// Platform-admin reads BELOW the merchant level: one company, its shops, its
// cameras, and the estate-wide totals.
//
// Every function here takes the merchant's client id as an ARGUMENT, because
// the caller is a platform admin who has no client of their own. That is the
// whole reason these exist rather than reusing the tenant handlers: those
// derive the tenant from the session, and an admin session carries none. The
// tenant STORE functions already take a client id explicitly, so this file
// adds the scoping the tenant handlers get for free and nothing else.
package store

import (
	"context"
	"errors"
	"time"

	"github.com/jackc/pgx/v5"

	"github.com/loyaly/behavision-server/internal/api"
)

// ClientDetail is one merchant, with the owner a support conversation starts
// from. ListClients cannot carry it: an owner lookup per row would be a query
// per merchant on a screen that only needs the name.
func (s *Store) ClientDetail(ctx context.Context, clientID string) (api.ClientDetail, error) {
	var c api.ClientDetail
	var at time.Time
	err := s.pool.QueryRow(ctx, `
		SELECT c.id::text, c.slug, c.name, c.active, c.created_at,
		       (SELECT count(*) FROM sites si     WHERE si.client_id = c.id),
		       (SELECT count(*) FROM app_users au WHERE au.client_id = c.id),
		       COALESCE((SELECT au.email     FROM app_users au
		                  WHERE au.client_id = c.id AND au.role = 'owner'
		                    AND au.active ORDER BY au.created_at LIMIT 1), ''),
		       COALESCE((SELECT au.full_name FROM app_users au
		                  WHERE au.client_id = c.id AND au.role = 'owner'
		                    AND au.active ORDER BY au.created_at LIMIT 1), '')
		  FROM clients c
		 WHERE c.id = $1::uuid`, clientID).
		Scan(&c.ID, &c.Slug, &c.Name, &c.Active, &at, &c.Sites, &c.Users,
			&c.OwnerEmail, &c.OwnerName)
	if errors.Is(err, pgx.ErrNoRows) {
		return api.ClientDetail{}, nil
	}
	if err != nil {
		return api.ClientDetail{}, err
	}
	c.CreatedAt = at.UTC().Format(time.RFC3339)
	return c, nil
}

// AdminSiteID resolves a shop reference WITHIN one merchant, by slug or uuid.
//
// The uuid branch is the point. The tenant resolver returns a uuid untouched
// and lets every downstream query's `client_id = $1` do the scoping, which is
// sound there because the client id comes from the session and cannot be
// chosen. Here the caller names BOTH, so an unowned uuid would otherwise reach
// a query that quietly returns nothing - an empty shop rather than "no such
// shop". Resolving through the database with both halves is what makes a
// broken chain a 404.
func (s *Store) AdminSiteID(ctx context.Context, clientID, ref string) (string, error) {
	var id string
	// `id::text = $2`, never `id = $2::uuid`. Using one parameter as both text
	// and uuid in the same statement is how Postgres ends up deducing two
	// types for it and refusing the whole query - the identical shape that
	// broke `'Visitor ' || $2::text` beside `number = $2`, which compiled,
	// passed every in-memory test and failed on the first real database.
	// Casting the COLUMN keeps one type per parameter, and it cannot raise an
	// invalid-uuid error on a malformed path segment either: it simply misses,
	// which is the 404 the caller should get anyway.
	err := s.pool.QueryRow(ctx, `
		SELECT id::text FROM sites
		 WHERE client_id = $1::uuid
		   AND (slug = $2 OR id::text = $2)`,
		clientID, ref).Scan(&id)
	if errors.Is(err, pgx.ErrNoRows) {
		return "", nil
	}
	return id, err
}

// AdminCameraID resolves a camera within one shop of one merchant.
//
// All three links are checked in the one statement, so there is no ordering in
// which a caller learns that a camera exists somewhere else.
func (s *Store) AdminCameraID(ctx context.Context, clientID, siteID, ref string) (string, error) {
	var id string
	err := s.pool.QueryRow(ctx, `
		SELECT c.id::text
		  FROM site_cameras c
		  JOIN sites si ON si.id = c.site_id
		 WHERE si.client_id = $1::uuid
		   AND c.site_id = $2::uuid
		   AND c.deleted_at IS NULL
		   AND (c.camera_id = $3 OR c.id::text = $3)`,
		clientID, siteID, ref).Scan(&id)
	if errors.Is(err, pgx.ErrNoRows) {
		return "", nil
	}
	return id, err
}

// PlatformSummary is counts and nothing else.
//
// Deliberately not a list: it backs a header strip, and an endpoint that
// returns every camera on the platform to render four numbers is one that gets
// slower with every customer signed.
func (s *Store) PlatformSummary(ctx context.Context) (api.PlatformSummary, error) {
	var out api.PlatformSummary
	err := s.pool.QueryRow(ctx, `
		SELECT
		  (SELECT count(*) FROM site_cameras WHERE deleted_at IS NULL),
		  (SELECT count(*) FROM site_cameras
		    WHERE deleted_at IS NULL AND connected IS TRUE),
		  (SELECT count(*) FROM clients WHERE active),
		  (SELECT count(*) FROM sites),
		  (SELECT count(*) FROM visits WHERE occurred_at >= date_trunc('day', now()))
	`).Scan(&out.CamerasTotal, &out.CamerasOnline, &out.MerchantsActive,
		&out.SitesTotal, &out.EventsToday)
	if err != nil {
		return api.PlatformSummary{}, err
	}
	out.AsOf = time.Now().UTC().Format(time.RFC3339)
	return out, nil
}