use std::time::Duration;

use models::users::user_recent_mentions;
use sea_orm::{ColumnTrait, EntityTrait, QueryFilter};
use time::OffsetDateTime;
use tracing::Instrument;

use crate::errors::ChatError;
use crate::services::service::ChatService;

pub(crate) const STUCK_CLAIM_MINUTES: i64 = 10;
const MENTION_RETENTION_DAYS: i64 = 90;

impl ChatService {
    pub async fn prune_old_mentions(&self) -> Result<(), ChatError> {
        let cutoff = OffsetDateTime::now_utc() - time::Duration::days(MENTION_RETENTION_DAYS);
        user_recent_mentions::Entity::delete_many()
            .filter(user_recent_mentions::Column::CreatedAt.lt(cutoff))
            .exec(self.database.write())
            .await?;
        Ok(())
    }
}

pub async fn run_background_tasks(service: ChatService) {
    let mut interval = tokio::time::interval(Duration::from_secs(30));
    interval.set_missed_tick_behavior(tokio::time::MissedTickBehavior::Delay);
    let mut tick: u32 = 0;
    loop {
        interval.tick().await;
        let request_id = uuid::Uuid::now_v7().to_string();
        let span = tracing::info_span!("chat.background", request_id = %request_id);
        if let Err(error) = export::middleware::with_request_id(
            Some(request_id.as_str()),
            service.deliver_due_reminders().instrument(span),
        )
        .await
        {
            tracing::warn!(%error, "chat reminder delivery failed");
        }
        let span = tracing::info_span!("chat.background", request_id = %request_id);
        if let Err(error) = export::middleware::with_request_id(
            Some(request_id.as_str()),
            service.deliver_pending_webhook_events().instrument(span),
        )
        .await
        {
            tracing::warn!(%error, "chat outbound webhook delivery failed");
        }
        tick = tick.wrapping_add(1);
        if tick.is_multiple_of(120) {
            if let Err(error) = export::middleware::with_request_id(
                Some(request_id.as_str()),
                service.prune_old_mentions(),
            )
            .await
            {
                tracing::warn!(%error, "chat mention prune failed");
            }
            if let Err(error) = export::middleware::with_request_id(
                Some(request_id.as_str()),
                service.cleanup_stale_attachments(),
            )
            .await
            {
                tracing::warn!(%error, "chat attachment cleanup failed");
            }
        }
    }
}