#[cfg(test)]
mod integration_tests {
    use rota_lib::{
        config::{ToxicPair, UserConfig},
        resident::Resident,
        schedule::{MonthlySchedule, ShiftType},
        scheduler::Scheduler,
        slot::{Day, ShiftPosition, Slot},
        workload::{WorkloadBounds, WorkloadTracker},
    };
    use rstest::{fixture, rstest};

    #[fixture]
    fn minimal_config() -> UserConfig {
        UserConfig::default().with_residents(vec![
            Resident::new(1, "R1"),
            Resident::new(2, "R2"),
            Resident::new(3, "R3"),
            Resident::new(4, "R4"),
        ])
    }

    #[fixture]
    fn maximal_config() -> UserConfig {
        UserConfig::default()
            .with_holidays(vec![2, 3, 10, 11, 12, 25])
            .with_residents(vec![
                Resident::new(1, "R1").with_max_shifts(3),
                Resident::new(2, "R2").with_max_shifts(4),
                Resident::new(3, "R3").with_reduced_load(),
                Resident::new(4, "R4").with_allowed_types(vec![ShiftType::Closed]),
                Resident::new(5, "R5")
                    .with_allowed_types(vec![ShiftType::OpenFirst, ShiftType::OpenSecond]),
                Resident::new(6, "R6").with_negative_shifts(vec![Day(5), Day(15), Day(25)]),
                Resident::new(7, "R7"),
                Resident::new(8, "R8"),
                Resident::new(9, "R9"),
                Resident::new(10, "R10"),
            ])
            .with_toxic_pairs(vec![
                ToxicPair::new(1, 2),
                ToxicPair::new(3, 4),
                ToxicPair::new(7, 8),
            ])
    }

    #[fixture]
    fn manual_shifts_heavy_config() -> UserConfig {
        UserConfig::default().with_residents(vec![
            Resident::new(1, "R1").with_manual_shifts(vec![
                Slot::new(Day(1), ShiftPosition::First),
                Slot::new(Day(3), ShiftPosition::First),
                Slot::new(Day(5), ShiftPosition::Second),
            ]),
            Resident::new(2, "R2").with_manual_shifts(vec![
                Slot::new(Day(2), ShiftPosition::First),
                Slot::new(Day(4), ShiftPosition::First),
            ]),
            Resident::new(3, "R3"),
            Resident::new(4, "R4"),
            Resident::new(5, "R5"),
            Resident::new(6, "R6"),
        ])
    }

    #[fixture]
    fn complex_config() -> UserConfig {
        UserConfig::default()
            .with_holidays(vec![5, 12, 19, 26])
            .with_residents(vec![
                Resident::new(1, "R1")
                    .with_max_shifts(3)
                    .with_negative_shifts(vec![Day(1), Day(2), Day(3)]),
                Resident::new(2, "R2")
                    .with_max_shifts(3)
                    .with_negative_shifts(vec![Day(4), Day(5), Day(6)]),
                Resident::new(3, "R3")
                    .with_max_shifts(3)
                    .with_negative_shifts(vec![Day(7), Day(8), Day(9)]),
                Resident::new(4, "R4").with_allowed_types(vec![ShiftType::Closed]),
                Resident::new(5, "R5")
                    .with_allowed_types(vec![ShiftType::OpenFirst, ShiftType::OpenSecond]),
                Resident::new(6, "R6"),
                Resident::new(7, "R7"),
                Resident::new(8, "R8"),
            ])
            .with_toxic_pairs(vec![
                ToxicPair::new(1, 2),
                ToxicPair::new(2, 3),
                ToxicPair::new(5, 6),
                ToxicPair::new(6, 7),
            ])
    }

    #[rstest]
    fn test_minimal_config(minimal_config: UserConfig) -> anyhow::Result<()> {
        let mut schedule = MonthlySchedule::new();
        let mut tracker = WorkloadTracker::default();
        let scheduler = Scheduler::new_with_config(minimal_config.clone());

        assert!(scheduler.run(&mut schedule, &mut tracker)?);

        validate_all_constraints(&schedule, &tracker, &minimal_config);

        Ok(())
    }

    #[rstest]
    fn test_maximal_config(maximal_config: UserConfig) -> anyhow::Result<()> {
        let mut schedule = MonthlySchedule::new();
        let mut tracker = WorkloadTracker::default();
        let scheduler = Scheduler::new_with_config(maximal_config.clone());

        assert!(scheduler.run(&mut schedule, &mut tracker)?);

        validate_all_constraints(&schedule, &tracker, &maximal_config);

        Ok(())
    }

    #[rstest]
    fn test_manual_shifts_heavy_config(
        manual_shifts_heavy_config: UserConfig,
    ) -> anyhow::Result<()> {
        let mut schedule = MonthlySchedule::new();
        let mut tracker = WorkloadTracker::default();
        let scheduler = Scheduler::new_with_config(manual_shifts_heavy_config.clone());

        assert!(scheduler.run(&mut schedule, &mut tracker)?);

        validate_all_constraints(&schedule, &tracker, &manual_shifts_heavy_config);

        Ok(())
    }

    #[rstest]
    fn test_complex_config(complex_config: UserConfig) -> anyhow::Result<()> {
        let mut schedule = MonthlySchedule::new();
        let mut tracker = WorkloadTracker::default();
        let scheduler = Scheduler::new_with_config(complex_config.clone());

        assert!(scheduler.run(&mut schedule, &mut tracker)?);

        validate_all_constraints(&schedule, &tracker, &complex_config);

        Ok(())
    }

    fn validate_all_constraints(
        schedule: &MonthlySchedule,
        tracker: &WorkloadTracker,
        config: &UserConfig,
    ) {
        assert_eq!(schedule.0.len() as u8, config.total_slots);

        for d in 2..=config.total_days {
            let current: Vec<_> = [ShiftPosition::First, ShiftPosition::Second]
                .iter()
                .filter_map(|&p| schedule.get_resident_id(&Slot::new(Day(d), p)))
                .collect();
            let previous: Vec<_> = [ShiftPosition::First, ShiftPosition::Second]
                .iter()
                .filter_map(|&p| schedule.get_resident_id(&Slot::new(Day(d - 1), p)))
                .collect();
            for res in current {
                assert!(!previous.contains(&res));
            }
        }

        for d in 1..=config.total_days {
            let day = Day(d);
            if day.is_open_shift() {
                let r1 = schedule.get_resident_id(&Slot::new(day, ShiftPosition::First));
                let r2 = schedule.get_resident_id(&Slot::new(day, ShiftPosition::Second));
                assert_ne!(r1, r2);
                if let (Some(id1), Some(id2)) = (r1, r2) {
                    let pair = ToxicPair::from((*id1, *id2));
                    assert!(config.toxic_pairs.iter().all(|t| !t.matches(&pair)));
                }
            }
        }

        let bounds = WorkloadBounds::new_with_config(config);
        for (slot, res_id) in &schedule.0 {
            let res = config
                .residents
                .iter()
                .find(|r| &r.id == res_id)
                .expect("Resident not found");
            assert!(res.allowed_types.contains(&slot.shift_type()));
            assert!(!res.negative_shifts.contains(&slot.day));
        }

        for resident in &config.residents {
            let workload = tracker.current_workload(&resident.id);
            let max = *bounds.max_workloads.get(&resident.id).unwrap();
            assert!(workload <= max);
        }
    }
}