package training

import (
	"sync"
	"time"
)

type InMemoryTrainingRepository struct {
	trainings map[ID]Training
	lock      sync.RWMutex
	ai        int
}

func NewInMemoryTrainingRepository() *InMemoryTrainingRepository {
	return &InMemoryTrainingRepository{
		trainings: make(map[ID]Training),
		ai:        1,
	}
}

func (r *InMemoryTrainingRepository) Create(training *Training) error {
	r.lock.Lock()
	defer r.lock.Unlock()

	training.ID = r.ai
	r.ai++
	r.trainings[training.ID] = *training
	return nil
}

func (r *InMemoryTrainingRepository) FindByID(id ID) (*Training, error) {
	r.lock.RLock()
	defer r.lock.RUnlock()

	training, ok := r.trainings[id]
	if !ok {
		return nil, ErrTrainingNotFound
	}
	return &training, nil
}

func (r *InMemoryTrainingRepository) FindAll() ([]Training, error) {
	r.lock.RLock()
	defer r.lock.RUnlock()

	trainings := make([]Training, 0, len(r.trainings))
	for _, training := range r.trainings {
		trainings = append(trainings, training)
	}
	return trainings, nil
}

func (r *InMemoryTrainingRepository) Update(training *Training) error {
	r.lock.Lock()
	defer r.lock.Unlock()

	r.trainings[training.ID] = *training
	return nil
}

func (r *InMemoryTrainingRepository) Delete(id ID) error {
	r.lock.Lock()
	defer r.lock.Unlock()

	_, ok := r.trainings[id]
	if !ok {
		return ErrTrainingNotFound
	}

	delete(r.trainings, id)
	return nil
}

type InMemoryDateRepository struct {
	trainingDates   map[DateID]Date
	trainingToDates map[ID][]DateID

	lock sync.RWMutex
	ai   int
}

func NewInMemoryDateRepository() *InMemoryDateRepository {
	return &InMemoryDateRepository{
		trainingDates:   make(map[DateID]Date),
		trainingToDates: make(map[ID][]DateID),
		ai:              1,
	}
}

func (r *InMemoryDateRepository) Create(trainingID ID, trainingDate *Date) error {
	r.lock.Lock()
	defer r.lock.Unlock()

	trainingDate.ID = r.ai
	r.ai++
	trainingDate.trainingID = trainingID

	r.trainingDates[trainingDate.ID] = *trainingDate
	r.trainingToDates[trainingID] = append(r.trainingToDates[trainingID], trainingDate.ID)
	return nil
}

func (r *InMemoryDateRepository) FindByID(id DateID) (*Date, error) {
	r.lock.RLock()
	defer r.lock.RUnlock()

	date, ok := r.trainingDates[id]
	if !ok {
		return nil, ErrTrainingDateNotFound
	}
	return &date, nil
}

func (r *InMemoryDateRepository) FindAll() ([]Date, error) {
	r.lock.RLock()
	defer r.lock.RUnlock()

	dates := make([]Date, len(r.trainingDates))
	for _, date := range r.trainingDates {
		dates = append(dates, date)
	}

	return dates, nil
}

func (r *InMemoryDateRepository) FindAllByTrainingID(trainingID ID) ([]Date, error) {
	r.lock.RLock()
	defer r.lock.RUnlock()

	dates := make([]Date, 0)
	for _, id := range r.trainingToDates[trainingID] {
		dates = append(dates, r.trainingDates[id])
	}

	return dates, nil
}

func (r *InMemoryDateRepository) FindUpcomingByTrainingID(trainingID ID) ([]Date, error) {
	r.lock.RLock()
	defer r.lock.RUnlock()

	now := time.Now()
	var dates []Date
	for _, id := range r.trainingToDates[trainingID] {
		date := r.trainingDates[id]
		if date.Date.After(now) {
			dates = append(dates, date)
		}
	}

	return dates, nil
}

func (r *InMemoryDateRepository) Update(trainingDate *Date) error {
	r.lock.Lock()
	defer r.lock.Unlock()

	oldDate := r.trainingDates[trainingDate.ID]
	trainingDate.trainingID = oldDate.trainingID
	r.trainingDates[trainingDate.ID] = *trainingDate
	return nil
}

func (r *InMemoryDateRepository) Delete(id DateID) error {
	r.lock.Lock()
	defer r.lock.Unlock()

	date, ok := r.trainingDates[id]
	if !ok {
		return ErrTrainingDateNotFound
	}

	delete(r.trainingDates, id)
	dates := r.trainingToDates[date.trainingID]
	for idx, d := range dates {
		if d == id {
			r.trainingToDates[date.trainingID] = append(dates[:idx], dates[idx+1:]...)
			break
		}
	}

	return nil
}

type InMemoryAttendeeRepository struct {
	attendees       map[AttendeeID]Attendee
	dateToAttendees map[DateID][]AttendeeID

	lock sync.RWMutex
	ai   int
}

func NewInMemoryAttendeeRepository() *InMemoryAttendeeRepository {
	return &InMemoryAttendeeRepository{
		attendees:       make(map[AttendeeID]Attendee),
		dateToAttendees: make(map[DateID][]AttendeeID),
		ai:              1,
	}
}

func (r *InMemoryAttendeeRepository) Create(trainingDateID DateID, attendee *Attendee) error {
	r.lock.Lock()
	defer r.lock.Unlock()

	attendee.ID = r.ai
	r.ai++
	attendee.trainingDateID = trainingDateID

	r.attendees[attendee.ID] = *attendee
	r.dateToAttendees[trainingDateID] = append(r.dateToAttendees[trainingDateID], attendee.ID)

	return nil
}

func (r *InMemoryAttendeeRepository) FindByID(id AttendeeID) (*Attendee, error) {
	r.lock.RLock()
	defer r.lock.RUnlock()

	attendee, ok := r.attendees[id]
	if !ok {
		return nil, ErrTrainingDateAttendeeNotFound
	}
	return &attendee, nil
}

func (r *InMemoryAttendeeRepository) FindAll() ([]Attendee, error) {
	r.lock.RLock()
	defer r.lock.RUnlock()

	attendees := make([]Attendee, len(r.attendees))
	for _, attendee := range r.attendees {
		attendees = append(attendees, attendee)
	}

	return attendees, nil
}

func (r *InMemoryAttendeeRepository) FindAllByTrainingDateID(trainingDateID DateID) ([]Attendee, error) {
	r.lock.RLock()
	defer r.lock.RUnlock()

	attendees := make([]Attendee, 0)
	for _, id := range r.dateToAttendees[trainingDateID] {
		attendees = append(attendees, r.attendees[id])
	}

	return attendees, nil
}

func (r *InMemoryAttendeeRepository) Update(attendee *Attendee) error {
	r.lock.Lock()
	defer r.lock.Unlock()

	oldAttendee := r.attendees[attendee.ID]
	attendee.trainingDateID = oldAttendee.trainingDateID
	r.attendees[attendee.ID] = *attendee
	return nil
}

func (r *InMemoryAttendeeRepository) Delete(id AttendeeID) error {
	r.lock.Lock()
	defer r.lock.Unlock()

	attendee, ok := r.attendees[id]
	if !ok {
		return ErrTrainingDateAttendeeNotFound
	}

	delete(r.attendees, id)
	attendees := r.dateToAttendees[attendee.trainingDateID]
	for idx, a := range attendees {
		if a == id {
			r.dateToAttendees[attendee.trainingDateID] = append(attendees[:idx], attendees[idx+1:]...)
			break
		}
	}

	return nil
}