Add new upload limit system (fix #4234).

app/logical/upload_limit.rb

@@ -0,0 +1,99 @@
+class UploadLimit
+  extend Memoist
+
+  INITIAL_POINTS = 1000
+  MAXIMUM_POINTS = 10000
+
+  attr_reader :user
+
+  def initialize(user)
+    @user = user
+  end
+
+  def limited?
+    used_upload_slots >= upload_slots
+  end
+
+  def used_upload_slots
+    pending = user.posts.pending
+    early_deleted = user.posts.deleted.where("created_at >= ?", 3.days.ago)
+
+    pending.or(early_deleted).count
+  end
+
+  def upload_slots
+    upload_level + 5
+  end
+
+  def upload_level
+    UploadLimit.points_to_level(user.upload_points)
+  end
+
+  def approvals_on_current_level
+    (user.upload_points - UploadLimit.level_to_points(upload_level)) / 10
+  end
+
+  def approvals_for_next_level
+    UploadLimit.points_for_next_level(upload_level) / 10
+  end
+
+  def update_limit!(post, incremental: true)
+    return if user.can_upload_free?
+
+    user.with_lock do
+      if incremental
+        user.upload_points += UploadLimit.upload_value(user.upload_points, post.is_deleted)
+        user.save!
+      else
+        user.update!(upload_points: UploadLimit.points_for_user(user))
+      end
+    end
+  end
+
+  def self.points_for_user(user)
+    points = INITIAL_POINTS
+
+    uploads = user.posts.where(is_pending: false).order(id: :asc).pluck(:is_deleted)
+    uploads.each do |is_deleted|
+      points += upload_value(points, is_deleted)
+      points = points.clamp(0, MAXIMUM_POINTS)
+
+      #warn "slots: %2d, points: %3d, value: %2d" % [UploadLimit.points_to_level(points) + 5, points, UploadLimit.upload_value(level, is_deleted)]
+    end
+
+    points
+  end
+
+  def self.upload_value(current_points, is_deleted)
+    if is_deleted
+      level = points_to_level(current_points)
+      -1 * (points_for_next_level(level) / 3.0).round.to_i
+    else
+      10
+    end
+  end
+
+  def self.points_for_next_level(level)
+    100 + 20 * [level - 10, 0].max
+  end
+
+  def self.points_to_level(points)
+    level = 0
+
+    loop do
+      points -= points_for_next_level(level)
+      break if points < 0
+      level += 1
+    end
+
+    level
+  end
+
+  def self.level_to_points(level)
+    (1..level).map do |n|
+      points_for_next_level(n - 1)
+    end.sum
+  end
+
+  memoize :used_upload_slots
+end