Account search service refactor (#1791)

* Begin coverage for account search service

* Coverage for hashtag query

* Coverage for calling local vs remote find based on domain presence

* Spec to check that exact matches are not duped

* Coverage of resolve option

* Coverage for account being provided

* Start to refactor account search service

* Isolate query username and domain methods

* Isolate exact_match method

* Extract methods for local and remote results

* Simplify local vs remote and account isoliation

* Extract methods for local and remote results

* Simplify de-dupe of exact match

* Simplify logic to check for non exact remotes

* Cache some methods

* Remove nil from exact_match from results array

* Return exact matches first

* Use find_remote even with no domain

Account.find_local is just an alias for Account.find_remote(user, nil) - so we
can not bother with the conditional here, and call find_remote directly.

app/services/account_search_service.rb

@@ -1,26 +1,86 @@
 # frozen_string_literal: true
 
 class AccountSearchService < BaseService
+  attr_reader :query, :limit, :resolve, :account
+
   def call(query, limit, resolve = false, account = nil)
-    return [] if query.blank? || query.start_with?('#')
+    @query = query
+    @limit = limit
+    @resolve = resolve
+    @account = account
 
-    username, domain = query.gsub(/\A@/, '').split('@')
-    domain = nil if TagManager.instance.local_domain?(domain)
+    search_service_results
+  end
 
-    if domain.nil?
-      exact_match = Account.find_local(username)
-      results     = account.nil? ? Account.search_for(username, limit) : Account.advanced_search_for(username, account, limit)
+  private
+
+  def search_service_results
+    return [] if query_blank_or_hashtag?
+
+    if resolving_non_matching_remote_account?
+      [FollowRemoteAccountService.new.call("#{query_username}@#{query_domain}")]
     else
-      exact_match = Account.find_remote(username, domain)
-      results     = account.nil? ? Account.search_for("#{username} #{domain}", limit) : Account.advanced_search_for("#{username} #{domain}", account, limit)
+      search_results_and_exact_match.compact.uniq
     end
+  end
 
-    results = [exact_match] + results.reject { |a| a.id == exact_match.id } if exact_match
+  def resolving_non_matching_remote_account?
+    resolve && !exact_match && !domain_is_local?
+  end
 
-    if resolve && !exact_match && !domain.nil?
-      results = [FollowRemoteAccountService.new.call("#{username}@#{domain}")]
+  def search_results_and_exact_match
+    [exact_match] + search_results.to_a
+  end
+
+  def query_blank_or_hashtag?
+    query.blank? || query.start_with?('#')
+  end
+
+  def split_query_string
+    @_split_query_string ||= query.gsub(/\A@/, '').split('@')
+  end
+
+  def query_username
+    @_query_username ||= split_query_string.first
+  end
+
+  def query_domain
+    @_query_domain ||= query_without_split? ? nil : split_query_string.last
+  end
+
+  def query_without_split?
+    split_query_string.size == 1
+  end
+
+  def domain_is_local?
+    @_domain_is_local ||= TagManager.instance.local_domain?(query_domain)
+  end
+
+  def exact_match
+    @_exact_match ||= Account.find_remote(query_username, query_domain)
+  end
+
+  def search_results
+    @_search_results ||= if account
+      advanced_search_results
+    else
+      simple_search_results
     end
+  end
 
-    results
+  def advanced_search_results
+    Account.advanced_search_for(terms_for_query, account, limit)
+  end
+
+  def simple_search_results
+    Account.search_for(terms_for_query, limit)
+  end
+
+  def terms_for_query
+    if domain_is_local?
+      query_username
+    else
+      "#{query_username} #{query_domain}"
+    end
   end
 end