package store

import (
	"context"
	"errors"

	"github.com/jackc/pgx/v5"
)

// Resolving a public reference to the uuid it names.
//
// Every id in this schema is a uuid and stays one. These three exist because a
// uuid is not something a person can say, type or recognise, and three of the
// four things anyone addresses by URL already HAD a human name that the API
// simply refused to accept: a site has a slug, a camera has the id the engine
// knows it by (and the one that lands in `visits.camera_id`), and a visitor now
// has a per-tenant number. See api/refs.go for the formats.
//
// All three answer "" with a nil error when nothing matches. A found id is
// never empty, so the two cases cannot be confused, and a mistyped reference is
// a 404 rather than an error the handler has to classify.

// SiteIDBySlug resolves a site slug within one tenant.
func (s *Store) SiteIDBySlug(ctx context.Context, clientID, slug string) (string, error) {
	var id string
	err := s.pool.QueryRow(ctx, `
		SELECT id::text FROM sites
		 WHERE client_id = $1::uuid AND slug = $2`,
		clientID, slug).Scan(&id)
	if errors.Is(err, pgx.ErrNoRows) {
		return "", nil
	}
	return id, err
}

// CameraIDByRef resolves the engine's own camera id - "Office1" - to the row
// uuid, within one tenant.
//
// A camera id is unique per SITE, not per tenant, so two shops may each have an
// "Office1". Ambiguity is resolved as no match rather than by picking one:
// silently acting on whichever row sorted first would edit or delete the wrong
// shop's camera. A caller in that position has the uuid, or can scope by site.
func (s *Store) CameraIDByRef(ctx context.Context, clientID, ref string) (string, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT id::text FROM site_cameras
		 WHERE client_id = $1::uuid AND camera_id = $2 AND deleted_at IS NULL
		 LIMIT 2`, clientID, ref)
	if err != nil {
		return "", err
	}
	defer rows.Close()

	var found []string
	for rows.Next() {
		var id string
		if err := rows.Scan(&id); err != nil {
			return "", err
		}
		found = append(found, id)
	}
	if err := rows.Err(); err != nil {
		return "", err
	}
	if len(found) != 1 {
		return "", nil
	}
	return found[0], nil
}

// VisitorIDByNumber resolves the number behind "V-42" within one tenant.
func (s *Store) VisitorIDByNumber(ctx context.Context, clientID string, number int64) (string, error) {
	var id string
	err := s.pool.QueryRow(ctx, `
		SELECT id::text FROM visitors
		 WHERE client_id = $1::uuid AND number = $2`,
		clientID, number).Scan(&id)
	if errors.Is(err, pgx.ErrNoRows) {
		return "", nil
	}
	return id, err
}