//! HTTP Request message related code.
use std::{io, str};
use std::collections::HashMap;
use bytes::{Bytes, BytesMut};
use futures::{Async, Future, Stream, Poll};
use url::form_urlencoded;
use multipart_async::server::BodyChunk;
use http::{header, Method, Version, Uri, HeaderMap};

use {Cookie, CookieParseError};
use {HttpRange, HttpRangeParseError};
use error::ParseError;
use recognizer::Params;
use multipart::Multipart;
use payload::{Payload, PayloadError};


#[derive(Debug)]
/// An HTTP Request
pub struct HttpRequest {
    version: Version,
    method: Method,
    uri: Uri,
    headers: HeaderMap,
    params: Params,
    cookies: Vec<Cookie<'static>>,
}

impl HttpRequest {
    /// Construct a new Request.
    #[inline]
    pub fn new(method: Method, uri: Uri, version: Version, headers: HeaderMap) -> Self {
        HttpRequest {
            method: method,
            uri: uri,
            version: version,
            headers: headers,
            params: Params::empty(),
            cookies: Vec::new(),
        }
    }

    /// Read the Request Uri.
    #[inline]
    pub fn uri(&self) -> &Uri { &self.uri }

    /// Read the Request method.
    #[inline]
    pub fn method(&self) -> &Method { &self.method }

    /// Read the Request Version.
    pub fn version(&self) -> Version {
        self.version
    }

    /// Read the Request Headers.
    pub fn headers(&self) -> &HeaderMap {
        &self.headers
    }

    /// The target path of this Request.
    #[inline]
    pub fn path(&self) -> &str {
        self.uri.path()
    }

    /// Return a new iterator that yields pairs of `Cow<str>` for query parameters
    #[inline]
    pub fn query(&self) -> form_urlencoded::Parse {
        form_urlencoded::parse(self.query_string().as_ref())
    }

    /// The query string in the URL.
    ///
    /// E.g., id=10
    #[inline]
    pub fn query_string(&self) -> &str {
        self.uri.query().unwrap_or("")
    }

    /// Return request cookies.
    pub fn cookies(&self) -> &Vec<Cookie<'static>> {
        &self.cookies
    }

    /// Return request cookie.
    pub fn cookie(&self, name: &str) -> Option<&Cookie> {
        for cookie in &self.cookies {
            if cookie.name() == name {
                return Some(cookie)
            }
        }
        None
    }

    /// Load cookies
    pub fn load_cookies(&mut self) -> Result<&Vec<Cookie>, CookieParseError>
    {
        if let Some(val) = self.headers.get(header::COOKIE) {
            let s = str::from_utf8(val.as_bytes())
                .map_err(CookieParseError::from)?;
            for cookie in s.split("; ") {
                self.cookies.push(Cookie::parse_encoded(cookie)?.into_owned());
            }
        }
        Ok(&self.cookies)
    }

    /// Get a reference to the Params object.
    /// Params is a container for url parameters.
    /// Route supports glob patterns: * for a single wildcard segment and :param
    /// for matching storing that segment of the request url in the Params object.
    #[inline]
    pub fn match_info(&self) -> &Params { &self.params }

    /// Create new request with Params object.
    pub fn with_match_info(self, params: Params) -> Self {
        HttpRequest {
            method: self.method,
            uri: self.uri,
            version: self.version,
            headers: self.headers,
            params: params,
            cookies: self.cookies,
        }
    }

    /// Checks if a connection should be kept alive.
    pub fn keep_alive(&self) -> bool {
        if let Some(conn) = self.headers.get(header::CONNECTION) {
            if let Ok(conn) = conn.to_str() {
                if self.version == Version::HTTP_10 && conn.contains("keep-alive") {
                    true
                } else {
                    self.version == Version::HTTP_11 &&
                        !(conn.contains("close") || conn.contains("upgrade"))
                }
            } else {
                false
            }
        } else {
            self.version != Version::HTTP_10
        }
    }

    /// Check if request requires connection upgrade
    pub(crate) fn upgrade(&self) -> bool {
        if let Some(conn) = self.headers().get(header::CONNECTION) {
            if let Ok(s) = conn.to_str() {
                return s.to_lowercase().contains("upgrade")
            }
        }
        self.method == Method::CONNECT
    }

    /// Check if request has chunked transfer encoding
    pub fn chunked(&self) -> Result<bool, ParseError> {
        if let Some(encodings) = self.headers().get(header::TRANSFER_ENCODING) {
            if let Ok(s) = encodings.to_str() {
                Ok(s.to_lowercase().contains("chunked"))
            } else {
                Err(ParseError::Header)
            }
        } else {
            Ok(false)
        }
    }

    /// Parses Range HTTP header string as per RFC 2616.
    /// `size` is full size of response (file).
    pub fn range(&self, size: u64) -> Result<Vec<HttpRange>, HttpRangeParseError> {
        if let Some(range) = self.headers().get(header::RANGE) {
            HttpRange::parse(unsafe{str::from_utf8_unchecked(range.as_bytes())}, size)
        } else {
            Ok(Vec::new())
        }
    }

    /// Return stream to process BODY as multipart.
    ///
    /// Content-type: multipart/form-data;
    pub fn multipart(&self, payload: Payload) -> Result<Multipart<Req>, Payload> {
        const BOUNDARY: &'static str = "boundary=";

        if let Some(content_type) = self.headers().get(header::CONTENT_TYPE) {
            if let Ok(content_type) = content_type.to_str() {
                if let Some(start) = content_type.find(BOUNDARY) {
                    let start = start + BOUNDARY.len();
                    let end = content_type[start..].find(';')
                        .map_or(content_type.len(), |end| start + end);
                    let boundary = &content_type[start .. end];

                    return Ok(Multipart::with_body(Req{pl: payload}, boundary))
                }
            }
        }
        Err(payload)
    }

    /// Parse `application/x-www-form-urlencoded` encoded body.
    /// Return `UrlEncoded` future. It resolves to a `HashMap<String, String>`.
    ///
    /// Returns error:
    ///
    /// * content type is not `application/x-www-form-urlencoded`
    /// * transfer encoding is `chunked`.
    /// * content-length is greater than 256k
    pub fn urlencoded(&self, payload: Payload) -> Result<UrlEncoded, Payload> {
        if let Ok(chunked) = self.chunked() {
            if chunked {
                return Err(payload)
            }
        }

        if let Some(len) = self.headers().get(header::CONTENT_LENGTH) {
            if let Ok(s) = len.to_str() {
                if let Ok(len) = s.parse::<u64>() {
                    if len > 262_144 {
                        return Err(payload)
                    }
                } else {
                    return Err(payload)
                }
            } else {
                return Err(payload)
            }
        }

        if let Some(content_type) = self.headers().get(header::CONTENT_TYPE) {
            if let Ok(content_type) = content_type.to_str() {
                if content_type.to_lowercase() == "application/x-www-form-urlencoded" {
                    return Ok(UrlEncoded{pl: payload, body: BytesMut::new()})
                }
            }
        }

        Err(payload)
    }
}


#[doc(hidden)]
pub struct Req {
    pl: Payload,
}

#[doc(hidden)]
pub struct Chunk(Bytes);

impl BodyChunk for Chunk {
    #[inline]
    fn split_at(mut self, idx: usize) -> (Self, Self) {
        (Chunk(self.0.split_to(idx)), self)
    }

    #[inline]
    fn as_slice(&self) -> &[u8] {
        self.0.as_ref()
    }
}

impl Stream for Req {
    type Item = Chunk;
    type Error = io::Error;

    fn poll(&mut self) -> Poll<Option<Chunk>, io::Error> {
        match self.pl.poll() {
            Err(_) =>
                Err(io::Error::new(io::ErrorKind::InvalidData, "incomplete")),
            Ok(Async::NotReady) => Ok(Async::NotReady),
            Ok(Async::Ready(None)) => Ok(Async::Ready(None)),
            Ok(Async::Ready(Some(item))) => match item {
                Ok(bytes) => Ok(Async::Ready(Some(Chunk(bytes)))),
                Err(err) => match err {
                    PayloadError::Incomplete =>
                        Err(io::Error::new(io::ErrorKind::InvalidData, "incomplete")),
                    PayloadError::ParseError(err) =>
                        Err(err.into())
                }
            }
        }
    }
}


/// Future that resolves to a parsed urlencoded values.
pub struct UrlEncoded {
    pl: Payload,
    body: BytesMut,
}

impl Future for UrlEncoded {
    type Item = HashMap<String, String>;
    type Error = PayloadError;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        loop {
            return match self.pl.poll() {
                Err(_) => unreachable!(),
                Ok(Async::NotReady) => Ok(Async::NotReady),
                Ok(Async::Ready(None)) => {
                    let mut m = HashMap::new();
                    for (k, v) in form_urlencoded::parse(&self.body) {
                        m.insert(k.into(), v.into());
                    }
                    Ok(Async::Ready(m))
                },
                Ok(Async::Ready(Some(item))) => match item {
                    Ok(bytes) => {
                        self.body.extend(bytes);
                        continue
                    },
                    Err(err) => Err(err),
                }
            }
        }
    }
}