package logic

import (
	"context"
	"strings"
	"time"

	uploadentity "spark-server/internal/module/upload/entity"
	"spark-server/internal/module/user/entity"
	"spark-server/internal/pkg/reqctx"
)

const defaultAvatarMIME = "image/png"

func (s *Service) ensureDefaultAvatar(ctx context.Context, u *entity.User) {
	if u == nil || strings.TrimSpace(u.Avatar) != "" {
		return
	}
	s.stampDefaultAvatar(ctx, u)
}

func (s *Service) stampDefaultAvatar(ctx context.Context, u *entity.User) {
	if u == nil || u.ID <= 0 {
		return
	}
	fallback := entity.LetterAvatarDataURI(u.Nickname)
	avatar := fallback
	if key := s.putLetterPNG(ctx, u); key != "" {
		avatar = key
	}
	prev := u.Avatar
	u.Avatar = avatar
	if s.repo == nil || prev == avatar {
		return
	}
	if err := s.repo.UpdateProfile(ctx, u); err == nil {
		return
	}
	u.Avatar = fallback
	if prev != fallback {
		_ = s.repo.UpdateProfile(ctx, u)
	}
}

func (s *Service) putLetterPNG(ctx context.Context, u *entity.User) string {
	if s == nil || s.objects == nil || u == nil || u.ID <= 0 {
		return ""
	}
	raw, err := entity.LetterAvatarPNG(u.Nickname)
	if err != nil || len(raw) == 0 {
		return ""
	}
	key := uploadentity.BuildObjectKey(uploadentity.PurposeAvatar, u.ID, reqctx.NewObjectName(), time.Now().UTC().Format("20060102"), "png")
	if err := s.objects.Put(ctx, key, raw, defaultAvatarMIME); err != nil {
		return ""
	}
	return key
}