// myCouples provides functions to manage a user's genome couples
// A couple is recorded as 2 person identifiers.

package myCouples

import "seekia/internal/myDatastores/myMapList"
import "seekia/internal/genetics/myAnalyses"

import "sync"
import "errors"

// This will be locked anytime Couples are being added/deleted
var updatingMyCouplesMutex sync.Mutex

var myGenomeCouplesMapListDatastore *myMapList.MyMapList

// This function must be called whenever an app user signs in
func InitializeMyGenomeCouplesDatastore()error{

	updatingMyCouplesMutex.Lock()
	defer updatingMyCouplesMutex.Unlock()

	newMyGenomeCouplesMapListDatastore, err := myMapList.CreateNewMapList("MyGenomeCouples")
	if (err != nil) { return err }

	myGenomeCouplesMapListDatastore = newMyGenomeCouplesMapListDatastore

	return nil
}

//Outputs:
//	-[]map[string]string
//		-PersonAIdentifier -> Person A Identifier
//		-PersonBIdentifier -> Person B Identifier
//	-error
func GetMyGenomeCouplesMapList()([]map[string]string, error){

	couplesMapList, err := myGenomeCouplesMapListDatastore.GetMapList()
	if (err != nil) { return nil, err }

	return couplesMapList, nil
}

//Outputs:
//	-bool: Couple already exists
//	-error
func AddCouple(inputPersonAIdentifier string, inputPersonBIdentifier string)(bool, error){
	
	personAIdentifier, personBIdentifier, err := getPeopleIdentifiersSortedForCouple(inputPersonAIdentifier, inputPersonBIdentifier)
	if (err != nil) { return false, err }

	updatingMyCouplesMutex.Lock()
	defer updatingMyCouplesMutex.Unlock()

	couplesMapList, err := myGenomeCouplesMapListDatastore.GetMapList()
	if (err != nil) { return false, err }

	for _, coupleMap := range couplesMapList{

		currentPersonAIdentifier, exists := coupleMap["PersonAIdentifier"]
		if (exists == false){
			return false, errors.New("MyGenomeCouplesMapList malformed: Contains entry missing PersonAIdentifier")
		}

		currentPersonBIdentifier, exists := coupleMap["PersonBIdentifier"]
		if (exists == false){
			return false, errors.New("MyGenomeCouplesMapList malformed: Contains entry missing PersonBIdentifier")
		}

		if (currentPersonAIdentifier == personAIdentifier && currentPersonBIdentifier == personBIdentifier){
			return true, nil
		}	
	}

	// Couple does not exist. We add it.

	newPersonMap := map[string]string{
		"PersonAIdentifier": personAIdentifier,
		"PersonBIdentifier": personBIdentifier,
	}

	newCouplesMapList := append(couplesMapList, newPersonMap)

	err = myGenomeCouplesMapListDatastore.OverwriteMapList(newCouplesMapList)
	if (err != nil) { return false, err }

	return false, nil
}

func DeleteCouple(inputPersonAIdentifier string, inputPersonBIdentifier string)error{

	personAIdentifier, personBIdentifier, err := getPeopleIdentifiersSortedForCouple(inputPersonAIdentifier, inputPersonBIdentifier)
	if (err != nil) { return err }

	updatingMyCouplesMutex.Lock()
	defer updatingMyCouplesMutex.Unlock()

	mapToDelete := map[string]string{
		"PersonAIdentifier": personAIdentifier,
		"PersonBIdentifier": personBIdentifier,
	}

	err = myGenomeCouplesMapListDatastore.DeleteMapListItems(mapToDelete)
	if (err != nil) { return err }

	err = myAnalyses.DeleteAllAnalysesForCouple(personAIdentifier, personBIdentifier)
	if (err != nil) { return err }

	return nil
}

func DeleteAllCouplesForPerson(personIdentifier string)error{

	updatingMyCouplesMutex.Lock()
	defer updatingMyCouplesMutex.Unlock()

	mapToDeleteA := map[string]string{
		"PersonAIdentifier": personIdentifier,
	}

	err := myGenomeCouplesMapListDatastore.DeleteMapListItems(mapToDeleteA)
	if (err != nil) { return err }

	mapToDeleteB := map[string]string{
		"PersonBIdentifier": personIdentifier,
	}

	err = myGenomeCouplesMapListDatastore.DeleteMapListItems(mapToDeleteB)
	if (err != nil) { return err }

	return nil
}

// This is used to show how many couples will be deleted if a user is deleting a person.
func GetNumberOfCouplesForPerson(personIdentifier string)(int, error){

	totalCouples := 0

	lookupMapA := map[string]string{
		"PersonAIdentifier": personIdentifier,
	}

	anyItemsFoundA, matchingItemsListA, err := myGenomeCouplesMapListDatastore.GetMapListItems(lookupMapA)
	if (err != nil){ return 0, err }
	if (anyItemsFoundA == true){
		totalCouples += len(matchingItemsListA)
	}

	lookupMapB := map[string]string{
		"PersonBIdentifier": personIdentifier,
	}

	anyItemsFoundB, matchingItemsListB, err := myGenomeCouplesMapListDatastore.GetMapListItems(lookupMapB)
	if (err != nil){ return 0, err }
	if (anyItemsFoundB == true){
		totalCouples += len(matchingItemsListB)
	}

	return totalCouples, nil
}


// This function is used to sort the person identifiers, so that each pair of identifiers will always map to the same couple when added
// The sorting method has no significance
func getPeopleIdentifiersSortedForCouple(personAIdentifier string, personBIdentifier string)(string, string, error){

	if (personAIdentifier == personBIdentifier){
		return "", "", errors.New("getPeopleIdentifiersSortedForCouple called with identical person identifiers: " + personAIdentifier)
	}

	if (personAIdentifier < personBIdentifier){
		return personAIdentifier, personBIdentifier, nil
	}
	return personBIdentifier, personAIdentifier, nil
}