fix up stats, allow more instance settings

internal/db/pg/instancestats.go

@@ -0,0 +1,52 @@
+package pg
+
+import (
+	"github.com/go-pg/pg/v10"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+func (ps *postgresService) GetUserCountForInstance(domain string) (int, error) {
+	q := ps.conn.Model(&[]*gtsmodel.Account{})
+
+	if domain == ps.config.Host {
+		// if the domain is *this* domain, just count where the domain field is null
+		q = q.Where("? IS NULL", pg.Ident("domain"))
+	} else {
+		q = q.Where("domain = ?", domain)
+	}
+
+	// don't count the instance account or suspended users
+	q = q.Where("username != ?", domain).Where("? IS NULL", pg.Ident("suspended_at"))
+
+	return q.Count()
+}
+
+func (ps *postgresService) GetStatusCountForInstance(domain string) (int, error) {
+	q := ps.conn.Model(&[]*gtsmodel.Status{})
+
+	if domain == ps.config.Host {
+		// if the domain is *this* domain, just count where local is true
+		q = q.Where("local = ?", true)
+	} else {
+		// join on the domain of the account
+		q = q.Join("JOIN accounts AS account ON account.id = status.account_id").
+		Where("account.domain = ?", domain)
+	}
+
+	return q.Count()
+}
+
+func (ps *postgresService) GetDomainCountForInstance(domain string) (int, error) {
+	q := ps.conn.Model(&[]*gtsmodel.Instance{})
+
+	if domain == ps.config.Host {
+		// if the domain is *this* domain, just count other instances it knows about
+		// TODO: exclude domains that are blocked or silenced
+		q = q.Where("domain != ?", domain)
+	} else {
+		// TODO: implement federated domain counting properly for remote domains
+		return 0, nil
+	}
+
+	return q.Count()
+}