use async_std::task;
use dnd_dice_roller::{dice::Dice, error::DiceError};
use maj::{
    gemini::{Builder, Node},
    route, seg,
    server::{Error, Handler as MajHandler, Request},
    split, Response,
};
use percent_encoding::percent_decode_str;
use rustls::{
    internal::pemfile::{certs, rsa_private_keys},
    AllowAnyAnonymousOrAuthenticatedClient, Certificate, PrivateKey, RootCertStore, ServerConfig,
};
use std::{
    fs::File,
    io::{self, BufReader},
    path::{Path, PathBuf},
    str::FromStr,
    sync::Arc,
};
use structopt::StructOpt;

#[derive(StructOpt, Debug)]
struct Options {
    /// host to listen on
    #[structopt(short = "H", long, env = "HOST", default_value = "0.0.0.0")]
    host: String,

    /// port to listen on
    #[structopt(short = "p", long, env = "PORT", default_value = "1965")]
    port: u16,

    /// cert file
    #[structopt(short = "c", long = "cert", env = "CERT_FILE")]
    cert: PathBuf,

    /// key file
    #[structopt(short = "k", long = "key", env = "KEY_FILE")]
    key: PathBuf,

    /// static path
    #[structopt(short = "s", long, env = "STATIC_PATH", default_value = "./static")]
    static_path: PathBuf,

    /// server hostname
    #[structopt(
        long = "hostname",
        env = "SERVER_HOSTNAME",
        default_value = "cetacean.club"
    )]
    hostname: String,
}

fn load_certs(path: &Path) -> io::Result<Vec<Certificate>> {
    certs(&mut BufReader::new(File::open(path)?))
        .map_err(|_| io::Error::new(io::ErrorKind::InvalidInput, "invalid cert"))
}

fn load_keys(path: &Path) -> io::Result<Vec<PrivateKey>> {
    rsa_private_keys(&mut BufReader::new(File::open(path)?))
        .map_err(|_| io::Error::new(io::ErrorKind::InvalidInput, "invalid key"))
}

fn main() -> Result<(), maj::server::Error> {
    env_logger::init();
    let opts = Options::from_args();
    let certs = load_certs(&opts.cert)?;
    let mut keys = load_keys(&opts.key)?;

    log::info!(
        "serving gemini://{} on {}:{}",
        opts.hostname,
        opts.host,
        opts.port
    );

    let mut config = ServerConfig::new(AllowAnyAnonymousOrAuthenticatedClient::new(
        RootCertStore::empty(),
    ));
    config
        .set_single_cert(certs, keys.remove(0))
        .map_err(|err| io::Error::new(io::ErrorKind::InvalidInput, err))?;

    task::block_on(maj::server::serve(
        Arc::new(Handler {
            hostname: opts.hostname,
            files: maj::server::files::Handler::new(opts.static_path),
        }),
        config,
        opts.host,
        opts.port,
    ))?;

    Ok(())
}

struct Handler {
    hostname: String,
    files: maj::server::files::Handler,
}

async fn dice(req: Request) -> Result<Response, Error> {
    fn dice_roll<T: Into<String>>(roll: T) -> Result<String, DiceError> {
        let mut dice = Dice::from_str(&roll.into())?;

        if dice.number_of_dice_to_roll > 100 {
            dice.number_of_dice_to_roll = 100;
        }

        if dice.sides > 100 {
            dice.sides = 100
        }

        if dice.sides == 0 {
            dice.sides = 6;
        }

        let res = dice.roll_dice();
        let reply = format!(
            "{}{} = {}\n",
            res.dice_results,
            match dice.modifier {
                Some(amt) => format!(" + {}", amt),
                None => "".into(),
            },
            res.final_result[0]
        );
        Ok(reply)
    }

    match req.url.query() {
        None => Ok(Response::input(
            "What do you want to roll? [n]dn[+n] [adv|dadv]",
        )),
        Some(q) => Ok({
            let dice = percent_decode_str(q).decode_utf8()?;
            let b = Builder::new()
                .heading(1, "Dice Results")
                .text("")
                .text(format!("You rolled {} and you got:", dice))
                .text("")
                .preformatted(format!("{}", dice_roll(dice)?));

            Response::render(b.build())
        }),
    }
}

#[async_trait::async_trait]
impl MajHandler for Handler {
    async fn handle(&self, req: Request) -> Result<Response, Error> {
        if req.url.has_host() && req.url.host_str().unwrap().to_string() != self.hostname {
            return Ok(Response::no_proxy());
        }

        if req.url.path() == "" {
            return Ok(Response::perm_redirect(format!(
                "gemini://{}/",
                self.hostname
            )));
        }

        route!(req.url.path(), {
            (/"dice") => dice(req).await;
        });

        self.files.handle(req).await
    }
}