//! This module contains the implementation of converse's actix-web
//! HTTP handlers.
//!
//! Most handlers have an associated rendering function using one of
//! the tera templates stored in the `/templates` directory in the
//! project root.

use actix::prelude::*;
use actix_web;
use actix_web::*;
use actix_web::middleware::{Started, Middleware, RequestSession};
use db::*;
use errors::{Result, ConverseError};
use futures::Future;
use models::*;
use oidc::*;
use tera;
use render::*;

type ConverseResponse = Box<Future<Item=HttpResponse, Error=ConverseError>>;

const HTML: &'static str = "text/html";

/// Represents the state carried by the web server actors.
pub struct AppState {
    /// Address of the database actor
    pub db: Addr<Syn, DbExecutor>,

    /// Address of the OIDC actor
    pub oidc: Addr<Syn, OidcExecutor>,

    /// Address of the rendering actor
    pub renderer: Addr<Syn, Renderer>,
}

// impl AppState {
//     fn render_ok<M>(self, msg: M) -> ConverseResponse
//         where M: Send + Message, Renderer: Handler<M> {
//         self.renderer.send(msg);
//         unimplemented!()
//     }
// }

pub fn forum_index(state: State<AppState>) -> ConverseResponse {
    state.db.send(ListThreads)
        .and_then(move |res| state.renderer.send(IndexPage { threads: res.unwrap() }))
        .from_err()
        .map(|res| HttpResponse::Ok().content_type(HTML).body(res.unwrap()))
        .responder()
}

/// This handler retrieves and displays a single forum thread.
pub fn forum_thread(state: State<AppState>, thread_id: Path<i32>) -> ConverseResponse {
    let id = thread_id.into_inner();
    state.db.send(GetThread(id))
        .and_then(move |res| {
            let u = res.unwrap();
            state.renderer.send(ThreadPage {
                thread: u.0,
                posts: u.1,
            })
        })
        .from_err()
        .map(|res| HttpResponse::Ok().content_type(HTML).body(res.unwrap()))
        .responder()
}

/// This handler presents the user with the "New Thread" form.
pub fn new_thread(state: State<AppState>) -> ConverseResponse {
    state.renderer.send(NewThreadPage).from_err()
        .map(|res| HttpResponse::Ok().content_type(HTML).body(res.unwrap()))
        .responder()
}

#[derive(Deserialize)]
pub struct NewThreadForm {
    pub title: String,
    pub body: String,
}

/// This handler receives a "New thread"-form and redirects the user
/// to the new thread after creation.
pub fn submit_thread(state: State<AppState>,
                     input: Form<NewThreadForm>,
                     mut req: HttpRequest<AppState>) -> ConverseResponse {
    // Author is "unwrapped" because the RequireLogin middleware
    // guarantees it to be present.
    let author: Author = req.session().get(AUTHOR).unwrap().unwrap();
    let new_thread = NewThread {
        title: input.0.title,
        body: input.0.body,
        author_name: author.name,
        author_email: author.email,
    };

    state.db.send(CreateThread(new_thread))
        .from_err()
        .and_then(move |res| {
            let thread = res?;
            info!("Created new thread \"{}\" with ID {}", thread.title, thread.id);
            Ok(HttpResponse::SeeOther()
               .header("Location", format!("/thread/{}", thread.id))
               .finish())
        })
        .responder()
}

#[derive(Deserialize)]
pub struct NewPostForm {
    pub thread_id: i32,
    pub body: String,
}

/// This handler receives a "Reply"-form and redirects the user to the
/// new post after creation.
pub fn reply_thread(state: State<AppState>,
                    input: Form<NewPostForm>,
                    mut req: HttpRequest<AppState>) -> ConverseResponse {
    // Author is "unwrapped" because the RequireLogin middleware
    // guarantees it to be present.
    let author: Author = req.session().get(AUTHOR).unwrap().unwrap();
    let new_post = NewPost {
        thread_id: input.thread_id,
        body: input.0.body,
        author_name: author.name,
        author_email: author.email,
    };

    state.db.send(CreatePost(new_post))
        .from_err()
        .and_then(move |res| {
            let post = res?;
            info!("Posted reply {} to thread {}", post.id, post.thread_id);
            Ok(HttpResponse::SeeOther()
               .header("Location", format!("/thread/{}#post{}", post.thread_id, post.id))
               .finish())
        })
        .responder()
}

/// This handler initiates an OIDC login.
pub fn login(state: State<AppState>) -> ConverseResponse {
    state.oidc.send(GetLoginUrl)
        .from_err()
        .and_then(|url| Ok(HttpResponse::TemporaryRedirect()
                           .header("Location", url)
                           .finish()))
        .responder()
}

const AUTHOR: &'static str = "author";

pub fn callback(state: State<AppState>,
                data: Form<CodeResponse>,
                mut req: HttpRequest<AppState>) -> ConverseResponse {
    state.oidc.send(RetrieveToken(data.0))
        .from_err()
        .and_then(move |result| {
            let author = result?;
            info!("Setting cookie for {} after callback", author.name);
            req.session().set(AUTHOR, author)?;
            Ok(HttpResponse::SeeOther()
               .header("Location", "/")
               .finish())})
        .responder()
}


/// Middleware used to enforce logins unceremonially.
pub struct RequireLogin;

impl <S> Middleware<S> for RequireLogin {
    fn start(&self, req: &mut HttpRequest<S>) -> actix_web::Result<Started> {
        let has_author = req.session().get::<Author>(AUTHOR)?.is_some();
        let is_oidc_req = req.path().starts_with("/oidc");

        if !is_oidc_req && !has_author {
            Ok(Started::Response(
                HttpResponse::SeeOther()
                    .header("Location", "/oidc/login")
                    .finish()
            ))
        } else {
            Ok(Started::Done)
        }
    }
}