//! Implement deserialization support of `ImmutableString` for [`serde`](https://crates.io/crates/serde).

use crate::result::EvalAltResult;
use crate::token::Position;
use crate::utils::ImmutableString;

use serde::de::{Deserializer, Visitor};

use crate::stdlib::{any::type_name, boxed::Box};

/// Deserializer for `ImmutableString`.
pub struct ImmutableStringDeserializer<'a> {
    value: &'a ImmutableString,
}

impl<'a> ImmutableStringDeserializer<'a> {
    /// Create an `ImmutableStringDeserializer` from an `ImmutableString` reference.
    pub fn from_str(value: &'a ImmutableString) -> Self {
        Self { value }
    }
    /// Shortcut for a type conversion error.
    fn type_error<T>(&self) -> Result<T, Box<EvalAltResult>> {
        Err(Box::new(EvalAltResult::ErrorMismatchOutputType(
            type_name::<T>().into(),
            "string".into(),
            Position::none(),
        )))
    }
}

impl<'de> Deserializer<'de> for &mut ImmutableStringDeserializer<'de> {
    type Error = Box<EvalAltResult>;

    fn deserialize_any<V: Visitor<'de>>(self, v: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.deserialize_str(v)
    }
    fn deserialize_bool<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_i8<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_i16<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_i32<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_i64<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_u8<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_u16<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_u32<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_u64<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_f32<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_f64<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_char<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_str<V: Visitor<'de>>(self, v: V) -> Result<V::Value, Box<EvalAltResult>> {
        // Only allow deserialization into a string.
        v.visit_borrowed_str(self.value.as_str())
    }
    fn deserialize_string<V: Visitor<'de>>(
        self,
        visitor: V,
    ) -> Result<V::Value, Box<EvalAltResult>> {
        self.deserialize_str(visitor)
    }
    fn deserialize_bytes<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_byte_buf<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_option<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_unit<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_unit_struct<V: Visitor<'de>>(
        self,
        _name: &'static str,
        v: V,
    ) -> Result<V::Value, Box<EvalAltResult>> {
        self.deserialize_unit(v)
    }
    fn deserialize_newtype_struct<V: Visitor<'de>>(
        self,
        _name: &'static str,
        v: V,
    ) -> Result<V::Value, Box<EvalAltResult>> {
        v.visit_newtype_struct(self)
    }
    fn deserialize_seq<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_tuple<V: Visitor<'de>>(
        self,
        _len: usize,
        v: V,
    ) -> Result<V::Value, Box<EvalAltResult>> {
        self.deserialize_seq(v)
    }
    fn deserialize_tuple_struct<V: Visitor<'de>>(
        self,
        _name: &'static str,
        _len: usize,
        v: V,
    ) -> Result<V::Value, Box<EvalAltResult>> {
        self.deserialize_seq(v)
    }
    fn deserialize_map<V: Visitor<'de>>(self, _: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_struct<V: Visitor<'de>>(
        self,
        _name: &'static str,
        _fields: &'static [&'static str],
        v: V,
    ) -> Result<V::Value, Box<EvalAltResult>> {
        self.deserialize_map(v)
    }
    fn deserialize_enum<V: Visitor<'de>>(
        self,
        _name: &'static str,
        _variants: &'static [&'static str],
        _: V,
    ) -> Result<V::Value, Box<EvalAltResult>> {
        self.type_error()
    }
    fn deserialize_identifier<V: Visitor<'de>>(self, v: V) -> Result<V::Value, Box<EvalAltResult>> {
        self.deserialize_str(v)
    }
    fn deserialize_ignored_any<V: Visitor<'de>>(
        self,
        v: V,
    ) -> Result<V::Value, Box<EvalAltResult>> {
        self.deserialize_any(v)
    }
}