use chrono::NaiveDate;
use serde::Serialize;
use sqlx::SqlitePool;

use super::{
    planned_event::{PlannedEvent, Registration},
    tripdetails::TripDetails,
    user::{CoxUser, User},
};

#[derive(Serialize, Clone, Debug)]
pub struct Trip {
    id: i64,
    cox_id: i64,
    cox_name: String,
    trip_details_id: Option<i64>,
    planned_starting_time: String,
    max_people: i64,
    day: String,
    notes: Option<String>,
}

#[derive(Serialize)]
pub struct TripWithUser {
    #[serde(flatten)]
    trip: Trip,
    rower: Vec<Registration>,
}

impl Trip {
    /// Cox decides to create own trip.
    pub async fn new_own(db: &SqlitePool, cox: &CoxUser, trip_details: TripDetails) {
        sqlx::query!(
            "INSERT INTO trip (cox_id, trip_details_id) VALUES(?, ?)",
            cox.id,
            trip_details.id
        )
        .execute(db)
        .await
        .unwrap(); //Okay, bc. CoxUser + TripDetails can only be created with proper DB backing
    }

    pub async fn find_by_id(db: &SqlitePool, id: i64) -> Option<Self> {
        sqlx::query_as!(
            Self,
            "
SELECT trip.id, cox_id, user.name as cox_name, trip_details_id, planned_starting_time, max_people, day, notes
FROM trip 
INNER JOIN trip_details ON trip.trip_details_id = trip_details.id
INNER JOIN user ON trip.cox_id = user.id
WHERE trip.id=?
        ",
            id
        )
        .fetch_one(db)
        .await
        .ok()
    }

    /// Cox decides to help in a planned event.
    pub async fn new_join(
        db: &SqlitePool,
        cox: &CoxUser,
        planned_event: &PlannedEvent,
    ) -> Result<(), CoxHelpError> {
        let is_rower = sqlx::query!(
            "SELECT count(*) as amount
            FROM user_trip
            WHERE trip_details_id =
                (SELECT trip_details_id FROM planned_event WHERE id = ?)
            AND user_id = ?",
            planned_event.id,
            cox.id
        )
        .fetch_one(db)
        .await
        .unwrap(); //Okay, bc planned_event can only be created with proper DB backing
        if is_rower.amount > 0 {
            return Err(CoxHelpError::AlreadyRegisteredAsRower);
        }

        match sqlx::query!(
            "INSERT INTO trip (cox_id, planned_event_id) VALUES(?, ?)",
            cox.id,
            planned_event.id
        )
        .execute(db)
        .await
        {
            Ok(_) => Ok(()),
            Err(_) => Err(CoxHelpError::AlreadyRegisteredAsCox),
        }
    }

    pub async fn get_for_day(db: &SqlitePool, day: NaiveDate) -> Vec<TripWithUser> {
        let day = format!("{day}");
        let trips = sqlx::query_as!(
            Trip,
            "
SELECT trip.id, cox_id, user.name as cox_name, trip_details_id, planned_starting_time, max_people, day, notes
FROM trip 
INNER JOIN trip_details ON trip.trip_details_id = trip_details.id
INNER JOIN user ON trip.cox_id = user.id
WHERE day=?
    ",
            day
        )
        .fetch_all(db)
        .await
        .unwrap(); //TODO: fixme
        let mut ret = Vec::new();
        for trip in trips {
            ret.push(TripWithUser {
                trip: trip.clone(),
                rower: trip.get_all_rower(db).await,
            });
        }
        ret
    }

    async fn get_all_rower(&self, db: &SqlitePool) -> Vec<Registration> {
        sqlx::query_as!(
            Registration,
            "
SELECT
    (SELECT name FROM user WHERE user_trip.user_id = user.id) as name,
    (SELECT created_at FROM user WHERE user_trip.user_id = user.id) as registered_at 
FROM user_trip WHERE trip_details_id = (SELECT trip_details_id FROM trip WHERE id = ?)",
            self.id
        )
        .fetch_all(db)
        .await
        .unwrap() //Okay, as Trip can only be created with proper DB backing
    }

    /// Cox decides to update own trip.
    pub async fn update_own(
        db: &SqlitePool,
        cox: &CoxUser,
        trip: &Trip,
        max_people: i32,
        notes: Option<String>,
    ) -> Result<(), TripUpdateError> {
        if !trip.is_trip_from_user(cox.id).await {
            return Err(TripUpdateError::NotYourTrip);
        }

        let trip_details = sqlx::query!(
            "SELECT trip_details_id as id FROM trip WHERE id = ?",
            trip.id
        )
        .fetch_one(db)
        .await
        .unwrap(); //Okay, as trip can only be created with proper DB backing
        let Some(trip_details_id) = trip_details.id else {
                return Err(TripUpdateError::TripDetailsDoesNotExist); //TODO: Remove?
        };

        sqlx::query!(
            "UPDATE trip_details SET max_people = ?, notes = ? WHERE id = ?",
            max_people,
            notes,
            trip_details_id
        )
        .execute(db)
        .await
        .unwrap(); //Okay, as trip_details can only be created with proper DB backing

        Ok(())
    }

    pub async fn delete_by_planned_event(
        db: &SqlitePool,
        cox: &CoxUser,
        planned_event: &PlannedEvent,
    ) {
        sqlx::query!(
            "DELETE FROM trip WHERE cox_id = ? AND planned_event_id = ?",
            cox.id,
            planned_event.id
        )
        .execute(db)
        .await
        .unwrap(); //TODO: handle case where cox is not registered
    }

    pub(crate) async fn delete(&self, db: &SqlitePool, user: &User) -> Result<(), TripDeleteError> {
        let registered_rower = self.get_all_rower(db).await;
        if registered_rower.is_empty() {
            return Err(TripDeleteError::SomebodyAlreadyRegistered);
        }

        if !self.is_trip_from_user(user.id).await {
            return Err(TripDeleteError::NotYourTrip);
        }

        sqlx::query!(
            "DELETE FROM trip WHERE cox_id = ? AND id = ?",
            user.id,
            self.id
        )
        .execute(db)
        .await
        .unwrap(); //TODO: fixme

        Ok(())
    }

    async fn is_trip_from_user(&self, user_id: i64) -> bool {
        self.cox_id == user_id
    }
}

#[derive(Debug)]
pub enum CoxHelpError {
    AlreadyRegisteredAsRower,
    AlreadyRegisteredAsCox,
}

#[derive(Debug)]
pub enum TripDeleteError {
    SomebodyAlreadyRegistered,
    NotYourTrip,
}

#[derive(Debug)]
pub enum TripUpdateError {
    NotYourTrip,
    TripDetailsDoesNotExist,
}

#[cfg(test)]
mod test {
    use crate::{
        model::{
            planned_event::PlannedEvent,
            tripdetails::TripDetails,
            user::{CoxUser, User},
        },
        testdb,
    };

    use chrono::NaiveDate;
    use sqlx::SqlitePool;

    use super::Trip;

    #[sqlx::test]
    fn test_new_own() {
        let pool = testdb!();

        let cox: CoxUser = User::find_by_name(&pool, "cox".into())
            .await
            .unwrap()
            .try_into()
            .unwrap();

        let trip_details = TripDetails::find_by_id(&pool, 1).await.unwrap();

        Trip::new_own(&pool, &cox, trip_details).await;

        assert!(Trip::find_by_id(&pool, 1).await.is_some());
    }

    #[sqlx::test]
    fn test_get_day_cox_trip() {
        let pool = testdb!();

        let res = Trip::get_for_day(&pool, NaiveDate::from_ymd_opt(1970, 1, 2).unwrap()).await;
        assert_eq!(res.len(), 1);
    }

    #[sqlx::test]
    fn test_new_succ_join() {
        let pool = testdb!();

        let cox: CoxUser = User::find_by_name(&pool, "cox2".into())
            .await
            .unwrap()
            .try_into()
            .unwrap();

        let planned_event = PlannedEvent::find_by_id(&pool, 1).await.unwrap();

        assert!(Trip::new_join(&pool, &cox, &planned_event).await.is_ok());
    }

    #[sqlx::test]
    fn test_new_failed_join_already_cox() {
        let pool = testdb!();

        let cox: CoxUser = User::find_by_name(&pool, "cox2".into())
            .await
            .unwrap()
            .try_into()
            .unwrap();

        let planned_event = PlannedEvent::find_by_id(&pool, 1).await.unwrap();

        Trip::new_join(&pool, &cox, &planned_event).await.unwrap();
        assert!(Trip::new_join(&pool, &cox, &planned_event).await.is_err());
    }

    #[sqlx::test]
    fn test_succ_update_own() {
        let pool = testdb!();

        let cox: CoxUser = User::find_by_name(&pool, "cox".into())
            .await
            .unwrap()
            .try_into()
            .unwrap();

        let trip = Trip::find_by_id(&pool, 1).await.unwrap();

        assert!(Trip::update_own(&pool, &cox, &trip, 10, None).await.is_ok());

        let trip = Trip::find_by_id(&pool, 1).await.unwrap();
        assert_eq!(trip.max_people, 10);
    }

    #[sqlx::test]
    fn test_fail_update_own_not_your_trip() {
        let pool = testdb!();

        let cox: CoxUser = User::find_by_name(&pool, "cox2".into())
            .await
            .unwrap()
            .try_into()
            .unwrap();

        let trip = Trip::find_by_id(&pool, 1).await.unwrap();

        assert!(Trip::update_own(&pool, &cox, &trip, 10, None)
            .await
            .is_err());
        assert_eq!(trip.max_people, 1);
    }

    #[sqlx::test]
    fn test_succ_delete_by_planned_event() {
        let pool = testdb!();

        let cox: CoxUser = User::find_by_name(&pool, "cox".into())
            .await
            .unwrap()
            .try_into()
            .unwrap();

        let planned_event = PlannedEvent::find_by_id(&pool, 1).await.unwrap();

        Trip::new_join(&pool, &cox, &planned_event).await.unwrap();

        //TODO: check why following assert fails
        //assert!(Trip::find_by_id(&pool, 2).await.is_some());
        Trip::delete_by_planned_event(&pool, &cox, &planned_event).await;
        assert!(Trip::find_by_id(&pool, 2).await.is_none());
    }

    //TODO: create tests for delete() function
}