// SPDX-License-Identifier: Apache-2.0
// Copyright © 2022 Roberto Hidalgo <nidito@un.rob.mx>
package user

import (
	"encoding/json"
	"fmt"
	"net/http"
	"time"

	"git.rob.mx/nidito/puerta/internal/constants"
	"git.rob.mx/nidito/puerta/internal/errors"
	"github.com/go-webauthn/webauthn/webauthn"
	"github.com/sirupsen/logrus"
	"github.com/upper/db/v4"
	"golang.org/x/crypto/bcrypt"
)

func FromContext(req *http.Request) *User {
	u := req.Context().Value(constants.ContextUser)

	if u != nil {
		return u.(*User)
	}
	return nil
}

type User struct {
	ID          int       `db:"id,omitempty" json:"-"`
	Expires     *UTCTime  `db:"expires,omitempty" json:"expires,omitempty"`
	Greeting    string    `db:"greeting" json:"greeting"`
	Handle      string    `db:"handle" json:"handle"`
	IsAdmin     bool      `db:"is_admin" json:"is_admin"`
	Name        string    `db:"name" json:"name"`
	Password    string    `db:"password" json:"password"`
	Require2FA  bool      `db:"second_factor" json:"second_factor"`
	Schedule    *Schedule `db:"schedule,omitempty" json:"schedule,omitempty"`
	TTL         *TTL      `db:"max_ttl,omitempty" json:"max_ttl,omitempty"`
	IsNotified  bool      `db:"receives_notifications" json:"receives_notifications"`
	subs        []*Subscription
	credentials []*Credential
}

func (u *User) WebAuthnID() []byte {
	return []byte(fmt.Sprintf("%d-%s", u.ID, u.Handle))
}

// User Name according to the Relying Party
func (u *User) WebAuthnName() string {
	return u.Handle
}

// Display Name of the user
func (u *User) WebAuthnDisplayName() string {
	return u.Name
}

// User's icon url
func (u *User) WebAuthnIcon() string {
	return ""
}

// Credentials owned by the user
func (u *User) WebAuthnCredentials() []webauthn.Credential {
	res := []webauthn.Credential{}
	if u.credentials != nil {
		for _, c := range u.credentials {
			res = append(res, c.AsWebAuthn())
		}
	}
	return res
}

func (u *User) Store(sess db.Session) db.Store {
	return sess.Collection("user")
}

func (u *User) FetchCredentials(sess db.Session) error {
	creds := []*Credential{}
	err := sess.Collection("credential").Find(db.Cond{"user": u.ID}).All(&creds)
	if err != nil {
		logrus.Errorf("could not fetch credentials: %s", err)
		return err
	}
	u.credentials = creds
	logrus.Debugf("fetched %d credentials", len(creds))

	return nil
}

func (u *User) DeleteCredentials(sess db.Session) error {
	err := sess.Collection("credential").Find(db.Cond{"user": u.ID}).Delete()
	if err != nil {
		return err
	}
	u.credentials = []*Credential{}
	logrus.Debugf("deleted all credentials for %d", u.ID)

	return nil
}

func (o *User) UnmarshalJSON(b []byte) error {
	type alias User
	xo := &alias{TTL: &DefaultTTL}
	if err := json.Unmarshal(b, xo); err != nil {
		return err
	}
	*o = User(*xo)
	return nil
}

func (u *User) MarshalJSON() ([]byte, error) {
	// prevent calling ourselves by subtyping
	type alias User
	x := alias(*u)
	x.Password = ""
	return json.Marshal(x)
}

func (user *User) Expired() bool {
	return user.Expires != nil && user.Expires.Before(time.Now())
}

func (user *User) IsAllowed(t time.Time) error {
	if user.Expired() {
		return fmt.Errorf("usuario expirado, avísale a Roberto")
	}

	if user.Schedule != nil && !user.Schedule.AllowedAt(t) {
		return fmt.Errorf("accesso denegado, intente nuevamente en otro momento")
	}

	return nil
}

func (user *User) Login(password string) error {
	if err := bcrypt.CompareHashAndPassword([]byte(user.Password), []byte(password)); err != nil {
		reason := fmt.Sprintf("Incorrect password for %s", user.Name)
		return &errors.InvalidCredentials{Status: http.StatusForbidden, Reason: reason}
	}

	if user.Expired() {
		reason := fmt.Sprintf("Expired user tried to login: %s", user.Name)
		return &errors.InvalidCredentials{Status: http.StatusForbidden, Reason: reason}
	}

	return nil
}

func (user *User) HasCredentials() bool {
	return len(user.credentials) > 0
}

// implement interfaces
var _ db.Record = &User{}
var _ webauthn.User = &User{}