use anyhow::{Context, Error, Result};
use chrono::{Days, NaiveTime, Utc};
use mininews::parser::{parse, EventBlock, PAGE_URL};
use rss::{ChannelBuilder, Guid, Item, ItemBuilder};
use uuid::{Timestamp, Uuid};

fn generate_feed(items: Vec<EventBlock>) -> Result<()> {
    let mut channel = ChannelBuilder::default()
        .title("Mininews")
        .link("https://example.com")
        .description("An RSS feed from Wikipedia's Current Events")
        .build();

    channel.set_items(
        items
            .iter()
            .filter(|x| x.date < Utc::now().date_naive())
            .map(|x| {
                let pub_date = x
                    .date
                    .checked_add_days(Days::new(1))
                    .context("failed to add to date")?
                    .and_time(NaiveTime::MIN)
                    .and_utc();
                Ok::<Item, Error>(
                    ItemBuilder::default()
                        .title(x.date.to_string())
                        .link(Some(PAGE_URL.to_string()))
                        .pub_date(pub_date.to_rfc2822())
                        .guid(Guid {
                            permalink: false,
                            value: Uuid::new_v7(Timestamp::from_unix_time(
                                pub_date.timestamp() as u64,
                                0,
                                0,
                                0,
                            ))
                            .to_string(),
                        })
                        .description(format!(
                            "Wikipedia current events from {}",
                            x.date.to_string()
                        ))
                        .content(x.content.clone())
                        .build(),
                )
            })
            .collect::<Result<Vec<Item>, _>>()?,
    );

    println!("{:?}", channel.to_string());

    Ok(())
}

fn main() -> Result<()> {
    generate_feed(parse()?)
}