package common

import (
	"database/sql"
	"errors"
	"strings"

	qgen "git.tuxpa.in/a/gosora/query_gen"
)

var MFAstore MFAStore
var ErrMFAScratchIndexOutOfBounds = errors.New("That MFA scratch index is out of bounds")

type MFAItemStmts struct {
    update *sql.Stmt
    delete *sql.Stmt
}

var mfaItemStmts MFAItemStmts

func init() {
    DbInits.Add(func(acc *qgen.Accumulator) error {
        mfaItemStmts = MFAItemStmts{
            update: acc.Update("users_2fa_keys").Set("scratch1=?,scratch2=?,scratch3=?,scratch4=?,scratch5=?,scratch6=?,scratch7=?,scratch8=?").Where("uid=?").Prepare(),
            delete: acc.Delete("users_2fa_keys").Where("uid=?").Prepare(),
        }
        return acc.FirstError()
    })
}

type MFAItem struct {
    UID     int
    Secret  string
    Scratch []string
}

func (i *MFAItem) BurnScratch(index int) error {
    if index < 0 || len(i.Scratch) <= index {
        return ErrMFAScratchIndexOutOfBounds
    }
    newScratch, err := mfaCreateScratch()
    if err != nil {
        return err
    }
    i.Scratch[index] = newScratch

    _, err = mfaItemStmts.update.Exec(i.Scratch[0], i.Scratch[1], i.Scratch[2], i.Scratch[3], i.Scratch[4], i.Scratch[5], i.Scratch[6], i.Scratch[7], i.UID)
    return err
}

func (i *MFAItem) Delete() error {
    _, err := mfaItemStmts.delete.Exec(i.UID)
    return err
}

func mfaCreateScratch() (string, error) {
    code, err := GenerateStd32SafeString(8)
    return strings.Replace(code, "=", "", -1), err
}

type MFAStore interface {
    Get(id int) (*MFAItem, error)
    Create(secret string, uid int) (err error)
}

type SQLMFAStore struct {
    get    *sql.Stmt
    create *sql.Stmt
}

func NewSQLMFAStore(acc *qgen.Accumulator) (*SQLMFAStore, error) {
    return &SQLMFAStore{
        get:    acc.Select("users_2fa_keys").Columns("secret,scratch1,scratch2,scratch3,scratch4,scratch5,scratch6,scratch7,scratch8").Where("uid=?").Prepare(),
        create: acc.Insert("users_2fa_keys").Columns("uid,secret,scratch1,scratch2,scratch3,scratch4,scratch5,scratch6,scratch7,scratch8,createdAt").Fields("?,?,?,?,?,?,?,?,?,?,UTC_TIMESTAMP()").Prepare(),
    }, acc.FirstError()
}

// TODO: Write a test for this
func (s *SQLMFAStore) Get(id int) (*MFAItem, error) {
    i := MFAItem{UID: id, Scratch: make([]string, 8)}
    err := s.get.QueryRow(id).Scan(&i.Secret, &i.Scratch[0], &i.Scratch[1], &i.Scratch[2], &i.Scratch[3], &i.Scratch[4], &i.Scratch[5], &i.Scratch[6], &i.Scratch[7])
    return &i, err

}

// TODO: Write a test for this
func (s *SQLMFAStore) Create(secret string, uid int) (err error) {
    params := make([]interface{}, 10)
    params[0] = uid
    params[1] = secret
    for i := 2; i < len(params); i++ {
        code, err := mfaCreateScratch()
        if err != nil {
            return err
        }
        params[i] = code
    }

    _, err = s.create.Exec(params...)
    return err
}