package files

import (
	"context"
	"fmt"
	"time"

	"go.uber.org/zap"

	"telesrv/internal/domain"
)

// maxBotAvatarSourceBytes bounds the source image @BotFather turns into a bot's
// profile photo. A profile photo a user sends in a chat is a server-rendered
// message-size JPEG, comfortably under this.
const maxBotAvatarSourceBytes = 12 << 20

// SetAvatarFromExistingPhoto renders an already-stored photo (typically one a
// user just sent to a service bot) into the s/a/c avatar size set and makes it
// the current profile photo of ownerType/ownerID.
//
// It is the path @BotFather's "Edit Botpic" uses: photos.uploadProfilePhoto#bot
// is not accepted, and the source is a message photo rather than a fresh upload,
// so the ordinary UploadProfilePhoto path does not apply.
func (s *Service) SetAvatarFromExistingPhoto(ctx context.Context, ownerType domain.PeerType, ownerID, sourcePhotoID int64, date int) (domain.Photo, error) {
	if ownerID <= 0 || sourcePhotoID <= 0 {
		return domain.Photo{}, domain.ErrPhotoInvalid
	}
	source, found, err := s.media.GetPhoto(ctx, sourcePhotoID)
	if err != nil {
		return domain.Photo{}, err
	}
	if !found {
		return domain.Photo{}, domain.ErrPhotoInvalid
	}
	data, ok := s.photoSourceBytes(ctx, source)
	if !ok || !s.ValidateAvatarUpload(data) {
		return domain.Photo{}, domain.ErrPhotoInvalid
	}
	if date == 0 {
		date = int(time.Now().Unix())
	}
	photo, err := s.createAvatarPhoto(ctx, data, ownerID)
	if err != nil {
		return domain.Photo{}, err
	}
	if err := s.media.AddProfilePhotoKind(ctx, ownerType, ownerID, domain.ProfilePhotoKindProfile, photo.ID, date); err != nil {
		return domain.Photo{}, err
	}
	return photo, nil
}

// PeerHasAvatar reports whether ownerType/ownerID has a current profile photo.
func (s *Service) PeerHasAvatar(ctx context.Context, ownerType domain.PeerType, ownerID int64) (bool, error) {
	_, ok, err := s.CurrentProfilePhotoKind(ctx, ownerType, ownerID, domain.ProfilePhotoKindProfile)
	return ok, err
}

// photoSourceBytes reads the original image bytes behind a stored photo. Every
// static size of a photo written by putPhotoStaticSizes points at the same
// stored object, so any one size yields the full image.
func (s *Service) photoSourceBytes(ctx context.Context, photo domain.Photo) ([]byte, bool) {
	for _, size := range photo.Sizes {
		if size.Type == "" {
			continue
		}
		key := fmt.Sprintf("photo:%d:%s", photo.ID, size.Type)
		blob, found, err := s.media.GetFileBlob(ctx, key)
		if err != nil || !found || blob.Size <= 0 || blob.Size > maxBotAvatarSourceBytes {
			continue
		}
		backend, err := s.backendFor(blob.Backend)
		if err != nil {
			continue
		}
		body, total, err := backend.GetRange(ctx, blob.ObjectKey, 0, blob.Size)
		if err != nil || total != blob.Size || int64(len(body)) != blob.Size {
			s.log.Warn("read bot avatar source blob failed", zap.String("location_key", key), zap.Error(err))
			continue
		}
		return body, true
	}
	return nil, false
}