#[macro_use]
extern crate rocket;

use core::panic;
use rocket_dyn_templates::{context, Template};
use std::fs;

mod challenge;
use challenge::Challenge;

#[get("/<challenge>")]
fn get_challenge(challenge: u32) -> Template {
    Template::render(
        "index",
        context! {
            challenge,
            content: {
                use comrak::{parse_document, Arena, ComrakOptions};
                let options = {
                    let mut options = ComrakOptions::default();
                    options.extension.front_matter_delimiter = Some("---".to_owned());
                    options
                };
                let arena = Arena::new();
                let root = parse_document(
                    &arena,
                    &fs::read_to_string(format!("content/challenges/{challenge}.md")).expect("Couldn't find challenge file"),
                    &options,
                );
                if let Some(node) = root.children().next() {
                    if let comrak::nodes::NodeValue::FrontMatter(frontmatter) = &node.data.borrow().value {
                        let frontmatter = {
                            // Trim starting and ending fences
                            let lines: Vec<&str> = frontmatter.trim().lines().collect();
                            lines[1..lines.len() - 1].join("\n")
                        };
                        let challenge: Challenge = serde_yaml::from_str(&frontmatter).unwrap();
                        challenge
                    } else {
                        panic!("No frontmatter!")
                    }
                } else {
                    panic!("Empty document!")
                }
            }
        },
    )
}

#[launch]
fn rocket() -> _ {
    let config = rocket::Config::figment().merge(("port", 1313));
    rocket::custom(config)
        .mount("/", routes![get_challenge])
        .attach(Template::fairing())
}