// Copyright 2019 The Gotts Developers
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use crate::rest::*;
use crate::router::ResponseFuture;
use futures::future::{err, ok};
use futures::{Future, Stream};
use hyper::{Body, Request, Response, StatusCode};
use serde::{Deserialize, Serialize};
use serde_json;
use std::collections::HashMap;
use std::fmt::Debug;
use url::form_urlencoded;

/// Parse request body
pub fn parse_body<T>(req: Request<Body>) -> Box<dyn Future<Item = T, Error = Error> + Send>
where
    for<'de> T: Deserialize<'de> + Send + 'static,
{
    Box::new(
        req.into_body()
            .concat2()
            .map_err(|e| ErrorKind::RequestError(format!("Failed to read request: {}", e)).into())
            .and_then(|body| match serde_json::from_reader(&body.to_vec()[..]) {
                Ok(obj) => ok(obj),
                Err(e) => {
                    err(ErrorKind::RequestError(format!("Invalid request body: {}", e)).into())
                }
            }),
    )
}

/// Convert Result to ResponseFuture
pub fn result_to_response<T>(res: Result<T, Error>) -> ResponseFuture
where
    T: Serialize,
{
    match res {
        Ok(s) => json_response_pretty(&s),
        Err(e) => match e.kind() {
            ErrorKind::Argument(msg) => response(StatusCode::BAD_REQUEST, msg.clone()),
            ErrorKind::RequestError(msg) => response(StatusCode::BAD_REQUEST, msg.clone()),
            ErrorKind::NotFound => response(StatusCode::NOT_FOUND, ""),
            ErrorKind::Internal(msg) => response(StatusCode::INTERNAL_SERVER_ERROR, msg.clone()),
            ErrorKind::ResponseError(msg) => {
                response(StatusCode::INTERNAL_SERVER_ERROR, msg.clone())
            }
        },
    }
}

/// Utility to serialize a struct into JSON and produce a sensible Response
/// out of it.
pub fn json_response<T>(s: &T) -> ResponseFuture
where
    T: Serialize,
{
    match serde_json::to_string(s) {
        Ok(json) => response(StatusCode::OK, json),
        Err(_) => response(StatusCode::INTERNAL_SERVER_ERROR, ""),
    }
}

/// Pretty-printed version of json response as future
pub fn json_response_pretty<T>(s: &T) -> ResponseFuture
where
    T: Serialize,
{
    match serde_json::to_string_pretty(s) {
        Ok(json) => response(StatusCode::OK, json),
        Err(e) => response(
            StatusCode::INTERNAL_SERVER_ERROR,
            format!("can't create json response: {}", e),
        ),
    }
}

/// Text response as HTTP response
pub fn just_response<T: Into<Body> + Debug>(status: StatusCode, text: T) -> Response<Body> {
    let mut resp = Response::new(text.into());
    *resp.status_mut() = status;
    resp
}

/// Text response as future
pub fn response<T: Into<Body> + Debug>(status: StatusCode, text: T) -> ResponseFuture {
    Box::new(ok(just_response(status, text)))
}

pub struct QueryParams {
    params: HashMap<String, Vec<String>>,
}

impl QueryParams {
    pub fn process_multival_param<F>(&self, name: &str, mut f: F)
    where
        F: FnMut(&str),
    {
        if let Some(ids) = self.params.get(name) {
            for id in ids {
                for id in id.split(',') {
                    f(id);
                }
            }
        }
    }

    pub fn get(&self, name: &str) -> Option<&String> {
        match self.params.get(name) {
            None => None,
            Some(v) => v.first(),
        }
    }
}

impl From<&str> for QueryParams {
    fn from(query_string: &str) -> Self {
        let params = form_urlencoded::parse(query_string.as_bytes())
            .into_owned()
            .fold(HashMap::new(), |mut hm, (k, v)| {
                hm.entry(k).or_insert(vec![]).push(v);
                hm
            });
        QueryParams { params }
    }
}

impl From<Option<&str>> for QueryParams {
    fn from(query_string: Option<&str>) -> Self {
        match query_string {
            Some(query_string) => Self::from(query_string),
            None => QueryParams {
                params: HashMap::new(),
            },
        }
    }
}

impl From<Request<Body>> for QueryParams {
    fn from(req: Request<Body>) -> Self {
        Self::from(req.uri().query())
    }
}

#[macro_export]
macro_rules! right_path_element(
	($req: expr) =>(
		match $req.uri().path().trim_end_matches('/').rsplit('/').next() {
			None => return response(StatusCode::BAD_REQUEST, "invalid url"),
			Some(el) => el,
		};
	));

#[macro_export]
macro_rules! must_get_query(
	($req: expr) =>(
		match $req.uri().query() {
			Some(q) => q,
			None => return Err(ErrorKind::RequestError("no query string".to_owned()))?,
		}
	));

#[macro_export]
macro_rules! parse_param(
	($param: expr, $name: expr, $default: expr) =>(
	match $param.get($name) {
		None => $default,
		Some(val) =>  match val.parse() {
			Ok(val) => val,
			Err(_) => return Err(ErrorKind::RequestError(format!("invalid value of parameter {}", $name)))?,
		}
	}
	));

#[macro_export]
macro_rules! parse_param_no_err(
	($param: expr, $name: expr, $default: expr) =>(
	match $param.get($name) {
		None => $default,
		Some(val) =>  match val.parse() {
			Ok(val) => val,
			Err(_) => $default,
		}
	}
	));

#[macro_export]
macro_rules! w_fut(
	($p: expr) =>(
		match w($p) {
			Ok(p) => p,
			Err(_) => return response(StatusCode::INTERNAL_SERVER_ERROR, "weak reference upgrade failed" ),
		}
	));
