//! Pieces pertaining to the HTTP message protocol.
use std::{io, str};
use url::form_urlencoded;
use http::{header, Method, Version, Uri, HeaderMap};

use Params;
use {Cookie, CookieParseError};
use {HttpRange, HttpRangeParseError};


#[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::new(),
            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 remote socket address of this request
    // ///
    // /// This is an `Option`, because some underlying transports may not have
    // /// a socket address, such as Unix Sockets.
    // ///
    // /// This field is not used for outgoing requests.
    // #[inline]
    // pub fn remote_addr(&self) -> Option<SocketAddr> { self.remote_addr }

    /// 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 mutable reference to the Request headers.
    #[inline]
    pub fn headers_mut(&mut self) -> &mut HeaderMap {
        &mut self.headers
    }

    /// 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 params(&self) -> &Params { &self.params }

    /// Create new request with Params object.
    pub fn with_params(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, io::Error> {
        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(io::Error::new(
                    io::ErrorKind::Other, "Can not read transfer-encoding 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())
        }
    }
}