use crate::{
	command,
	sql::Db,
};

use std::{
	borrow::Cow,
	collections::{
		BTreeMap,
		HashSet,
	},
	sync::Arc,
};

use async_compat::Compat;






use chrono::{
	DateTime,
	Local,
};
use lazy_static::lazy_static;
use regex::Regex;
use reqwest::header::{
	CACHE_CONTROL,
	EXPIRES,
	LAST_MODIFIED
};
use smol::{
	Timer,
	lock::Mutex,
};
use tgbot::{
	api::Client,
	handler::UpdateHandler,
	types::{
		Bot,
		ChatPeerId,
		Command,

	// max_delay: u16,
	pub tg: Client,
	pub me: Bot,
	pub db: Db,
	sources: Arc<Mutex<HashSet<Arc<i32>>>>,
	http_client: reqwest::Client,
}

pub struct Post {
	uri: String,
	title: String,
	authors: String,
	summary: String,
}

impl Core {
	pub async fn new(settings: config::Config) -> Result<Core> {
		let owner_chat = ChatPeerId::from(settings.get_int("owner").stack()?);
		let api_key = settings.get_string("api_key").stack()?;
		let tg = Client::new(&api_key).stack()?
			.with_host(settings.get_string("api_gateway").stack()?);

			owner_chat,
			db: Db::new(&settings.get_string("pg").stack()?)?,
			sources: Arc::new(Mutex::new(HashSet::new())),
			http_client,
			// max_delay: 60,
		};
		let clone = core.clone();
		smol::spawn(Compat::new(async move {
			loop {
				let delay = match &clone.autofetch().await {
					Err(err) => {
						if let Err(err) = clone.send(format!("🛑 {err}"), None, None).await {
							eprintln!("Autofetch error: {err:?}");
						};
						std::time::Duration::from_secs(60)
					},
					Ok(time) => *time,
				};
				Timer::after(delay).await;
			}
		})).detach();
		Ok(core)
	}

	pub async fn send <S>(&self, msg: S, target: Option<ChatPeerId>, mode: Option<ParseMode>) -> Result<Message>
	where S: Into<String> {
		let msg = msg.into();

			let source = conn.get_source(*id, self.owner_chat).await.stack()?;
			conn.set_scrape(*id).await.stack()?;
			let destination = ChatPeerId::from(match real {
				true => source.channel_id,
				false => source.owner,
			});
			let mut this_fetch: Option<DateTime<chrono::FixedOffset>> = None;
			let mut posts: BTreeMap<DateTime<chrono::FixedOffset>, Post> = BTreeMap::new();

			let mut builder = self.http_client.get(&source.url);
			if let Some(last_scrape) = last_scrape {
				builder = builder.header(LAST_MODIFIED, last_scrape.to_rfc2822());
			};
			let response = builder.send().await.stack()?;
			{

				Ok(feed) => {
					for item in feed.items() {
						if let Some(link) = item.link() {
							let date = match item.pub_date() {
								Some(feed_date) => DateTime::parse_from_rfc2822(feed_date),
								None => DateTime::parse_from_rfc3339(&item.dublin_core_ext().unwrap().dates()[0]),
							}.stack()?;
							let uri = link.to_string();
							let title = item.title().unwrap_or("").to_string();
							let authors = item.author().unwrap_or("").to_string();
							let summary = item.content().unwrap_or("").to_string();
							posts.insert(date, Post{
								uri,
								title,
								authors,
								summary,
							});
						}
					};
				},
				Err(err) => match err {
					rss::Error::InvalidStartTag => {
						match atom_syndication::Feed::read_from(&content[..]) {
							Ok(feed) => {
								for item in feed.entries() {
									let date = item.published().unwrap();
									let uri = item.links()[0].href().to_string();
									let title = item.title().to_string();
									let authors = item.authors().iter().map(|x| format!("{} <{:?}>", x.name(), x.email())).collect::<Vec<String>>().join(", ");
									let summary = if let Some(sum) = item.summary() { sum.value.clone() } else { String::new() };
									posts.insert(*date, Post{
										uri,
										title,
										authors,
										summary,
									});
								};
							},
							Err(err) => {
								bail!("Unsupported or mangled content:\n{:?}\n{err}\n{status:#?}\n", &source.url)
							},
						}
					},
					rss::Error::Eof => (),
					_ => bail!("Unsupported or mangled content:\n{:?}\n{err}\n{status:#?}\n", &source.url)
				}
			};
			for (date, post) in posts.iter() {
				let post_url: Cow<str> = match source.url_re {
					Some(ref x) => sedregex::ReplaceCommand::new(x).stack()?.execute(&post.uri),
					None => post.uri.clone().into(),
				};
				if let Some(exists) = conn.exists(&post_url, *id).await.stack()? {
					if ! exists {
						if this_fetch.is_none() || *date > this_fetch.unwrap() {
							this_fetch = Some(*date);
						};
						self.send( match &source.iv_hash {

							let mut conn = self.db.begin().await.stack()?;
							match conn.get_one(owner, source_id).await {
								Ok(Some(source)) => source.to_string(),
								Ok(None) => "Source not found in database.stack()?".to_string(),
								Err(err) => format!("Failed to fetch source data:\n{err}"),
							}
						};
						smol::spawn(Compat::new(async move {
							if let Err(err) = clone.check(source_id, true, Some(last_scrape)).await {
								if let Err(err) = clone.send(&format!("{source}\n\n🛑 {}", encode(&err.to_string())), None, Some(ParseMode::MarkdownV2)).await {
									eprintln!("Check error: {err}");
									// clone.disable(&source_id, owner).await.unwrap();
								};
							};
						})).detach();
					}
				} else if next_fetch - now < delay {
					delay = next_fetch - now;
				}
			}
		};
		delay.to_std().stack()