use std::sync::Arc;

use axum::{
    extract::{Path, State},
    response::{Html, Redirect, IntoResponse},
    routing::get,
    Router,
};
use serde_derive::Serialize;
use tracing::{instrument, log::*};

use crate::{
    post::{render_post, Post},
    AppState, WebsiteError,
};

pub fn router() -> Router<Arc<AppState>> {
    Router::new()
        .route("/posts", get(|| async { Redirect::permanent("/") }))
        .route("/posts/", get(index))
        .route("/posts/:slug", get(redirect))
        .route("/posts/:slug/", get(view))
        .route("/posts/:slug/index.md", get(super::not_found))
}

pub fn alias_router<'a>(posts: impl IntoIterator<Item = &'a Post>) -> Router<Arc<AppState>> {
    let mut router = Router::new();

    for post in posts {
        for alias in &post.aliases {
            let path = post.absolute_path.to_owned();
            router = router.route(
                alias,
                get(move || async {
                    let path = path;
                    Redirect::permanent(&path)
                }),
            );
        }
    }
    router
}

#[derive(Serialize, Debug)]
struct PageContext<'a> {
    title: &'a str,
}

#[instrument(skip(state))]
pub async fn index(State(state): State<Arc<AppState>>) -> Result<Html<String>, WebsiteError> {
    let mut posts: Vec<&Post> = state.posts.values().filter(|p| p.is_published()).collect();

    posts.sort_by_key(|p| &p.date);
    posts.reverse();

    let ctx = PageContext { title: "Posts" };

    let mut c = tera::Context::new();
    c.insert("page", &ctx);
    c.insert("posts", &posts);

    let res = state.tera.render("posts_index.html", &c)?;

    Ok(Html(res))
}

#[instrument(skip(state))]
pub async fn view(
    Path(slug): Path<String>,
    State(state): State<Arc<AppState>>,
) -> Result<Html<String>, WebsiteError> {
    let post = state.posts.get(&slug).ok_or(WebsiteError::NotFound)?;
    if !post.is_published() {
        warn!("attempted to view post before it has been published!");
        return Err(WebsiteError::NotFound);
    }

    let res = render_post(&state.tera, post).await?;

    Ok(Html(res))
}

#[instrument(skip(state))]
pub async fn redirect(
    Path(slug): Path<String>,
    State(state): State<Arc<AppState>>,
) -> Result<Redirect, WebsiteError> {
    if state.posts.contains_key(&slug) {
        Ok(Redirect::permanent(&format!("/posts/{slug}/")))
    }
    else {
        Err(WebsiteError::NotFound)
    }
}

#[cfg(test)]
mod tests {
    use chrono::DateTime;

    use crate::post::Post;

    use super::PageContext;

    #[test]
    fn render_index() {
        let posts = vec![
            Post {
                title: "test".into(),
                slug: "test".into(),
                date: Some(DateTime::parse_from_rfc3339("2023-03-26T13:04:01+02:00").unwrap()),
                ..Default::default()
            },
            Post {
                title: "test2".into(),
                slug: "test2".into(),
                date: None,
                ..Default::default()
            },
        ];
        let page = PageContext { title: "Posts" };
        let mut ctx = tera::Context::new();
        ctx.insert("page", &page);
        ctx.insert("posts", &posts);

        let tera = tera::Tera::new("templates/**/*").unwrap();
        let _res = tera.render("posts_index.html", &ctx).unwrap();
    }
}