use anyhow::{anyhow, Result};
use atom_syndication as atom;
use maj::gemini::Node;
use rustls::ClientConfig;
use std::io::{self, BufReader, Cursor, Write};
use std::ops::Sub;
use std::str;
use chrono::{Duration, prelude::*};

mod tls;

fn gem_to_md(tcana: Vec<Node>, out: &mut impl Write) -> io::Result<()> {
    use Node::*;

    for tcan in tcana {
        match tcan {
            Text(body) => {
                if body == "---" {
                    break;
                }

                write!(out, "{}\n", body)?;
            }
            Link { to, name } => match name {
                Some(name) => write!(out, "[{}]({})\n\n", name, to)?,
                None => write!(out, "[{0}]({0})", to)?,
            },
            Preformatted(body) => write!(out, "```\n{}\n```\n\n", body)?,
            Heading { level, body } => {
                write!(out, "##{} {}\n\n", "#".repeat(level as usize), body)?
            }
            ListItem(body) => write!(out, "* {}\n", body)?,
            Quote(body) => write!(out, "> {}\n\n", body)?,
        }
    }

    Ok(())
}

async fn read_feed(gurl: String, cfg: ClientConfig) -> Result<atom::Feed> {
    let resp = maj::get(gurl, cfg).await?;
    if resp.status != maj::StatusCode::Success {
        Err(anyhow!(
            "expected success, got: {} {}",
            resp.status as u8,
            resp.meta
        ))?;
    }

    let body = Cursor::new(resp.body);
    let feed = atom::Feed::read_from(BufReader::new(body))?;

    Ok(feed)
}

pub async fn run(nuzyurli: Vec<String>, seldei: usize) -> Result<()> {
    let cfg = tls::config();
    let ca: atom::FixedDateTime = Utc::now().into();

    for urli in nuzyurli {
        let feed = read_feed(urli.clone(), cfg.clone()).await?;
        log::info!("reading entries for {}: {}", urli, feed.title);
        println!("## {}\nBy {}\n\n", feed.title, feed.authors[0].name);
        println!("[Site link]({})\n\n", feed.id);

        for entry in feed.entries {
            if ca.sub(entry.updated) > Duration::days(seldei as i64) {
                continue;
            }
            let href: String = entry.links()[0].href.clone();
            let resp = maj::get(href, cfg.clone()).await?;
            if resp.status != maj::StatusCode::Success {
                return Err(anyhow!(
                    "expected success, got: {} {}",
                    resp.status as u8,
                    resp.meta
                ));
            }

            let body = str::from_utf8(&resp.body)?;
            let body = maj::gemini::parse(body);
            let mut buf: Vec<u8> = vec![];
            gem_to_md(body, &mut buf)?;
            println!("{}", str::from_utf8(&buf)?);
        }
    }

    Ok(())
}