use std::time::Instant;

use assetserver::Asset;
use chrono::TimeDelta;
use maud::{Markup, PreEscaped, html};
use serde::Deserialize;
use tracing::{debug, warn};

use crate::{
	components::{
		md::Markdown,
		misc::{Backlinks, FarLink},
	},
	page::{Page, PageMetadata},
	routes::assets::Image_Icon,
};

#[derive(Debug, Deserialize)]
struct HandoutEntry {
	title: String,
	group: String,
	handout: String,
	solutions: Option<String>,
}

async fn get_index() -> Result<Vec<HandoutEntry>, reqwest::Error> {
	let start = Instant::now();
	let res = reqwest::get(
		"https://git.betalupi.com/api/packages/Mark/generic/ormc-handouts/latest/index.json",
	)
	.await;

	let res = match res {
		Ok(x) => x,
		Err(err) => {
			warn!("Error while getting index: {err:?}");
			return Err(err);
		}
	};

	let mut res: Vec<HandoutEntry> = res.json().await?;
	res.sort_by_key(|x| x.title.clone());

	debug!(
		message = "Fetched handout index",
		n_handouts = res.len(),
		time_ms = start.elapsed().as_millis()
	);
	return Ok(res);
}

fn build_list_for_group(handouts: &[HandoutEntry], group: &str) -> Markup {
	html! {
		ul class="handout-ul" {

			@for h in handouts {
				@if h.group ==group {
					li {
						span class="handdout-li-title" {
							strong { (h.title) }
						}
						" "
						span class="handout-li-links" {
							"[ "

							@if let Some(solutions) = &h.solutions {
								a href=(h.handout) {"handout"}
								" | "
								a href=(solutions) {"solutions"}
							} @else {
								a href=(h.handout) {"handout"}
							}
							" ]"
						}
					}
				}
			}
		}
	}
}

//
// MARK: page
//

pub fn handouts() -> Page {
	let md = Markdown::parse(include_str!("handouts.md"));

	#[expect(clippy::unwrap_used)]
	let mut meta = PageMetadata::from_markdown_frontmatter(&md)
		.unwrap()
		.unwrap();

	if meta.image.is_none() {
		meta.image = Some(Image_Icon::URL.to_owned());
	}

	let html = PreEscaped(md.render());

	Page {
		meta,
		html_ttl: Some(TimeDelta::seconds(300)),

		generate_html: Box::new(move |page| {
			let html = html.clone(); // TODO: find a way to not clone here
			Box::pin(async move {
				let handouts = get_index().await;

				let warmups = match &handouts {
					Ok(handouts) => build_list_for_group(handouts, "Warm-Ups"),
					Err(error) => {
						warn!("Could not load handout index: {error:?}");
						html! {
							span style="color:var(--yellow)" {
								"Could not load handouts, something broke."
							}
							" "
							(
								FarLink(
									"https://git.betalupi.com/Mark/-/packages/generic/ormc-handouts/latest",
									"Try this direct link."
								)
							)
						}
					}
				};

				let advanced = match &handouts {
					Ok(handouts) => build_list_for_group(handouts, "Advanced"),
					Err(_) => html! {
						span style="color:var(--yellow)" {
							"Could not load handouts, something broke."
						}
						" "
						(
							FarLink(
								"https://git.betalupi.com/Mark/-/packages/generic/ormc-handouts/latest",
								"Try this direct link."
							)
						)
					},
				};

				html! {
						@if let Some(slug) = &page.meta.slug {
							(Backlinks(&[("/", "home")], slug))
						}

						(html)

						(Markdown(concat!(
							"## Warm-Ups",
							"\n\n",
							"Students never show up on time. Some come early, some come late. Warm-ups ",
							"are my solution to this problem: we hand these out as students walk in, ",
							"giving them something to do until we can start the lesson.",
						)))
						(warmups)
						br {}

						(Markdown(concat!(
							"## Advanced",
							"\n\n",
							"The highest level of the ORMC, and the group I spend most of my time with. ",
							"Students in ORMC Advanced are in high school, which means ",
							"they're ~14-18 years old.",
						)))
						(advanced)
						br {}
				}
			})
		}),
	}
}