use crate::structs::{Settings, StructError, StructResult};
use crate::ArchiveError;
use serde::de;

pub struct ArchiveDeserializer<'de> {
    bytes: &'de [u8],
    pointer: usize,
    settings: Settings,
}

struct SeqDeserializer<'a, 'de: 'a> {
    de: &'a mut ArchiveDeserializer<'de>,
    len: usize,
}

struct EnumDeserializer<'a, 'de: 'a> {
    de: &'a mut ArchiveDeserializer<'de>,
}

impl<'de> ArchiveDeserializer<'de> {
    pub fn new(bytes: &'de [u8], settings: Settings) -> Self {
        Self {
            bytes,
            pointer: 0,
            settings,
        }
    }

    fn take<const S: usize>(&mut self) -> StructResult<[u8; S]> {
        let bytes = self
            .bytes
            .get(self.pointer..self.pointer + S)
            .ok_or(StructError::UnexpectedEOF)?
            .try_into()
            .unwrap();
        self.pointer += S;
        Ok(bytes)
    }

    fn take_byte(&mut self) -> StructResult<u8> {
        let byte = self
            .bytes
            .get(self.pointer)
            .ok_or(StructError::UnexpectedEOF)?;
        self.pointer += 1;
        Ok(*byte)
    }
}

impl<'a, 'de> SeqDeserializer<'a, 'de> {
    pub fn new(de: &'a mut ArchiveDeserializer<'de>, len: usize) -> Self {
        Self { de, len }
    }
}

impl<'a, 'de> EnumDeserializer<'a, 'de> {
    pub fn new(de: &'a mut ArchiveDeserializer<'de>) -> Self {
        Self { de }
    }
}

impl<'de> de::Deserializer<'de> for &mut ArchiveDeserializer<'de> {
    type Error = ArchiveError<StructError>;

    fn deserialize_any<V>(self, _visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        Err(StructError::DeserializationNotSupported { type_name: "any" }.into())
    }

    fn deserialize_bool<V>(self, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        visitor.visit_bool(self.take_byte()? != 0)
    }

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

    fn deserialize_i16<V>(self, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        let bytes = self.take()?;
        visitor.visit_i16(self.settings.byte_order.to_i16(bytes))
    }

    fn deserialize_i32<V>(self, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        let bytes = self.take()?;
        visitor.visit_i32(self.settings.byte_order.to_i32(bytes))
    }

    fn deserialize_i64<V>(self, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        let bytes = self.take()?;
        visitor.visit_i64(self.settings.byte_order.to_i64(bytes))
    }

    fn deserialize_u8<V>(self, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        visitor.visit_u8(self.take_byte()?)
    }

    fn deserialize_u16<V>(self, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        let bytes = self.take()?;
        visitor.visit_u16(self.settings.byte_order.to_u16(bytes))
    }

    fn deserialize_u32<V>(self, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        let bytes = self.take()?;
        visitor.visit_u32(self.settings.byte_order.to_u32(bytes))
    }

    fn deserialize_u64<V>(self, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        let bytes = self.take()?;
        visitor.visit_u64(self.settings.byte_order.to_u64(bytes))
    }

    fn deserialize_f32<V>(self, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        let bytes = self.take()?;
        visitor.visit_f32(self.settings.byte_order.to_f32(bytes))
    }

    fn deserialize_f64<V>(self, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        let bytes = self.take()?;
        visitor.visit_f64(self.settings.byte_order.to_f64(bytes))
    }

    fn deserialize_char<V>(self, _visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        Err(StructError::DeserializationNotSupported { type_name: "char" }.into())
    }

    fn deserialize_str<V>(self, _visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        Err(StructError::DeserializationNotSupported { type_name: "str" }.into())
    }

    fn deserialize_string<V>(self, _visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        Err(StructError::DeserializationNotSupported {
            type_name: "string",
        }
        .into())
    }

    fn deserialize_bytes<V>(self, _visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        Err(StructError::DeserializationNotSupported { type_name: "bytes" }.into())
    }

    fn deserialize_byte_buf<V>(self, _visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        Err(StructError::DeserializationNotSupported { type_name: "bytes" }.into())
    }

    fn deserialize_option<V>(self, _visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        Err(StructError::DeserializationNotSupported {
            type_name: "optional",
        }
        .into())
    }

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

    fn deserialize_unit_struct<V>(self, _name: &'static str, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        self.deserialize_unit(visitor)
    }

    fn deserialize_newtype_struct<V>(
        self,
        _name: &'static str,
        visitor: V,
    ) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        visitor.visit_newtype_struct(self)
    }

    fn deserialize_seq<V>(self, _visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        Err(StructError::DeserializationNotSupported { type_name: "seq" }.into())
    }

    fn deserialize_tuple<V>(self, len: usize, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        visitor.visit_seq(SeqDeserializer::new(self, len))
    }

    fn deserialize_tuple_struct<V>(
        self,
        _name: &'static str,
        len: usize,
        visitor: V,
    ) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        self.deserialize_tuple(len, visitor)
    }

    fn deserialize_map<V>(self, _visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        Err(StructError::DeserializationNotSupported { type_name: "map" }.into())
    }

    fn deserialize_struct<V>(
        self,
        _name: &'static str,
        fields: &'static [&'static str],
        visitor: V,
    ) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        self.deserialize_tuple(fields.len(), visitor)
    }

    fn deserialize_enum<V>(
        self,
        _name: &'static str,
        _variants: &'static [&'static str],
        visitor: V,
    ) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        visitor.visit_enum(EnumDeserializer::new(self))
    }

    fn deserialize_identifier<V>(self, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        match self.settings.variant_index_type {
            super::VariantIndexType::U8 => self.deserialize_u8(visitor),
            super::VariantIndexType::U16 => self.deserialize_u16(visitor),
            super::VariantIndexType::U32 => self.deserialize_u32(visitor),
            super::VariantIndexType::U64 => self.deserialize_u64(visitor),
        }
    }

    #[inline]
    fn deserialize_ignored_any<V>(self, visitor: V) -> StructResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        self.deserialize_any(visitor)
    }
}

impl<'a, 'de> de::SeqAccess<'de> for SeqDeserializer<'a, 'de> {
    type Error = ArchiveError<StructError>;

    fn next_element_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>, Self::Error>
    where
        T: de::DeserializeSeed<'de>,
    {
        if self.len == 0 {
            return Ok(None);
        }
        seed.deserialize(&mut *self.de).map(Some)
    }
}

impl<'a, 'de> de::EnumAccess<'de> for EnumDeserializer<'a, 'de> {
    type Error = ArchiveError<StructError>;
    type Variant = Self;

    fn variant_seed<V>(self, seed: V) -> Result<(V::Value, Self::Variant), Self::Error>
    where
        V: de::DeserializeSeed<'de>,
    {
        Ok((seed.deserialize(&mut *self.de)?, self))
    }
}

impl<'a, 'de> de::VariantAccess<'de> for EnumDeserializer<'a, 'de> {
    type Error = ArchiveError<StructError>;

    fn unit_variant(self) -> Result<(), Self::Error> {
        Ok(())
    }

    fn newtype_variant_seed<T>(self, seed: T) -> Result<T::Value, Self::Error>
    where
        T: de::DeserializeSeed<'de>,
    {
        seed.deserialize(&mut *self.de)
    }

    fn tuple_variant<V>(self, len: usize, visitor: V) -> Result<V::Value, Self::Error>
    where
        V: de::Visitor<'de>,
    {
        de::Deserializer::deserialize_tuple(self.de, len, visitor)
    }

    fn struct_variant<V>(
        self,
        fields: &'static [&'static str],
        visitor: V,
    ) -> Result<V::Value, Self::Error>
    where
        V: de::Visitor<'de>,
    {
        de::Deserializer::deserialize_tuple(self.de, fields.len(), visitor)
    }
}