package mongodb

import (
	"context"
	"sort"
	"strings"

	"git.aiterp.net/rpdata/api/models"
	"git.aiterp.net/rpdata/api/repositories"
	"github.com/globalsign/mgo"
	"go.mongodb.org/mongo-driver/bson"
)

type tagRepository struct {
	stories *mgo.Collection
}

func newTagRepository(db *mgo.Database) repositories.TagRepository {
	return &tagRepository{
		stories: db.C("story.stories"),
	}
}

func (r *tagRepository) Find(ctx context.Context, kind models.TagKind, name string) (*models.Tag, error) {
	tags := make([]*models.Tag, 0, 1)
	err := r.stories.Find(bson.M{"listed": true, "tags": bson.M{"kind": kind, "name": name}}).Distinct("tag", &tags)
	if err != nil {
		return nil, err
	} else if len(tags) == 0 {
		return nil, repositories.ErrNotFound
	}

	for _, tag := range tags {
		if tag.Kind == kind && tag.Name == name {
			return tag, nil
		}
	}

	return nil, repositories.ErrNotFound
}

func (r *tagRepository) List(ctx context.Context, filter models.TagFilter) ([]*models.Tag, error) {
	tags := make([]*models.Tag, 0, 64)

	query := bson.M{"listed": true, "tags": bson.M{"$ne": nil}}
	if filter.Kind != nil {
		query["tags.kind"] = *filter.Kind
	}

	err := r.stories.Find(query).Distinct("tags", &tags)
	if err != nil {
		return nil, err
	}

	if filter.Kind != nil {
		// While it's unsorted, delete any incorrect tags with replacement.
		for i := 0; i < len(tags); i++ {
			if tags[i].Kind != *filter.Kind {
				tags[i] = tags[len(tags)-1]
				tags = tags[:len(tags)-1]
				i--
			}
		}
	}

	sort.Slice(tags, func(i, j int) bool {
		if filter.Kind == nil {
			kindCmp := strings.Compare(string(tags[i].Kind), string(tags[j].Kind))
			if kindCmp != 0 {
				return kindCmp < 0
			}
		}

		return strings.Compare(tags[i].Name, tags[j].Name) < 0
	})

	return tags, nil
}