package dbAccess

import (
	"context"
	"errors"
	"time"

	"git.fjla.uk/owlboard/go-types/pkg/database"
	"git.fjla.uk/owlboard/timetable-mgr/log"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
	"go.uber.org/zap"
)

const StationsMetaDoctype string = "StationsMetadata"

type StationsMetadata struct {
	Doctype    string
	LastUpdate time.Time
}

// Fetches the CifMetadata from the database, returns nil if no metadata exists - before first initialisation for example.
func GetStationsMetadata() (*StationsMetadata, error) {
	database := MongoClient.Database(DatabaseName)
	collection := database.Collection(MetaCollection)
	filter := bson.M{"type": StationsMetaDoctype}
	var result StationsMetadata
	err := collection.FindOne(context.Background(), filter).Decode(&result)
	if err != nil {
		if errors.Is(err, mongo.ErrNoDocuments) {
			return nil, nil
		}
		return nil, err
	}

	log.Debug("Fetched Stations Metadata from database", zap.Any("Metadata", result))

	return &result, nil
}

func SetStationsMetadata(time time.Time) bool {
	database := MongoClient.Database(DatabaseName)
	collection := database.Collection(MetaCollection)
	options := options.Update().SetUpsert(true)
	filter := bson.M{"type": StationsMetaDoctype}
	update := bson.M{
		"$set": bson.M{
			"type":       StationsMetaDoctype,
			"lastUpdate": time,
		},
	}

	_, err := collection.UpdateOne(context.Background(), filter, update, options)

	if err != nil {
		log.Error("Error updating Stations Metadata", zap.Error(err))
		return false
	}

	log.Info("New Stations Metadata written", zap.Time("Update time", time))
	return true
}

// Puts an array of Stations documents into the database
func PutManyNewStations(stationsData *[]database.Station) error {
	collection := MongoClient.Database(DatabaseName).Collection(StationsCollection)

	documents := convertNewStationsToInterfaceSlice(stationsData)

	_, err := collection.InsertMany(context.Background(), *documents)
	if err != nil {
		return err
	}

	return nil
}

// Converts []database.Station types into interface slices required to put them into the database
func convertNewStationsToInterfaceSlice(stationsData *[]database.Station) *[]interface{} {
	interfaceSlice := make([]interface{}, len(*stationsData))
	for i, doc := range *stationsData {
		interfaceSlice[i] = doc
	}
	return &interfaceSlice
}

func CreateStationIndeces() error {
	coll := MongoClient.Database(DatabaseName).Collection(StationsCollection)

	locationIndex := mongo.IndexModel{
		Keys:    bson.D{{"location", "2dsphere"}},
		Options: nil,
	}

	crsIndex := mongo.IndexModel{
		Keys: bson.D{{"3ALPHA", 1}},
	}

	tiplocIndex := mongo.IndexModel{
		Keys: bson.D{{"TIPLOC", 1}},
	}

	_, err := coll.Indexes().CreateMany(context.Background(), []mongo.IndexModel{locationIndex, crsIndex, tiplocIndex})
	if err != nil {
		return err
	}

	return nil
}