// locusMetadata provides information about locations in the human genome.

package locusMetadata

// Locus position information should correspond to Human genome reference build 38.

import "seekia/internal/helpers"

import _ "embed"

import "encoding/gob"
import "errors"
import "bytes"


//go:embed LocusMetadata.gob
var LocusMetadataFile []byte


type LocusMetadata struct{

	// A list of RSIDs that refer to this location
	// Each RSID is equivalent and refers to the same location
	// rsID stands for Reference SNP cluster ID.
	// Each rsID is an "rs" followed by a number.
	// We store the number after the rs as an int64.
	RSIDsList []int64

	// The chromosome which this location exists on
	Chromosome int

	// The position of this locus
	// This is a number describing its location on the chromosome it exists on.
	Position int

	// This is true if we know any information about the gene this locus belongs to, and if there even is a gene
	GeneInfoIsKnown bool

	// This is true if the locus exists within a gene
	// Some loci are non-coding, meaning they don't exist within a gene and code for a protein
	GeneExists bool

	// A list of gene names which refer to the gene which this locus belongs to.
	// Each gene name refers to the same gene.
	// Will be a nil list if gene info is not known, or no gene exists
	GeneNamesList []string

	// A list of alternate names for the rsid used by companies
	// These are the names that the raw genome files exported from companies sometimes use instead of rsIDs
	// Example: TwentyThreeAndMe -> []string{"i5010839", "i5006049", "i4000295", "i5010838", "i5010837"}
	CompanyAliases map[GeneticsCompany][]string

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

// We use this data structure to save space, rather than using String
type GeneticsCompany byte

const TwentyThreeAndMe GeneticsCompany = 1
const FamilyTreeDNA GeneticsCompany = 2
const MyHeritage GeneticsCompany = 3

// Map Structure: RSID -> Locus Metadata Object
var lociMetadataMap map[int64]LocusMetadata

// This map stores a list of aliases for rsids which have aliases
// An alias is a different rsid which represents the same locus
var rsidAliasesMap map[int64][]int64

// We use these maps to store the locus aliases for rsIDs used by companies
// Map structure: Alias -> Primary rsID (there may be aliases)
// Example: "i5010839" -> 78655421
var companyAliasesMap_23andMe map[string]int64
var companyAliasesMap_FamilyTreeDNA map[string]int64
var companyAliasesMap_MyHeritage map[string]int64


func InitializeLocusMetadataVariables()error{

	lociMetadataMap = make(map[int64]LocusMetadata)
	rsidAliasesMap = make(map[int64][]int64)

	companyAliasesMap_23andMe = make(map[string]int64)
	companyAliasesMap_FamilyTreeDNA = make(map[string]int64)
	companyAliasesMap_MyHeritage = make(map[string]int64)

	locusObjectsList, err := GetLocusMetadataObjectsList()
	if (err != nil) { return err }

	for _, locusObject := range locusObjectsList{

		rsidsList := locusObject.RSIDsList

		for _, rsID := range rsidsList{

			_, exists := lociMetadataMap[rsID]
			if (exists == true){
				return errors.New("lociMetadataMap contains duplicate rsID.")
			}

			lociMetadataMap[rsID] = locusObject
		}

		if (len(rsidsList) > 1){

			// We add rsid aliases to map

			for _, rsID := range rsidsList{

				rsidAliasesList := make([]int64, 0)

				for _, rsidInner := range rsidsList{

					if (rsID != rsidInner){
						rsidAliasesList = append(rsidAliasesList, rsidInner)
					}
				}

				rsidAliasesMap[rsID] = rsidAliasesList
			}
		}

		companyAliasesMap := locusObject.CompanyAliases

		if (len(companyAliasesMap) > 0){

			// Now we add company aliases to maps

			primaryRSID := rsidsList[0]

			for companyObject, companyAliasesList := range companyAliasesMap{

				if (companyObject == TwentyThreeAndMe){

					for _, locusAlias := range companyAliasesList{
						companyAliasesMap_23andMe[locusAlias] = primaryRSID
					}

				} else if (companyObject == FamilyTreeDNA){

					for _, locusAlias := range companyAliasesList{
						companyAliasesMap_FamilyTreeDNA[locusAlias] = primaryRSID
					}

				} else if (companyObject == MyHeritage){

					for _, locusAlias := range companyAliasesList{
						companyAliasesMap_MyHeritage[locusAlias] = primaryRSID
					}

				} else {
					companyByteString := helpers.ConvertIntToString(int(companyObject))
					return errors.New("Locus Object company aliases map contains invalid company object: " + companyByteString)
				}
			}
		}
	}

	return nil
}

//Outputs:
//	-bool: Locus metadata exists
//	-LocusMetadata
//	-error
func GetLocusMetadata(inputRSID int64)(bool, LocusMetadata, error){

	if (lociMetadataMap == nil){
		return false, LocusMetadata{}, errors.New("GetLocusMetadata called when lociMetadataMap is not initialized.")
	}

	locusMetadataObject, exists := lociMetadataMap[inputRSID]
	if (exists == false){
		return false, LocusMetadata{}, nil
	}

	return true, locusMetadataObject, nil
}

// This function will return a list of RSIDs which refer to the same location as the input RSID
//	-bool: Any Aliases exist
//	-[]int64: List of alias RSIDs
//	-error (if RSID is unknown)
func GetRSIDAliases(inputRSID int64)(bool, []int64, error){

	if (rsidAliasesMap == nil){
		return false, nil, errors.New("rsidAliasesMap called when rsidAliasesMap is not initialized.")
	}

	aliasesList, exists := rsidAliasesMap[inputRSID]
	if (exists == false){
		return false, nil, nil
	}

	return true, aliasesList, nil
}


//Outputs:
//	-bool: Alias found
//	-int64: Primary rsID alias to use to represent this locus
//	-error
func GetCompanyAliasRSID(companyName string, locusAlias string)(bool, int64, error){

	if (companyName == "23andMe"){

		locusRSID, exists := companyAliasesMap_23andMe[locusAlias]
		if (exists == false){
			return false, 0, nil
		}

		return true, locusRSID, nil

	} else if (companyName == "FamilyTreeDNA"){

		locusRSID, exists := companyAliasesMap_FamilyTreeDNA[locusAlias]
		if (exists == false){
			return false, 0, nil
		}

		return true, locusRSID, nil

	} else if (companyName == "MyHeritage"){

		locusRSID, exists := companyAliasesMap_MyHeritage[locusAlias]
		if (exists == false){
			return false, 0, nil
		}

		return true, locusRSID, nil
	}

	return false, 0, errors.New("GetCompanyAliasRSID called with invalid companyName: " + companyName)
}

func GetLocusMetadataObjectsList()([]LocusMetadata, error){

	buffer := bytes.NewBuffer(LocusMetadataFile)

	decoder := gob.NewDecoder(buffer)

	var locusMetadataObjectsList []LocusMetadata

	err := decoder.Decode(&locusMetadataObjectsList)
	if (err != nil){ return nil, err }

	return locusMetadataObjectsList, nil
}