package runner

import (
	"sync"
)

// NomadEnvironmentStorage is an interface for storing NomadJobs.
type NomadEnvironmentStorage interface {
	// List returns all keys of environments stored in this storage.
	List() []EnvironmentID

	// Add adds a job to the storage.
	// It overwrites the old job if one with the same id was already stored.
	Add(job *NomadEnvironment)

	// Get returns a job from the storage.
	// Iff the job does not exist in the store, ok will be false.
	Get(id EnvironmentID) (job *NomadEnvironment, ok bool)

	// Delete deletes the job with the passed id from the storage. It does nothing if no job with the id is present in
	// the storage.
	Delete(id EnvironmentID)

	// Length returns the number of currently stored environments in the storage.
	Length() int
}

// localNomadJobStorage stores NomadEnvironment objects in the local application memory.
type localNomadJobStorage struct {
	sync.RWMutex
	jobs map[EnvironmentID]*NomadEnvironment
}

// NewLocalNomadJobStorage responds with an empty localNomadJobStorage.
// This implementation stores the data thread-safe in the local application memory.
func NewLocalNomadJobStorage() *localNomadJobStorage {
	return &localNomadJobStorage{
		jobs: make(map[EnvironmentID]*NomadEnvironment),
	}
}

func (s *localNomadJobStorage) List() []EnvironmentID {
	keys := make([]EnvironmentID, 0, len(s.jobs))
	for k := range s.jobs {
		keys = append(keys, k)
	}
	return keys
}

func (s *localNomadJobStorage) Add(job *NomadEnvironment) {
	s.Lock()
	defer s.Unlock()
	s.jobs[job.ID()] = job
}

func (s *localNomadJobStorage) Get(id EnvironmentID) (job *NomadEnvironment, ok bool) {
	s.RLock()
	defer s.RUnlock()
	job, ok = s.jobs[id]
	return
}

func (s *localNomadJobStorage) Delete(id EnvironmentID) {
	s.Lock()
	defer s.Unlock()
	delete(s.jobs, id)
}

func (s *localNomadJobStorage) Length() int {
	s.RLock()
	defer s.RUnlock()
	return len(s.jobs)
}