 bytes"#.into()),
    }
}

#[derive(Clone, Copy, Debug)]
pub struct IpNtop;

impl Function for IpNtop {
    fn identifier(&self) -> &'static str {
        "ip_ntop"
    }

    fn usage(&self) -> &'static str {
        indoc! {"
            Converts IPv4 and IPv6 addresses from binary to text form.

            This behavior mimics [inet_ntop](https://linux.die.net/man/3/inet_ntop).
        "}
    }

    fn category(&self) -> &'static str {
        Category::Ip.as_ref()
    }

    fn internal_failure_reasons(&self) -> &'static [&'static str] {
        &["`value` must be of length 4 or 16 bytes."]
    }

    fn return_kind(&self) -> u16 {
        kind::BYTES
    }

    fn notices(&self) -> &'static [&'static str] {
        &[indoc! {"
            The binary data for this function is not easily printable. However, the results from
            functions such as `decode_base64` or `decode_percent` can still be used correctly.
        "}]
    }

    fn parameters(&self) -> &'static [Parameter] {
        const PARAMETERS: &[Parameter] = &[Parameter::required(
            "value",
            kind::BYTES,
            "The binary data to convert from.
For IPv4 addresses, it must be 4 bytes (32 bits) long.
For IPv6 addresses, it must be 16 bytes (128 bits) long.",
        )];
        PARAMETERS
    }

    fn examples(&self) -> &'static [Example] {
        &[
            example! {
                title: "Convert IPv4 address from bytes after decoding from Base64",
                source: r#"ip_ntop!(decode_base64!("wKgAAQ=="))"#,
                result: Ok("192.168.0.1"),
            },
            example! {
                title: "Convert IPv6 address from bytes after decoding from Base64",
                source: r#"ip_ntop!(decode_base64!("IAENuIWjAAAAAIouA3BzNA=="))"#,
                result: Ok("2001:db8:85a3::8a2e:370:7334"),
            },
        ]
    }

    fn compile(
        &self,
        _state: &state::TypeState,
        _ctx: &mut FunctionCompileContext,
        arguments: ArgumentList,
    ) -> Compiled {
        let value = arguments.required("value");

        Ok(IpNtopFn { value }.as_expr())
    }
}

#[derive(Debug, Clone)]
struct IpNtopFn {
    value: Box<dyn Expression>,
}

impl FunctionExpression for IpNtopFn {
    fn resolve(&self, ctx: &mut Context) -> Resolved {
        let value = self.value.resolve(ctx)?;
        ip_ntop(value)
    }

    fn type_def(&self, _: &state::TypeState) -> TypeDef {
        TypeDef::bytes().fallible()
    }
}

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

    test_function![
        ip_ntop => IpNtop;

        invalid {
            args: func_args![value: "\x01\x02"],
            want: Err(r#""value" must be of length 4 or 16 bytes"#),
            tdef: TypeDef::bytes().fallible(),
        }

        valid_ipv4 {
            args: func_args![value: "\x01\x02\x03\x04"],
            want: Ok(value!("1.2.3.4")),
            tdef: TypeDef::bytes().fallible(),
        }

        valid_ipv6 {
            args: func_args![value: "\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10"],
            want: Ok(value!("102:304:506:708:90a:b0c:d0e:f10")),
            tdef: TypeDef::bytes().fallible(),
        }
    ];
}