#!/usr/bin/env ruby

require 'Paludis'
require 'getoptlong'
require 'pathname'
require 'shellwords'
begin
	require 'irb-pager'
rescue LoadError
	STDERR.puts <<EOF
Loading IRB::Pager failed. Please install it first:
	sudo gem install irb-pager
EOF
	raise
end

include Paludis

class Object
	def with &block
		yield self
	end
	def self.with &block
		yield self
	end
end

def path_cmd cmd
	ENV['PATH'].split( ':').each do |dir|
		dir = Pathname.new dir
		next  unless dir.directory?
		dir.each_child {|f| return f  if cmd == f.basename.to_s and f.file? }
	end
	nil
end

def system *a
	Kernel.system *a.map(&:to_s)
end

class UsageError <Exception
end

class NoSelection <UsageError
	def new x = nil
		super x || 'Select a file first.'
	end
end

if cmd = ENV['ECLECTIC_CONFIG_DIFF_COMMAND']
	def diff( f1, f2) system "#{cmd} #{Shellwords.escape f1} #{Shellwords.escape f2}" end
elsif path_cmd 'git'
	def diff( f1, f2) system *%w[git --no-pager --git-dir=: diff --color-words], f1, f2 end
elsif path_cmd 'colordiff'
	def diff( f1, f2) system 'colordiff', f1, f2 end
else
	def diff( f1, f2) system 'diff', f1, f2 end
end

def list_cfgs selected, list
	keys = {}
	list.keys.sort.map do |i|
		file = list[i]
		keys[["\\#{i}"]] = (selected == file ? '* ' : '')+file.to_s
	end
	list_keys keys
end

Log.instance.with do |nst|
	nst.log_level = LogLevel::Warning
	nst.program_name = $0
end

env = EnvironmentFactory.instance.create ''
dirs = Pathname.new( env.fetch_repository( 'installed')['location'].parse_value).join( '.cache', 'all_CONFIG_PROTECT').each_line.map {|l| Pathname.new l.chomp }

def find_cfgs dirs, &exe
	block_given? or return to_enum( __method__, dirs)
	dirs.each do |dir|
		dir.find do |e|
			yield e  if /^\._cfg...._/ =~ e.basename.to_s and e.file?
		end  if dir.exist?
	end
end

def accept_cfg config, update
	backup = config.dirname + "._cfg_backuped_#{Time.now.strftime '%FT%T'}_#{config.basename}"
	puts "#{config}: backup to [#{backup}]"
	config.rename backup
	puts "#{config}: accept [#{update}]"
	update.rename config
end

def reject_cfg config, update
	backup = config.dirname + "._cfg_rejected_#{Time.now.strftime '%FT%T'}_#{config.basename}"
	puts "#{config}: reject [#{update}] backup to [#{backup}]"
	update.rename backup
end

def list_keys cmds
	len = cmds.keys.map {|cmd| cmd.map {|c| c.sub /(?<!\\)\\/, '' }.join( ', ').gsub( "\\\\", "\\").length }.max+2
	cmds.each do |cmd, text|
		l = cmd.map {|c| c.sub /(?<!\\)\\/, '' }.join( ', ').gsub( "\\\\", "\\").length
		cmd = cmd.map {|c| c.sub /(?<!\\)\\([^\\])/, "\e[1m\\1\e[0m" }.join( ', ').gsub "\\\\", "\\"
		printf "  [%s]%s%s\n", cmd, ' '*(len-l), text
	end
end

selected = nil
loop do
	begin
		found = Hash.new {|h,k| h[k] = [] }
		list = {}
		find_cfgs( dirs).each do |cfg|
			found[cfg.dirname + cfg.basename.to_s.sub( /^\._cfg...._/, '')] += [cfg]
		end
		if found.empty?
			puts "No files to update."
			exit 0
		end
		found.each_with_index do |(file,cfgs),i|
			i += 1
			list[i] = file
		end
		selected = nil  unless found[selected]
		if selected
			print "(cfg:\e[1m#{selected}\e[0m)# "
		else
			puts
			list_cfgs selected, list
			puts
			print "(select?)# "
		end
		line = STDIN.gets or exit(0)
		line = line.chomp.split /\s+/
		line.each do |x|
			case x
			when /^\d+$/
				m = list[x.to_i]
				raise UsageError, "Unknown index #{x}"  unless m
				selected = m
			when *%w[h help ?]
				puts
				list_keys( {
					%w[\help \?] => 'Help',
					%w[\1 \2 ...] => 'Select file via index',
					%w[FILENAME] => 'Select file via filename',
					%w[\list] => 'List all files need updates',
					%w[\diff] => 'Displays difference of selected file',
					%w[\accept \yes] => 'Accepts selected file',
					%w[\reject \no] => 'Rejects selected file',
					%w[\quit \exit] => 'Quit',
				})
				puts
			when *%w[d diff]
				raise NoSelection  unless selected
				puts
				IRB::Pager::pager( pager: 'less -R') { diff selected, found[selected][0] }
				puts
			when *%w[l list]
				list_cfgs selected, list  if selected
			when *%w[a accept y yes]
				raise NoSelection  unless selected
				accept_cfg selected, found[selected][0]
				selected = nil
			when *%w[r reject n no]
				raise NoSelection  unless selected
				reject_cfg selected, found[selected][0]
				selected = nil
			when *%w[q quit e exit] then exit(0)
			else
				m = Pathname.new x
				if f = found[m]
					selected = m
				else
					raise UsageError, "Uknown command #{x}"
				end
			end
		end
	rescue UsageError
		puts $!
	end
end