package planner

import (
	"errors"
	"sync"

	"github.com/rs/xid"
)

var (
	list []Besucher
	mtx  sync.RWMutex
	once sync.Once
)

func init() {
	once.Do(initialiseList)
}

func initialiseList() {
	list = []Besucher{}
}

// Get retrieves all elements from the Besucher list
func Get() []Besucher {
	return list
}

// Add will add a new Besucher
func Add(newClient Besucher) string {
	t := newBesucher(newClient)
	mtx.Lock()
	list = append(list, t)
	mtx.Unlock()
	return t.ID
}

// Delete will remove a Besucher from the Besucher list
func Delete(id string) error {
	location, err := findBesucherLocation(id)
	if err != nil {
		return err
	}
	removeElementByLocation(location)
	return nil
}

func removeElementByLocation(i int) {
	mtx.Lock()
	list = append(list[:i], list[i+1:]...)
	mtx.Unlock()
}

func findBesucherLocation(id string) (int, error) {
	mtx.RLock()
	defer mtx.RUnlock()
	for i, t := range list {
		if isMatchingID(t.ID, id) {
			return i, nil
		}
	}
	return 0, errors.New("Could not find Besucher based on id")
}

func isMatchingID(a, b string) bool {
	return a == b
}

func newBesucher(newBesucher Besucher) Besucher {
	return Besucher{
		ID:      xid.New().String(),
		Name:    newBesucher.Name,
		Message: newBesucher.Message,
		Come:    newBesucher.Come,
	}
}