firestore.rules

service cloud.firestore {

  match /databases/{database}/documents {

        function userOwnsCourse(userId, courseId) {
            return exists(/databases/$(database)/documents/users/$(userId)/coursesOwned/$(courseId))
        }

        function isSubscriber(userId) {
            return "pricingPlanId" in get(/databases/$(database)/documents/users/$(userId)).data
        }

        function isUserWithId(userId) {
            return request.auth.uid == userId;
        }

        match /courses/{courseId} {
            allow read: if true;

            match /lessons/{lessonId} {
                allow read: if userOwnsCourse(request.auth.uid,courseId) || isSubscriber(request.auth.uid)
            }
        }

        match /purchaseSessions/{purchaseId} {
            allow read: if request.auth.uid == resource.data.userId;
        }

        match /users/{userId} {
            allow read: if isUserWithId(userId);

            match /coursesOwned/{courseId} {
                allow read: if isUserWithId(userId);
            }

        }

  }

}