use crate::dom::array::ArrayIter;
use crate::dom::element::{Element, ElementType};
use crate::dom::object::ObjectIter;

use crate::error::SimdJsonError;
use crate::libsimdjson::ffi;
use serde::de::{
    Deserialize, DeserializeSeed, Deserializer, IntoDeserializer, MapAccess, SeqAccess, Visitor,
};

// pub struct ElementVisitor;

// impl<'de> Visitor for ElementVisitor {

// }

pub fn from_element<'a, T>(element: &'a Element<'a>) -> Result<T, SimdJsonError>
where
    T: Deserialize<'a>,
{
    // let mut parser = Parser::default();
    // let mut doc = parser.parse_str(s)?;
    let t = T::deserialize(element)?;
    Ok(t)
}

impl<'de, 'a> Deserializer<'de> for &'a Element<'a> {
    type Error = SimdJsonError;

    fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        match self.get_type() {
            ElementType::NullValue => self.deserialize_unit(visitor),
            ElementType::Bool => self.deserialize_bool(visitor),
            ElementType::String => self.deserialize_str(visitor),
            ElementType::Uint64 => self.deserialize_u64(visitor),
            ElementType::Int64 => self.deserialize_i64(visitor),
            ElementType::Array => self.deserialize_seq(visitor),
            ElementType::Object => self.deserialize_map(visitor),
            ElementType::Double => self.deserialize_f64(visitor),
        }
    }

    fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_bool(self.get_bool()?)
    }

    fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_unit()
    }

    fn deserialize_i8<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_i8(self.get_i64()? as i8)
    }

    fn deserialize_i16<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_i16(self.get_i64()? as i16)
    }

    fn deserialize_i32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_i32(self.get_i64()? as i32)
    }

    fn deserialize_i64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_i64(self.get_i64()?)
    }

    fn deserialize_u8<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_u8(self.get_u64()? as u8)
    }

    fn deserialize_u16<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_u16(self.get_u64()? as u16)
    }

    fn deserialize_u32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_u32(self.get_u64()? as u32)
    }

    fn deserialize_u64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_u64(self.get_u64()?)
    }

    // Float parsing is stupidly hard.
    fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_f32(self.get_f64()? as f32)
    }

    // Float parsing is stupidly hard.
    fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_f64(self.get_f64()?)
    }

    // The `Serializer` implementation on the previous page serialized chars as
    // single-character strings so handle that representation here.
    fn deserialize_char<V>(self, _visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        // Parse a string, check that it is one character, call `visit_char`.
        unimplemented!()
    }

    // Refer to the "Understanding deserializer lifetimes" page for information
    // about the three deserialization flavors of strings in Serde.
    fn deserialize_str<V>(self, _visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        unimplemented!()
    }

    fn deserialize_string<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_string(self.get_string()?)
    }

    // The `Serializer` implementation on the previous page serialized byte
    // arrays as JSON arrays of bytes. Handle that representation here.
    fn deserialize_bytes<V>(self, _visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        unimplemented!()
    }

    fn deserialize_byte_buf<V>(self, _visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        unimplemented!()
    }

    // An absent optional is represented as the JSON `null` and a present
    // optional is represented as just the contained value.
    //
    // As commented in `Serializer` implementation, this is a lossy
    // representation. For example the values `Some(())` and `None` both
    // serialize as just `null`. Unfortunately this is typically what people
    // expect when working with JSON. Other formats are encouraged to behave
    // more intelligently if possible.
    fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        if self.is_null() {
            visitor.visit_none()
        } else {
            visitor.visit_some(self)
        }
    }

    // Unit struct means a named value containing no data.
    fn deserialize_unit_struct<V>(
        self,
        _name: &'static str,
        visitor: V,
    ) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        self.deserialize_unit(visitor)
    }

    // As is done here, serializers are encouraged to treat newtype structs as
    // insignificant wrappers around the data they contain. That means not
    // parsing anything other than the contained value.
    fn deserialize_newtype_struct<V>(
        self,
        _name: &'static str,
        visitor: V,
    ) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_newtype_struct(self)
    }

    // Deserialization of compound types like sequences and maps happens by
    // passing the visitor an "Access" object that gives it the ability to
    // iterate through the data contained in the sequence.
    fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        // Parse the opening bracket of the sequence.
        // de::Deserializer::deserialize_seq(self.into_iter(), visitor)
        // unimplemented!()
        let value = visitor.visit_seq(ArrayIter::new(&self.get_array()?))?;
        Ok(value)
    }

    // Tuples look just like sequences in JSON. Some formats may be able to
    // represent tuples more efficiently.
    //
    // As indicated by the length parameter, the `Deserialize` implementation
    // for a tuple in the Serde data model is required to know the length of the
    // tuple before even looking at the input data.
    fn deserialize_tuple<V>(self, _len: usize, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        self.deserialize_seq(visitor)
    }

    // Tuple structs look just like sequences in JSON.
    fn deserialize_tuple_struct<V>(
        self,
        _name: &'static str,
        _len: usize,
        visitor: V,
    ) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        self.deserialize_seq(visitor)
    }

    // Much like `deserialize_seq` but calls the visitors `visit_map` method
    // with a `MapAccess` implementation, rather than the visitor's `visit_seq`
    // method with a `SeqAccess` implementation.
    fn deserialize_map<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        visitor.visit_map(ObjectIter::new(&self.get_object()?))
    }

    // Structs look just like maps in JSON.
    //
    // Notice the `fields` parameter - a "struct" in the Serde data model means
    // that the `Deserialize` implementation is required to know what the fields
    // are before even looking at the input data. Any key-value pairing in which
    // the fields cannot be known ahead of time is probably a map.
    fn deserialize_struct<V>(
        self,
        _name: &'static str,
        _fields: &'static [&'static str],
        visitor: V,
    ) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        self.deserialize_map(visitor)
    }

    fn deserialize_enum<V>(
        self,
        _name: &'static str,
        _variants: &'static [&'static str],
        _visitor: V,
    ) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        unimplemented!()
    }

    // An identifier in Serde is the type that identifies a field of a struct or
    // the variant of an enum. In JSON, struct fields and enum variants are
    // represented as strings. In other formats they may be represented as
    // numeric indices.
    fn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        self.deserialize_str(visitor)
    }

    // Like `deserialize_any` but indicates to the `Deserializer` that it makes
    // no difference which `Visitor` method is called because the data is
    // ignored.
    //
    // Some deserializers are able to implement this more efficiently than
    // `deserialize_any`, for example by rapidly skipping over matched
    // delimiters without paying close attention to the data in between.
    //
    // Some formats are not able to implement this at all. Formats that can
    // implement `deserialize_any` and `deserialize_ignored_any` are known as
    // self-describing.
    fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: Visitor<'de>,
    {
        self.deserialize_any(visitor)
    }
}

impl<'de, 'a> SeqAccess<'de> for ArrayIter<'a> {
    type Error = SimdJsonError;

    fn next_element_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>, Self::Error>
    where
        T: DeserializeSeed<'de>,
    {
        if let Some(element) = self.next() {
            seed.deserialize(&element).map(Some)
        } else {
            Ok(None)
        }
    }
}

impl<'de, 'a> MapAccess<'de> for ObjectIter<'a> {
    type Error = SimdJsonError;

    fn next_key_seed<K>(&mut self, seed: K) -> Result<Option<K::Value>, Self::Error>
    where
        K: DeserializeSeed<'de>,
    {
        if self.has_next() {
            seed.deserialize(self.key().into_deserializer()).map(Some)
        } else {
            Ok(None)
        }
    }

    fn next_value_seed<V>(&mut self, seed: V) -> Result<V::Value, Self::Error>
    where
        V: DeserializeSeed<'de>,
    {
        let result = seed.deserialize(&self.value());
        ffi::object_iterator_next(self.ptr.pin_mut());
        result
    }
}