package common

import (
	"crypto/subtle"
	"database/sql"
	"errors"

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

var PasswordResetter *DefaultPasswordResetter
var ErrBadResetToken = errors.New("This reset token has expired.")

type DefaultPasswordResetter struct {
    getTokens *sql.Stmt
    create    *sql.Stmt
    delete    *sql.Stmt
}

/*
    type PasswordReset struct {
        Email string `q:"email"`
        Uid int `q:"uid"`
        Validated bool `q:"validated"`
        Token string `q:"token"`
        CreatedAt time.Time `q:"createdAt"`
    }
*/

func NewDefaultPasswordResetter(acc *qgen.Accumulator) (*DefaultPasswordResetter, error) {
    pr := "password_resets"
    return &DefaultPasswordResetter{
        getTokens: acc.Select(pr).Columns("token").Where("uid=?").Prepare(),
        create:    acc.Insert(pr).Columns("email,uid,validated,token,createdAt").Fields("?,?,0,?,UTC_TIMESTAMP()").Prepare(),
        //create: acc.Insert(pr).Cols("email,uid,validated=0,token,createdAt=UTC_TIMESTAMP()").Prep(),
        delete: acc.Delete(pr).Where("uid=?").Prepare(),
        //model:  acc.Model(w).Cols("email,uid,validated=0,token").Key("uid").CreatedAt("createdAt").Prep(),
    }, acc.FirstError()
}

func (r *DefaultPasswordResetter) Create(email string, uid int, token string) error {
    _, err := r.create.Exec(email, uid, token)
    return err
}

func (r *DefaultPasswordResetter) FlushTokens(uid int) error {
    _, err := r.delete.Exec(uid)
    return err
}

func (r *DefaultPasswordResetter) ValidateToken(uid int, token string) error {
    rows, err := r.getTokens.Query(uid)
    if err != nil {
        return err
    }
    defer rows.Close()

    success := false
    for rows.Next() {
        var rtoken string
        if err := rows.Scan(&rtoken); err != nil {
            return err
        }
        if subtle.ConstantTimeCompare([]byte(token), []byte(rtoken)) == 1 {
            success = true
        }
    }
    if err = rows.Err(); err != nil {
        return err
    }

    if !success {
        return ErrBadResetToken
    }
    return nil
}