implement paywall (#161)

* implement core foundation

* inject deps

* fix incorrect migration

* tail migration

* use transaction for migration

* fix: inject deps for tests

* cleanup billing management for admin

* upgrade stripe sdk to v85

* set price env variables

* cleanup billing management

* allow multiple dev windows

* fix: settings scroll

* feat: show nice video thumbnail in listview

* feat: implement freemium restrictions

* remove unnecessary comments

* refactor

* docs

* format

* tweak network settings better hierarchy

go/internal/billing/usage_repository.go

@@ -0,0 +1,49 @@
+package billing
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+type usageRepository interface {
+	incrementDaily(ctx context.Context, networkID string, at time.Time) error
+	getDaily(ctx context.Context, networkID string, at time.Time) (int, error)
+}
+
+type usageRepositoryImpl struct {
+	pool *pgxpool.Pool
+}
+
+func newUsageRepository(pool *pgxpool.Pool) usageRepository {
+	return &usageRepositoryImpl{pool: pool}
+}
+
+func (r *usageRepositoryImpl) incrementDaily(ctx context.Context, networkID string, at time.Time) error {
+	_, err := r.pool.Exec(ctx, `
+		INSERT INTO network_message_usage (network_id, usage_date, message_count, updated_at)
+		VALUES ($1, ($2 AT TIME ZONE 'UTC')::date, 1, NOW())
+		ON CONFLICT (network_id, usage_date) DO UPDATE
+		SET message_count = network_message_usage.message_count + 1,
+		    updated_at    = NOW()
+	`, networkID, at)
+	return err
+}
+
+func (r *usageRepositoryImpl) getDaily(ctx context.Context, networkID string, at time.Time) (int, error) {
+	var count int
+	err := r.pool.QueryRow(ctx, `
+		SELECT message_count FROM network_message_usage
+		WHERE network_id = $1 AND usage_date = ($2 AT TIME ZONE 'UTC')::date
+	`, networkID, at).Scan(&count)
+	if errors.Is(err, pgx.ErrNoRows) {
+		return 0, nil
+	}
+	if err != nil {
+		return 0, err
+	}
+	return count, nil
+}