package logic

import (
	"context"
	"strconv"
	"time"

	"spark-server/internal/pkg/ratelimit"
)

// Presigner issues short-lived object-storage URLs. Infrastructure implements it.
type Presigner interface {
	PresignPut(ctx context.Context, key, contentType string, ttl time.Duration) (string, error)
	PresignGet(ctx context.Context, key string, ttl time.Duration) (string, error)
}

type IDGen interface {
	NextID() (int64, error)
}

// AvatarACL gates group_avatar uploads. Nil skips the check (tests).
type AvatarACL interface {
	CanSetAvatar(ctx context.Context, userID, groupID int64) error
}

type Options struct {
	TTL    time.Duration
	Limit  *ratelimit.Limiter
	Now    func() time.Time
	Groups AvatarACL
}

// Service issues upload/download credentials. HTTP and TCP share it.
type Service struct {
	store  Presigner
	ids    IDGen
	ttl    time.Duration
	limit  *ratelimit.Limiter
	now    func() time.Time
	groups AvatarACL
}

func NewService(store Presigner, ids IDGen, opt Options) *Service {
	ttl := opt.TTL
	if ttl <= 0 {
		ttl = 15 * time.Minute
	}
	clock := opt.Now
	if clock == nil {
		clock = func() time.Time { return time.Now().UTC() }
	}
	return &Service{store: store, ids: ids, ttl: ttl, limit: opt.Limit, now: clock, groups: opt.Groups}
}

func (s *Service) ready() bool {
	return s != nil && s.store != nil && s.ids != nil
}

func (s *Service) expiresIn() int64 {
	return int64(s.ttl / time.Second)
}

func (s *Service) allow(userID int64) bool {
	if s.limit == nil {
		return true
	}
	return s.limit.Allow("upload:" + strconv.FormatInt(userID, 10))
}

func dayOf(t time.Time) string {
	return t.UTC().Format("20060102")
}