#!ruby
# frozen_string_literal: true

# Copyright (c) 2016 sawa

class Manager
	class AnnotationExtractor
		AnnotationLine = /#(?<scope>!{1,2})\s*(?:(?<tag>[^\s:]*):)?\s*(?<text>.+)?/
		ContinuationOrCommentLine = /^#\s*(?<text>.+)?/
		ContinuationLine = /^\s+#\s*(?<text>.+)?/
		BlockCommentStart = /^=begin\s/
		BlockCommentEnd = /^=end[\s\z]/
		DebugCommand = /^puts\b|^p\b|\.intercept\b/

		def initialize f
			#! Annotation and block comment can expand for multiple lines, hence the need of flag.
			@tag, @block_comment, @io, @f, @l = nil, nil, File.new(f), f, 0
			@feature = []
		end
		def read_upto modul, type, alt, (f, l)
			#! The reported event might not be directly defining a method, but instead, for example,
			#   aliasing a method name to a method already defined at some other location. These
			#   cases will occur with a combination of a file name and a line number that do not 
			#   point toward a forward location relative to the current read point, and hence 
			#   can be ignored.
			return unless f == @f and l > @l
			read_line until @l == l
			case @feature.last &.[](1) when :instance, :singleton
				@feature.pop
			end
			case type
			when :module_end
				@feature.pop
			else
				@feature.push([modul, type, Manager.main_method(alt)])
			end
		end
		def close
			read_line until @io.eof?
			@io.close
		end
		def read_line
			@l += 1
			s = @io.gets
			return if @feature.empty?
			case s
			when AnnotationLine
				@global = $~[:scope].length == 2
				@tag = $~[:tag] || Manager.current.counts[:annotation] += 1
				text = $~[:text] &.strip
			when DebugCommand
				@tag = :debug
				text = nil
			when BlockCommentStart
				@tag = :comment
				@block_comment = true
				text = nil
			when BlockCommentEnd
				@tag = :comment
				@block_comment = nil
				text = nil
			when ContinuationOrCommentLine
				case @tag
				when String, Integer
					text = $~[:text] &.strip
				else
					@tag = :comment
					text = nil
				end
			when ContinuationLine
				case @tag
				when String, Integer
					text = $~[:text] &.strip
				else
					@tag = nil
					return
				end
			else
				if @block_comment
					@tag = :comment
					text = nil
				else
					@tag = nil
					return
				end
			end
			feature = @tag.is_a?(String) && @global ? [Main, @f, nil] : @feature.last
			a, s = (Manager.current.annotations[feature] ||= {})[@tag] ||= [[], +""]
			a.push([@f, text.!.!, @l])
			if text
				s.concat(Render::Annotation::Joiner) unless s.empty?
				s.concat(text)
			end
		end
	end
end