package server

import (
	"errors"
	"math/rand"
	"time"

	"github.com/go-redis/redis"
)

func (r *RedisRouter) CreateInvitation(invitation []byte, timeout int, password string, serverTimeout int, urlLen int) (string, time.Time) {
	id := r.createShortId(urlLen)
	if timeout > serverTimeout {
		timeout = serverTimeout
	}
	r.Client.Set("mwiv:"+id, invitation, time.Duration(timeout*1000000))
	if len(password) > 0 {
		r.Client.Set("mwpw:"+id, password, time.Duration(timeout*1000000))
	}
	return id, time.Now().Add(time.Duration(timeout * 1000000)).UTC()
}

func (r *RedisRouter) GetInvitation(id string, password string) ([]byte, error) {
	passRequired := false
	expectedpass, err := r.Client.Get("mwpw:" + id).Result()
	if err != nil {
		passRequired = false
	} else {
		passRequired = true
	}
	if passRequired && password != expectedpass {
		return nil, errors.New("auth failed")
	}
	mwiv, err := r.Client.Get("mwiv:" + id).Result()
	if err != nil {
		return nil, err
	}
	return []byte(mwiv), nil
}

func (r *RedisRouter) AnswerInvitation(id string, timeout int, invitation []byte, serverTimeout int) time.Time {
	if timeout > serverTimeout {
		timeout = serverTimeout
	}
	r.Client.Set("mwan:"+id, invitation, time.Duration(timeout*1000000))
	return time.Now().Add(time.Duration(timeout * 1000000)).UTC()
}

func (r *RedisRouter) GetInvitationAnswer(id string) ([]byte, error) {
	mwan, err := r.Client.Get("mwiv:" + id).Result()
	if err != nil {
		return nil, err
	}
	return []byte(mwan), nil
}

func (r *RedisRouter) createShortId(length int) string {
	id := ""
	alphabet := "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
	// for not in redis
	for {
		for i := 1; i <= length; i++ {
			id += string(alphabet[rand.Intn(61)])
		}
		if r.Client.Get("mwiv:"+id).Err() == redis.Nil {
			break
		}
	}
	return id
}