package users

import (
    "context"
    "database/sql"
    "unicode"
    "unicode/utf8"

    "google.golang.org/grpc/codes"
    "google.golang.org/grpc/status"

    "golang.org/x/crypto/bcrypt"

    "users/proto"
)

// ChangePassword changes the password of a specific user
func (u *Users) ChangePassword(ctx context.Context, req *pbusers.ChangePasswordRequest) (*pbusers.ChangePasswordResponse, error) {
    rsp := &pbusers.ChangePasswordResponse{}

    // Check if the password meets the security requirements
    if utf8.RuneCountInString(req.Password) <= 9 {
        return rsp, status.Error(codes.InvalidArgument, "the new password didn't meet the security requirements: the password needs to be at least 10 characters long")
    }

    hasUppercase := false
    hasLowercase := false
    hasDigit := false

    for _, c := range req.Password {
        if unicode.IsDigit(c) {
            hasDigit = true
        }

        if unicode.IsUpper(c) {
            hasUppercase = true
        }

        if unicode.IsLower(c) {
            hasLowercase = true
        }
    }

    if !hasUppercase || !hasLowercase {
        return rsp, status.Error(codes.InvalidArgument, "the new password didn't meet the security requirements: the password needs to have at least one uppercase and one lowercase letter")
    }

    if !hasDigit {
        return rsp, status.Error(codes.InvalidArgument, "the new password didn't meet the security requirements: the password needs to have at least one digit")
    }

    type userStruct struct {
        ID       string
        Email    string
        Password string
    }

    user := userStruct{}

    err := u.DB.QueryRow("SELECT * FROM user WHERE id = ?", req.Id).Scan(
        &user.ID,
        &user.Email,
        &user.Password,
    )
    if err != nil {
        if err == sql.ErrNoRows {
            return rsp, status.Errorf(codes.NotFound, "user with id %s wasn't found in the DB", req.Id)
        }

        return rsp, status.Errorf(codes.Internal, "there was an error querying the DB: %v", err)
    }

    password, err := bcrypt.GenerateFromPassword([]byte(req.Password), 12)
    if err != nil {
        panic(err)
    }

    _, err = u.DB.Exec(`UPDATE user
SET password = ?
WHERE id = ?`, string(password[:]), user.ID)
    if err != nil {
        panic(err)
    }

    return rsp, nil
}