use std::fmt;

use base64::encode;
use serde::Serialize;
use serde_json;
use serde_urlencoded;

use body::{self, Body};
use header::{HeaderMap, HeaderName, HeaderValue, CONTENT_TYPE};
use http::HttpTryFrom;
use {async_impl, Client, Method, Url};

/// A request which can be executed with `Client::execute()`.
pub struct Request {
    body: Option<Body>,
    inner: async_impl::Request,
}

/// A builder to construct the properties of a `Request`.
#[derive(Debug)]
pub struct RequestBuilder {
    client: Client,
    request: ::Result<Request>,
}

impl Request {
    /// Constructs a new request.
    #[inline]
    pub fn new(method: Method, url: Url) -> Self {
        Request {
            body: None,
            inner: async_impl::Request::new(method, url),
        }
    }

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

    /// Get a mutable reference to the method.
    #[inline]
    pub fn method_mut(&mut self) -> &mut Method {
        self.inner.method_mut()
    }

    /// Get the url.
    #[inline]
    pub fn url(&self) -> &Url {
        self.inner.url()
    }

    /// Get a mutable reference to the url.
    #[inline]
    pub fn url_mut(&mut self) -> &mut Url {
        self.inner.url_mut()
    }

    /// Get the headers.
    #[inline]
    pub fn headers(&self) -> &HeaderMap {
        self.inner.headers()
    }

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

    /// Get the body.
    #[inline]
    pub fn body(&self) -> Option<&Body> {
        self.body.as_ref()
    }

    /// Get a mutable reference to the body.
    #[inline]
    pub fn body_mut(&mut self) -> &mut Option<Body> {
        &mut self.body
    }

    /// Attempts to clone the `Request`.
    ///
    /// None is returned if a body is which can not be cloned. This can be because the body is a
    /// stream.
    pub fn try_clone(&self) -> Option<Request> {
        let body = if let Some(ref body) = self.body.as_ref() {
            if let Some(body) = body.try_clone() {
                Some(body)
            } else {
                return None;
            }
        } else {
            None
        };
        let mut req = Request::new(self.method().clone(), self.url().clone());
        *req.headers_mut() = self.headers().clone();
        req.body = body;
        Some(req)
    }

    pub(crate) fn into_async(self) -> (async_impl::Request, Option<body::Sender>) {
        use header::CONTENT_LENGTH;

        let mut req_async = self.inner;
        let body = self.body.and_then(|body| {
            let (tx, body, len) = body.into_async();
            if let Some(len) = len {
                req_async.headers_mut().insert(CONTENT_LENGTH, len.into());
            }
            *req_async.body_mut() = Some(body);
            tx
        });
        (req_async, body)
    }
}

impl RequestBuilder {
    pub(crate) fn new(client: Client, request: ::Result<Request>) -> RequestBuilder {
        RequestBuilder {
            client,
            request,
        }
    }

    /// Add a `Header` to this Request.
    ///
    /// ```rust
    /// use reqwest::header::USER_AGENT;
    ///
    /// # fn run() -> Result<(), Box<::std::error::Error>> {
    /// let client = reqwest::Client::new();
    /// let res = client.get("https://www.rust-lang.org")
    ///     .header(USER_AGENT, "foo")
    ///     .send()?;
    /// # Ok(())
    /// # }
    /// ```
    pub fn header<K, V>(mut self, key: K, value: V) -> RequestBuilder
    where
        HeaderName: HttpTryFrom<K>,
        HeaderValue: HttpTryFrom<V>,
    {
        let mut error = None;
        if let Ok(ref mut req) = self.request {
            match <HeaderName as HttpTryFrom<K>>::try_from(key) {
                Ok(key) => {
                    match <HeaderValue as HttpTryFrom<V>>::try_from(value) {
                        Ok(value) => { req.headers_mut().append(key, value); }
                        Err(e) => error = Some(::error::from(e.into())),
                    }
                },
                Err(e) => error = Some(::error::from(e.into())),
            };
        }
        if let Some(err) = error {
            self.request = Err(err);
        }
        self
    }

    /// Add a set of Headers to the existing ones on this Request.
    ///
    /// The headers will be merged in to any already set.
    ///
    /// ```rust
    /// use reqwest::header::{HeaderMap, HeaderValue, USER_AGENT, CONTENT_TYPE};
    /// # use std::fs;
    ///
    /// fn construct_headers() -> HeaderMap {
    ///     let mut headers = HeaderMap::new();
    ///     headers.insert(USER_AGENT, HeaderValue::from_static("reqwest"));
    ///     headers.insert(CONTENT_TYPE, HeaderValue::from_static("image/png"));
    ///     headers
    /// }
    ///
    /// # fn run() -> Result<(), Box<::std::error::Error>> {
    /// let file = fs::File::open("much_beauty.png")?;
    /// let client = reqwest::Client::new();
    /// let res = client.post("http://httpbin.org/post")
    ///     .headers(construct_headers())
    ///     .body(file)
    ///     .send()?;
    /// # Ok(())
    /// # }
    /// ```
    pub fn headers(mut self, headers: ::header::HeaderMap) -> RequestBuilder {
        if let Ok(ref mut req) = self.request {
            async_impl::request::replace_headers(req.headers_mut(), headers);
        }
        self
    }

    /// Set a header with a type implementing hyper v0.11's `Header` trait.
    ///
    /// This method is provided to ease migration, and requires the `hyper-011`
    /// Cargo feature enabled on `reqwest`.
    #[cfg(feature = "hyper-011")]
    pub fn header_011<H>(self, header: H) -> RequestBuilder
    where
        H: ::hyper_011::header::Header,
    {
        let mut headers = ::hyper_011::Headers::new();
        headers.set(header);
        let map = ::header::HeaderMap::from(headers);
        self.headers(map)
    }

    /// Set multiple headers using hyper v0.11's `Headers` map.
    ///
    /// This method is provided to ease migration, and requires the `hyper-011`
    /// Cargo feature enabled on `reqwest`.
    #[cfg(feature = "hyper-011")]
    pub fn headers_011(self, headers: ::hyper_011::Headers) -> RequestBuilder {
        let map = ::header::HeaderMap::from(headers);
        self.headers(map)
    }

    /// Enable HTTP basic authentication.
    ///
    /// ```rust
    /// # fn run() -> Result<(), Box<::std::error::Error>> {
    /// let client = reqwest::Client::new();
    /// let resp = client.delete("http://httpbin.org/delete")
    ///     .basic_auth("admin", Some("good password"))
    ///     .send()?;
    /// # Ok(())
    /// # }
    /// ```
    pub fn basic_auth<U, P>(self, username: U, password: Option<P>) -> RequestBuilder
    where
        U: fmt::Display,
        P: fmt::Display,
    {
        let auth = match password {
            Some(password) => format!("{}:{}", username, password),
            None => format!("{}:", username)
        };
        let header_value = format!("Basic {}", encode(&auth));
        self.header(::header::AUTHORIZATION, &*header_value)
    }

    /// Enable HTTP bearer authentication.
    ///
    /// ```rust
    /// # fn run() -> Result<(), Box<::std::error::Error>> {
    /// let client = reqwest::Client::new();
    /// let resp = client.delete("http://httpbin.org/delete")
    ///     .bearer_auth("token")
    ///     .send()?;
    /// # Ok(())
    /// # }
    /// ```
    pub fn bearer_auth<T>(self, token: T) -> RequestBuilder
    where
        T: fmt::Display,
    {
        let header_value = format!("Bearer {}", token);
        self.header(::header::AUTHORIZATION, &*header_value)
    }

    /// Set the request body.
    ///
    /// # Examples
    ///
    /// Using a string:
    ///
    /// ```rust
    /// # fn run() -> Result<(), Box<::std::error::Error>> {
    /// let client = reqwest::Client::new();
    /// let res = client.post("http://httpbin.org/post")
    ///     .body("from a &str!")
    ///     .send()?;
    /// # Ok(())
    /// # }
    /// ```
    ///
    /// Using a `File`:
    ///
    /// ```rust
    /// # use std::fs;
    /// # fn run() -> Result<(), Box<::std::error::Error>> {
    /// let file = fs::File::open("from_a_file.txt")?;
    /// let client = reqwest::Client::new();
    /// let res = client.post("http://httpbin.org/post")
    ///     .body(file)
    ///     .send()?;
    /// # Ok(())
    /// # }
    /// ```
    ///
    /// Using arbitrary bytes:
    ///
    /// ```rust
    /// # use std::fs;
    /// # fn run() -> Result<(), Box<::std::error::Error>> {
    /// // from bytes!
    /// let bytes: Vec<u8> = vec![1, 10, 100];
    /// let client = reqwest::Client::new();
    /// let res = client.post("http://httpbin.org/post")
    ///     .body(bytes)
    ///     .send()?;
    /// # Ok(())
    /// # }
    /// ```
    pub fn body<T: Into<Body>>(mut self, body: T) -> RequestBuilder {
        if let Ok(ref mut req) = self.request {
            *req.body_mut() = Some(body.into());
        }
        self
    }

    /// Modify the query string of the URL.
    ///
    /// Modifies the URL of this request, adding the parameters provided.
    /// This method appends and does not overwrite. This means that it can
    /// be called multiple times and that existing query parameters are not
    /// overwritten if the same key is used. The key will simply show up
    /// twice in the query string.
    /// Calling `.query(&[("foo", "a"), ("foo", "b")])` gives `"foo=a&foo=b"`.
    ///
    /// ```rust
    /// # use reqwest::Error;
    /// #
    /// # fn run() -> Result<(), Error> {
    /// let client = reqwest::Client::new();
    /// let res = client.get("http://httpbin.org")
    ///     .query(&[("lang", "rust")])
    ///     .send()?;
    /// # Ok(())
    /// # }
    /// ```
    ///
    /// # Note
    /// This method does not support serializing a single key-value
    /// pair. Instead of using `.query(("key", "val"))`, use a sequence, such
    /// as `.query(&[("key", "val")])`. It's also possible to serialize structs
    /// and maps into a key-value pair.
    ///
    /// # Errors
    /// This method will fail if the object you provide cannot be serialized
    /// into a query string.
    pub fn query<T: Serialize + ?Sized>(mut self, query: &T) -> RequestBuilder {
        let mut error = None;
        if let Ok(ref mut req) = self.request {
            let url = req.url_mut();
            let mut pairs = url.query_pairs_mut();
            let serializer = serde_urlencoded::Serializer::new(&mut pairs);

            if let Err(err) = query.serialize(serializer) {
                error = Some(::error::from(err));
            }
        }
        if let Ok(ref mut req) = self.request {
            if let Some("") = req.url().query() {
                req.url_mut().set_query(None);
            }
        }
        if let Some(err) = error {
            self.request = Err(err);
        }
        self
    }

    /// Send a form body.
    ///
    /// Sets the body to the url encoded serialization of the passed value,
    /// and also sets the `Content-Type: application/x-www-form-urlencoded`
    /// header.
    ///
    /// ```rust
    /// # use reqwest::Error;
    /// # use std::collections::HashMap;
    /// #
    /// # fn run() -> Result<(), Error> {
    /// let mut params = HashMap::new();
    /// params.insert("lang", "rust");
    ///
    /// let client = reqwest::Client::new();
    /// let res = client.post("http://httpbin.org")
    ///     .form(&params)
    ///     .send()?;
    /// # Ok(())
    /// # }
    /// ```
    ///
    /// # Errors
    ///
    /// This method fails if the passed value cannot be serialized into
    /// url encoded format
    pub fn form<T: Serialize + ?Sized>(mut self, form: &T) -> RequestBuilder {
        let mut error = None;
        if let Ok(ref mut req) = self.request {
            match serde_urlencoded::to_string(form) {
                Ok(body) => {
                    req.headers_mut().insert(
                        CONTENT_TYPE,
                        HeaderValue::from_static("application/x-www-form-urlencoded")
                    );
                    *req.body_mut() = Some(body.into());
                },
                Err(err) => error = Some(::error::from(err)),
            }
        }
        if let Some(err) = error {
            self.request = Err(err);
        }
        self
    }

    /// Send a JSON body.
    ///
    /// Sets the body to the JSON serialization of the passed value, and
    /// also sets the `Content-Type: application/json` header.
    ///
    /// ```rust
    /// # use reqwest::Error;
    /// # use std::collections::HashMap;
    /// #
    /// # fn run() -> Result<(), Error> {
    /// let mut map = HashMap::new();
    /// map.insert("lang", "rust");
    ///
    /// let client = reqwest::Client::new();
    /// let res = client.post("http://httpbin.org")
    ///     .json(&map)
    ///     .send()?;
    /// # Ok(())
    /// # }
    /// ```
    ///
    /// # Errors
    ///
    /// Serialization can fail if `T`'s implementation of `Serialize` decides to
    /// fail, or if `T` contains a map with non-string keys.
    pub fn json<T: Serialize + ?Sized>(mut self, json: &T) -> RequestBuilder {
        let mut error = None;
        if let Ok(ref mut req) = self.request {
            match serde_json::to_vec(json) {
                Ok(body) => {
                    req.headers_mut().insert(
                        CONTENT_TYPE,
                        HeaderValue::from_static("application/json")
                    );
                    *req.body_mut() = Some(body.into());
                },
                Err(err) => error = Some(::error::from(err)),
            }
        }
        if let Some(err) = error {
            self.request = Err(err);
        }
        self
    }

    /// Sends a multipart/form-data body.
    ///
    /// ```
    /// # use reqwest::Error;
    ///
    /// # fn run() -> Result<(), Box<std::error::Error>> {
    /// let client = reqwest::Client::new();
    /// let form = reqwest::multipart::Form::new()
    ///     .text("key3", "value3")
    ///     .file("file", "/path/to/field")?;
    ///
    /// let response = client.post("your url")
    ///     .multipart(form)
    ///     .send()?;
    /// # Ok(())
    /// # }
    /// ```
    ///
    /// See [`multipart`](multipart/) for more examples.
    pub fn multipart(self, mut multipart: ::multipart::Form) -> RequestBuilder {
        let mut builder = self.header(
            CONTENT_TYPE,
            format!(
                "multipart/form-data; boundary={}",
                multipart.boundary()
            ).as_str()
        );
        if let Ok(ref mut req) = builder.request {
            *req.body_mut() = Some(match multipart.compute_length() {
                Some(length) => Body::sized(multipart.reader(), length),
                None => Body::new(multipart.reader()),
            })
        }
        builder
    }

    /// Build a `Request`, which can be inspected, modified and executed with
    /// `Client::execute()`.
    pub fn build(self) -> ::Result<Request> {
        self.request
    }

    /// Constructs the Request and sends it the target URL, returning a Response.
    ///
    /// # Errors
    ///
    /// This method fails if there was an error while sending request,
    /// redirect loop was detected or redirect limit was exhausted.
    pub fn send(self) -> ::Result<::Response> {
        self.client.execute(self.request?)
    }

    /// Attempts to clone the `RequestBuilder`.
    ///
    /// None is returned if a body is which can not be cloned. This can be because the body is a
    /// stream.
    ///
    /// # Examples
    ///
    /// With a static body
    ///
    /// ```rust
    /// # fn run() -> Result<(), Box<::std::error::Error>> {
    /// let client = reqwest::Client::new();
    /// let builder = client.post("http://httpbin.org/post")
    ///     .body("from a &str!");
    /// let clone = builder.try_clone();
    /// assert!(clone.is_some());
    /// # Ok(())
    /// # }
    /// ```
    ///
    /// Without a body
    ///
    /// ```rust
    /// # fn run() -> Result<(), Box<::std::error::Error>> {
    /// let client = reqwest::Client::new();
    /// let builder = client.get("http://httpbin.org/get");
    /// let clone = builder.try_clone();
    /// assert!(clone.is_some());
    /// # Ok(())
    /// # }
    /// ```
    ///
    /// With a non-clonable body
    ///
    /// ```rust
    /// # fn run() -> Result<(), Box<::std::error::Error>> {
    /// let client = reqwest::Client::new();
    /// let builder = client.get("http://httpbin.org/get")
    ///     .body(reqwest::Body::new(std::io::empty()));
    /// let clone = builder.try_clone();
    /// assert!(clone.is_none());
    /// # Ok(())
    /// # }
    /// ```
    pub fn try_clone(&self) -> Option<RequestBuilder> {
        self.request.as_ref()
            .ok()
            .and_then(|req| req.try_clone())
            .map(|req| {
                RequestBuilder{
                    client: self.client.clone(),
                    request: Ok(req),
                }
            })
    }
}

impl fmt::Debug for Request {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        fmt_request_fields(&mut f.debug_struct("Request"), self)
            .finish()
    }
}

fn fmt_request_fields<'a, 'b>(f: &'a mut fmt::DebugStruct<'a, 'b>, req: &Request) -> &'a mut fmt::DebugStruct<'a, 'b> {
    f.field("method", req.method())
        .field("url", req.url())
        .field("headers", req.headers())
}

#[cfg(test)]
mod tests {
    use {body, Client, Method};
    use header::{HOST, HeaderMap, HeaderValue, CONTENT_TYPE};
    use std::collections::{BTreeMap, HashMap};
    use serde_json;
    use serde_urlencoded;

    #[test]
    fn basic_get_request() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let r = client.get(some_url).build().unwrap();

        assert_eq!(r.method(), &Method::GET);
        assert_eq!(r.url().as_str(), some_url);
    }

    #[test]
    fn basic_head_request() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let r = client.head(some_url).build().unwrap();

        assert_eq!(r.method(), &Method::HEAD);
        assert_eq!(r.url().as_str(), some_url);
    }

    #[test]
    fn basic_post_request() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let r = client.post(some_url).build().unwrap();

        assert_eq!(r.method(), &Method::POST);
        assert_eq!(r.url().as_str(), some_url);
    }

    #[test]
    fn basic_put_request() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let r = client.put(some_url).build().unwrap();

        assert_eq!(r.method(), &Method::PUT);
        assert_eq!(r.url().as_str(), some_url);
    }

    #[test]
    fn basic_patch_request() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let r = client.patch(some_url).build().unwrap();

        assert_eq!(r.method(), &Method::PATCH);
        assert_eq!(r.url().as_str(), some_url);
    }

    #[test]
    fn basic_delete_request() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let r = client.delete(some_url).build().unwrap();

        assert_eq!(r.method(), &Method::DELETE);
        assert_eq!(r.url().as_str(), some_url);
    }

    #[test]
    fn add_header() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let r = client.post(some_url);

        let header = HeaderValue::from_static("google.com");

        // Add a copy of the header to the request builder
        let r = r.header(HOST, header.clone()).build().unwrap();

        // then check it was actually added
        assert_eq!(r.headers().get(HOST), Some(&header));
    }

    #[test]
    fn add_headers() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let r = client.post(some_url);

        let header = HeaderValue::from_static("google.com");

        let mut headers = HeaderMap::new();
        headers.insert(HOST, header);

        // Add a copy of the headers to the request builder
        let r = r.headers(headers.clone()).build().unwrap();

        // then make sure they were added correctly
        assert_eq!(r.headers(), &headers);
    }

    #[test]
    fn add_body() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let r = client.post(some_url);

        let body = "Some interesting content";

        let mut r = r.body(body).build().unwrap();

        let buf = body::read_to_string(r.body_mut().take().unwrap()).unwrap();

        assert_eq!(buf, body);
    }

    #[test]
    fn add_query_append() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let mut r = client.get(some_url);

        r = r.query(&[("foo", "bar")]);
        r = r.query(&[("qux", 3)]);

        let req = r.build().expect("request is valid");
        assert_eq!(req.url().query(), Some("foo=bar&qux=3"));
    }

    #[test]
    fn add_query_append_same() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let mut r = client.get(some_url);

        r = r.query(&[("foo", "a"), ("foo", "b")]);

        let req = r.build().expect("request is valid");
        assert_eq!(req.url().query(), Some("foo=a&foo=b"));
    }

    #[test]
    fn add_query_struct() {
        #[derive(Serialize)]
        struct Params {
            foo: String,
            qux: i32,
        }

        let client = Client::new();
        let some_url = "https://google.com/";
        let mut r = client.get(some_url);

        let params = Params { foo: "bar".into(), qux: 3 };

        r = r.query(&params);

        let req = r.build().expect("request is valid");
        assert_eq!(req.url().query(), Some("foo=bar&qux=3"));
    }

    #[test]
    fn add_query_map() {
        let mut params = BTreeMap::new();
        params.insert("foo", "bar");
        params.insert("qux", "three");

        let client = Client::new();
        let some_url = "https://google.com/";
        let mut r = client.get(some_url);

        r = r.query(&params);

        let req = r.build().expect("request is valid");
        assert_eq!(req.url().query(), Some("foo=bar&qux=three"));
    }

    #[test]
    fn add_form() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let r = client.post(some_url);

        let mut form_data = HashMap::new();
        form_data.insert("foo", "bar");

        let mut r = r.form(&form_data).build().unwrap();

        // Make sure the content type was set
        assert_eq!(r.headers().get(CONTENT_TYPE).unwrap(), &"application/x-www-form-urlencoded");

        let buf = body::read_to_string(r.body_mut().take().unwrap()).unwrap();

        let body_should_be = serde_urlencoded::to_string(&form_data).unwrap();
        assert_eq!(buf, body_should_be);
    }

    #[test]
    fn add_json() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let r = client.post(some_url);

        let mut json_data = HashMap::new();
        json_data.insert("foo", "bar");

        let mut r = r.json(&json_data).build().unwrap();

        // Make sure the content type was set
        assert_eq!(r.headers().get(CONTENT_TYPE).unwrap(), &"application/json");

        let buf = body::read_to_string(r.body_mut().take().unwrap()).unwrap();

        let body_should_be = serde_json::to_string(&json_data).unwrap();
        assert_eq!(buf, body_should_be);
    }

    #[test]
    fn add_json_fail() {
        use serde::{Serialize, Serializer};
        use serde::ser::Error;
        struct MyStruct;
        impl Serialize for MyStruct {
            fn serialize<S>(&self, _serializer: S) -> Result<S::Ok, S::Error>
                where S: Serializer
                {
                    Err(S::Error::custom("nope"))
                }
        }

        let client = Client::new();
        let some_url = "https://google.com/";
        let r = client.post(some_url);
        let json_data = MyStruct;
        assert!(r.json(&json_data).build().unwrap_err().is_serialization());
    }

    #[test]
    fn test_replace_headers() {
        use http::HeaderMap;

        let mut headers = HeaderMap::new();
        headers.insert("foo", "bar".parse().unwrap());
        headers.append("foo", "baz".parse().unwrap());

        let client = Client::new();
        let req = client
            .get("https://hyper.rs")
            .header("im-a", "keeper")
            .header("foo", "pop me")
            .headers(headers)
            .build()
            .expect("request build");

        assert_eq!(req.headers()["im-a"], "keeper");

        let foo = req
            .headers()
            .get_all("foo")
            .iter()
            .collect::<Vec<_>>();
        assert_eq!(foo.len(), 2);
        assert_eq!(foo[0], "bar");
        assert_eq!(foo[1], "baz");
    }

    #[test]
    fn normalize_empty_query() {
        let client = Client::new();
        let some_url = "https://google.com/";
        let empty_query: &[(&str, &str)] = &[];

        let req = client
            .get(some_url)
            .query(empty_query)
            .build()
            .expect("request build");

        assert_eq!(req.url().query(), None);
        assert_eq!(req.url().as_str(), "https://google.com/");
    }
}
