Implement UI for Admin Search of Hashtags (#30880)

app/models/admin/tag_filter.rb

@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+class Admin::TagFilter
+  KEYS = %i(
+    status
+    name
+    order
+  ).freeze
+
+  attr_reader :params
+
+  def initialize(params)
+    @params = params.to_h.symbolize_keys
+  end
+
+  def results
+    scope = Tag.reorder(nil)
+
+    params.each do |key, value|
+      next if key == :page
+
+      scope.merge!(scope_for(key, value)) if value.present?
+    end
+
+    scope
+  end
+
+  private
+
+  def scope_for(key, value)
+    case key
+    when :status
+      status_scope(value)
+    when :name
+      Tag.search_for(value.to_s.strip, params[:limit], params[:offset], exclude_unlistable: false)
+    when :order
+      order_scope(value)
+    else
+      raise Mastodon::InvalidParameterError, "Unknown filter: #{key}"
+    end
+  end
+
+  def status_scope(value)
+    case value.to_s
+    when 'reviewed'
+      Tag.reviewed
+    when 'review_requested'
+      Tag.pending_review
+    when 'unreviewed'
+      Tag.unreviewed
+    when 'trendable'
+      Tag.trendable
+    when 'not_trendable'
+      Tag.not_trendable
+    when 'usable'
+      Tag.usable
+    when 'not_usable'
+      Tag.not_usable
+    else
+      raise Mastodon::InvalidParameterError, "Unknown status: #{value}"
+    end
+  end
+
+  def order_scope(value)
+    case value.to_s
+    when 'newest'
+      Tag.order(created_at: :desc)
+    when 'oldest'
+      Tag.order(created_at: :asc)
+    else
+      raise Mastodon::InvalidParameterError, "Unknown order: #{value}"
+    end
+  end
+end