/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#![feature(box_syntax)]
#![feature(collections)]
#![feature(core)]
#![feature(rustc_private)]

extern crate geom;
extern crate hyper;
#[macro_use]
extern crate log;
extern crate png;
extern crate profile;
extern crate stb_image;
extern crate url;
extern crate util;

use hyper::header::{ContentType, Headers};
use hyper::http::RawStatus;
use hyper::method::Method;
use hyper::mime::{Mime, Attr};
use url::Url;

use std::borrow::IntoCow;
use std::sync::mpsc::{channel, Receiver, Sender};

pub mod image_cache_task;
pub mod storage_task;

/// Image handling.
///
/// It may be surprising that this goes in the network crate as opposed to the graphics crate.
/// However, image handling is generally very integrated with the network stack (especially where
/// caching is involved) and as a result it must live in here.
pub mod image {
    pub mod base;
}

#[derive(Clone)]
pub struct LoadData {
    pub url: Url,
    pub method: Method,
    /// Headers that will apply to the initial request only
    pub headers: Headers,
    /// Headers that will apply to the initial request and any redirects
    pub preserved_headers: Headers,
    pub data: Option<Vec<u8>>,
    pub cors: Option<ResourceCORSData>,
}

impl LoadData {
    pub fn new(url: Url) -> LoadData {
        LoadData {
            url: url,
            method: Method::Get,
            headers: Headers::new(),
            preserved_headers: Headers::new(),
            data: None,
            cors: None,
        }
    }
}

/// A listener for asynchronous network events. Cancelling the underlying request is unsupported.
pub trait AsyncResponseListener {
    /// The response headers for a request have been received.
    fn headers_available(&self, metadata: Metadata);
    /// A portion of the response body has been received. This data is unavailable after
    /// this method returned, and must be stored accordingly.
    fn data_available(&self, payload: Vec<u8>);
    /// The response is complete. If the provided status is an Err value, there is no guarantee
    /// that the response body was completely read.
    fn response_complete(&self, status: Result<(), String>);
}

/// Data for passing between threads/processes to indicate a particular action to
/// take on a provided network listener.
pub enum ResponseAction {
    /// Invoke headers_available
    HeadersAvailable(Metadata),
    /// Invoke data_available
    DataAvailable(Vec<u8>),
    /// Invoke response_complete
    ResponseComplete(Result<(), String>)
}

impl ResponseAction {
    /// Execute the default action on a provided listener.
    pub fn process(self, listener: &AsyncResponseListener) {
        match self {
            ResponseAction::HeadersAvailable(m) => listener.headers_available(m),
            ResponseAction::DataAvailable(d) => listener.data_available(d),
            ResponseAction::ResponseComplete(r) => listener.response_complete(r),
        }
    }
}

/// A target for async networking events. Commonly used to dispatch a runnable event to another
/// thread storing the wrapped closure for later execution.
pub trait AsyncResponseTarget {
    fn invoke_with_listener(&self, action: ResponseAction);
}

/// A wrapper for a network load that can either be channel or event-based.
pub enum LoadConsumer {
    Channel(Sender<LoadResponse>),
    Listener(Box<AsyncResponseTarget + Send>),
}

/// Handle to a resource task
pub type ResourceTask = Sender<ControlMsg>;

pub enum ControlMsg {
    /// Request the data associated with a particular URL
    Load(LoadData, LoadConsumer),
    /// Store a set of cookies for a given originating URL
    SetCookiesForUrl(Url, String, CookieSource),
    /// Retrieve the stored cookies for a given URL
    GetCookiesForUrl(Url, Sender<Option<String>>, CookieSource),
    Exit
}

/// Message sent in response to `Load`.  Contains metadata, and a port
/// for receiving the data.
///
/// Even if loading fails immediately, we send one of these and the
/// progress_port will provide the error.
pub struct LoadResponse {
    /// Metadata, such as from HTTP headers.
    pub metadata: Metadata,
    /// Port for reading data.
    pub progress_port: Receiver<ProgressMsg>,
}

#[derive(Clone)]
pub struct ResourceCORSData {
    /// CORS Preflight flag
    pub preflight: bool,
    /// Origin of CORS Request
    pub origin: Url
}

/// Metadata about a loaded resource, such as is obtained from HTTP headers.
#[derive(Clone)]
pub struct Metadata {
    /// Final URL after redirects.
    pub final_url: Url,

    /// MIME type / subtype.
    pub content_type: Option<(ContentType)>,

    /// Character set.
    pub charset: Option<String>,

    /// Headers
    pub headers: Option<Headers>,

    /// HTTP Status
    pub status: Option<RawStatus>,
}

impl Metadata {
    /// Metadata with defaults for everything optional.
    pub fn default(url: Url) -> Self {
        Metadata {
            final_url:    url,
            content_type: None,
            charset:      None,
            headers: None,
            // https://fetch.spec.whatwg.org/#concept-response-status-message
            status: Some(RawStatus(200, "OK".into_cow())),
        }
    }

    /// Extract the parts of a Mime that we care about.
    pub fn set_content_type(&mut self, content_type: Option<&Mime>) {
        match content_type {
            None => (),
            Some(mime) => {
                self.content_type = Some(ContentType(mime.clone()));
                let &Mime(_, _, ref parameters) = mime;
                for &(ref k, ref v) in parameters.iter() {
                    if &Attr::Charset == k {
                        self.charset = Some(v.to_string());
                    }
                }
            }
        }
    }
}

/// The creator of a given cookie
#[derive(PartialEq, Copy, Clone)]
pub enum CookieSource {
    /// An HTTP API
    HTTP,
    /// A non-HTTP API
    NonHTTP,
}

/// Messages sent in response to a `Load` message
#[derive(PartialEq,Debug)]
pub enum ProgressMsg {
    /// Binary data - there may be multiple of these
    Payload(Vec<u8>),
    /// Indicates loading is complete, either successfully or not
    Done(Result<(), String>)
}

/// Convenience function for synchronously loading a whole resource.
pub fn load_whole_resource(resource_task: &ResourceTask, url: Url)
        -> Result<(Metadata, Vec<u8>), String> {
    let (start_chan, start_port) = channel();
    resource_task.send(ControlMsg::Load(LoadData::new(url), LoadConsumer::Channel(start_chan))).unwrap();
    let response = start_port.recv().unwrap();

    let mut buf = vec!();
    loop {
        match response.progress_port.recv().unwrap() {
            ProgressMsg::Payload(data) => buf.push_all(&data),
            ProgressMsg::Done(Ok(()))  => return Ok((response.metadata, buf)),
            ProgressMsg::Done(Err(e))  => return Err(e)
        }
    }
}

/// Load a URL asynchronously and iterate over chunks of bytes from the response.
pub fn load_bytes_iter(resource_task: &ResourceTask, url: Url) -> (Metadata, ProgressMsgPortIterator) {
    let (input_chan, input_port) = channel();
    resource_task.send(ControlMsg::Load(LoadData::new(url), LoadConsumer::Channel(input_chan))).unwrap();

    let response = input_port.recv().unwrap();
    let iter = ProgressMsgPortIterator { progress_port: response.progress_port };
    (response.metadata, iter)
}

/// Iterator that reads chunks of bytes from a ProgressMsg port
pub struct ProgressMsgPortIterator {
    progress_port: Receiver<ProgressMsg>
}

impl Iterator for ProgressMsgPortIterator {
    type Item = Vec<u8>;

    fn next(&mut self) -> Option<Vec<u8>> {
        match self.progress_port.recv().unwrap() {
            ProgressMsg::Payload(data) => Some(data),
            ProgressMsg::Done(Ok(()))  => None,
            ProgressMsg::Done(Err(e))  => {
                error!("error receiving bytes: {}", e);
                None
            }
        }
    }
}