package database

import (
	"time"

	log "github.com/cihub/seelog"
)

type Visit struct {
	ID        int
	Downloads int `sql:",notnull"`
	Views     int `sql:",notnull"`
	BookID    string
	Book      *Book
}

func (db *pgDB) IncViews(ID string) error {
	visit := &Visit{
		Downloads: 0,
		Views:     1,
		BookID:    ID,
	}
	_, err := db.sql.Model(visit).
		OnConflict("(book_id) DO UPDATE").
		Set("views = Visit.views + 1").
		Insert()
	return err
}

func (db *pgDB) IncDownloads(ID string) error {
	visit := &Visit{
		Downloads: 1,
		Views:     0,
		BookID:    ID,
	}
	_, err := db.sql.Model(visit).
		OnConflict("(book_id) DO UPDATE").
		Set("downloads = Visit.downloads + 1").
		Insert()
	return err
}

/* GetVisitedBooks get the most visited books
 */
func (db *pgDB) GetVisitedBooks(num int) (books []Book, err error) {
	err = db.sql.Model(&books).
		Column("Visit").
		Order("views DESC NULLS LAST").
		Limit(num).
		Select()
	return
}

/* GetDownloadedBooks the most downloaded books
 */
func (db *pgDB) GetDownloadedBooks(num int) (books []Book, err error) {
	err = db.sql.Model(&books).
		Column("Visit").
		Order("downloads DESC NULLS LAST").
		Limit(num).
		Select()
	return
}

func (db *pgDB) GetTags() ([]string, error) {
	return db.tags, nil
}

func (db *pgDB) updateTags() {
	var tags []string
	err := db.sql.Model(&Book{}).
		ColumnExpr("unnest(tags) as tag").
		Where("active = true").
		Group("tag").
		OrderExpr("count(*) DESC").
		Limit(tagsDisplay).
		Select(&tags)
	if err != nil {
		log.Error("Error updating tags: ", err)
	} else {
		db.tags = tags
	}
}

func (db *pgDB) tagUpdater() {
	periodicity := 57 * time.Minute

	for true {
		db.updateTags()
		time.Sleep(periodicity)
	}
}