1 files changed, 85 insertions, 0 deletions
diff --git a/lib/syntax_suggest/capture/before_after_keyword_ends.rb b/lib/syntax_suggest/capture/before_after_keyword_ends.rb
new file mode 100644
index 0000000000..f53c57a4d1
--- /dev/null
+++ b/lib/syntax_suggest/capture/before_after_keyword_ends.rb
@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+module SyntaxSuggest
+  module Capture
+    # Shows surrounding kw/end pairs
+    #
+    # The purpose of showing these extra pairs is due to cases
+    # of ambiguity when only one visible line is matched.
+    #
+    # For example:
+    #
+    #     1  class Dog
+    #     2    def bark
+    #     4    def eat
+    #     5    end
+    #     6  end
+    #
+    # In this case either line 2 could be missing an `end` or
+    # line 4 was an extra line added by mistake (it happens).
+    #
+    # When we detect the above problem it shows the issue
+    # as only being on line 2
+    #
+    #     2    def bark
+    #
+    # Showing "neighbor" keyword pairs gives extra context:
+    #
+    #     2    def bark
+    #     4    def eat
+    #     5    end
+    #
+    #
+    # Example:
+    #
+    #   lines = BeforeAfterKeywordEnds.new(
+    #     block: block,
+    #     code_lines: code_lines
+    #   ).call()
+    #
+    class BeforeAfterKeywordEnds
+      def initialize(code_lines:, block:)
+        @scanner = ScanHistory.new(code_lines: code_lines, block: block)
+        @original_indent = block.current_indent
+      end
+
+      def call
+        lines = []
+
+        @scanner.scan(
+          up: ->(line, kw_count, end_count) {
+            next true if line.empty?
+            break if line.indent < @original_indent
+            next true if line.indent != @original_indent
+
+            # If we're going up and have one complete kw/end pair, stop
+            if kw_count != 0 && kw_count == end_count
+              lines << line
+              break
+            end
+
+            lines << line if line.is_kw? || line.is_end?
+            true
+          },
+          down: ->(line, kw_count, end_count) {
+            next true if line.empty?
+            break if line.indent < @original_indent
+            next true if line.indent != @original_indent
+
+            # if we're going down and have one complete kw/end pair,stop
+            if kw_count != 0 && kw_count == end_count
+              lines << line
+              break
+            end
+
+            lines << line if line.is_kw? || line.is_end?
+            true
+          }
+        )
+        @scanner.stash_changes
+
+        lines
+      end
+    end
+  end
+end