set-section

#!/usr/bin/env ruby
# encoding: utf-8

def set_section(filename, section_name, content)
	section_begin_str = "###### BEGIN #{section_name} ######"
	section_end_str   = "###### END #{section_name} ######"

	lines = File.open(filename, 'r') do |f|
		f.binmode
		f.read.split("\n", -1)
	end

	content.chomp!

	start_index = lines.find_index(section_begin_str)
	if !start_index
		# Section is not in file.
		return if content.empty?
		lines << section_begin_str
		lines << content
		lines << section_end_str
	else
		end_index = start_index + 1
		while end_index < lines.size && lines[end_index] != section_end_str
			end_index += 1
		end
		if end_index == lines.size
			# End not found. Pretend like the section is empty.
			end_index = start_index
		end
		lines.slice!(start_index, end_index - start_index + 1)
		if !content.empty?
			lines.insert(start_index, section_begin_str, content, section_end_str)
		end
	end
	
	File.open(filename, "w") do |f|
		f.binmode
		if lines.last && lines.last.empty?
			lines.pop
		end
		f.write(lines.join("\n"))
		f.write("\n")
	end
end

if ARGV.size != 2
	abort "Usage: set-section <FILENAME> <SECTION NAME>"
else
	set_section(ARGV[0], ARGV[1], STDIN.read)
end