doge 0.1.0

use error;
use serde;
use std;

pub(crate) struct Serializer<W: std::io::Write> {
    writer: W,
    buf: [u8; 4],
}

pub fn to_writer<T, W: std::io::Write>(writer: W, value: &T) -> error::Result<()>
where
    T: serde::Serialize,
{
    let mut serializer = Serializer {
        writer,
        buf: Default::default(),
    };
    value.serialize(&mut serializer)
}

pub fn to_vec<T>(value: &T) -> error::Result<Vec<u8>>
where
    T: serde::Serialize,
{
    let mut writer = Vec::with_capacity(128);
    to_writer(&mut writer, value)?;
    Ok(writer)
}

pub fn to_string<T>(value: &T) -> error::Result<String>
where
    T: serde::Serialize,
{
    let vec = to_vec(value)?;
    let string = String::from_utf8(vec).expect("Output should be valid"); // TODO consider using unchecked
    Ok(string)
}

impl<'a, W: std::io::Write> serde::ser::Serializer for &'a mut Serializer<W> {
    type Ok = ();

    type Error = error::Error;

    type SerializeSeq = SeqSerializer<'a, W>;
    type SerializeTuple = SeqSerializer<'a, W>;
    type SerializeTupleStruct = SeqSerializer<'a, W>;
    type SerializeTupleVariant = SeqSerializer<'a, W>;
    type SerializeMap = MapSerializer<'a, W>;
    type SerializeStruct = MapSerializer<'a, W>;
    type SerializeStructVariant = MapSerializer<'a, W>;

    fn serialize_bool(self, v: bool) -> error::Result<()> {
        self.writer.write_all(if v { b"yes" } else { b"no" })?;
        Ok(())
    }

    fn serialize_i8(self, v: i8) -> error::Result<()> {
        write!(self.writer, "{}", v)?;
        Ok(())
    }

    fn serialize_i16(self, v: i16) -> error::Result<()> {
        write!(self.writer, "{}", v)?;
        Ok(())
    }

    fn serialize_i32(self, v: i32) -> error::Result<()> {
        write!(self.writer, "{}", v)?;
        Ok(())
    }

    fn serialize_i64(self, v: i64) -> error::Result<()> {
        // TODO potentially optimize this
        write!(self.writer, "{}", v)?;
        Ok(())
    }

    fn serialize_u8(self, v: u8) -> error::Result<()> {
        write!(self.writer, "{}", v)?;
        Ok(())
    }

    fn serialize_u16(self, v: u16) -> error::Result<()> {
        write!(self.writer, "{}", v)?;
        Ok(())
    }

    fn serialize_u32(self, v: u32) -> error::Result<()> {
        write!(self.writer, "{}", v)?;
        Ok(())
    }

    fn serialize_u64(self, v: u64) -> error::Result<()> {
        write!(self.writer, "{}", v)?;
        Ok(())
    }

    fn serialize_f32(self, v: f32) -> error::Result<()> {
        write!(self.writer, "{}", v)?;
        Ok(())
    }

    fn serialize_f64(self, v: f64) -> error::Result<()> {
        write!(self.writer, "{}", v)?;
        Ok(())
    }

    fn serialize_char(self, v: char) -> error::Result<()> {
        self.serialize_str(&v.to_string())
    }

    fn serialize_str(self, v: &str) -> error::Result<()> {
        self.writer.write_all(b"\"")?;
        for c in v.chars() {
            match c {
                '"' => self.writer.write_all(b"\\\""),
                '\\' => self.writer.write_all(b"\\\\"),
                '\x08' => self.writer.write_all(b"\\b"),
                '\x0c' => self.writer.write_all(b"\\f"),
                '\n' => self.writer.write_all(b"\\n"),
                '\t' => self.writer.write_all(b"\\t"),
                '\r' => self.writer.write_all(b"\\r"),
                _ if c.is_control() => {
                    let len = c.encode_utf8(&mut self.buf).len();
                    match len {
                        1 => write!(self.writer, "\\x{:02X}", self.buf[0]),
                        _ => panic!("unexpected byte length"),
                    }
                }
                _ => write!(self.writer, "{}", c),
            }?
        }
        self.writer.write_all(b"\"")?;
        Ok(())
    }

    fn serialize_none(self) -> error::Result<()> {
        self.serialize_unit()
    }

    fn serialize_some<T>(self, v: &T) -> error::Result<()>
    where
        T: ?Sized + serde::ser::Serialize,
    {
        v.serialize(self)
    }

    fn serialize_unit(self) -> error::Result<()> {
        self.writer.write_all(b"empty")?;
        Ok(())
    }

    fn serialize_unit_struct(self, _name: &'static str) -> error::Result<()> {
        self.serialize_unit()
    }

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

    fn serialize_newtype_struct<T>(self, _name: &'static str, v: &T) -> error::Result<()>
    where
        T: ?Sized + serde::ser::Serialize,
    {
        v.serialize(self)
    }

    fn serialize_newtype_variant<T>(
        self,
        _name: &'static str,
        _variant_index: u32,
        variant: &'static str,
        v: &T,
    ) -> error::Result<()>
    where
        T: ?Sized + serde::ser::Serialize,
    {
        self.writer.write_all(b"such ")?;
        self.serialize_str(variant)?;
        self.writer.write_all(b" is ")?;
        v.serialize(&mut *self)?;
        self.writer.write_all(b" wow")?;
        Ok(())
    }

    fn serialize_bytes(self, v: &[u8]) -> error::Result<()> {
        use serde::ser::SerializeSeq;
        let mut seq = self.serialize_seq(Some(v.len()))?;
        for byte in v {
            seq.serialize_element(byte)?;
        }
        seq.end()
    }

    fn serialize_seq(self, _len: Option<usize>) -> error::Result<Self::SerializeSeq> {
        self.writer.write_all(b"so ")?;
        Ok(SeqSerializer::new(self))
    }

    fn serialize_tuple(self, len: usize) -> error::Result<Self::SerializeTuple> {
        self.serialize_seq(Some(len))
    }

    fn serialize_tuple_struct(
        self,
        _name: &'static str,
        len: usize,
    ) -> error::Result<Self::SerializeTupleStruct> {
        self.serialize_seq(Some(len))
    }

    fn serialize_tuple_variant(
        self,
        _name: &'static str,
        _variant_index: u32,
        variant: &'static str,
        _len: usize,
    ) -> error::Result<Self::SerializeTupleVariant> {
        self.writer.write_all(b"such ")?;
        self.serialize_str(variant)?;
        self.writer.write_all(b" is so ")?;
        Ok(SeqSerializer::new(self))
    }

    fn serialize_map(self, _len: Option<usize>) -> error::Result<Self::SerializeMap> {
        self.writer.write_all(b"such ")?;
        Ok(MapSerializer::new(self))
    }

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

    fn serialize_struct_variant(
        self,
        _name: &'static str,
        _variant_index: u32,
        variant: &'static str,
        _len: usize,
    ) -> error::Result<Self::SerializeStructVariant> {
        self.writer.write_all(b"such ")?;
        self.serialize_str(variant)?;
        self.writer.write_all(b" is such ")?;
        Ok(MapSerializer::new(self))
    }
}

pub(crate) struct SeqSerializer<'a, W: 'a + std::io::Write> {
    first: bool,
    ser: &'a mut Serializer<W>,
}

impl<'a, W: std::io::Write> SeqSerializer<'a, W> {
    pub fn new(ser: &'a mut Serializer<W>) -> Self {
        Self { first: true, ser }
    }
}

impl<'a, W: std::io::Write> serde::ser::SerializeSeq for SeqSerializer<'a, W> {
    type Ok = ();
    type Error = error::Error;

    fn serialize_element<T>(&mut self, v: &T) -> error::Result<()>
    where
        T: ?Sized + serde::ser::Serialize,
    {
        if self.first {
            self.first = false;
        } else {
            self.ser.writer.write_all(b"and ")?;
        }
        v.serialize(&mut *self.ser)?;
        self.ser.writer.write_all(b" ")?;
        Ok(())
    }

    fn end(self) -> error::Result<()> {
        self.ser.writer.write_all(b"many")?;
        Ok(())
    }
}

/* implemented to simply delegate to SerializeSeq */
impl<'a, W: std::io::Write> serde::ser::SerializeTuple for SeqSerializer<'a, W> {
    type Ok = ();
    type Error = error::Error;

    fn serialize_element<T>(&mut self, v: &T) -> error::Result<()>
    where
        T: ?Sized + serde::ser::Serialize,
    {
        serde::ser::SerializeSeq::serialize_element(self, v)
    }

    fn end(self) -> error::Result<()> {
        serde::ser::SerializeSeq::end(self)
    }
}

/* implemented to simply delegate to SerializeSeq */
impl<'a, W: std::io::Write> serde::ser::SerializeTupleStruct for SeqSerializer<'a, W> {
    type Ok = ();
    type Error = error::Error;

    fn serialize_field<T>(&mut self, v: &T) -> error::Result<()>
    where
        T: ?Sized + serde::ser::Serialize,
    {
        serde::ser::SerializeSeq::serialize_element(self, v)
    }

    fn end(self) -> error::Result<()> {
        serde::ser::SerializeSeq::end(self)
    }
}

/* delegate to SerializeSeq except for end */
impl<'a, W: std::io::Write> serde::ser::SerializeTupleVariant for SeqSerializer<'a, W> {
    type Ok = ();
    type Error = error::Error;

    fn serialize_field<T>(&mut self, v: &T) -> error::Result<()>
    where
        T: ?Sized + serde::ser::Serialize,
    {
        serde::ser::SerializeSeq::serialize_element(self, v)
    }

    fn end(self) -> error::Result<()> {
        self.ser.writer.write_all(b" many wow")?;
        Ok(())
    }
}

pub(crate) struct MapSerializer<'a, W: 'a + std::io::Write> {
    first: bool,
    ser: &'a mut Serializer<W>,
}

impl<'a, W: 'a + std::io::Write> MapSerializer<'a, W> {
    pub fn new(ser: &'a mut Serializer<W>) -> Self {
        Self { ser, first: true }
    }
}

impl<'a, W: std::io::Write> serde::ser::SerializeMap for MapSerializer<'a, W> {
    type Ok = ();
    type Error = error::Error;

    fn serialize_key<T>(&mut self, key: &T) -> error::Result<()>
    where
        T: ?Sized + serde::ser::Serialize,
    {
        if self.first {
            self.first = false;
        } else {
            self.ser.writer.write_all(b",")?;
        }
        key.serialize(&mut *self.ser)
    }

    fn serialize_value<T>(&mut self, v: &T) -> error::Result<()>
    where
        T: ?Sized + serde::ser::Serialize,
    {
        self.ser.writer.write_all(b" is ")?;
        v.serialize(&mut *self.ser)
    }

    fn end(self) -> error::Result<()> {
        self.ser.writer.write_all(b" wow")?;
        Ok(())
    }
}

/* delegates to SerializeMap */
impl<'a, W: std::io::Write> serde::ser::SerializeStruct for MapSerializer<'a, W> {
    type Ok = ();
    type Error = error::Error;

    fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> error::Result<()>
    where
        T: ?Sized + serde::ser::Serialize,
    {
        serde::ser::SerializeMap::serialize_key(self, key)?;
        serde::ser::SerializeMap::serialize_value(self, value)
    }

    fn end(self) -> error::Result<()> {
        serde::ser::SerializeMap::end(self)
    }
}

/* delegates to SerializeMap, except for end */
impl<'a, W: std::io::Write> serde::ser::SerializeStructVariant for MapSerializer<'a, W> {
    type Ok = ();
    type Error = error::Error;

    fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> error::Result<()>
    where
        T: ?Sized + serde::ser::Serialize,
    {
        serde::ser::SerializeMap::serialize_key(self, key)?;
        serde::ser::SerializeMap::serialize_value(self, value)
    }

    fn end(self) -> error::Result<()> {
        self.ser.writer.write_all(b" wow wow")?;
        Ok(())
    }
}