package database

import (
	"math/rand"
	"time"

	"git.phc.dm.unipi.it/phc/cluster-dashboard/backend/executor"
	"git.phc.dm.unipi.it/phc/cluster-dashboard/backend/model"
)

// simpleDB è una implementazione di [database.Database] che tiene giusto una cache in memoria e
// quando il server viene riavviato perde tutte le statistiche che ha accumulato. Più avanti si
// potrebbe pensare di scrivere queste informazioni in un file o usare un vero database.
type simpleDB struct {
	Executor executor.Service

	// lastUpdate tiene traccia di quando abbiamo aggiornato l'ultima volta tutti i dati
	lastUpdate *time.Time

	// Nodes is a map from hostname to node info
	nodes map[string]*model.Node

	// Jobs is a map from job id to job info
	jobs map[string]*model.Job

	// The following are maps from hostname to a list of sampled temperatures, used memory, used storage space and network upload and download rate.

	temperatureSamples     map[string][]model.Sample[float64]
	memorySamples          map[string][]model.Sample[int64]
	storageSamples         map[string][]model.Sample[int64]
	networkUploadSamples   map[string][]model.Sample[int64]
	networkDownloadSamples map[string][]model.Sample[int64]
}

func NewSimpleDatabase(ex executor.Service) Database {
	return &simpleDB{Executor: ex}
}

func (s *simpleDB) GetNode(hostname string) (*model.Node, error) {
	return &model.Node{
		Hostname:  hostname,
		StartTime: time.Now().Add(-1 * time.Hour),
	}, nil
}

func (s *simpleDB) GetJob(id string) (*model.Job, error) {
	return &model.Job{
		Id:        id,
		Name:      "example-job",
		Status:    "active",
		Nodes:     []string{"node-1", "node-2"},
		Resources: []string{},
	}, nil
}

func (s *simpleDB) AllNodes() ([]*model.Node, error) {
	return []*model.Node{
		{
			Hostname:  "node-1",
			StartTime: time.Now().Add(-1 * time.Hour),
		},
		{
			Hostname:  "node-2",
			StartTime: time.Now().Add(-1 * time.Hour),
		},
		{
			Hostname:  "node-3",
			StartTime: time.Now().Add(-1 * time.Hour),
		},
	}, nil
}

func (s *simpleDB) AllJobs() ([]*model.Job, error) {
	return []*model.Job{
		{
			Id:        "job-1",
			Name:      "example-job",
			Status:    "active",
			Nodes:     []string{"node-1", "node-2"},
			Resources: []string{},
		},
		{
			Id:        "job-2",
			Name:      "example-job",
			Status:    "active",
			Nodes:     []string{"node-1", "node-2"},
			Resources: []string{},
		},
		{
			Id:        "job-3",
			Name:      "example-job",
			Status:    "active",
			Nodes:     []string{"node-1", "node-2"},
			Resources: []string{},
		},
		{
			Id:        "job-4",
			Name:      "example-job",
			Status:    "active",
			Nodes:     []string{"node-1", "node-2"},
			Resources: []string{},
		},
		{
			Id:        "job-5",
			Name:      "example-job",
			Status:    "active",
			Nodes:     []string{"node-1", "node-2"},
			Resources: []string{},
		},
	}, nil
}

func (s *simpleDB) QueryTemperatureSamples(from, to time.Time) ([]model.Sample[float64], error) {
	return generateFakeFloat64Samples(100), nil
}

func (s *simpleDB) QueryMemorySamples(from, to time.Time) ([]model.Sample[int64], error) {
	return generateFakeInt64Samples(100), nil
}

func (s *simpleDB) QueryStorageSamples(from, to time.Time) ([]model.Sample[int64], error) {
	return generateFakeInt64Samples(100), nil
}

func (s *simpleDB) QueryNetworkUploadSamples(from, to time.Time) ([]model.Sample[int64], error) {
	return generateFakeInt64Samples(100), nil
}

func (s *simpleDB) QueryNetworkDownloadSamples(from, to time.Time) ([]model.Sample[int64], error) {
	return generateFakeInt64Samples(100), nil
}

func generateFakeFloat64Samples(amount int) []model.Sample[float64] {
	fakeSamples := make([]model.Sample[float64], amount)

	for i := range fakeSamples {
		fakeSamples[i] = model.Sample[float64]{
			Timestamp: time.Now().Add(time.Duration(i-amount) * time.Second),
			Value:     rand.Float64(),
		}
	}

	return fakeSamples
}

func generateFakeInt64Samples(amount int) []model.Sample[int64] {
	fakeSamples := make([]model.Sample[int64], amount)

	for i := range fakeSamples {
		fakeSamples[i] = model.Sample[int64]{
			Timestamp: time.Now().Add(time.Duration(i-amount) * time.Second),
			Value:     rand.Int63n(1000),
		}
	}

	return fakeSamples
}