// This file is part of ICU4X. For terms of use, please see the file

// called LICENSE at the top level of the ICU4X source tree

// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).

use crate::ParseError;

use crate::TinyAsciiStr;

use core::fmt;

/// A fixed-length bytes array that is expected to be an ASCII string but does not enforce that invariant.

///

/// Use this type instead of `TinyAsciiStr` if you don't need to enforce ASCII during deserialization. For

/// example, strings that are keys of a map don't need to ever be reified as `TinyAsciiStr`s.

///

/// The main advantage of this type over `[u8; N]` is that it serializes as a string in

/// human-readable formats like JSON.

#[derive(PartialEq, PartialOrd, Eq, Ord, Clone, Copy)]

pub struct UnvalidatedTinyAsciiStr<const N: usize>(pub(crate) [u8; N]);

impl<const N: usize> fmt::Debug for UnvalidatedTinyAsciiStr<N> {

    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {

        // Debug as a string if possible

        match self.try_into_tinystr() {

            Ok(s) => fmt::Debug::fmt(&s, f),

            Err(_) => fmt::Debug::fmt(&self.0, f),

        }

    }

}

impl<const N: usize> UnvalidatedTinyAsciiStr<N> {

    #[inline]

    /// Converts into a [`TinyAsciiStr`]. Fails if the bytes are not valid ASCII.

    pub fn try_into_tinystr(self) -> Result<TinyAsciiStr<N>, ParseError> {

        TinyAsciiStr::try_from_raw(self.0)

    }

    #[inline]

    /// Creates one of these from a byte slice. Fails if the bytes are too long, but

    /// does not check whether the bytes are a valid ASCII string.

    pub fn try_from_utf8(bytes: &[u8]) -> Result<Self, ParseError> {

        if bytes.len() > N {

            return Err(ParseError::TooLong {

                max: N,

                len: bytes.len(),

            });

        }

        let mut target = [0u8; N];

        target[0..bytes.len()].copy_from_slice(bytes);

        Ok(Self(target))

    }

    #[inline]

    /// Creates one of these from a raw byte array.

    pub const fn from_utf8_unchecked(bytes: [u8; N]) -> Self {

        Self(bytes)

    }

    #[inline]

    /// Returns the empty string.

    pub const fn default() -> Self {

        TinyAsciiStr::EMPTY.to_unvalidated()

    }

}

impl<const N: usize> Default for UnvalidatedTinyAsciiStr<N> {

    fn default() -> Self {

        Self::default()

    }

}

impl<const N: usize> TinyAsciiStr<N> {

    #[inline]

    // Converts into a [`UnvalidatedTinyAsciiStr`]

    pub const fn to_unvalidated(self) -> UnvalidatedTinyAsciiStr<N> {

        UnvalidatedTinyAsciiStr(*self.all_bytes())

    }

}

impl<const N: usize> From<TinyAsciiStr<N>> for UnvalidatedTinyAsciiStr<N> {

    fn from(other: TinyAsciiStr<N>) -> Self {

        other.to_unvalidated()

    }

}

#[cfg(feature = "serde")]

impl<const N: usize> serde_core::Serialize for UnvalidatedTinyAsciiStr<N> {

    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

    where

        S: serde_core::Serializer,

    {

        use serde_core::ser::Error;

        self.try_into_tinystr()

            .map_err(|_| S::Error::custom("invalid ascii in UnvalidatedTinyAsciiStr"))?

            .serialize(serializer)

    }

}

macro_rules! deserialize {

    ($size:literal) => {

        #[cfg(feature = "serde")]

        impl<'de, 'a> serde_core::Deserialize<'de> for UnvalidatedTinyAsciiStr<$size>

        where

            'de: 'a,

        {

            fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

            where

                D: serde_core::Deserializer<'de>,

            {

                if deserializer.is_human_readable() {

                    Ok(TinyAsciiStr::deserialize(deserializer)?.to_unvalidated())

                } else {

                    Ok(Self(<[u8; $size]>::deserialize(deserializer)?))

                }

            }

        }

    };

}

deserialize!(1);

deserialize!(2);

deserialize!(3);

deserialize!(4);

deserialize!(5);

deserialize!(6);

deserialize!(7);

deserialize!(8);

deserialize!(9);

deserialize!(10);

deserialize!(11);

deserialize!(12);

deserialize!(13);

deserialize!(14);

deserialize!(15);

deserialize!(16);

deserialize!(17);

deserialize!(18);

deserialize!(19);

deserialize!(20);

deserialize!(21);

deserialize!(22);

deserialize!(23);

deserialize!(24);

deserialize!(25);

deserialize!(26);

deserialize!(27);

deserialize!(28);

deserialize!(29);

deserialize!(30);

deserialize!(31);

deserialize!(32);