// 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::{LanguageIdentifier, Locale};
use core::{fmt::Display, marker::PhantomData, str::FromStr};
use serde::{Deserialize, Deserializer, Serialize, Serializer};
use writeable::Writeable;

impl Serialize for LanguageIdentifier {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        serializer.serialize_str(&self.write_to_string())
    }
}

impl Serialize for Locale {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        serializer.serialize_str(&self.write_to_string())
    }
}

struct ParseVisitor<T>(PhantomData<T>);

impl<T> serde::de::Visitor<'_> for ParseVisitor<T>
where
    T: FromStr,
    <T as FromStr>::Err: Display,
{
    type Value = T;

    fn expecting(&self, formatter: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        write!(formatter, "a valid Unicode Language or Locale Identifier")
    }

    fn visit_str<E>(self, s: &str) -> Result<Self::Value, E>
    where
        E: serde::de::Error,
    {
        s.parse::<T>().map_err(serde::de::Error::custom)
    }
}

impl<'de> Deserialize<'de> for LanguageIdentifier {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        deserializer.deserialize_str(ParseVisitor(PhantomData))
    }
}

impl<'de> Deserialize<'de> for Locale {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        deserializer.deserialize_str(ParseVisitor(PhantomData))
    }
}

#[test]
fn json() {
    use crate::subtags::{Language, Region, Script};
    use crate::{langid, locale};

    assert_eq!(
        serde_json::to_string(&langid!("en-US")).unwrap(),
        r#""en-US""#
    );
    assert_eq!(
        serde_json::from_str::<LanguageIdentifier>(r#""en-US""#).unwrap(),
        langid!("en-US")
    );
    assert_eq!(
        serde_json::from_reader::<_, LanguageIdentifier>(&br#""en-US""#[..]).unwrap(),
        langid!("en-US")
    );
    assert!(serde_json::from_str::<LanguageIdentifier>(r#""2Xs""#).is_err());

    assert_eq!(
        serde_json::to_string(&locale!("en-US-u-hc-h12")).unwrap(),
        r#""en-US-u-hc-h12""#
    );
    assert_eq!(
        serde_json::from_str::<Locale>(r#""en-US-u-hc-h12""#).unwrap(),
        locale!("en-US-u-hc-h12")
    );
    assert_eq!(
        serde_json::from_reader::<_, Locale>(&br#""en-US-u-hc-h12""#[..]).unwrap(),
        locale!("en-US-u-hc-h12")
    );
    assert!(serde_json::from_str::<Locale>(r#""2Xs""#).is_err());

    assert_eq!(
        serde_json::to_string(&"fr".parse::<Language>().unwrap()).unwrap(),
        r#""fr""#
    );
    assert_eq!(
        serde_json::from_str::<Language>(r#""fr""#).unwrap(),
        "fr".parse::<Language>().unwrap()
    );
    assert_eq!(
        serde_json::from_reader::<_, Language>(&br#""fr""#[..]).unwrap(),
        "fr".parse::<Language>().unwrap()
    );
    assert!(serde_json::from_str::<Language>(r#""2Xs""#).is_err());

    assert_eq!(
        serde_json::to_string(&"Latn".parse::<Script>().unwrap()).unwrap(),
        r#""Latn""#
    );
    assert_eq!(
        serde_json::from_str::<Script>(r#""Latn""#).unwrap(),
        "Latn".parse::<Script>().unwrap()
    );
    assert_eq!(
        serde_json::from_reader::<_, Script>(&br#""Latn""#[..]).unwrap(),
        "Latn".parse::<Script>().unwrap()
    );
    assert!(serde_json::from_str::<Script>(r#""2Xs""#).is_err());

    assert_eq!(
        serde_json::to_string(&"US".parse::<Region>().unwrap()).unwrap(),
        r#""US""#
    );
    assert_eq!(
        serde_json::from_str::<Region>(r#""US""#).unwrap(),
        "US".parse::<Region>().unwrap()
    );
    assert_eq!(
        serde_json::from_reader::<_, Region>(&br#""US""#[..]).unwrap(),
        "US".parse::<Region>().unwrap()
    );
    assert!(serde_json::from_str::<Region>(r#""2Xs""#).is_err());
}

#[test]
fn postcard() {
    use crate::subtags::{Language, Region, Script};
    use crate::{langid, locale};

    assert_eq!(
        postcard::to_stdvec(&langid!("en-US")).unwrap(),
        b"\x05en-US"
    );
    assert_eq!(
        postcard::from_bytes::<LanguageIdentifier>(b"\x05en-US").unwrap(),
        langid!("en-US")
    );
    assert!(postcard::from_bytes::<LanguageIdentifier>(b"\x032Xs").is_err());

    assert_eq!(
        postcard::to_stdvec(&locale!("en-US-u-hc-h12")).unwrap(),
        b"\x0Een-US-u-hc-h12"
    );
    assert_eq!(
        postcard::from_bytes::<Locale>(b"\x0Een-US-u-hc-h12").unwrap(),
        locale!("en-US-u-hc-h12")
    );
    assert!(postcard::from_bytes::<Locale>(b"\x032Xs").is_err());

    assert_eq!(
        postcard::to_stdvec(&"fr".parse::<Language>().unwrap()).unwrap(),
        b"fr\0"
    );
    assert_eq!(
        postcard::from_bytes::<Language>(b"fr\0").unwrap(),
        "fr".parse::<Language>().unwrap()
    );
    assert!(postcard::from_bytes::<Language>(b"2Xs").is_err());

    assert_eq!(
        postcard::to_stdvec(&"Latn".parse::<Script>().unwrap()).unwrap(),
        b"Latn"
    );
    assert_eq!(
        postcard::from_bytes::<Script>(b"Latn").unwrap(),
        "Latn".parse::<Script>().unwrap()
    );
    assert!(postcard::from_bytes::<Script>(b"2Xss").is_err());

    assert_eq!(
        postcard::to_stdvec(&"US".parse::<Region>().unwrap()).unwrap(),
        b"US\0"
    );
    assert_eq!(
        postcard::from_bytes::<Region>(b"US\0").unwrap(),
        "US".parse::<Region>().unwrap()
    );
    assert!(postcard::from_bytes::<Region>(b"2Xs").is_err());
}