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

use config;

use tokio;

use rss;

struct Core {
	owner: i64,
	api_key: String,
	owner_chat: UserId,
	tg: telegram_bot::Api,
	my: User,
	pool: sqlx::Pool<sqlx::Postgres>,
	sources: Arc<Mutex<HashSet<Arc<i32>>>>,
}

impl Core {
	async fn new(settings: config::Config) -> Result<Core> {
		let owner = settings.get_int("owner")?;
		let api_key = settings.get_str("api_key")?;
		let tg = Api::new(&api_key);
		let core = Core {
			owner: owner,
			api_key: api_key.clone(),
			my: tg.send(telegram_bot::GetMe).await?,
			tg: tg,
			owner_chat: UserId::new(owner),
			pool: PgPoolOptions::new()
				.max_connections(5)
				.connect_timeout(std::time::Duration::new(300, 0))
				.idle_timeout(std::time::Duration::new(60, 0))
				.connect_lazy(&settings.get_str("pg")?)?,
			sources: Arc::new(Mutex::new(HashSet::new())),
		};
		let clone = core.clone();
		tokio::spawn(async move {
			if let Err(err) = &clone.autofetch().await {
				if let Err(err) = clone.debug(&format!("🛑 {:?}", err)) {
					eprintln!("Autofetch error: {}", err);
				};

	}

	fn debug(&self, msg: &str) -> Result<()> {
		self.tg.spawn(SendMessage::new(self.owner_chat, msg));
		Ok(())
	}

	async fn check<S>(&self, id: i32, owner: S, real: bool) -> Result<()>
	where S: Into<i64> {
		let owner: i64 = owner.into();
		let id = {
			let mut set = self.sources.lock().unwrap();
			match set.get(&id) {
				Some(id) => id.clone(),
				None => {
					let id = Arc::new(id);
					set.insert(id.clone());
					id.clone()
				},
			}
		};
		let count = Arc::strong_count(&id);
		if count == 2 {
			let mut conn = self.pool.acquire().await
				.with_context(|| format!("Query queue fetch conn:\n{:?}", &self.pool))?;
			let row = sqlx::query("select source_id, channel_id, url, iv_hash, owner from rsstg_source where source_id = $1 and owner = $2")
				.bind(*id)
				.bind(owner)
				.fetch_one(&mut conn).await
				.with_context(|| format!("Query source:\n{:?}", &self.pool))?;
			drop(conn);
			let channel_id: i64 = row.try_get("channel_id")?;
			let destination = match real {
				true => UserId::new(channel_id),
				false => UserId::new(row.try_get("owner")?),
			};
			let url: &str = row.try_get("url")?;
			let mut this_fetch: Option<DateTime<chrono::FixedOffset>> = None;
			let iv_hash: Option<&str> = row.try_get("iv_hash")?;
			let mut posts: BTreeMap<DateTime<chrono::FixedOffset>, String> = BTreeMap::new();
			let feed = rss::Channel::from_url(url)
				.with_context(|| format!("Problem opening feed url:\n{}", &url))?;
			for item in feed.items() {
				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]),
				}?;
				let url = item.link().unwrap().to_string();
				posts.insert(date.clone(), url.clone());
			};
			for (date, url) in posts.iter() {
				let mut conn = self.pool.acquire().await
					.with_context(|| format!("Check post fetch conn:\n{:?}", &self.pool))?;
				let row = sqlx::query("select exists(select true from rsstg_post where url = $1 and source_id = $2) as exists;")
					.bind(&url)
					.bind(*id)
					.fetch_one(&mut conn).await
					.with_context(|| format!("Check post:\n{:?}", &conn))?;
				let exists: bool = row.try_get("exists")?;
				if ! exists {
					if this_fetch == None || *date > this_fetch.unwrap() {
						this_fetch = Some(*date);
					};
					self.tg.send( match iv_hash {
							Some(x) => SendMessage::new(destination, format!("<a href=\"https://t.me/iv?url={}&rhash={}\"> </a>{0}", url, x)),
							None => SendMessage::new(destination, format!("{}", url)),
						}.parse_mode(types::ParseMode::Html)).await
						.context("Can't post message:")?;
					sqlx::query("insert into rsstg_post (source_id, posted, url) values ($1, $2, $3);")
						.bind(*id)
						.bind(date)
						.bind(url)
						.execute(&mut conn).await
						.with_context(|| format!("Record post:\n{:?}", &conn))?;
					drop(conn);
					tokio::time::delay_for(std::time::Duration::new(4, 0)).await;
				};
			};
			posts.clear();
		};
		let mut conn = self.pool.acquire().await
			.with_context(|| format!("Update scrape fetch conn:\n{:?}", &self.pool))?;
		sqlx::query("update rsstg_source set last_scrape = now() where source_id = $1;")
			.bind(*id)
			.execute(&mut conn).await
			.with_context(|| format!("Update scrape:\n{:?}", &conn))?;
		Ok(())
	}

	async fn delete<S>(&self, source_id: &i32, owner: S) -> Result<String>
	where S: Into<i64> {

	async fn autofetch(&self) -> Result<()> {
		let mut delay = chrono::Duration::minutes(5);
		let mut now;
		loop {
			let mut conn = self.pool.acquire().await
				.with_context(|| format!("Autofetch fetch conn:\n{:?}", &self.pool))?;
			now = chrono::Local::now();
			let mut queue = sqlx::query("select source_id, next_fetch, owner from rsstg_order natural left join rsstg_source where next_fetch < now() + interval '5 minutes';")
				.fetch_all(&mut conn).await?;
			for row in queue.iter() {
				let source_id: i32 = row.try_get("source_id")?;
				let owner: i64 = row.try_get("owner")?;
				let next_fetch: DateTime<chrono::Local> = row.try_get("next_fetch")?;
				if next_fetch < now {


					//let clone = self.clone();

					//clone.owner_chat(UserId::new(owner));
					let clone = Core {
						owner_chat: UserId::new(owner),
						..self.clone()
					};
					tokio::spawn(async move {
						if let Err(err) = clone.check(source_id, owner, true).await {
							if let Err(err) = clone.debug(&format!("🛑 {:?}", err)) {
								eprintln!("Check error: {}", err);
							};
						};
					});
				} else {
					if next_fetch - now < delay {

						"/check" => {
							match &words.next().unwrap().parse::<i32>() {
								Err(err) => {
									reply.push(format!("I need a number\\.\n{}", &err));
								},
								Ok(number) => {
									core.check(*number, message.from.id, false).await
										.context("Channel check failed.")?;
								},
							};
						},

// clean