// polygenicDiseases provides information about polygenic diseases and the SNP base changes that effect a person's risk of becoming victim to them.

package polygenicDiseases

// Polygenic diseases are different from monogenicDiseases
// Monogenic diseases are well understood to be caused by mutations in a single gene, and thus have more accurate risk probabilities.
// Polygenic disease probabilities are less accurate, because individual base pair changes only cause comparatively small changes in the disease risk.
// Polygenic diseases are also more influenced by environmental factors, further decreasing risk accuracy.

//TODO: Eventually we want to use neural networks for both polygenic disease and trait prediction.
//	This package is currently a temporary, less accurate solution until we get access to the necessary training data.
//	It may still be worth keeping this method in place for polygenic diseases and using neural networks in tandem.

import "errors"

// DiseaseLocus is a location on a human genome that has an effect on the disease
type DiseaseLocus struct{

	// 3 byte identifier, encoded in Hex.
	LocusIdentifier string

	// RSID that represents this locus
	// If multiple RSIDs represent the same locus, use the first rsID for the locus in the locusMetadata package
	LocusRSID int64

	// Map Structure: Base pair -> Effect weight (Positive number = increased risk, negative number = decreased risk)
	// The number only indicates a general effect of the base, for bases for which we do not have risk probability statistics
	// 0 indicates that the base has no effect
	RiskWeightsMap map[string]int

	// Minimum and maximum values in above map
	MinimumRiskWeight int
	MaximumRiskWeight int

	// Map Structure: Base Pair -> Odds ratio of BasePair/Normal (common) Base pair
	// Number is greater than 1 = Increases risk, Number is less than 1 = decreases risk
	// 1 indicates that the base has no impact
	OddsRatiosMap map[string]float64

	// Map Structure: Base Pair -> Probability that a person will have that base pair for the general population
	BasePairProbabilitiesMap map[string]float64 

	// Map Structure: Reference name -> Reference link
	References map[string]string
}


type PolygenicDisease struct{

	DiseaseName string

	DiseaseDescription string

	// Is either "Mate"/"Female"/"Both"
	EffectedSex string

	LociList []DiseaseLocus

	// Inputs:
	//	-string: "Mate"/"Female"
	//	-int: Age
	// Output:
	//	-float64: Average probability of having had the disease at that point in person's life
	//	-error
	GetAverageRiskProbabilitiesFunction func(string, int)(float64, error)

	// Map Structure: Reference name -> Reference link
	References map[string]string
}

var polygenicDiseaseNamesList []string
var polygenicDiseaseObjectsList []PolygenicDisease

// This must be called once during application startup
func InitializePolygenicDiseaseVariables(){

	breastCancerObject := getBreastCancerDiseaseObject()

	polygenicDiseaseObjectsList = []PolygenicDisease{breastCancerObject}

	polygenicDiseaseNamesList = make([]string, 0, len(polygenicDiseaseObjectsList))

	for _, diseaseObject := range polygenicDiseaseObjectsList{

		diseaseName := diseaseObject.DiseaseName

		polygenicDiseaseNamesList = append(polygenicDiseaseNamesList, diseaseName)
	}
}

// Be aware that all of these functions are returning original objects/slices, not copies
// Thus, we cannot edit the objects/slices that are returned. We must copy the fields first if we want to edit them.

func GetPolygenicDiseaseNamesList()([]string, error){

	if (polygenicDiseaseNamesList == nil){
		return nil, errors.New("GetDiseaseNamesList called when list is not initialized.")
	}

	return polygenicDiseaseNamesList, nil
}

func GetPolygenicDiseaseObjectsList()([]PolygenicDisease, error){

	if (polygenicDiseaseObjectsList == nil){
		return nil, errors.New("GetPolygenicDiseaseObjectsList called when list is not initialized.")
	}

	return polygenicDiseaseObjectsList, nil
}

func GetPolygenicDiseaseObject(diseaseName string)(PolygenicDisease, error){

	polygenicDiseaseObjectsList, err := GetPolygenicDiseaseObjectsList()
	if (err != nil) { return PolygenicDisease{}, err }

	for _, diseaseObject := range polygenicDiseaseObjectsList{

		currentDiseaseName := diseaseObject.DiseaseName
		if (currentDiseaseName != diseaseName){
			continue
		}

		return diseaseObject, nil
	}

	return PolygenicDisease{}, errors.New("GetPolygenicDiseaseObject called with unknown disease name: " + diseaseName)
}


//Outputs:
//	-map[string]DiseaseLocus: Map of LocusIdentifier -> LocusObject
//	-error (will return err if diseaseName is not found)
func GetPolygenicDiseaseLociMap(diseaseName string)(map[string]DiseaseLocus, error){

	diseaseObject, err := GetPolygenicDiseaseObject(diseaseName)
	if (err != nil) { return nil, err }

	diseaseLociList := diseaseObject.LociList

	diseaseLociMap := make(map[string]DiseaseLocus)

	for _, locusObject := range diseaseLociList{

		locusIdentifier := locusObject.LocusIdentifier
		diseaseLociMap[locusIdentifier] = locusObject
	}

	return diseaseLociMap, nil
}

func GetPolygenicDiseaseLocusObject(diseaseName string, locusIdentifier string)(DiseaseLocus, error){

	diseaseLociMap, err := GetPolygenicDiseaseLociMap(diseaseName)
	if (err != nil){ return DiseaseLocus{}, err }

	locusObject, exists := diseaseLociMap[locusIdentifier]
	if (exists == false){
		return DiseaseLocus{}, errors.New("GetDiseaseLocusObject called with unknown locus identifier: " + locusIdentifier)
	}

	return locusObject, nil
}