use axum::{Router, extract::Path, response::IntoResponse, routing::get};
use chrono::NaiveDate;
use icalendar::{Calendar, Component, Event, EventLike};
use regex::Regex;

use crate::models::user::{AuthSession, User};
use crate::models::{Birthday, HydratedContact};
use crate::{AppError, AppState, Database};

pub fn router() -> Router<AppState> {
    Router::new().route("/cal/{path}", get(self::get::calendar))
}

mod get {
    use super::*;

    pub async fn calendar(
        auth_session: AuthSession,
        Path(ics_path): Path<String>,
    ) -> Result<impl IntoResponse, AppError> {
        let path_re = Regex::new(r"^(?<username>.+)-(?<hash>[0-9a-zA-Z]+).ics$").unwrap();

        let username = if let Some(caps) = path_re.captures(&ics_path) {
            caps.name("username").unwrap().as_str()
        } else {
            tracing::debug!(
                "No username match in path {:?} for re /^.+-[0-9a-zA-Z]+.ics$/",
                ics_path
            );
            return Err(AppError(anyhow::Error::msg("TODO: 404")));
        };

        let user: Option<User> = auth_session.backend.find_user(username).await?;
        if user.is_none() {
            tracing::debug!("No matching user for username {:?}", username);
            return Err(AppError(anyhow::Error::msg("TODO: 404")));
        }

        let user = user.unwrap();
        let pool = Database::for_user(&user).await?.pool;
        let expected_path: (Option<String>,) = sqlx::query_as("select ics_path from settings")
            .fetch_one(&pool)
            .await?;
        let debug_ics_path = ics_path.clone();
        if expected_path.0 != Some(ics_path) {
            tracing::debug!(
                "Expected path {:?} did not match request path {:?}",
                expected_path.0,
                debug_ics_path
            );
            return Err(AppError(anyhow::Error::msg("TODO: 404")));
        }

        let calname = format!("Contact birthdays for {}", user.username);
        let mut calendar = Calendar::new();
        calendar.name(&calname);
        calendar.append_property(("PRODID", "Mascarpone CRM"));

        // TODO; this does some db work to pull in last_modified_date that we don't use
        let contacts = HydratedContact::all(&pool).await?;
        for contact in &contacts {
            if let Some(Birthday::Date(yo_date)) = &contact.birthday {
                if let Some(date) = NaiveDate::from_ymd_opt(
                    yo_date.year.unwrap_or(1900).into(),
                    yo_date.month.try_into().unwrap(),
                    yo_date.day.try_into().unwrap(),
                ) {
                    calendar.push(
                        Event::new()
                            .starts(date) // start-with-no-end is "all day"
                            .summary(&format!("{}'s Birthday", &contact.display_name()))
                            .add_property("RRULE", "FREQ=YEARLY"),
                    );
                }
            }
        }

        tracing::debug!("{}", calendar);

        Ok(calendar.to_string())
    }
}