table 0.4.0

// Copyright (C) 2018  Project Tsukurou!
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

use std::collections::HashMap;
use std::fmt;

use serde::ser::{self, SerializeSeq, SerializeMap};
use serde::ser::Error as SerError;

use key::Key;
use value::Value;
use list::List;
use table::Table;
use error::Error;

impl<'a> ser::Serialize for Key<'a> {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: ser::Serializer,
    {
        match self {
            Key::Bool(value) => value.serialize(serializer),
            Key::I64(value) => value.serialize(serializer),
            Key::Bytes(value) => value.serialize(serializer),
            Key::String(value) => value.serialize(serializer),
        }
    }
}

impl<'a> ser::Serialize for Value<'a> {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: ser::Serializer,
    {
        match self {
            Value::Null => ().serialize(serializer),
            Value::Bool(value) => value.serialize(serializer),
            Value::I64(value) => value.serialize(serializer),
            Value::F64(value) => value.serialize(serializer),
            Value::Bytes(value) => value.serialize(serializer),
            Value::String(value) => value.serialize(serializer),
            Value::List(value) => value.serialize(serializer),
            Value::Table(value) => value.serialize(serializer),
        }
    }
}

impl<'a> ser::Serialize for List<'a> {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: ser::Serializer,
    {
        let mut seq = serializer.serialize_seq(Some(self.len()))?;
        for element in self.iter() {
            seq.serialize_element(element)?;
        }
        seq.end()
    }
}

impl<'a> ser::Serialize for Table<'a> {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: ser::Serializer,
    {
        let mut map = serializer.serialize_map(Some(self.len()))?;
        for (key, value) in self.iter() {
            map.serialize_entry(key, value)?;
        }
        map.end()
    }
}

impl ser::Error for Error {
    fn custom<T>(msg: T) -> Self
    where
        T: fmt::Display,
    {
        Error {
            message: msg.to_string(),
        }
    }
}

pub struct KeySerializer;

impl ser::Serializer for KeySerializer {
    type Ok = Key<'static>;
    type Error = Error;
    type SerializeSeq = ser::Impossible<Key<'static>, Error>;
    type SerializeTuple = ser::Impossible<Key<'static>, Error>;
    type SerializeTupleStruct = ser::Impossible<Key<'static>, Error>;
    type SerializeTupleVariant = ser::Impossible<Key<'static>, Error>;
    type SerializeMap = ser::Impossible<Key<'static>, Error>;
    type SerializeStruct = ser::Impossible<Key<'static>, Error>;
    type SerializeStructVariant = ser::Impossible<Key<'static>, Error>;

    fn serialize_bool(self, value: bool) -> Result<Self::Ok, Self::Error> {
        Ok(Key::from(value))
    }

    fn serialize_i8(self, value: i8) -> Result<Self::Ok, Self::Error> {
        Ok(Key::from(value))
    }

    fn serialize_i16(self, value: i16) -> Result<Self::Ok, Self::Error> {
        Ok(Key::from(value))
    }

    fn serialize_i32(self, value: i32) -> Result<Self::Ok, Self::Error> {
        Ok(Key::from(value))
    }

    fn serialize_i64(self, value: i64) -> Result<Self::Ok, Self::Error> {
        Ok(Key::from(value))
    }

    fn serialize_u8(self, value: u8) -> Result<Self::Ok, Self::Error> {
        Ok(Key::from(value))
    }

    fn serialize_u16(self, value: u16) -> Result<Self::Ok, Self::Error> {
        Ok(Key::from(value))
    }
    
    fn serialize_u32(self, value: u32) -> Result<Self::Ok, Self::Error> {
        Ok(Key::from(value))
    }

    fn serialize_u64(self, value: u64) -> Result<Self::Ok, Self::Error> {
        if value > i64::max_value() as u64 {
            Err(Error::custom("Value is out of bounds of an i64"))
        } else {
            Ok(Key::from(value))
        }
    }

    fn serialize_f32(self, _value: f32) -> Result<Self::Ok, Self::Error> {
        Err(Error::custom("Table keys do not support floating-point."))
    }

    fn serialize_f64(self, _value: f64) -> Result<Self::Ok, Self::Error> {
        Err(Error::custom("Table keys do not support floating-point."))
    }

    fn serialize_char(self, value: char) -> Result<Self::Ok, Self::Error> {
        Ok(Key::from(value.to_string()))
    }

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

    fn serialize_bytes(self, _value: &[u8]) -> Result<Self::Ok, Self::Error> {
        Err(Error::custom("Table keys do not support byte strings."))
    }

    fn serialize_none(self) -> Result<Self::Ok, Self::Error> {
        Err(Error::custom("Table keys do not support optionals."))
    }

    fn serialize_some<T>(self, _value: &T) -> Result<Self::Ok, Self::Error>
    where
        T: ser::Serialize + ?Sized,
    {
        Err(Error::custom("Table keys do not support optionals."))
    }

    fn serialize_unit(self) -> Result<Self::Ok, Self::Error> {
        Err(Error::custom("Table keys do not support unit types."))
    }

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

    fn serialize_unit_variant(
        self, 
        _name: &'static str,
        _index: u32,
        _variant: &'static str,
    ) -> Result<Self::Ok, Self::Error>
    {
        Err(Error::custom("Table keys do not support compound types."))
    }

    fn serialize_newtype_struct<T>(
        self,
        _name: &'static str,
        _value: &T
    ) -> Result<Self::Ok, Self::Error>
    where
        T: ser::Serialize + ?Sized,
    {
        Err(Error::custom("Table keys do not support compound types."))
    }

    fn serialize_newtype_variant<T>(
        self,
        _name: &'static str,
        _index: u32,
        _variant: &'static str,
        _value: &T
    ) -> Result<Self::Ok, Self::Error>
    where
        T: ser::Serialize + ?Sized,
    {
        Err(Error::custom("Table keys do not support compound types."))
    }

    fn serialize_seq(self, _len: Option<usize>)
        -> Result<Self::SerializeSeq, Self::Error>
    {
        Err(Error::custom("Table keys do not support compound types."))
    }

    fn serialize_tuple(self, _len: usize)
        -> Result<Self::SerializeTuple, Self::Error>
    {
        Err(Error::custom("Table keys do not support compound types."))
    }

    fn serialize_tuple_struct(self, _name: &'static str, _len: usize)
        -> Result<Self::SerializeTupleStruct, Self::Error>
    {    
        Err(Error::custom("Table keys do not support compound types."))
    }

    fn serialize_tuple_variant(
        self,
        _name: &'static str,
        _index: u32,
        _variant: &'static str,
        _len: usize,
    ) -> Result<Self::SerializeTupleVariant, Self::Error>
    {
        Err(Error::custom("Table keys do not support compound types."))
    }

    fn serialize_map(self, _len: Option<usize>)
        -> Result<Self::SerializeMap, Self::Error>
    {
        Err(Error::custom("Table keys do not support compound types."))
    }

    fn serialize_struct(self, _name: &'static str, _len: usize)
        -> Result<Self::SerializeStruct, Self::Error>
    {
        Err(Error::custom("Table keys do not support compound types."))
    }

    fn serialize_struct_variant(
        self,
        _name: &'static str,
        _index: u32,
        _variant: &'static str,
        _len: usize
    ) -> Result<Self::SerializeStructVariant, Self::Error>
    {
        Err(Error::custom("Table keys do not support compound types."))
    }
}

pub struct ValueSerializer;

impl ser::Serializer for ValueSerializer {
    type Ok = Value<'static>;
    type Error = Error;
    type SerializeSeq = ListSerializer;
    type SerializeTuple = ListSerializer;
    type SerializeTupleStruct = ListSerializer;
    type SerializeTupleVariant = ListSerializer;
    type SerializeMap = TableSerializer;
    type SerializeStruct = TableSerializer;
    type SerializeStructVariant = TableSerializer;

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

    fn serialize_i8(self, value: i8) -> Result<Self::Ok, Self::Error> {
        Ok(Value::from(value))
    }

    fn serialize_i16(self, value: i16) -> Result<Self::Ok, Self::Error> {
        Ok(Value::from(value))
    }

    fn serialize_i32(self, value: i32) -> Result<Self::Ok, Self::Error> {
        Ok(Value::from(value))
    }

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

    fn serialize_u8(self, value: u8) -> Result<Self::Ok, Self::Error> {
        Ok(Value::from(value))
    }

    fn serialize_u16(self, value: u16) -> Result<Self::Ok, Self::Error> {
        Ok(Value::from(value))
    }
    
    fn serialize_u32(self, value: u32) -> Result<Self::Ok, Self::Error> {
        Ok(Value::from(value))
    }

    fn serialize_u64(self, value: u64) -> Result<Self::Ok, Self::Error> {
        if value > i64::max_value() as u64 {
            Err(Error::custom("Value is out of bounds of an i64"))
        } else {
            Ok(Value::from(value))
        }
    }

    fn serialize_f32(self, value: f32) -> Result<Self::Ok, Self::Error> {
        Ok(Value::from(value))
    }

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

    fn serialize_char(self, value: char) -> Result<Self::Ok, Self::Error> {
        Ok(Value::from(value.to_string()))
    }

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

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

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

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

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

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

    fn serialize_unit_variant(
        self, 
        _name: &'static str,
        _index: u32,
        _variant: &'static str,
    ) -> Result<Self::Ok, Self::Error>
    {
        self.serialize_unit()
    }

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

    fn serialize_newtype_variant<T>(
        self,
        _name: &'static str,
        _index: u32,
        variant: &'static str,
        value: &T
    ) -> Result<Self::Ok, Self::Error>
    where
        T: ser::Serialize + ?Sized,
    {
        let mut table = Table::new();
        table.insert(variant, value.serialize(self)?);
        Ok(Value::from(table))
    }

    fn serialize_seq(self, len: Option<usize>)
        -> Result<Self::SerializeSeq, Self::Error>
    {
        Ok(ListSerializer::new(len, None))
    }

    fn serialize_tuple(self, len: usize)
        -> Result<Self::SerializeTuple, Self::Error>
    {
        Ok(ListSerializer::new(Some(len), None))
    }

    fn serialize_tuple_struct(self, _name: &'static str, len: usize)
        -> Result<Self::SerializeTupleStruct, Self::Error>
    {    
        Ok(ListSerializer::new(Some(len), None))
    }

    fn serialize_tuple_variant(
        self,
        _name: &'static str,
        _index: u32,
        variant: &'static str,
        len: usize,
    ) -> Result<Self::SerializeTupleVariant, Self::Error>
    {
        Ok(ListSerializer::new(Some(len), Some(variant)))
    }

    fn serialize_map(self, len: Option<usize>)
        -> Result<Self::SerializeMap, Self::Error>
    {
        Ok(TableSerializer::new(len, None))
    }

    fn serialize_struct(self, _name: &'static str, len: usize)
        -> Result<Self::SerializeStruct, Self::Error>
    {
        Ok(TableSerializer::new(Some(len), None))
    }

    fn serialize_struct_variant(
        self,
        _name: &'static str,
        _index: u32,
        variant: &'static str,
        len: usize
    ) -> Result<Self::SerializeStructVariant, Self::Error>
    {
        Ok(TableSerializer::new(Some(len), Some(variant)))
    }
}

pub struct ListSerializer {
    list: List<'static>,
    variant: Option<&'static str>,
}

impl ListSerializer {
    fn new(len: Option<usize>, variant: Option<&'static str>)
        -> ListSerializer
    {
        ListSerializer {
            list: List::with_vec(Vec::with_capacity(len.unwrap_or(0))),
            variant,
        }
    }
}

impl ser::SerializeSeq for ListSerializer {
    type Ok = Value<'static>;
    type Error = Error;

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

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

impl ser::SerializeTuple for ListSerializer {
    type Ok = Value<'static>;
    type Error = Error;

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

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

impl ser::SerializeTupleStruct for ListSerializer {
    type Ok = Value<'static>;
    type Error = Error;

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

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

impl ser::SerializeTupleVariant for ListSerializer {
    type Ok = Value<'static>;
    type Error = Error;

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

    fn end(self) -> Result<Self::Ok, Self::Error> {
        let mut tagged = Table::new();
        tagged.insert(self.variant.unwrap(), self.list);
        Ok(Value::from(tagged))
    }
}

pub struct TableSerializer {
    table: Table<'static>,
    key: Option<Key<'static>>,
    variant: Option<&'static str>,
}

impl TableSerializer {
    fn new(len: Option<usize>, variant: Option<&'static str>)
        -> TableSerializer
    {
        TableSerializer {
            table: Table::with_map(HashMap::with_capacity(len.unwrap_or(0))),
            key: None,
            variant,
        }
    }
}

impl ser::SerializeMap for TableSerializer {
    type Ok = Value<'static>;
    type Error = Error;

    fn serialize_key<K>(&mut self, key: &K) -> Result<(), Self::Error>
    where
        K: ser::Serialize + ?Sized,
    {
        debug_assert!(self.key.is_none());
        self.key = Some(key.serialize(KeySerializer)?);
        Ok(())
    }

    fn serialize_value<V>(&mut self, value: &V) -> Result<(), Self::Error>
    where
        V: ser::Serialize + ?Sized,
    {
        self.table.insert(
            self.key.take().unwrap(),
            value.serialize(ValueSerializer)?,
        );
        Ok(())
    }

    fn serialize_entry<K, V>(&mut self, key: &K, value: &V)
        -> Result<(), Self::Error>
    where
        K: ser::Serialize + ?Sized,
        V: ser::Serialize + ?Sized,
    {
        self.table.insert(
            key.serialize(KeySerializer)?,
            value.serialize(ValueSerializer)?,
        );
        Ok(())
    }
    
    fn end(self) -> Result<Self::Ok, Self::Error> {
        Ok(Value::from(self.table))
    }
}

impl ser::SerializeStruct for TableSerializer {
    type Ok = Value<'static>;
    type Error = Error;

    fn serialize_field<T>(&mut self, key: &'static str, value: &T)
        -> Result<(), Self::Error>
    where
        T: ser::Serialize + ?Sized,
    {
        self.table.insert(key, value.serialize(ValueSerializer)?);
        Ok(())
    }

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

impl ser::SerializeStructVariant for TableSerializer {
    type Ok = Value<'static>;
    type Error = Error;

    fn serialize_field<T>(&mut self, key: &'static str, value: &T)
        -> Result<(), Self::Error>
    where
        T: ser::Serialize + ?Sized,
    {
        self.table.insert(key, value.serialize(ValueSerializer)?);
        Ok(())
    }

    fn end(self) -> Result<Self::Ok, Self::Error> {
        let mut tagged = Table::new();
        tagged.insert(self.variant.unwrap(), self.table);
        Ok(Value::from(tagged))
    }
}