package postgres

import (
	"database/sql"
	"log"

	"github.com/dustinpianalto/quartermaster"
)

type locationService struct {
	db *sql.DB
}

func (s locationService) Location(id int) (*quartermaster.Location, error) {
	var l quartermaster.Location
	var parent_id sql.NullInt32
	queryString := "SELECT id, name, description, parent_id FROM locations WHERE id = $1"
	row := s.db.QueryRow(queryString, id)
	err := row.Scan(&l.ID, &l.Name, &l.Description, &parent_id)
	if err != nil {
		return nil, err
	}
	if parent_id.Valid {
		p, err := s.Location(int(parent_id.Int32))
		if err != nil {
			return nil, err
		}
		l.Parent = p
	}
	return &l, nil
}

func (s locationService) AddLocation(l *quartermaster.Location) (*quartermaster.Location, error) {
	queryString := "INSERT INTO locations (name, description, parent_id VALUES ($1, $2, $3) RETURNING id"
	var err error
	if l.Parent != nil {
		err = s.db.QueryRow(queryString, l.Name, l.Description, l.Parent.ID).Scan(&l.ID)
	} else {
		err = s.db.QueryRow(queryString, l.Name, l.Description, nil).Scan(&l.ID)
	}
	return l, err
}

func (s locationService) UpdateLocation(l *quartermaster.Location) error {
	queryString := "UPDATE locations SET name = $2, description = $3, parent_id = $4 WHERE id = $1"
	var err error
	if l.Parent != nil {
		_, err = s.db.Exec(queryString, l.ID, l.Name, l.Description, l.Parent.ID)
	} else {
		_, err = s.db.Exec(queryString, l.ID, l.Name, l.Description, nil)
	}
	return err
}

func (s locationService) DeleteLocation(l *quartermaster.Location) error {
	queryString := "DELETE FROM locations WHERE id = $1"
	_, err := s.db.Exec(queryString, l.ID)
	return err
}

func (s locationService) GetChildren(l *quartermaster.Location) ([]*quartermaster.Location, error) {
	var locations []*quartermaster.Location
	queryString := "SELECT id FROM locations WHERE parent_id = $1"
	rows, err := s.db.Query(queryString, l.ID)
	if err != nil {
		return nil, err
	}
	for rows.Next() {
		var id int
		err = rows.Scan(&id)
		if err != nil {
			log.Println(err)
			continue
		}
		location, err := s.Location(id)
		if err != nil {
			log.Println(err)
			continue
		}
		locations = append(locations, location)
	}
	return locations, nil
}

func (s locationService) GetItems(l *quartermaster.Location) (map[*quartermaster.Item]int, error) {
	items := make(map[*quartermaster.Item]int)
	queryString := "SELECT item_id, count FROM x_items_locations WHERE location_id = $1"
	rows, err := s.db.Query(queryString, l.ID)
	if err != nil {
		return nil, err
	}
	for rows.Next() {
		var id, count int
		err = rows.Scan(&id, &count)
		if err != nil {
			log.Println(err)
			continue
		}
		item, err := ItemService.Item(id)
		if err != nil {
			log.Println(err)
			continue
		}
		items[item] = count
	}
	return items, nil
}

func (s locationService) GetTopLocations() ([]*quartermaster.Location, error) {
	var locations []*quartermaster.Location
	queryString := "SELECT id FROM locations WHERE parent_id IS NULL"
	rows, err := s.db.Query(queryString)
	if err != nil {
		return nil, err
	}
	for rows.Next() {
		var id int
		err = rows.Scan(&id)
		if err != nil {
			log.Println(err)
			continue
		}
		l, err := s.Location(id)
		if err != nil {
			log.Println(err)
			continue
		}
		locations = append(locations, l)
	}
	return locations, nil
}