use std::io::{self, Write, Read};
use std::process;

const TEXT_PARAM: &'static str = "text";
const TOKEN_PARAM: &'static str = "TOKEN";
const URL_PARAM: &'static str = "URL";
const OPEN_ENDPOINT: &'static str = "dev/open";
const LINK_ENDPONT: &'static str = "dev/link";
const COPY_ENDPOINT: &'static str = "dev/push";
const PASTE_ENDPONT: &'static str = "dev/pull";
const HASH_SHORT_SIZE: usize = 6;

mod config;
mod http;

pub fn push(input: &mut dyn Read) {
    let config_context = config::load_config();
    if config_context.token.is_empty() {
        fail("No clipboard linked, please link or open a new clipboard");
    }

    let mut url = http::prepare_endpoint(&config_context, COPY_ENDPOINT);
    http::append_query(&mut url, input, &TEXT_PARAM);
    http::get_http_or_fail(&url);
}

pub fn pull(stdout: io::Stdout) {
    let config_context = config::load_config();
    if config_context.token.is_empty() {
        fail("No clipboard linked, please link or open a new clipboard");
    }

    let url = http::prepare_endpoint(&config_context, PASTE_ENDPONT);
    let resp = http::get_http_response_or_fail(&url);
    let _ = match resp.get(&String::from(TEXT_PARAM)) {
        Some(number) => stdout.lock().write(number.as_ref()),
        _ => stdout.lock().write(b""),
    };
}

pub fn open(stdout: io::Stdout) {
    let config_context = config::load_config();

    let url = http::prepare_endpoint(&config_context, OPEN_ENDPOINT);
    let resp = http::get_http_response_or_fail(&url);
    let _ = match resp.get(&String::from(TEXT_PARAM)) {
        Some(token) => {
            config::store_config(&config_context, &token);
            stdout.lock().write(&token.as_bytes()[..HASH_SHORT_SIZE])
        },
        _ => fail("Failed to open new link with back-end"),
    };
}

pub fn link(stdout: io::Stdout, input: &mut dyn Read) {
    let config_context = config::load_config();

    let mut url = http::prepare_endpoint(&config_context, LINK_ENDPONT);
    http::append_query(&mut url, input, TEXT_PARAM);
    let resp = http::get_http_response_or_fail(&url);
    let _ = match resp.get(&String::from(TOKEN_PARAM)) {
        Some(token) => {
            config::store_config(&config_context, &token);
            stdout.lock().write(token.as_ref())
        },
        _ => fail("Failed to link with the back-end"),
    };
}

pub fn fail(s: &str) -> ! {
    let stderr = io::stderr();
    let mut stderr = stderr.lock();

    let _ = stderr.write(format!("{}{}{}", "error: ", s, "\n").as_bytes());
    let _ = stderr.flush();
    process::exit(1);
}