Add sort operator, default to newest first

app/chewy/statuses_index.rb

@@ -65,6 +65,7 @@ class StatusesIndex < Chewy::Index
   root date_detection: false do
     field :id, type: 'long'
     field :account_id, type: 'long'
+    field :created_at, type: 'date'
     field :visibility, type: 'keyword'
 
     field :text, type: 'text', value: ->(status) { status.searchable_text } do

app/lib/search_query_transformer.rb

@@ -2,7 +2,7 @@
 
 class SearchQueryTransformer < Parslet::Transform
   class Query
-    attr_reader :should_clauses, :must_not_clauses, :must_clauses, :filter_clauses
+    attr_reader :should_clauses, :must_not_clauses, :must_clauses, :filter_clauses, :order_clauses
 
     def initialize(clauses)
       grouped = clauses.chunk(&:operator).to_h
@@ -10,6 +10,7 @@ class SearchQueryTransformer < Parslet::Transform
       @must_not_clauses = grouped.fetch(:must_not, [])
       @must_clauses = grouped.fetch(:must, [])
       @filter_clauses = grouped.fetch(:filter, [])
+      @order_clauses = grouped.fetch(:order, [])
     end
 
     def apply(search)
@@ -17,6 +18,12 @@ class SearchQueryTransformer < Parslet::Transform
       must_clauses.each { |clause| search = search.query.must(clause_to_query(clause)) }
       must_not_clauses.each { |clause| search = search.query.must_not(clause_to_query(clause)) }
       filter_clauses.each { |clause| search = search.filter(**clause_to_filter(clause)) }
+      if order_clauses.empty?
+        # Default to most recent results first.
+        search = search.order(created_at: :desc)
+      else
+        order_clauses.each { |clause| search = search.order(**clause_to_order(clause)) }
+      end
       search.query.minimum_should_match(1)
     end
 
@@ -41,6 +48,15 @@ class SearchQueryTransformer < Parslet::Transform
         raise "Unexpected clause type: #{clause}"
       end
     end
+
+    def clause_to_order(clause)
+      case clause
+      when PrefixClause
+        { clause.term => clause.order }
+      else
+        raise "Unexpected clause type: #{clause}"
+      end
+    end
   end
 
   class Operator
@@ -81,12 +97,12 @@ class SearchQueryTransformer < Parslet::Transform
   end
 
   class PrefixClause
-    attr_reader :filter, :operator, :term
+    attr_reader :filter, :operator, :term, :order
 
     def initialize(prefix, term)
-      @operator = :filter
       case prefix
       when 'from'
+        @operator = :filter
         @filter = :account_id
 
         username, domain = term.gsub(/\A@/, '').split('@')
@@ -94,6 +110,18 @@ class SearchQueryTransformer < Parslet::Transform
         account          = Account.find_remote!(username, domain)
 
         @term = account.id
+      when 'sort'
+        @operator = :order
+        @term = :created_at
+
+        case term
+        when 'oldest'
+          @order = :asc
+        when 'newest'
+          @order = :desc
+        else
+          raise Mastodon::SyntaxError
+        end
       else
         raise Mastodon::SyntaxError
       end