Documentation
use std::collections::BTreeMap;

use serde::{ser::Impossible, Serialize};

use crate::{
    ser::map_key_serializer::MapKeySerializer, to_value, value::Value, ByteString, Dictionary,
    Error,
};

impl Serialize for Value {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: serde::Serializer,
    {
        match self {
            Value::ByteString(byte_string) => byte_string.serialize(serializer),
            Value::Integer(integer) => integer.serialize(serializer),
            Value::List(list) => list.serialize(serializer),
            Value::Dictionary(dictionary) => dictionary.serialize(serializer),
        }
    }
}

pub struct ValueSerializer;

impl ValueSerializer {
    pub const fn new() -> Self {
        Self {}
    }
}

impl Default for ValueSerializer {
    fn default() -> Self {
        Self::new()
    }
}

impl serde::Serializer for ValueSerializer {
    type Ok = Value;

    type Error = Error;

    // TODO: remove all this impossible with actual serializers.
    type SerializeSeq = SerializeVec;

    type SerializeTuple = Impossible<Value, Error>;

    type SerializeTupleStruct = Impossible<Value, Error>;

    type SerializeTupleVariant = Impossible<Value, Error>;

    type SerializeMap = SerializeMap;

    type SerializeStruct = SerializeMap;

    type SerializeStructVariant = Impossible<Value, Error>;

    fn serialize_bool(self, _value: bool) -> Result<Self::Ok, Self::Error> {
        Err(Error::Unsupported("bool"))
    }

    #[inline]
    fn serialize_i8(self, value: i8) -> Result<Self::Ok, Self::Error> {
        self.serialize_i64(value as i64)
    }

    #[inline]
    fn serialize_i16(self, value: i16) -> Result<Self::Ok, Self::Error> {
        self.serialize_i64(value as i64)
    }

    #[inline]
    fn serialize_i32(self, value: i32) -> Result<Self::Ok, Self::Error> {
        self.serialize_i64(value as i64)
    }

    fn serialize_i64(self, value: i64) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Integer(value.into()))
    }

    #[inline]
    fn serialize_u8(self, value: u8) -> Result<Self::Ok, Self::Error> {
        self.serialize_u64(value as u64)
    }

    #[inline]
    fn serialize_u16(self, value: u16) -> Result<Self::Ok, Self::Error> {
        self.serialize_u64(value as u64)
    }

    #[inline]
    fn serialize_u32(self, value: u32) -> Result<Self::Ok, Self::Error> {
        self.serialize_u64(value as u64)
    }

    fn serialize_u64(self, value: u64) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Integer(value.into()))
    }

    fn serialize_f32(self, _value: f32) -> Result<Self::Ok, Self::Error> {
        Err(Error::Unsupported("f32"))
    }

    fn serialize_f64(self, _value: f64) -> Result<Self::Ok, Self::Error> {
        Err(Error::Unsupported("f64"))
    }

    fn serialize_char(self, _value: char) -> Result<Self::Ok, Self::Error> {
        Err(Error::Unsupported("char"))
    }

    fn serialize_str(self, value: &str) -> Result<Self::Ok, Self::Error> {
        Ok(Value::ByteString(ByteString::from(value)))
    }

    fn serialize_bytes(self, value: &[u8]) -> Result<Self::Ok, Self::Error> {
        Ok(Value::ByteString(ByteString::from(value)))
    }

    fn serialize_none(self) -> Result<Self::Ok, Self::Error> {
        Err(Error::Unsupported("None"))
    }

    fn serialize_some<T: ?Sized>(self, value: &T) -> Result<Self::Ok, Self::Error>
    where
        T: Serialize,
    {
        value.serialize(self)
    }

    fn serialize_unit(self) -> Result<Self::Ok, Self::Error> {
        Err(Error::Unsupported("unit"))
    }

    fn serialize_unit_struct(self, _name: &'static str) -> Result<Self::Ok, Self::Error> {
        Err(Error::Unsupported("unit"))
    }

    fn serialize_unit_variant(
        self,
        _name: &'static str,
        _variant_index: u32,
        variant: &'static str,
    ) -> Result<Self::Ok, Self::Error> {
        self.serialize_str(variant)
    }

    fn serialize_newtype_struct<T: ?Sized>(
        self,
        _name: &'static str,
        value: &T,
    ) -> Result<Self::Ok, Self::Error>
    where
        T: Serialize,
    {
        value.serialize(self)
    }

    fn serialize_newtype_variant<T: ?Sized>(
        self,
        _name: &'static str,
        _variant_index: u32,
        _variant: &'static str,
        _value: &T,
    ) -> Result<Self::Ok, Self::Error>
    where
        T: Serialize,
    {
        todo!()
    }

    fn serialize_seq(self, len: Option<usize>) -> Result<Self::SerializeSeq, Self::Error> {
        Ok(SerializeVec {
            vec: Vec::with_capacity(len.unwrap_or(0)),
        })
    }

    fn serialize_tuple(self, _len: usize) -> Result<Self::SerializeTuple, Self::Error> {
        todo!()
    }

    fn serialize_tuple_struct(
        self,
        _name: &'static str,
        _len: usize,
    ) -> Result<Self::SerializeTupleStruct, Self::Error> {
        todo!()
    }

    fn serialize_tuple_variant(
        self,
        _name: &'static str,
        _variant_index: u32,
        _variant: &'static str,
        _len: usize,
    ) -> Result<Self::SerializeTupleVariant, Self::Error> {
        todo!()
    }

    fn serialize_map(self, _len: Option<usize>) -> Result<Self::SerializeMap, Self::Error> {
        Ok(SerializeMap::new())
    }

    fn serialize_struct(
        self,
        _name: &'static str,
        len: usize,
    ) -> Result<Self::SerializeStruct, Self::Error> {
        self.serialize_map(Some(len))
    }

    fn serialize_struct_variant(
        self,
        _name: &'static str,
        _variant_index: u32,
        _variant: &'static str,
        _len: usize,
    ) -> Result<Self::SerializeStructVariant, Self::Error> {
        todo!()
    }
}

pub struct SerializeVec {
    vec: Vec<Value>,
}

impl serde::ser::SerializeSeq for SerializeVec {
    type Ok = Value;
    type Error = Error;

    fn serialize_element<T>(&mut self, value: &T) -> Result<(), Error>
    where
        T: ?Sized + Serialize,
    {
        self.vec.push(to_value(value)?);
        Ok(())
    }

    fn end(self) -> Result<Value, Error> {
        Ok(Value::List(self.vec))
    }
}

pub struct SerializeMap {
    dictionary: Dictionary,
}

impl SerializeMap {
    pub const fn new() -> Self {
        Self {
            dictionary: BTreeMap::new(),
        }
    }
}

impl serde::ser::SerializeMap for SerializeMap {
    type Ok = Value;

    type Error = Error;

    fn serialize_key<T: ?Sized>(&mut self, _key: &T) -> Result<(), Error>
    where
        T: Serialize,
    {
        unreachable!()
    }

    fn serialize_value<T: ?Sized>(&mut self, _value: &T) -> Result<(), Error>
    where
        T: Serialize,
    {
        unreachable!()
    }

    fn serialize_entry<K: ?Sized, V: ?Sized>(
        &mut self,
        key: &K,
        value: &V,
    ) -> Result<(), Self::Error>
    where
        K: Serialize,
        V: Serialize,
    {
        let key = key.serialize(MapKeySerializer::new())?;
        let value = value.serialize(ValueSerializer::new())?;

        self.dictionary.insert(key, value);

        Ok(())
    }

    fn end(self) -> Result<Self::Ok, Error> {
        Ok(Value::Dictionary(self.dictionary))
    }
}

impl serde::ser::SerializeStruct for SerializeMap {
    type Ok = Value;

    type Error = Error;

    fn serialize_field<T: ?Sized>(
        &mut self,
        key: &'static str,
        value: &T,
    ) -> Result<(), Self::Error>
    where
        T: Serialize,
    {
        let key = key.serialize(MapKeySerializer::new())?;
        let value = value.serialize(ValueSerializer::new())?;

        self.dictionary.insert(key, value);

        Ok(())
    }

    fn end(self) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Dictionary(self.dictionary))
    }
}