use crate::database::models::Event;
use crate::hypebot_config::HypeBotConfig;
use chrono::{Duration, NaiveDateTime, Utc};
use serenity::prelude::TypeMapKey;

/// Event Reminder
#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
pub struct Reminder {
    pub event_id: i32,
    pub time: NaiveDateTime,
    pub reminder_id: usize,
}

/// Set of reminders for currently active events
#[derive(Debug, Clone, Default)]
pub struct Reminders {
    reminders: Vec<Reminder>,
}

impl TypeMapKey for Reminders {
    type Value = Reminders;
}

impl Reminders {
    /// Add all the reminders for an event
    pub fn add_reminders(&mut self, event: &Event, config: &HypeBotConfig) {
        if let Some(event_reminders) = &config.reminders {
            for (reminder_id, event_reminder) in event_reminders.iter().enumerate() {
                let reminder_time = event.event_time
                    - chrono::Duration::minutes(event_reminder.reminder_time as i64);

                if reminder_time > Utc::now().naive_utc() {
                    self.reminders.push(Reminder {
                        event_id: event.id,
                        time: reminder_time,
                        reminder_id,
                    });
                }
            }
        }
    }

    /// Get reminders that need to be sent
    pub fn get_reminders(&mut self) -> Vec<Reminder> {
        let reminders: Vec<Reminder> = self
            .reminders
            .iter()
            .filter(|r| {
                let time_diff = r.time - Utc::now().naive_utc();
                time_diff > Duration::seconds(-5) && time_diff < Duration::seconds(5)
            })
            .copied()
            .collect();

        self.reminders.retain(|r| !reminders.contains(r));

        reminders
    }

    /// Removes reminders for an event
    pub fn remove_reminders(&mut self, event: &Event) {
        self.reminders.retain(|e| e.event_id != event.id)
    }

    /// Update reminders for an event
    #[allow(dead_code)]
    pub fn update_reminders(&mut self, event: &Event, config: &HypeBotConfig) {
        self.remove_reminders(event);
        self.add_reminders(event, config);
    }
}

#[cfg(test)]
mod tests {
    use crate::hypebot_config::{EventReminder, HypeBotConfig};
    use crate::models::Event;
    use crate::reminder::Reminders;
    use chrono::{Duration, Utc};

    fn setup() -> (Reminders, HypeBotConfig, Event) {
        let r = Reminders::default();

        let c = HypeBotConfig {
            db_url: "".to_string(),
            default_thumbnail_link: "".to_string(),
            discord_key: "".to_string(),
            prefix: "".to_string(),
            event_channel: 0,
            event_roles: vec![],
            ping_roles: vec![],
            event_timezone: chrono_tz::UTC,
            log_path: "".to_string(),
            reminders: Some(
                [EventReminder {
                    msg: "".to_string(),
                    reminder_time: 5,
                },
                EventReminder {
                    msg: "".to_string(),
                    reminder_time: 1,
                }]
                .to_vec(),
            ),
        };

        let e = Event {
            id: 0,
            event_name: "".to_string(),
            event_desc: "".to_string(),
            event_loc: "".to_string(),
            organizer: "".to_string(),
            event_time: Utc::now().naive_utc() + Duration::minutes(5) + Duration::seconds(5),
            message_id: "".to_string(),
            thumbnail_link: "".to_string(),
            reminder_sent: 0,
        };

        (r, c, e)
    }

    #[test]
    fn test_add_reminders() {
        let (mut r, c, e) = setup();
        r.add_reminders(&e, &c);

        assert_eq!(r.reminders.len(), c.reminders.unwrap().len());
    }

    #[test]
    fn test_get_reminders() {
        let (mut r, c, e) = setup();
        r.add_reminders(&e, &c);

        assert_eq!(r.get_reminders().len(), 1);
        assert_eq!(r.reminders.len(), c.reminders.unwrap().len()-1);
    }

    #[test]
    fn test_remove_reminders() {
        let (mut r, c, e) = setup();
        r.add_reminders(&e, &c);

        r.remove_reminders(&e);
        assert_eq!(r.reminders.len(), 0);
    }

    #[test]
    fn test_update_reminders() {
        let (mut r, c, e) = setup();
        r.add_reminders(&e, &c);

        r.update_reminders(&e, &c);

        assert_eq!(r.get_reminders().len(), 1);
    }
}