package tags

import (
    "database/sql"	
	_ "github.com/lib/pq"
	"fmt"
)

type Tag struct {
    Id int
    Name string
    Parent sql.NullInt64
    Children []*Tag
}

var Tags []*Tag

func LoadTags(db *sql.DB) {
    Tags = []*Tag{}
   	//rows, err := db.Query("select tags.tag_id, tags.name, tags.parent_id, array_agg(distinct(parent_of.tag_id)) as children from tags left join tags as parent_of on parent_of.parent_id=tags.tag_id group by tags.tag_id")
   	rows, err := db.Query("select tags.tag_id, tags.name, tags.parent_id from tags order by tag_id,tags.parent_id desc")
    if err != nil {
        fmt.Println("DB Error loading tags:", err)
        return
    }	
	
	var flatMap map[int]*Tag = make(map[int]*Tag)
	
	for rows.Next() {
		tag := &Tag{Children: []*Tag{}}

		err = rows.Scan(&tag.Id, &tag.Name, &tag.Parent)
		if err != nil {
			fmt.Println("tags DB Error: ", err)
		}
		
		flatMap[tag.Id] = tag
		
		if tag.Parent.Valid {
		    pid := int(tag.Parent.Int64)
		    flatMap[pid].Children = append(flatMap[pid].Children, tag)
		} else {
		    Tags = append(Tags, tag)
		}    
	}
}