// zotapi - Rust wrapper for Sot API as implemented by Hubzilla
// Copyright (C) 2018  Harald Eilertsen <haraldei@anduin.net>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

extern crate reqwest;
extern crate serde;

use reqwest::{
    header::{Accept, ContentType, qitem},
    mime,
    StatusCode,
};
use serde::Serialize;
use std::io::Read;

const ZOTAPI_CHANNEL_STREAM_PATH : &str = "/api/z/1.0/channel/stream";
const ZOTAPI_NETWORK_STREAM_PATH : &str = "/api/z/1.0/network/stream";
const ZOTAPI_ITEM_UPDATE_PATH : &str = "/api/z/1.0/item/update";

#[derive(Debug)]
pub enum Error {
    Http(reqwest::Error),
    Io(std::io::Error),
    Unauthorized,
    Unknown,
}

impl From<reqwest::Error> for Error {
    fn from(e: reqwest::Error) -> Error {
        Error::Http(e)
    }
}

impl From<std::io::Error> for Error {
    fn from(e: std::io::Error) -> Error {
        Error::Io(e)
    }
}

pub struct ItemBuilder<'a> {
    client : &'a Client,
    body: &'a str,
}

impl<'a> ItemBuilder<'a> {
    fn new(client: &'a Client) -> ItemBuilder<'a> {
        ItemBuilder {
            client: client,
            body: "",
        }
    }
    pub fn body(&mut self, text: &'a str) -> &mut ItemBuilder<'a> {
        self.body = text;
        self
    }

    pub fn create(&self) -> Result<String, Error> {
        self.client.post_data(ZOTAPI_ITEM_UPDATE_PATH, &[("body", self.body)])
    }
}

pub struct Client {
    inner: reqwest::Client,
    base_url: String,
    user: String,
    pw: String,
}

impl Client {
    pub fn channel_stream(&self) -> Result<String, Error> {
        self.fetch_stream(ZOTAPI_CHANNEL_STREAM_PATH)
    }

    pub fn network_stream(&self) -> Result<String, Error> {
        self.fetch_stream(ZOTAPI_NETWORK_STREAM_PATH)
    }

    pub fn item(&self) -> ItemBuilder {
        ItemBuilder::new(self)
    }

    fn url(&self, path: &str) -> String {
        self.base_url.clone() + path
    }

    fn fetch_stream(&self, path: &str) -> Result<String, Error> {
        let url = self.url(path);
        let mut res = self.inner.get(&url)
            .header(Accept(vec![qitem(mime::APPLICATION_JSON)]))
            .basic_auth(self.user.clone(), Some(self.pw.clone()))
            .send()?;

        match res.status() {
            StatusCode::Unauthorized => Err(Error::Unauthorized),
            StatusCode::Ok => {
                let mut body = String::new();
                res.read_to_string(&mut body)?;
                Ok(body)
            },
            _ => Err(Error::Unknown)
        }
    }

    fn post_data<T>(&self, path: &str, data: &T) -> Result<String, Error>
        where T: Serialize,
    {
        let url = self.url(path);
        let mut res = self.inner.post(&url)
            .header(Accept(vec![qitem(mime::APPLICATION_JSON)]))
            .header(ContentType::form_url_encoded())
            .basic_auth(self.user.clone(), Some(self.pw.clone()))
            .form(&data)
            .send()?;

        match res.status() {
            StatusCode::Unauthorized => Err(Error::Unauthorized),
            StatusCode::Ok => {
                let mut body = String::new();
                res.read_to_string(&mut body)?;
                Ok(body)
            },
            _ => Err(Error::Unknown)
        }
    }
}

pub fn client(url: &str, user: &str, pw: &str) -> Client
{
    Client {
        inner: reqwest::Client::new(),
        base_url: String::from(url),
        user: String::from(user),
        pw: String::from(pw),
    }
}

#[cfg(test)]
mod tests {
    #[test]
    fn it_works() {
        assert_eq!(2 + 2, 4);
    }
}