package storage

import (
	"fmt"
	"strings"
)

// ListCategories returns all categories ordered by label.
func (s *Store) ListCategories() ([]Lookup, error) { return s.listLookup("categories") }

// ListPeople returns all people ("Who") ordered by label.
func (s *Store) ListPeople() ([]Lookup, error) { return s.listLookup("people") }

// AddCategory inserts a new category label and returns its id.
func (s *Store) AddCategory(label string) (int64, error) { return s.addLookup("categories", label) }

// AddPerson inserts a new person label and returns its id.
func (s *Store) AddPerson(label string) (int64, error) { return s.addLookup("people", label) }

// RenameCategory updates a category's label (the change propagates to every
// receipt referencing it, since receipts hold the id, not the text).
func (s *Store) RenameCategory(id int64, label string) error {
	return s.renameLookup("categories", id, label)
}

// RenamePerson updates a person's label.
func (s *Store) RenamePerson(id int64, label string) error {
	return s.renameLookup("people", id, label)
}

func (s *Store) listLookup(table string) ([]Lookup, error) {
	rows, err := s.db.Query(`SELECT id, label FROM ` + table + ` ORDER BY label COLLATE NOCASE`)
	if err != nil {
		return nil, fmt.Errorf("list %s: %w", table, err)
	}
	defer rows.Close()

	var out []Lookup
	for rows.Next() {
		var l Lookup
		if err := rows.Scan(&l.ID, &l.Label); err != nil {
			return nil, fmt.Errorf("scan %s: %w", table, err)
		}
		out = append(out, l)
	}
	return out, rows.Err()
}

func (s *Store) addLookup(table, label string) (int64, error) {
	label = strings.TrimSpace(label)
	if label == "" {
		return 0, fmt.Errorf("label cannot be empty")
	}
	res, err := s.db.Exec(`INSERT INTO `+table+`(label) VALUES (?)`, label)
	if err != nil {
		return 0, fmt.Errorf("add %s: %w", table, err)
	}
	return res.LastInsertId()
}

func (s *Store) renameLookup(table string, id int64, label string) error {
	label = strings.TrimSpace(label)
	if label == "" {
		return fmt.Errorf("label cannot be empty")
	}
	if _, err := s.db.Exec(`UPDATE `+table+` SET label = ? WHERE id = ?`, label, id); err != nil {
		return fmt.Errorf("rename %s: %w", table, err)
	}
	return nil
}