use rusqlite::{Connection, params};
use smalldog::{ModuleRequest, ModuleResponse, Request, Response};
use time::{Duration, OffsetDateTime};

#[unsafe(no_mangle)]
extern "C" fn cgi_handle(req: *const ModuleRequest) -> *const ModuleResponse {
	let mut response = Response::new();
	let mut body = String::new();

	let request = Request::from_mod_request(req);
	let db = if let Some(path) = request.header("CORGI_STATS_DB") {
		Connection::open(path).unwrap()
	} else {
		return make_error(500, "could not open stats database");
	};

	let now = OffsetDateTime::now_utc();
	let fifteen_ago = now - Duration::minutes(15);

	let query = "SELECT count(requests.id) AS request_count, agents.agent FROM requests \
		INNER JOIN agents ON requests.agent_id = agents.id \
		WHERE requests.timestamp > ?1 \
		GROUP BY requests.agent_id;";

	let mut prepared = db.prepare(query).unwrap();
	let mut agents: Vec<(usize, String)> = prepared
		.query_map(params![fifteen_ago], |row| Ok((row.get(0)?, row.get(1)?)))
		.unwrap()
		.map(|r| r.unwrap())
		.collect();

	agents.sort_by(|a, b| a.0.cmp(&b.0).reverse());

	body.push_str("<p>In the last fifteen minutes:<br/><code><pre>");
	body.push_str("total | req/m | agent\n");
	for (count, agent) in &agents {
		body.push_str(&format!(
			"{count:<5} | {:<5.1} | {agent}\n",
			*count as f32 / 15.0
		));
	}
	body.push_str("</pre></code></p>");
	response.body(body.into_bytes());

	response.into_mod_response(200)
}

fn make_error<S: AsRef<str>>(code: u16, msg: S) -> *const ModuleResponse {
	let mut response = Response::new();
	response.header(c"Content-Length", c"text/html");
	response.body(msg.as_ref().as_bytes().to_vec());

	response.into_mod_response(code)
}

#[unsafe(no_mangle)]
extern "C" fn cgi_cleanup(response: *const ModuleResponse) {
	Response::cleanup(response);
}