# Fenced code blocks parser
class MdFencedCodeBlockParser
	super MdBlockParser

	redef type BLOCK: MdFencedCodeBlock
	redef var block = new MdFencedCodeBlock(location, fence_char, fence_length, fence_indent) is lazy

	# Fence character
	var fence_char: Char

	# Fence length
	var fence_length: Int

	# Fence indent
	var fence_indent: Int

	# Fence first line
	var first_line: nullable String = null

	# Fence other lines
	var other_lines = new Buffer

	redef fun try_continue(state) do
		var next_non_space = state.next_non_space_index
		var new_index = state.index
		var line = state.line_string

		if state.indent <= 3 and next_non_space < line.length and
		   line.chars[next_non_space] == fence_char then

			var match = line.substring(next_non_space, line.length - next_non_space).
				search(re_closing_fence)
			if match != null and match.subs[0].as(not null).length >= fence_length then
				# closing fence - we're at end of line, so we can finalize now
				return new MdBlockContinue.finished
			end
		end

		# skip optional spaces of fence indent
		var i = fence_indent
		while i > 0 and new_index < line.length and line.chars[new_index] == ' ' do
			new_index += 1
			i -= 1
		end

		return new MdBlockContinue.at_index(new_index)
	end

	redef fun add_line(line) do
		if first_line == null then
			first_line = line
		else
			other_lines.append(line)
			other_lines.add '\n'
		end
	end

	redef fun finalize(parser) do
		super

		# first line become info string
		var first_line = self.first_line
		if first_line != null then
			var info = first_line.trim.unescape_string
			if not info.is_empty then block.info = info
		end

		var content = other_lines.to_s
		block.literal =  content

		var lines = content.split("\n")
		location.line_end = location.line_start + lines.length
		location.column_end = content_offset + fence_indent + fence_length
	end
end