use crate::{
    error::{Error, UPnPError},
    find_in_xml,
    scpd::SCPD,
    utils::{self, HttpResponseExt},
    Result,
};

#[cfg(feature = "subscribe")]
use futures_core::stream::Stream;
#[cfg(feature = "subscribe")]
use genawaiter::sync::{Co, Gen};
#[cfg(feature = "subscribe")]
use tokio::{
    io::{AsyncBufReadExt, BufReader},
    net::TcpListener,
};

use http::{uri::PathAndQuery, Request, Uri};
use roxmltree::{Document, Node};
use ssdp_client::URN;

use std::collections::HashMap;
use utils::HyperBodyExt;

/// A UPnP Service is the description of endpoints on a device for performing actions and reading
/// the service definition.
/// For a list of actions and state variables the service provides, take a look at [`scpd`](struct.Service.html#method.scpd).
#[derive(Debug, Clone)]
pub struct Service {
    service_type: URN,
    service_id: String,
    scpd_endpoint: PathAndQuery,
    control_endpoint: PathAndQuery,
    event_sub_endpoint: PathAndQuery,
}

impl Service {
    pub(crate) fn from_xml(node: Node<'_, '_>) -> Result<Self> {
        #[allow(non_snake_case)]
        let (service_type, service_id, scpd_endpoint, control_endpoint, event_sub_endpoint) =
            find_in_xml! { node => serviceType, serviceId, SCPDURL, controlURL, eventSubURL };

        Ok(Self {
            service_type: utils::parse_node_text(service_type)?,
            service_id: utils::parse_node_text(service_id)?,
            scpd_endpoint: utils::parse_node_text(scpd_endpoint)?,
            control_endpoint: utils::parse_node_text(control_endpoint)?,
            event_sub_endpoint: utils::parse_node_text(event_sub_endpoint)?,
        })
    }

    /// Returns the [URN](ssdp_client::URN) of this service.
    pub fn service_type(&self) -> &URN {
        &self.service_type
    }

    /// Returns the `Service Identifier`.
    pub fn service_id(&self) -> &str {
        &self.service_id
    }

    pub(crate) fn control_url(&self, url: &Uri) -> Uri {
        replace_url_path(url, &self.control_endpoint)
    }
    pub(crate) fn scpd_url(&self, url: &Uri) -> Uri {
        replace_url_path(url, &self.scpd_endpoint)
    }
    pub(crate) fn event_sub_url(&self, url: &Uri) -> Uri {
        replace_url_path(url, &self.event_sub_endpoint)
    }

    /// Fetches the [`SCPD`](scpd/struct.SCPD.html) of this service.
    pub async fn scpd(&self, url: &Uri) -> Result<SCPD> {
        Ok(SCPD::from_url(&self.scpd_url(url), self.service_type().clone()).await?)
    }

    /// Execute some UPnP Action on this service.
    /// The URL is usually obtained by the device this service was found on.
    /// The payload is xml-formatted data.
    ///
    /// # Example usage:
    ///
    /// ```rust,no_run
    /// # use ssdp_client::URN;
    /// # async fn rendering_control_example() -> Result<(), rupnp::Error> {
    /// # let some_url = unimplemented!();
    /// use rupnp::ssdp::URN;
    /// use rupnp::Device;
    ///
    /// let urn = URN::service("schemas-upnp-org", "RenderingControl", 1);
    ///
    /// let device = Device::from_url( some_url ).await?;
    /// let service = device.find_service(&urn)
    ///     .expect("service exists");
    ///
    /// let args = "<InstanceID>0</InstanceID><Channel>Master</Channel>";
    /// let response = service.action(device.url(), "GetVolume", args).await?;
    ///
    /// let volume = response
    ///     .get("CurrentVolume")
    ///     .expect("exists");
    ///
    /// println!("Volume: {}", volume);
    /// # Ok(())
    /// # }
    /// ```
    pub async fn action(
        &self,
        url: &Uri,
        action: &str,
        payload: &str,
    ) -> Result<HashMap<String, String>> {
        let body = format!(
            r#"
            <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"
                s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
                <s:Body>
                    <u:{action} xmlns:u="{service}">
                        {payload}
                    </u:{action}>
                </s:Body>
            </s:Envelope>"#,
            service = &self.service_type,
            action = action,
            payload = payload
        );

        let soap_action = format!("\"{}#{}\"", &self.service_type, action);

        let request = Request::post(self.control_url(url))
            .header("CONTENT-TYPE", "text/xml; charset=\"utf-8\"")
            .header("SOAPAction", soap_action)
            .body(body.into())
            .expect("infallible");
        let doc = hyper::Client::new()
            .request(request)
            .await?
            .err_if_not_200()?
            .into_body()
            .text()
            .await?;
        let doc = std::str::from_utf8(&doc)?;

        let document = Document::parse(&doc)?;
        let response = utils::find_root(&document, "Body", "UPnP Response")?
            .first_element_child()
            .ok_or_else(|| {
                Error::XmlMissingElement("Body".to_string(), format!("{}Response", action))
            })?;

        if response.tag_name().name().eq_ignore_ascii_case("Fault") {
            return Err(UPnPError::from_fault_node(response)?.into());
        }

        let values: HashMap<_, _> = response
            .children()
            .filter(Node::is_element)
            .filter_map(|node| -> Option<(String, String)> {
                if let Some(text) = node.text() {
                    Some((node.tag_name().name().to_string(), text.to_string()))
                } else {
                    None
                }
            })
            .collect();

        Ok(values)
    }

    #[cfg(feature = "subscribe")]
    async fn make_subscribe_request(
        &self,
        url: &Uri,
        callback: &str,
        timeout_secs: u32,
    ) -> Result<String> {
        let req = Request::builder()
            .uri(self.event_sub_url(url))
            .method("SUBSCRIBE")
            .header("CALLBACK", format!("<{}>", callback))
            .header("NT", "upnp:event")
            .header("TIMEOUT", format!("Second-{}", timeout_secs))
            .body(hyper::Body::empty())
            .expect("infallible");

        let response = hyper::Client::new().request(req).await?.err_if_not_200()?;

        let sid = response
            .headers()
            .get("sid")
            .ok_or_else(|| Error::ParseError("missing http header `SID`"))?
            .to_str()
            .map_err(|_| Error::ParseError("SID header contained non-visible ASCII bytes"))?
            .to_string();

        Ok(sid)
    }

    /// Subscribe for state variable changes.
    ///
    /// It returns the SID which can be used to unsubscribe to the service and a stream of
    /// responses.
    ///
    /// Each response is a [HashMap](std::collections::HashMap) of the state variables.
    ///
    /// # Example usage:
    /// ```rust,no_run
    /// # use futures::prelude::*;
    /// # async fn subscribe_example() -> Result<(), rupnp::Error> {
    /// # let device: rupnp::Device = unimplemented!();
    /// # let service: rupnp::Service = unimplemented!();
    /// let (_sid, stream) = service.subscribe(device.url(), 300).await?;
    ///
    /// while let Some(state_vars) = stream.try_next().await? {
    ///     for (key, value) in state_vars {
    ///         println!("{} => {}", key, value);
    ///     }
    /// }
    /// # Ok(())
    /// # }
    /// ```
    #[cfg(feature = "subscribe")]
    pub async fn subscribe(
        &self,
        url: &Uri,
        timeout_secs: u32,
    ) -> Result<(String, impl Stream<Item = Result<HashMap<String, String>>>)> {
        let addr = utils::get_local_addr()?;
        let listener = TcpListener::bind(addr).await?;

        let addr = format!("http://{}", listener.local_addr()?);

        let sid = self
            .make_subscribe_request(url, &addr, timeout_secs)
            .await?;

        let stream = Gen::new(move |co: Co<Result<_>>| subscribe_stream(listener, co));

        Ok((sid, stream))
    }

    /// Renew a subscription made with the [subscribe](struct.Service.html#method.subscribe) method.
    ///
    /// When the sid is invalid, the control point will respond with a `412 Preconditition failed`.
    pub async fn renew_subscription(&self, url: &Uri, sid: &str, timeout_secs: u32) -> Result<()> {
        let req = Request::builder()
            .uri(self.event_sub_url(url))
            .method("SUBSCRIBE")
            .header("SID", sid)
            .header("TIMEOUT", format!("Second-{}", timeout_secs))
            .body(hyper::Body::empty())
            .expect("infallible");
        hyper::Client::new().request(req).await?.err_if_not_200()?;

        Ok(())
    }

    /// Unsubscribe from further event notifications.
    ///
    /// The SID is usually obtained by the [subscribe](struct.Service.html#method.subscribe) method.
    ///
    /// When the sid is invalid, the control point will respond with a `412 Preconditition failed`.
    pub async fn unsubscribe(&self, url: &Uri, sid: &str) -> Result<()> {
        let req = Request::builder()
            .uri(self.event_sub_url(url))
            .method("UNSUBSCRIBE")
            .header("SID", sid)
            .body(hyper::Body::empty())
            .expect("infallible");

        hyper::Client::new().request(req).await?.err_if_not_200()?;

        Ok(())
    }
}

#[cfg(feature = "subscribe")]
macro_rules! yield_try {
    ( $co:expr => $expr:expr ) => {
        match $expr {
            Ok(val) => val,
            Err(e) => {
                $co.yield_(Err(e.into())).await;
                continue;
            }
        }
    };
}

#[cfg(feature = "subscribe")]
fn propertyset_to_map(input: &str) -> Result<HashMap<String, String>, roxmltree::Error> {
    let doc = Document::parse(&input)?;
    let hashmap: HashMap<String, String> = doc
        .root_element() // <e:propertyset />
        .children() // <e:property />
        .filter_map(|child| child.first_element_child()) // actual tag
        .filter_map(|node| {
            if let Some(text) = node.text() {
                Some((node.tag_name().name().to_string(), text.to_string()))
            } else {
                None
            }
        })
        .collect();

    Ok(hashmap)
}

#[cfg(feature = "subscribe")]
async fn subscribe_stream(listener: TcpListener, co: Co<Result<HashMap<String, String>>>) {
    loop {
        let (stream, _) = yield_try!(co => listener.accept().await);
        let mut lines = BufReader::new(stream).lines();

        let mut input = String::new();
        let mut is_xml = false;

        // sometimes the xml is on one line, sometimes on multiple ones.
        // we dont care about the http stuff before the "<e:propertyset>"
        while let Ok(Some(line)) = lines.next_line().await {
            if is_xml || line.starts_with("<e:propertyset") {
                input.push_str(&line);
                is_xml = true;
            }

            if line.ends_with("</e:propertyset>") {
                break;
            };
        }

        let hashmap = yield_try!(co => propertyset_to_map(&input));

        co.yield_(Ok(hashmap)).await;
    }
}

fn replace_url_path(url: &Uri, path: &PathAndQuery) -> Uri {
    let mut parts = url.clone().into_parts();
    parts.path_and_query = Some(path.clone());
    Uri::from_parts(parts).expect("infallible")
}