use anyhow::{bail, Context, Result};
use crate::core::Core;
use regex::Regex;
use sedregex::ReplaceCommand;
use std::borrow::Cow;

lazy_static! {
	static ref RE_USERNAME: Regex = Regex::new(r"^@[a-zA-Z][a-zA-Z0-9_]+$").unwrap();
	static ref RE_LINK: Regex = Regex::new(r"^https?://[a-zA-Z.0-9-]+/[-_a-zA-Z.0-9/?=]+$").unwrap();
	static ref RE_IV_HASH: Regex = Regex::new(r"^[a-f0-9]{14}$").unwrap();
}

pub async fn start(core: &Core, sender: telegram_bot::UserId) -> Result<()> {
	core.send("We are open. Probably. Visit [channel](https://t.me/rsstg_bot_help/3) for details.", Some(sender), None).await?;
	Ok(())
}

pub async fn list(core: &Core, sender: telegram_bot::UserId) -> Result<()> {
	core.send(core.list(sender).await?, Some(sender), Some(telegram_bot::types::ParseMode::MarkdownV2)).await?;
	Ok(())
}

pub async fn command(core: &Core, sender: telegram_bot::UserId, command: Vec<&str>) -> Result<()> {
	let msg: Cow<str> = match &command[1].parse::<i32>() {
		Err(err) => format!("I need a number.\n{}", &err).into(),
		Ok(number) => match command[0] {
			"/check" => core.check(number, sender, false).await
				.context("Channel check failed.")?,
			"/clean" => core.clean(number, sender).await?,
			"/enable" => core.enable(number, sender).await?.into(),
			"/delete" => core.delete(number, sender).await?,
			"/disable" => core.disable(number, sender).await?.into(),
			_ => bail!("Command {} not handled.", &command[0]),
		},
	};
	core.send(msg, Some(sender), None).await?;
	Ok(())
}

pub async fn update(core: &Core, sender: telegram_bot::UserId, command: Vec<&str>) -> Result<()> {
	let mut source_id: Option<i32> = None;
	let at_least = "Requires at least 3 parameters.";
	let first_word = command[0];

		};
		if admin.user.id == sender {
			user = true;
		};
	};
	if ! me   { bail!("I need to be admin on that channel."); };
	if ! user { bail!("You should be admin on that channel."); };
	core.send(core.update(source_id, channel, channel_id, url, iv_hash, url_re, sender).await?, Some(sender), None).await?;
	Ok(())
}

				.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 {
			loop {
				let delay = match &clone.autofetch().await {
					Err(err) => {
						if let Err(err) = clone.send(format!("🛑 {:?}", err), None, None).await {
							eprintln!("Autofetch error: {}", err);
						};
						tokio::time::Duration::from_secs(60)
					},
					Ok(time) => *time,
				};
				tokio::time::sleep(delay).await;
			}
		});
		Ok(core)
	}

	pub fn stream(&self) -> telegram_bot::UpdatesStream {
		self.tg.stream()
	}

	pub async fn send<'a, S>(&self, msg: S, target: Option<telegram_bot::UserId>, mode: Option<telegram_bot::types::ParseMode>) -> Result<()>
	where S: Into<Cow<'a, str>> {
		let msg = msg.into();



		let mode = mode.unwrap_or(telegram_bot::types::ParseMode::Html);



		let target = target.unwrap_or(self.owner_chat);
		self.tg.send(telegram_bot::SendMessage::new(target, msg).parse_mode(mode)).await?;
		Ok(())
	}

	pub async fn check<S>(&self, id: &i32, owner: S, real: bool) -> Result<Cow<'_, str>>
	where S: Into<i64> {
		let owner = owner.into();

					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]),
							}?;
							let url = link;
							posts.insert(date, url.to_string());
						}
					};
				},
				Err(err) => match err {
					rss::Error::InvalidStartTag => {
						let feed = atom_syndication::Feed::read_from(&content[..])
							.with_context(|| format!("Problem opening feed url:\n{}\n{}", &url, status))?;
						for item in feed.entries() {
							let date = item.published().unwrap();
							let url = item.links()[0].href();
							posts.insert(*date, url.to_string());
						};
					},
					rss::Error::Eof => (),
					_ => bail!("Unsupported or mangled content:\n{:?}\n{:#?}\n{:#?}\n", &url, err, status)
				}
			};
			for (date, url) in posts.iter() {

			.rows_affected() {
			1 => { Ok("Source disabled.") },
			0 => { Ok("Source not found.") },
			_ => { Err(anyhow!("Database error.")) },
		}
	}

	pub async fn update<S>(&self, update: Option<i32>, channel: &str, channel_id: i64, url: &str, iv_hash: Option<&str>, url_re: Option<&str>, owner: S) -> Result<&str>
	where S: Into<i64> {
		let owner = owner.into();

		let mut conn = self.pool.acquire().await
			.with_context(|| format!("Update fetch conn:\n{:?}", &self.pool))?;

		match match update {
				Some(id) => {
					sqlx::query("update rsstg_source set channel_id = $2, url = $3, iv_hash = $4, owner = $5, channel = $6, url_re = $7 where source_id = $1").bind(id)

			},
			Err(err) => {
				bail!("Sorry, unknown error:\n{:#?}\n", err);
			},
		}
	}

	async fn autofetch(&self) -> Result<std::time::Duration> {
		let mut delay = chrono::Duration::minutes(1);


		let mut conn = self.pool.acquire().await
			.with_context(|| format!("Autofetch fetch conn:\n{:?}", &self.pool))?;
		let 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 '1 minute';")
			.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 = Core {
					owner_chat: telegram_bot::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.send(&format!("🛑 {:?}", err), None, None).await {
							eprintln!("Check error: {}", err);
						};
					};
				});
			} else if next_fetch - now < delay {
				delay = next_fetch - now;
			}
		};
		queue.clear();
		Ok(delay.to_std()?)


	}

	pub async fn list<S>(&self, owner: S) -> Result<String>
	where S: Into<i64> {
		let owner = owner.into();

		let mut reply: Vec<Cow<str>> = vec![];

	let mut reply_to: Option<telegram_bot::UserId>;

	loop {
		reply_to = None;
		match stream.next().await {
			Some(update) => {
				if let Err(err) = handle(update?, &core, &reply_to).await {
					core.send(&format!("🛑 {:?}", err), reply_to, None).await?;
				};
			},
			None => {
				core.send("🛑 None error.", None, None).await?;
			}
		};
	}
}

async fn handle(update: telegram_bot::Update, core: &core::Core, mut _reply_to: &Option<telegram_bot::UserId>) -> Result<()> {
	if let telegram_bot::UpdateKind::Message(message) = update.kind {
		if let telegram_bot::MessageKind::Text { ref data, .. } = message.kind {
			let sender = message.from.id;
			let words: Vec<&str> = data.split_whitespace().collect();
			match match words[0] {
				"/check" | "/clean" | "/enable" | "/delete" | "/disable" => command::command(core, sender, words).await,
				"/start" => command::start(core, sender).await,
				"/list" => command::list(core, sender).await,
				"/add" | "/update" => command::update(core, sender, words).await,
				_ => Ok(()),
			} {
				Err(err) => core.send(format!("🛑 {:?}", err), Some(sender), None).await?,
				Ok(()) => {},
			};
		};
	};

	Ok(())
}