use std::collections::HashSet;

use futures::Sink;
use tokio::io::AsyncWrite;

use crate::{
    element::{Element, Name, NamespaceDeclaration},
    error::Error,
    xml::{self, composers::Composer, parsers_complete::Parser, ETag},
};

// pub struct Writer<W, C = Composer> {
pub struct Writer<W> {
    inner: W,
    depth: Vec<Name>,
    namespaces: Vec<HashSet<NamespaceDeclaration>>,
}

impl<W: AsyncWrite + Unpin> Writer<W> {
    pub async fn write(&mut self, element: Element) -> Result<(), Error> {
        todo!()
    }

    pub async fn write_start(&mut self, element: Element) -> Result<(), Error> {
        todo!()
    }

    pub async fn write_end(&mut self) -> Result<(), Error> {
        todo!()
        // let e_tag;
        // if let Some(name) = self.depth.pop() {
        //     if let Some(prefix) = name.namespace.prefix {
        //         e_tag = xml::ETag {
        //             name: xml::QName::PrefixedName(xml::PrefixedName {
        //                 prefix: xml::Prefix::parse_full(&prefix)?,
        //                 local_part: xml::LocalPart::parse_full(&name.name)?,
        //             }),
        //         };
        //         e_tag.write(&mut self.inner).await?;
        //         Ok(())
        //     } else {
        //         e_tag = xml::ETag {
        //             name: xml::QName::UnprefixedName(xml::UnprefixedName::parse_full(&name.name)?),
        //         };
        //         e_tag.write(&mut self.inner).await?;
        //         Ok(())
        //     }
        // } else {
        //     return Err(Error::NotInElement("".to_string()));
        // }
    }
}

impl<W: AsyncWrite, E: Into<Element>> Sink<E> for Writer<W> {
    type Error = Error;

    fn poll_ready(
        self: std::pin::Pin<&mut Self>,
        cx: &mut std::task::Context<'_>,
    ) -> std::task::Poll<Result<(), Self::Error>> {
        todo!()
    }

    fn start_send(self: std::pin::Pin<&mut Self>, item: E) -> Result<(), Self::Error> {
        todo!()
    }

    fn poll_flush(
        self: std::pin::Pin<&mut Self>,
        cx: &mut std::task::Context<'_>,
    ) -> std::task::Poll<Result<(), Self::Error>> {
        todo!()
    }

    fn poll_close(
        self: std::pin::Pin<&mut Self>,
        cx: &mut std::task::Context<'_>,
    ) -> std::task::Poll<Result<(), Self::Error>> {
        todo!()
    }
}