package main

import (
	"errors"
	"fmt"
	"github.com/google/uuid"
	"go-nkode/hashset"
	"go-nkode/models"
	py_builtin "go-nkode/py-builtin"
	"go-nkode/util"
)

type UserSignSession struct {
	SessionId        uuid.UUID
	CustomerId       uuid.UUID
	LoginInterface   UserInterface
	KeypadSize       models.KeypadSize
	SetInterface     []int
	ConfirmInterface []int
	SetKeyEntry      []int
	Username         string
}

func NewSignupSession(keypadSize models.KeypadSize, customerId uuid.UUID) (*UserSignSession, error) {
	loginInterface, err := NewUserInterface(keypadSize)
	if err != nil {
		return nil, err
	}
	signupInter, err := signupInterface(*loginInterface)
	session := UserSignSession{
		SessionId:        uuid.New(),
		CustomerId:       customerId,
		LoginInterface:   *loginInterface,
		SetInterface:     signupInter.IdxInterface,
		ConfirmInterface: nil,
		SetKeyEntry:      nil,
		Username:         "",
		KeypadSize:       signupInter.KeypadSize,
	}

	return &session, nil
}

func (s *UserSignSession) DeducePasscode(confirmKeyEntry []int) ([]int, error) {
	validEntry := py_builtin.All[int](confirmKeyEntry, func(i int) bool {
		return 0 <= i && i < s.LoginInterface.KeypadSize.NumbOfKeys
	})

	if !validEntry {
		return nil, errors.New(fmt.Sprintf("Invalid Key entry. One or more key index: %#v, not in range 0-%d", confirmKeyEntry, s.LoginInterface.KeypadSize.NumbOfKeys))
	}

	if s.SetInterface == nil {
		return nil, errors.New("signup session set interface is nil")
	}

	if s.ConfirmInterface == nil {
		return nil, errors.New("signup session confirm interface is nil")
	}

	if s.SetKeyEntry == nil {
		return nil, errors.New("signup session set key entry is nil")
	}

	if s.Username == "" {
		return nil, errors.New("signup session username is nil")
	}

	if len(confirmKeyEntry) == len(s.SetKeyEntry) {
		return nil, errors.New(fmt.Sprintf("confirm and set key entry lenght mismatch %d != %d", len(confirmKeyEntry), len(s.SetKeyEntry)))
	}

	passcodeLen := len(confirmKeyEntry)
	setKeyVals, err := s.getSelectedKeyVals(s.SetKeyEntry, s.SetInterface)
	if err != nil {
		return nil, err
	}
	confirmKeyVals, err := s.getSelectedKeyVals(confirmKeyEntry, s.ConfirmInterface)
	passcode := make([]int, passcodeLen)

	for idx := 0; idx < passcodeLen; idx++ {
		setKey := hashset.NewSetFromSlice[int](setKeyVals[idx])
		confirmKey := hashset.NewSetFromSlice[int](confirmKeyVals[idx])
		intersection := setKey.Intersect(confirmKey)
		if intersection.Size() < 1 {
			return nil, errors.New(fmt.Sprintf("set and confirm do not intersect at index %d", idx))
		}
		if intersection.Size() > 1 {
			return nil, errors.New(fmt.Sprintf("set and confirm intersect at more than one point at index %d", idx))
		}
		intersectionSlice := intersection.ToSlice()
		passcode[idx] = intersectionSlice[0]
	}
	return passcode, nil
}

func (s *UserSignSession) SetUserNKode(username string, keySelection []int) ([]int, error) {
	validKeySelection := py_builtin.All[int](keySelection, func(i int) bool {
		return 0 <= i && i < s.KeypadSize.NumbOfKeys
	})
	if !validKeySelection {
		return nil, errors.New(fmt.Sprintf("one or key selection is out of range 0-%d", s.KeypadSize.NumbOfKeys-1))
	}

	s.SetKeyEntry = keySelection
	s.Username = username

	setInterface := UserInterface{IdxInterface: s.SetInterface, KeypadSize: s.KeypadSize}
	err := setInterface.DisperseInterface()
	if err != nil {
		return nil, err
	}
	s.ConfirmInterface = setInterface.IdxInterface
	return s.ConfirmInterface, nil
}

func (s *UserSignSession) getSelectedKeyVals(keySelections []int, userInterface []int) ([][]int, error) {
	keypadInterface, err := util.ListToMatrix(userInterface, s.KeypadSize.AttrsPerKey)
	if err != nil {
		return nil, err
	}
	keyVals := make([][]int, len(keySelections))

	for idx, keyIdx := range keySelections {
		keyVals[idx] = keypadInterface[keyIdx]
	}
	return keyVals, nil
}

func signupInterface(baseUserInterface UserInterface) (*UserInterface, error) {
	if baseUserInterface.KeypadSize.IsDispersable() {
		return nil, errors.New("keypad is dispersable, can't use signupInterface")
	}
	err := baseUserInterface.RandomShuffle()
	if err != nil {
		return nil, err
	}
	interfaceMatrix, err := baseUserInterface.InterfaceMatrix()
	if err != nil {
		return nil, err
	}
	attrSetView, err := util.MatrixTranspose(interfaceMatrix)
	if err != nil {
		return nil, err
	}
	err = util.FisherYatesShuffle[[]int](&attrSetView)
	if err != nil {
		return nil, err
	}
	numbOfKeys := baseUserInterface.KeypadSize.NumbOfKeys
	attrSetView = attrSetView[:numbOfKeys]
	attrSetView, err = util.MatrixTranspose(attrSetView)
	if err != nil {
		return nil, err
	}
	signupUserInterface := UserInterface{
		IdxInterface: util.MatrixToList(attrSetView),
		KeypadSize: models.KeypadSize{
			AttrsPerKey: numbOfKeys,
			NumbOfKeys:  numbOfKeys,
		},
	}
	return &signupUserInterface, nil
}