simuldb 0.12.3

//! Serialization into [Value]

use std::collections::BTreeMap;

use serde::{
    ser::{
        SerializeMap, SerializeSeq, SerializeStruct, SerializeStructVariant, SerializeTuple,
        SerializeTupleStruct, SerializeTupleVariant,
    },
    Serialize, Serializer,
};

use thiserror::Error;

use crate::value::{Float, Map, Value};
#[derive(Debug, Error)]
pub enum SerializationError {
    #[error("Can not write value without key")]
    ValueWithoutKey,
    #[error("Key must be a string: {0:?}")]
    NonStringKey(Value),
    #[error("{0}")]
    Other(String),
}

impl serde::ser::Error for SerializationError {
    fn custom<T>(msg: T) -> Self
    where
        T: std::fmt::Display,
    {
        SerializationError::Other(format!("{msg}"))
    }
}

pub struct ValueSerializer;

impl Serializer for ValueSerializer {
    type Ok = Value;
    type Error = SerializationError;
    type SerializeSeq = SeqSerializer;
    type SerializeTuple = SeqSerializer;
    type SerializeTupleStruct = SeqSerializer;
    type SerializeTupleVariant = TupleVariantSerializer;
    type SerializeMap = MapSerializer;
    type SerializeStruct = MapSerializer;
    type SerializeStructVariant = StructVariantSerializer;

    fn serialize_bool(self, v: bool) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Bool(v))
    }

    fn serialize_i8(self, v: i8) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Int(v as i64))
    }

    fn serialize_i16(self, v: i16) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Int(v as i64))
    }

    fn serialize_i32(self, v: i32) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Int(v as i64))
    }

    fn serialize_i64(self, v: i64) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Int(v))
    }

    fn serialize_u8(self, v: u8) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Int(v as i64))
    }

    fn serialize_u16(self, v: u16) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Int(v as i64))
    }

    fn serialize_u32(self, v: u32) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Int(v as i64))
    }

    fn serialize_u64(self, v: u64) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Int(v as i64))
    }

    fn serialize_f32(self, v: f32) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Float(Float(v as f64)))
    }

    fn serialize_f64(self, v: f64) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Float(Float(v)))
    }

    fn serialize_char(self, v: char) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Char(v))
    }

    fn serialize_str(self, v: &str) -> Result<Self::Ok, Self::Error> {
        Ok(Value::String(v.to_string()))
    }

    fn serialize_bytes(self, v: &[u8]) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Seq(
            v.iter().map(|&x| Value::Int(x as i64)).collect(),
        ))
    }

    fn serialize_none(self) -> Result<Self::Ok, Self::Error> {
        self.serialize_unit()
    }

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

    fn serialize_unit(self) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Unit)
    }

    fn serialize_unit_struct(self, _name: &'static str) -> Result<Self::Ok, Self::Error> {
        self.serialize_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: serde::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: serde::Serialize,
    {
        Ok(Value::Variant(
            name.to_string(),
            Box::new(value.serialize(self)?),
        ))
    }

    fn serialize_seq(self, _len: Option<usize>) -> Result<Self::SerializeSeq, Self::Error> {
        Ok(SeqSerializer::default())
    }

    fn serialize_tuple(self, _len: usize) -> Result<Self::SerializeTuple, Self::Error> {
        Ok(SeqSerializer::default())
    }

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

    fn serialize_tuple_variant(
        self,
        _name: &'static str,
        _variant_index: u32,
        variant: &'static str,
        _len: usize,
    ) -> Result<Self::SerializeTupleVariant, Self::Error> {
        Ok(TupleVariantSerializer::new(variant))
    }

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

    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> {
        Ok(StructVariantSerializer::new(variant))
    }
}

#[derive(Default)]
pub struct SeqSerializer {
    values: Vec<Value>,
}

impl SerializeSeq for SeqSerializer {
    type Ok = Value;
    type Error = SerializationError;

    fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
    where
        T: serde::Serialize,
    {
        self.values.push(value.serialize(ValueSerializer)?);
        Ok(())
    }

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

impl SerializeTuple for SeqSerializer {
    type Ok = Value;
    type Error = SerializationError;

    fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
    where
        T: serde::Serialize,
    {
        self.values.push(value.serialize(ValueSerializer)?);
        Ok(())
    }

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

impl SerializeTupleStruct for SeqSerializer {
    type Ok = Value;
    type Error = SerializationError;

    fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
    where
        T: serde::Serialize,
    {
        self.values.push(value.serialize(ValueSerializer)?);
        Ok(())
    }

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

pub struct TupleVariantSerializer {
    name: String,
    values: Vec<Value>,
}

impl TupleVariantSerializer {
    pub fn new(name: &str) -> Self {
        TupleVariantSerializer {
            name: name.to_string(),
            values: Vec::new(),
        }
    }
}

impl SerializeTupleVariant for TupleVariantSerializer {
    type Ok = Value;
    type Error = SerializationError;

    fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
    where
        T: serde::Serialize,
    {
        self.values.push(value.serialize(ValueSerializer)?);
        Ok(())
    }

    fn end(self) -> Result<Self::Ok, Self::Error> {
        Ok(Value::Variant(self.name, Box::new(Value::Seq(self.values))))
    }
}

#[derive(Default)]
pub struct MapSerializer {
    map: Map,
    key: Option<String>,
}

impl SerializeMap for MapSerializer {
    type Ok = Value;
    type Error = SerializationError;

    fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), Self::Error>
    where
        T: serde::Serialize,
    {
        match key.serialize(ValueSerializer)? {
            Value::String(s) => self.key = Some(s),
            v => return Err(SerializationError::NonStringKey(v)),
        }
        Ok(())
    }

    fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
    where
        T: serde::Serialize,
    {
        match self.key.take() {
            Some(x) => {
                self.map.insert(x, value.serialize(ValueSerializer)?);
            }
            None => return Err(SerializationError::ValueWithoutKey),
        }
        Ok(())
    }

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

impl SerializeStruct for MapSerializer {
    type Ok = Value;
    type Error = SerializationError;

    fn serialize_field<T: ?Sized>(
        &mut self,
        key: &'static str,
        value: &T,
    ) -> Result<(), Self::Error>
    where
        T: serde::Serialize,
    {
        match key.serialize(ValueSerializer)? {
            Value::String(s) => {
                self.map.insert(s, value.serialize(ValueSerializer)?);
            }
            v => return Err(SerializationError::NonStringKey(v)),
        }
        Ok(())
    }

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

pub struct StructVariantSerializer {
    name: String,
    map: Map,
}

impl StructVariantSerializer {
    pub fn new(name: &str) -> Self {
        StructVariantSerializer {
            name: name.to_string(),
            map: BTreeMap::new(),
        }
    }
}

impl SerializeStructVariant for StructVariantSerializer {
    type Ok = Value;
    type Error = SerializationError;

    fn serialize_field<T: ?Sized>(
        &mut self,
        key: &'static str,
        value: &T,
    ) -> Result<(), Self::Error>
    where
        T: Serialize,
    {
        match key.serialize(ValueSerializer)? {
            Value::String(s) => {
                self.map.insert(s, value.serialize(ValueSerializer)?);
            }
            v => return Err(SerializationError::NonStringKey(v)),
        }
        Ok(())
    }

    fn end(self) -> Result<Self::Ok, Self::Error> {
        Ok(Value::StructVariant(self.name, self.map))
    }
}