vrl 0.37.0

use super::util::hex_encode;
use crate::compiler::function::EnumVariant;
use crate::compiler::prelude::*;
use crate::value;
use sha2::{Digest, Sha224, Sha256, Sha384, Sha512, Sha512_224, Sha512_256};

static DEFAULT_VARIANT: Value = Value::from_static_str("SHA-512/256");

static VARIANT_ENUM: &[EnumVariant] = &[
    EnumVariant {
        value: "SHA-224",
        description: "SHA-224 algorithm",
    },
    EnumVariant {
        value: "SHA-256",
        description: "SHA-256 algorithm",
    },
    EnumVariant {
        value: "SHA-384",
        description: "SHA-384 algorithm",
    },
    EnumVariant {
        value: "SHA-512",
        description: "SHA-512 algorithm",
    },
    EnumVariant {
        value: "SHA-512/224",
        description: "SHA-512/224 algorithm",
    },
    EnumVariant {
        value: "SHA-512/256",
        description: "SHA-512/256 algorithm",
    },
];

const PARAMETERS: &[Parameter] = &[
    Parameter::required(
        "value",
        kind::BYTES,
        "The string to calculate the hash for.",
    ),
    Parameter::optional(
        "variant",
        kind::BYTES,
        "The variant of the algorithm to use.",
    )
    .default(&DEFAULT_VARIANT)
    .enum_variants(VARIANT_ENUM),
];

fn sha2_hex(value: &[u8], variant: &[u8]) -> bytestring::ByteString {
    match variant {
        b"SHA-224" => hex_encode::<56>(Sha224::digest(value)),
        b"SHA-256" => hex_encode::<64>(Sha256::digest(value)),
        b"SHA-384" => hex_encode::<96>(Sha384::digest(value)),
        b"SHA-512" => hex_encode::<128>(Sha512::digest(value)),
        b"SHA-512/224" => hex_encode::<56>(Sha512_224::digest(value)),
        b"SHA-512/256" => hex_encode::<64>(Sha512_256::digest(value)),
        _ => unreachable!("enum invariant"),
    }
}

fn sha2(value: Value, variant: &Bytes) -> Resolved {
    let value = value.try_bytes()?;
    Ok(Value::String(sha2_hex(&value, variant)))
}

#[derive(Clone, Copy, Debug)]
pub struct Sha2;

fn variants() -> Vec<Value> {
    vec![
        value!("SHA-224"),
        value!("SHA-256"),
        value!("SHA-384"),
        value!("SHA-512"),
        value!("SHA-512/224"),
        value!("SHA-512/256"),
    ]
}

impl Function for Sha2 {
    fn identifier(&self) -> &'static str {
        "sha2"
    }

    fn usage(&self) -> &'static str {
        "Calculates a [SHA-2](https://en.wikipedia.org/wiki/SHA-2) hash of the `value`."
    }

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

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

    fn parameters(&self) -> &'static [Parameter] {
        PARAMETERS
    }

    fn examples(&self) -> &'static [Example] {
        &[
            example! {
                title: "Calculate sha2 hash using default variant",
                source: r#"sha2("foobar")"#,
                result: Ok("d014c752bc2be868e16330f47e0c316a5967bcbc9c286a457761d7055b9214ce"),
            },
            example! {
                title: "Calculate sha2 hash with SHA-512/224",
                source: r#"sha2("foo", variant: "SHA-512/224")"#,
                result: Ok("d68f258d37d670cfc1ec1001a0394784233f88f056994f9a7e5e99be"),
            },
            example! {
                title: "Calculate sha2 hash with SHA-384",
                source: r#"sha2("foobar", "SHA-384")"#,
                result: Ok(
                    "3c9c30d9f665e74d515c842960d4a451c83a0125fd3de7392d7b37231af10c72ea58aedfcdf89a5765bf902af93ecf06",
                ),
            },
        ]
    }

    fn compile(
        &self,
        state: &state::TypeState,
        _ctx: &mut FunctionCompileContext,
        arguments: ArgumentList,
    ) -> Compiled {
        let value = arguments.required("value");
        let variant = arguments
            .optional_enum("variant", &variants(), state)?
            .unwrap_or_else(|| DEFAULT_VARIANT.clone())
            .try_bytes()
            .expect("variant not bytes");

        if let Some(val) = value.resolve_constant(state)
            && let Ok(bytes) = val.try_bytes()
        {
            Ok(Box::new(crate::compiler::expression::Literal::from(
                sha2_hex(&bytes, &variant),
            )))
        } else {
            Ok(Sha2Fn { value, variant }.as_expr())
        }
    }
}

#[derive(Debug, Clone)]
struct Sha2Fn {
    value: Box<dyn Expression>,
    variant: Bytes,
}

impl FunctionExpression for Sha2Fn {
    fn resolve(&self, ctx: &mut Context) -> Resolved {
        let value = self.value.resolve(ctx)?;
        let variant = &self.variant;

        sha2(value, variant)
    }

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

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

    test_function![
        sha2 => Sha2;

        sha2 {
             args: func_args![value: "foo"],
             want: Ok("d58042e6aa5a335e03ad576c6a9e43b41591bfd2077f72dec9df7930e492055d"),
             tdef: TypeDef::bytes().infallible(),
         }

        sha2_224 {
            args: func_args![value: "foo",
                             variant: "SHA-224"
            ],
            want: Ok("0808f64e60d58979fcb676c96ec938270dea42445aeefcd3a4e6f8db"),
            tdef: TypeDef::bytes().infallible(),
        }

        sha2_256 {
             args: func_args![value: "foo",
                              variant: "SHA-256"
             ],
             want: Ok("2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae"),
             tdef: TypeDef::bytes().infallible(),
         }

        sha2_385 {
            args: func_args![value: "foo",
                             variant: "SHA-384"
            ],
            want: Ok("98c11ffdfdd540676b1a137cb1a22b2a70350c9a44171d6b1180c6be5cbb2ee3f79d532c8a1dd9ef2e8e08e752a3babb"),
            tdef: TypeDef::bytes().infallible(),
        }

        sha2_512 {
             args: func_args![value: "foo",
                              variant: "SHA-512"
             ],
             want: Ok("f7fbba6e0636f890e56fbbf3283e524c6fa3204ae298382d624741d0dc6638326e282c41be5e4254d8820772c5518a2c5a8c0c7f7eda19594a7eb539453e1ed7"),
             tdef: TypeDef::bytes().infallible(),
         }

        sha2_512_224 {
             args: func_args![value: "foo",
                              variant: "SHA-512/224"
             ],
             want: Ok("d68f258d37d670cfc1ec1001a0394784233f88f056994f9a7e5e99be"),
             tdef: TypeDef::bytes().infallible(),
         }

        sha2_512_256 {
             args: func_args![value: "foo",
                              variant: "SHA-512/256"
             ],
             want: Ok("d58042e6aa5a335e03ad576c6a9e43b41591bfd2077f72dec9df7930e492055d"),
             tdef: TypeDef::bytes().infallible(),
         }
    ];

    #[test]
    fn test_sha2_compiles_to_literal() {
        use crate::compiler::CompileConfig;

        let state = state::TypeState::default();
        let mut ctx = FunctionCompileContext::new(Span::default(), CompileConfig::default());
        let mut args = ArgumentList::default();
        args.insert("value", Value::from("foo").into());

        let expr = Sha2.compile(&state, &mut ctx, args).unwrap();
        assert_eq!(
            expr.resolve_constant(&state),
            Some(Value::from(
                "d58042e6aa5a335e03ad576c6a9e43b41591bfd2077f72dec9df7930e492055d"
            ))
        );
    }

    #[test]
    fn test_sha2_compiles_dynamic() {
        use crate::compiler::CompileConfig;
        use crate::compiler::expression::Variable;
        use crate::compiler::parser::Ident;

        let mut state = state::TypeState::default();
        state.local.insert_variable(
            Ident::new("foo"),
            type_def::Details {
                type_def: TypeDef::bytes(),
                value: None,
            },
        );

        let mut ctx = FunctionCompileContext::new(Span::default(), CompileConfig::default());
        let var = Variable::new((0, 0).into(), Ident::new("foo"), &state.local).unwrap();

        let mut args = ArgumentList::default();
        args.insert("value", var.into());

        let expr = Sha2.compile(&state, &mut ctx, args).unwrap();
        assert!(expr.resolve_constant(&state).is_none());
    }
}