use std::fmt::Formatter;

use serde::de::value::SeqAccessDeserializer;
use serde::de::{Error, SeqAccess, Unexpected, Visitor};
use serde::ser::SerializeSeq;
use serde::{Deserialize, Deserializer, Serialize, Serializer};

use crate::{JavaCodePoint, JavaStr, JavaString};

impl Serialize for JavaString {
    #[inline]
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        match self.as_str() {
            Ok(str) => str.serialize(serializer),
            Err(_) => {
                let mut seq = serializer.serialize_seq(None)?;
                for ch in self.chars() {
                    seq.serialize_element(&ch.as_u32())?;
                }
                seq.end()
            }
        }
    }
}

impl<'de> Deserialize<'de> for JavaString {
    #[inline]
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        deserializer.deserialize_any(JavaStringVisitor)
    }
}

struct JavaStringVisitor;

impl<'de> Visitor<'de> for JavaStringVisitor {
    type Value = JavaString;

    fn expecting(&self, formatter: &mut Formatter) -> std::fmt::Result {
        formatter.write_str("a JavaString")
    }

    fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
    where
        E: Error,
    {
        Ok(JavaString::from(v))
    }

    fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
    where
        E: Error,
    {
        Ok(JavaString::from(v))
    }

    fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
    where
        E: Error,
    {
        match JavaStr::from_semi_utf8(v) {
            Ok(str) => Ok(str.to_owned()),
            Err(_) => Err(Error::invalid_value(Unexpected::Bytes(v), &self)),
        }
    }

    fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<Self::Value, E>
    where
        E: Error,
    {
        JavaString::from_semi_utf8(v)
            .map_err(|err| Error::invalid_value(Unexpected::Bytes(&err.into_bytes()), &self))
    }

    fn visit_seq<A>(self, seq: A) -> Result<Self::Value, A::Error>
    where
        A: SeqAccess<'de>,
    {
        let vec = Vec::<u8>::deserialize(SeqAccessDeserializer::new(seq))?;
        JavaString::from_semi_utf8(vec).map_err(|_| Error::invalid_value(Unexpected::Seq, &self))
    }
}

impl Serialize for JavaStr {
    #[inline]
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        match self.as_str() {
            Ok(str) => str.serialize(serializer),
            Err(_) => {
                let mut seq = serializer.serialize_seq(None)?;
                for ch in self.chars() {
                    seq.serialize_element(&ch.as_u32())?;
                }
                seq.end()
            }
        }
    }
}

impl<'de: 'a, 'a> Deserialize<'de> for &'a JavaStr {
    #[inline]
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        deserializer.deserialize_any(JavaStrVisitor)
    }
}

struct JavaStrVisitor;

impl<'de> Visitor<'de> for JavaStrVisitor {
    type Value = &'de JavaStr;

    fn expecting(&self, formatter: &mut Formatter) -> std::fmt::Result {
        formatter.write_str("a borrowed JavaStr")
    }

    fn visit_borrowed_str<E>(self, v: &'de str) -> Result<Self::Value, E>
    where
        E: Error,
    {
        Ok(JavaStr::from_str(v))
    }

    fn visit_borrowed_bytes<E>(self, v: &'de [u8]) -> Result<Self::Value, E>
    where
        E: Error,
    {
        JavaStr::from_semi_utf8(v).map_err(|_| Error::invalid_value(Unexpected::Bytes(v), &self))
    }
}

impl Serialize for JavaCodePoint {
    #[inline]
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        match self.as_char() {
            Some(ch) => ch.serialize(serializer),
            None => self.as_u32().serialize(serializer),
        }
    }
}

impl<'de> Deserialize<'de> for JavaCodePoint {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        deserializer.deserialize_any(JavaCodePointVisitor)
    }
}

struct JavaCodePointVisitor;

impl Visitor<'_> for JavaCodePointVisitor {
    type Value = JavaCodePoint;

    fn expecting(&self, formatter: &mut Formatter) -> std::fmt::Result {
        formatter.write_str("a character")
    }

    #[inline]
    fn visit_i8<E>(self, v: i8) -> Result<Self::Value, E>
    where
        E: Error,
    {
        self.visit_i32(v.into())
    }

    #[inline]
    fn visit_i16<E>(self, v: i16) -> Result<Self::Value, E>
    where
        E: Error,
    {
        self.visit_i32(v.into())
    }

    fn visit_i32<E>(self, v: i32) -> Result<Self::Value, E>
    where
        E: Error,
    {
        if v < 0 {
            Err(Error::invalid_value(Unexpected::Signed(v.into()), &self))
        } else {
            self.visit_u32(v as u32)
        }
    }

    fn visit_i64<E>(self, v: i64) -> Result<Self::Value, E>
    where
        E: Error,
    {
        if v < 0 {
            Err(Error::invalid_value(Unexpected::Signed(v), &self))
        } else {
            self.visit_u64(v as u64)
        }
    }

    #[inline]
    fn visit_u8<E>(self, v: u8) -> Result<Self::Value, E>
    where
        E: Error,
    {
        self.visit_u32(v.into())
    }

    #[inline]
    fn visit_u16<E>(self, v: u16) -> Result<Self::Value, E>
    where
        E: Error,
    {
        self.visit_u32(v.into())
    }

    fn visit_u32<E>(self, v: u32) -> Result<Self::Value, E>
    where
        E: Error,
    {
        JavaCodePoint::from_u32(v)
            .ok_or_else(|| Error::invalid_value(Unexpected::Unsigned(v.into()), &self))
    }

    fn visit_u64<E>(self, v: u64) -> Result<Self::Value, E>
    where
        E: Error,
    {
        match u32::try_from(v) {
            Ok(v) => self.visit_u32(v),
            Err(_) => Err(Error::invalid_value(Unexpected::Unsigned(v), &self)),
        }
    }

    fn visit_char<E>(self, v: char) -> Result<Self::Value, E>
    where
        E: Error,
    {
        Ok(JavaCodePoint::from_char(v))
    }

    fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
    where
        E: Error,
    {
        let mut iter = v.chars();
        match (iter.next(), iter.next()) {
            (Some(c), None) => Ok(JavaCodePoint::from_char(c)),
            _ => Err(Error::invalid_value(Unexpected::Str(v), &self)),
        }
    }
}