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use crate::{PgArgumentBuffer, PgTypeInfo, PgValueRef, Postgres};
use sqlx_core::decode::Decode;
use sqlx_core::encode::{Encode, IsNull};
use sqlx_core::error::BoxDynError;
use sqlx_core::types::{Text, Type};
use std::fmt::Display;
use std::str::FromStr;

use std::io::Write;

impl<T> Type<Postgres> for Text<T> {
    fn type_info() -> PgTypeInfo {
        <String as Type<Postgres>>::type_info()
    }

    fn compatible(ty: &PgTypeInfo) -> bool {
        <String as Type<Postgres>>::compatible(ty)
    }
}

impl<'q, T> Encode<'q, Postgres> for Text<T>
where
    T: Display,
{
    fn encode_by_ref(&self, buf: &mut PgArgumentBuffer) -> IsNull {
        // Unfortunately, our API design doesn't give us a way to bubble up the error here.
        //
        // Fortunately, writing to `Vec<u8>` is infallible so the only possible source of
        // errors is from the implementation of `Display::fmt()` itself,
        // where the onus is on the user.
        //
        // The blanket impl of `ToString` also panics if there's an error, so this is not
        // unprecedented.
        //
        // However, the panic should be documented anyway.
        write!(**buf, "{}", self.0).expect("unexpected error from `Display::fmt()`");
        IsNull::No
    }
}

impl<'r, T> Decode<'r, Postgres> for Text<T>
where
    T: FromStr,
    BoxDynError: From<<T as FromStr>::Err>,
{
    fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError> {
        let s: &str = Decode::<Postgres>::decode(value)?;
        Ok(Self(s.parse()?))
    }
}