use std::result::Result as StdResult;
#[cfg(feature = "napi6")]
use std::slice;

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

use super::*;
use crate::{Env, Error, Result};

pub(crate) struct Ser<'env>(pub(crate) &'env Env);

impl<'env> Ser<'env> {
  fn new(env: &'env Env) -> Self {
    Self(env)
  }
}

impl<'env> Serializer for Ser<'env> {
  type Ok = Value;
  type Error = Error;

  type SerializeSeq = SeqSerializer;
  type SerializeTuple = SeqSerializer;
  type SerializeTupleStruct = SeqSerializer;
  type SerializeTupleVariant = SeqSerializer;
  type SerializeMap = MapSerializer;
  type SerializeStruct = StructSerializer;
  type SerializeStructVariant = StructSerializer;

  #[inline]
  fn serialize_bool(self, v: bool) -> Result<Self::Ok> {
    self.0.get_boolean(v).map(|js_value| js_value.0)
  }

  #[inline]
  fn serialize_bytes(self, v: &[u8]) -> Result<Self::Ok> {
    self
      .0
      .create_buffer_with_data(v.to_owned())
      .map(|js_value| js_value.value.0)
  }

  #[inline]
  fn serialize_char(self, v: char) -> Result<Self::Ok> {
    let mut b = [0; 4];
    let result = v.encode_utf8(&mut b);
    self.0.create_string(result).map(|js_string| js_string.0)
  }

  #[inline]
  fn serialize_f32(self, v: f32) -> Result<Self::Ok> {
    self.0.create_double(v as _).map(|js_number| js_number.0)
  }

  #[inline]
  fn serialize_f64(self, v: f64) -> Result<Self::Ok> {
    self.0.create_double(v).map(|js_number| js_number.0)
  }

  #[inline]
  fn serialize_i16(self, v: i16) -> Result<Self::Ok> {
    self.0.create_int32(v as _).map(|js_number| js_number.0)
  }

  #[inline]
  fn serialize_i32(self, v: i32) -> Result<Self::Ok> {
    self.0.create_int32(v).map(|js_number| js_number.0)
  }

  #[inline]
  fn serialize_i64(self, v: i64) -> Result<Self::Ok> {
    self.0.create_int64(v).map(|js_number| js_number.0)
  }

  #[inline]
  fn serialize_i8(self, v: i8) -> Result<Self::Ok> {
    self.0.create_int32(v as _).map(|js_number| js_number.0)
  }

  #[inline]
  fn serialize_u8(self, v: u8) -> Result<Self::Ok> {
    self.0.create_uint32(v as _).map(|js_number| js_number.0)
  }

  #[inline]
  fn serialize_u16(self, v: u16) -> Result<Self::Ok> {
    self.0.create_uint32(v as _).map(|js_number| js_number.0)
  }

  #[inline]
  fn serialize_u32(self, v: u32) -> Result<Self::Ok> {
    self.0.create_uint32(v).map(|js_number| js_number.0)
  }

  #[cfg(all(
    any(
      feature = "napi2",
      feature = "napi3",
      feature = "napi4",
      feature = "napi5"
    ),
    not(feature = "napi6")
  ))]
  #[inline]
  fn serialize_u64(self, v: u64) -> Result<Self::Ok> {
    self.0.create_int64(v as _).map(|js_number| js_number.0)
  }

  #[cfg(feature = "napi6")]
  #[inline]
  fn serialize_u64(self, v: u64) -> Result<Self::Ok> {
    self
      .0
      .create_bigint_from_u64(v)
      .map(|js_number| js_number.raw)
  }

  #[cfg(all(
    any(
      feature = "napi2",
      feature = "napi3",
      feature = "napi4",
      feature = "napi5"
    ),
    not(feature = "napi6")
  ))]
  #[inline]
  fn serialize_u128(self, v: u128) -> Result<Self::Ok> {
    self.0.create_string(v.to_string().as_str()).map(|v| v.0)
  }

  #[cfg(feature = "napi6")]
  #[inline]
  fn serialize_u128(self, v: u128) -> Result<Self::Ok> {
    let words_ref = &v as *const _;
    let words = unsafe { slice::from_raw_parts(words_ref as *const u64, 2) };
    self
      .0
      .create_bigint_from_words(false, words.to_vec())
      .map(|v| v.raw)
  }

  #[cfg(all(
    any(
      feature = "napi2",
      feature = "napi3",
      feature = "napi4",
      feature = "napi5"
    ),
    not(feature = "napi6")
  ))]
  #[inline]
  fn serialize_i128(self, v: i128) -> Result<Self::Ok> {
    self.0.create_string(v.to_string().as_str()).map(|v| v.0)
  }

  #[cfg(feature = "napi6")]
  #[inline]
  fn serialize_i128(self, v: i128) -> Result<Self::Ok> {
    let words_ref = &(v as u128) as *const _;
    let words = unsafe { slice::from_raw_parts(words_ref as *const u64, 2) };
    self
      .0
      .create_bigint_from_words(v < 0, words.to_vec())
      .map(|v| v.raw)
  }

  #[inline]
  fn serialize_unit(self) -> Result<Self::Ok> {
    self.0.get_null().map(|null| null.0)
  }

  #[inline]
  fn serialize_none(self) -> Result<Self::Ok> {
    self.0.get_null().map(|null| null.0)
  }

  #[inline]
  fn serialize_str(self, v: &str) -> Result<Self::Ok> {
    self.0.create_string(v).map(|string| string.0)
  }

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

  #[inline]
  fn serialize_map(self, _len: Option<usize>) -> Result<Self::SerializeMap> {
    let env = self.0;
    let key = env.create_string("")?;
    let obj = env.create_object()?;
    Ok(MapSerializer { key, obj })
  }

  #[inline]
  fn serialize_seq(self, len: Option<usize>) -> Result<Self::SerializeSeq> {
    let array = self.0.create_array_with_length(len.unwrap_or(0))?;
    Ok(SeqSerializer {
      current_index: 0,
      array,
    })
  }

  #[inline]
  fn serialize_tuple_variant(
    self,
    _name: &'static str,
    _variant_index: u32,
    variant: &'static str,
    len: usize,
  ) -> Result<Self::SerializeTupleVariant> {
    let env = self.0;
    let array = env.create_array_with_length(len)?;
    let mut object = env.create_object()?;
    object.set_named_property(
      variant,
      JsObject(Value {
        value: array.0.value,
        env: array.0.env,
        value_type: ValueType::Object,
      }),
    )?;
    Ok(SeqSerializer {
      current_index: 0,
      array,
    })
  }

  #[inline]
  fn serialize_unit_struct(self, _name: &'static str) -> Result<Self::Ok> {
    self.0.get_null().map(|null| null.0)
  }

  #[inline]
  fn serialize_unit_variant(
    self,
    _name: &'static str,
    _variant_index: u32,
    variant: &'static str,
  ) -> Result<Self::Ok> {
    self.0.create_string(variant).map(|string| string.0)
  }

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

  #[inline]
  fn serialize_newtype_variant<T: ?Sized>(
    self,
    _name: &'static str,
    _variant_index: u32,
    variant: &'static str,
    value: &T,
  ) -> Result<Self::Ok>
  where
    T: Serialize,
  {
    let mut obj = self.0.create_object()?;
    obj.set_named_property(variant, JsUnknown(value.serialize(self)?))?;
    Ok(obj.0)
  }

  #[inline]
  fn serialize_tuple(self, len: usize) -> Result<Self::SerializeTuple> {
    Ok(SeqSerializer {
      array: self.0.create_array_with_length(len)?,
      current_index: 0,
    })
  }

  #[inline]
  fn serialize_tuple_struct(
    self,
    _name: &'static str,
    len: usize,
  ) -> Result<Self::SerializeTupleStruct> {
    Ok(SeqSerializer {
      array: self.0.create_array_with_length(len)?,
      current_index: 0,
    })
  }

  #[inline]
  fn serialize_struct(self, _name: &'static str, _len: usize) -> Result<Self::SerializeStruct> {
    Ok(StructSerializer {
      obj: self.0.create_object()?,
    })
  }

  #[inline]
  fn serialize_struct_variant(
    self,
    _name: &'static str,
    _variant_index: u32,
    variant: &'static str,
    _len: usize,
  ) -> Result<Self::SerializeStructVariant> {
    let mut outer = self.0.create_object()?;
    let inner = self.0.create_object()?;
    outer.set_named_property(
      variant,
      JsObject(Value {
        env: inner.0.env,
        value: inner.0.value,
        value_type: ValueType::Object,
      }),
    )?;
    Ok(StructSerializer {
      obj: self.0.create_object()?,
    })
  }
}

pub struct SeqSerializer {
  array: JsObject,
  current_index: usize,
}

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

  fn serialize_element<T: ?Sized>(&mut self, value: &T) -> StdResult<(), Self::Error>
  where
    T: Serialize,
  {
    let env = unsafe { Env::from_raw(self.array.0.env) };
    self.array.set_element(
      self.current_index as _,
      JsUnknown(value.serialize(Ser::new(&env))?),
    )?;
    self.current_index += 1;
    Ok(())
  }

  fn end(self) -> Result<Self::Ok> {
    Ok(self.array.0)
  }
}

#[doc(hidden)]
impl ser::SerializeTuple for SeqSerializer {
  type Ok = Value;
  type Error = Error;

  #[inline]
  fn serialize_element<T: ?Sized>(&mut self, value: &T) -> StdResult<(), Self::Error>
  where
    T: Serialize,
  {
    let env = unsafe { Env::from_raw(self.array.0.env) };
    self.array.set_element(
      self.current_index as _,
      JsUnknown(value.serialize(Ser::new(&env))?),
    )?;
    self.current_index += 1;
    Ok(())
  }

  #[inline]
  fn end(self) -> StdResult<Self::Ok, Self::Error> {
    Ok(self.array.0)
  }
}

#[doc(hidden)]
impl ser::SerializeTupleStruct for SeqSerializer {
  type Ok = Value;
  type Error = Error;

  #[inline]
  fn serialize_field<T: ?Sized>(&mut self, value: &T) -> StdResult<(), Self::Error>
  where
    T: Serialize,
  {
    let env = unsafe { Env::from_raw(self.array.0.env) };
    self.array.set_element(
      self.current_index as _,
      JsUnknown(value.serialize(Ser::new(&env))?),
    )?;
    self.current_index += 1;
    Ok(())
  }

  #[inline]
  fn end(self) -> StdResult<Self::Ok, Self::Error> {
    Ok(self.array.0)
  }
}

#[doc(hidden)]
impl ser::SerializeTupleVariant for SeqSerializer {
  type Ok = Value;
  type Error = Error;

  #[inline]
  fn serialize_field<T: ?Sized>(&mut self, value: &T) -> StdResult<(), Self::Error>
  where
    T: Serialize,
  {
    let env = unsafe { Env::from_raw(self.array.0.env) };
    self.array.set_element(
      self.current_index as _,
      JsUnknown(value.serialize(Ser::new(&env))?),
    )?;
    self.current_index += 1;
    Ok(())
  }

  #[inline]
  fn end(self) -> Result<Self::Ok> {
    Ok(self.array.0)
  }
}

pub struct MapSerializer {
  key: JsString,
  obj: JsObject,
}

#[doc(hidden)]
impl ser::SerializeMap for MapSerializer {
  type Ok = Value;
  type Error = Error;

  #[inline]
  fn serialize_key<T: ?Sized>(&mut self, key: &T) -> StdResult<(), Self::Error>
  where
    T: Serialize,
  {
    let env = unsafe { Env::from_raw(self.obj.0.env) };
    self.key = JsString(key.serialize(Ser::new(&env))?);
    Ok(())
  }

  #[inline]
  fn serialize_value<T: ?Sized>(&mut self, value: &T) -> StdResult<(), Self::Error>
  where
    T: Serialize,
  {
    let env = unsafe { Env::from_raw(self.obj.0.env) };
    self.obj.set_property(
      JsString(Value {
        env: self.key.0.env,
        value: self.key.0.value,
        value_type: ValueType::String,
      }),
      JsUnknown(value.serialize(Ser::new(&env))?),
    )?;
    Ok(())
  }

  #[inline]
  fn serialize_entry<K: ?Sized, V: ?Sized>(
    &mut self,
    key: &K,
    value: &V,
  ) -> StdResult<(), Self::Error>
  where
    K: Serialize,
    V: Serialize,
  {
    let env = unsafe { Env::from_raw(self.obj.0.env) };
    self.obj.set_property(
      JsString(key.serialize(Ser::new(&env))?),
      JsUnknown(value.serialize(Ser::new(&env))?),
    )?;
    Ok(())
  }

  #[inline]
  fn end(self) -> Result<Self::Ok> {
    Ok(self.obj.0)
  }
}

pub struct StructSerializer {
  obj: JsObject,
}

#[doc(hidden)]
impl ser::SerializeStruct for StructSerializer {
  type Ok = Value;
  type Error = Error;

  #[inline]
  fn serialize_field<T: ?Sized>(&mut self, key: &'static str, value: &T) -> StdResult<(), Error>
  where
    T: Serialize,
  {
    let env = unsafe { Env::from_raw(self.obj.0.env) };
    self
      .obj
      .set_named_property(key, JsUnknown(value.serialize(Ser::new(&env))?))?;
    Ok(())
  }

  #[inline]
  fn end(self) -> Result<Self::Ok> {
    Ok(self.obj.0)
  }
}

#[doc(hidden)]
impl ser::SerializeStructVariant for StructSerializer {
  type Ok = Value;
  type Error = Error;

  #[inline]
  fn serialize_field<T: ?Sized>(&mut self, key: &'static str, value: &T) -> StdResult<(), Error>
  where
    T: Serialize,
  {
    let env = unsafe { Env::from_raw(self.obj.0.env) };
    self
      .obj
      .set_named_property(key, JsUnknown(value.serialize(Ser::new(&env))?))?;
    Ok(())
  }

  #[inline]
  fn end(self) -> Result<Self::Ok> {
    Ok(self.obj.0)
  }
}