package logic

import (
	"context"

	"spark-server/internal/module/moment/entity"
	"spark-server/internal/pkg/errs"
)

func (s *Service) Album(ctx context.Context, viewerID, ownerID, cursor int64, limit int) (*ListResult, error) {
	if !s.ready() || viewerID <= 0 {
		return nil, errs.ErrUnauthorized
	}
	if ownerID <= 0 {
		return nil, errs.ErrInvalidArgument
	}
	if ownerID != viewerID {
		ok, err := s.friends.AreFriends(ctx, viewerID, ownerID)
		if err != nil {
			return nil, err
		}
		if !ok {
			return nil, errs.ErrNotFound
		}
		blocked, err := s.friends.BlockedEither(ctx, viewerID, ownerID)
		if err != nil {
			return nil, err
		}
		if blocked {
			return nil, errs.ErrNotFound
		}
	}
	limit = entity.ClampLimit(limit)
	picked := make([]*entity.Post, 0, limit)
	self := ownerID == viewerID
	for range entity.OverfetchRounds {
		batch, err := s.repo.ListByAuthor(ctx, ownerID, cursor, entity.Overfetch)
		if err != nil {
			return nil, err
		}
		if len(batch) == 0 {
			break
		}
		vis, err := s.visFor(ctx, viewerID, batch, self)
		if err != nil {
			return nil, err
		}
		for _, p := range batch {
			cursor = p.ID
			if !vis.canSee(p) {
				continue
			}
			picked = append(picked, p)
			if len(picked) >= limit {
				break
			}
		}
		if len(picked) >= limit || len(batch) < entity.Overfetch {
			break
		}
	}
	return s.listResult(ctx, viewerID, picked, false)
}