require 'pathname'
require 'shellwords'
require 'optparse'
require 'securerandom'
require 'to_lvm_xfs/exts'
require 'to_lvm_xfs/sh'
require 'to_lvm_xfs/structs'

class ProgrammError < RuntimeError
end

class Pathname
	def self.which cmd
		ENV['PATH'].split(':').each do |path|
			path = Pathname.new( path) + cmd
			return path  if path.executable?
		end
		nil
	end
end

module OutputHelper
	def d msg, eq
		raise ProgrammError, msg, caller[1..-1]  unless eq
	end

	def err *args
		STDERR.puts "\e[31;1m#{args.join ' '}\e[0m"
	end

	def msg first, *args
		STDERR.puts "\e[33m#{first}\e[35m #{args.join ' '}\e[0m"
	end

	def task name, &exe
		STDERR.puts   "\e[30;1m***\e[0m #{name} \e[30;1m#{'*' * [0,80-name.length].max}\e[0m"
		if yield
			STDERR.puts "\e[32;1m---\e[0m #{name} \e[32;1m#{'-' * [0,80-name.length].max}\e[0m\n"
		else
			STDERR.puts "\e[35;1m---\e[0m #{name} \e[35;1m#{'-' * [0,80-name.length].max}\e[0m\n"
		end
	rescue Object
		STDERR.puts   "\n\e[31;1m|||\e[0m #{name} \e[31;1m#{'|' * [0,80-name.length].max}\e[0m\n"
		raise
	end
end

class Base
	include OutputHelper

	def self.run *args, &exe
		new( *args).instance_eval &exe
	end

	def kpartx image, read_only: nil
		sh.kpartx "-sa#{read_only ? :r : ''}", image
		lpartx image
	end
	
	def lpartx image
		mapper = XPathname.new '/dev/mapper'
		lines = sh.kpartx( -:al, image, return: :lines)[0..-1]
		if lines.grep( /^loop deleted/).empty?
			lines.map do |line|
				d "cannot extract partition «#{line}»", line =~ /^([^ :]+) : /
				mapper + $1
			end
		else
			[]
		end
	end

	def lsblk path, *output
		output = %w[NAME TYPE MOUNTPOINT]  if output.empty?
		output = output.map {|o| o.to_s }
		lines =
			sh.lsblk %w[--output], output.join(','), path
		op = output.map {|o| o.downcase.to_sym }
		lines.map {|l| Hash[*op.zip(l.split( /\s+/)).flatten]}
	end

	def departx image
		sh.kpartx -:sd, image
	end

	def kpartxed? image
		lines = sh.kpartx -:l, image, return: :lines
		not lines.grep( /^loop deleted/).empty?
	end


	def get_vgname_of_pv *a, &exe
		return to_enum( __method__, *a)  unless block_given?
		sh.pvs( --:options, :vg_name, *a, return: :lines).each do |l|
			yield l.chomp.sub( /^\s*/, '')
		end
	end

	def remove_all_partitions_from image
		sh[].parted( -:ms, image, :print).each do
			sh.parted image, :rm, 1
		end
	end

	def manipulate_file file, &exe
		flags = 'r+'
		msg :manipulate, file
		File.open file.to_s, flags do |file|
			lines = []
			exe.call file, &lines.method( :push)
			file.truncate 0
			file.pos = 0
			lines.each &file.method( :puts)
		end
	end

	def capsulated_rescue
		yield
	rescue Object => e
		STDERR.puts "\e[0;1mTraceback\e[0m (most recent call last):"
		e.backtrace[1..-1].
			each_with_index.
			reverse_each {|s,i| STDERR.puts "\t#{i}: #{s}" }
		STDERR.puts "#{e.backtrace}: \e[31;1m#{e} (#{e.class})\e[0m"
	end

	def check_programm cmd
		path = Pathname.which cmd
		raise ProgrammError, "#{cmd} not found."  unless path&.executable?
		path
	end

	attr_reader :sh, :mounted, :looped, :base, :dest, :vgname
	def initialize *args
		OptionParser.new do |opts|
			getopts opts
			opts.parse! args
		end

		%w[kpartx parted rsync lvm lvs pvs vgs mkfs.xfs mkfs.vfat dmsetup losetup lsblk blkid].each do |cmd|
			check_programm cmd
		end
		@qemu_bin_src = check_programm 'qemu-arm-static'
		raise ProgrammError, "qemu-arm-static not found.  Please install qemu-user-static"  unless @qemu_bin_src&.executable?

		if :ask == @password
			v = b = nil
			require 'io/console'
			STDERR.print "Type Password. "
			v = STDIN.getpass
			STDERR.print "Type password again. "
			b = STDIN.getpass
			d "Password missmatch", v == b
			d "Password is empty", !v.empty?
			@password = v.crypt "$6$#{SecureRandom.urlsafe_base64 6}$"
		end

		@sh = Sh.new immediately: true, expect_status: 0
		#x = sh.system :echo, :hallo, :welt, as_io: true do |io|
		#	STDERR.puts io.inspect
		#	STDERR.puts '---',io.readlines,'---'
		#end
		#STDERR.puts x.inspect
		#exit 1
		@mounted, @activated_vgs = Hash.new.tap {|h| h.default = 0 }, []
		@looped = Hash.new {|h,k| h[k] = [] }
		@base = Image.new self, 'base', image: @baseimage
		@dest = Image.new self, 'dest', image: @destination

		@qemu_bin = dest.root.join 'usr/bin/qemu-arm-static'

		STDERR.print <<-EOF.gsub( /^\s+#/, '')
			#Settings:
			#     username: #{@username || '(default)'}
			#     password: #{@password ? '*********' : '(default)'}
			#    baseimage: #{@base.image}
			#  destination: #{@dest.image}
			#       vgname: #{@vgname}
			#     hostname: #{@hostname || '(default)'}
			EOF

		sh.def_system_commands *%i[echo sed mount umount partx kpartx sync rsync xz gzip bzip2 zip tar bash dpkg apt]
		sh.def_system_commands *%i[losetup dmsetup lvcreate vgcreate pvcreate vgchange mkswap vgscan]
		sh.alias_command :losetup_list, *%w[losetup --list --json],                                 return: :json, could_be_empty: true
		sh.alias_command :pvs,          *%w[pvs --noheadings]
		sh.alias_command :blkid,        'blkid',                                                    return: :line
		sh.alias_command :lsblk,        *%w[lsblk --noheadings --paths --list],                     return: :lines
		sh.alias_command :parted,       *%w[parted --machine --script]
		sh.alias_command :mkxfs,        *%w[mkfs.xfs -f]
		sh.alias_command :mkext2fs,     *%w[mkfs.ext2]
		sh.alias_command :mkext4fs,     *%w[mkfs.ext4]
		sh.alias_command :mkvfat,       *%w[mkfs.vfat]
		sh.alias_command :rsync_all,    *%w[rsync --archive --hard-links --acls --xattrs --sparse]
		sh.alias_command :mount_ro,     *%w[mount -oro]
		sh.alias_command :fs_uuid,      *%w[blkid -ovalue -sUUID],                                  return: :line
		sh.alias_command :fs_type,      *%w[blkid -ovalue -sTYPE],                                  return: :line
	end

	def getopts opts
		opts.on '-h', '--help' do
			STDERR.puts opts
			exit 1
		end

		opts.on '-bIMAGE', '--baseimage=IMAGE', 'Read image from IMAGE.  Device or file' do |v|
			@baseimage = v
		end

		opts.on '-dIMAGE', '--destination=IMAGE', 'Write image to IMAGE.  Device or file' do |v|
			@destination = v
		end

		opts.on '-uUSER', '--user=USER', 'Change username of user pi to this USERname' do |v|
			@username = v
		end

		opts.on '-W', '--ask-pass', 'Ask for password for user via CLI.' do
			@password = :ask
		end

		opts.on '-wPASSWORD', '--password=PASSWORD', 'Set password for user' do |v|
			@password = v.crypt "$6$#{SecureRandom.urlsafe_base64 6}$"
		end

		opts.on '-nVGNAME', '--vgname=VGNAME', 'Name for volume group' do |v|
			@vgname = v
		end

		opts.on '-HNAME', '--hostname=NAME', 'Set hostname to NAME' do |v|
			@hostname = v
		end

		opts.on '-aAUTHKEYS', '--auth-keys=AUTHKEYS', 'SSH-Keys for user' do |f|
			f = XPathname.new f
			d "#{f} not found.", f.exist?
			@authorized_keys = f
		end

		opts.on '-AAUTHKEYS', '--root-auth-keys=AUTHKEYS', 'SSH-Keys for root' do |f|
			f = XPathname.new f
			d "#{f} not found.", f.exist?
			@root_authorized_keys = f
		end
	end

	def cleanup &exe
		@cleanup ||= []
		@cleanup.unshift exe
	end

	def after &exe
		@after ||= []
		@after.unshift exe
	end

	def run
		@after ||= []
		@cleanup ||= []
		nok = false
		build

		task "After run" do
			@after.each {|exe| exe.call }

			if @qemu_bin.exist?
				#msg :remove, "/usr/bin/qemu-arm-static"
				@qemu_bin.unlink
			end
		end

	rescue ProgrammError
		nok = true
		err $!
		raise
	ensure
		STDERR.puts "\e[1;36m#{"<"*80}\e[0m"
		@cleanup.each {|exe| exe.call }
		umount_all ignore_exceptions: true
		umount dest.root, -:R     rescue Object
		umount base.root, -:R     rescue Object
		sh.vgchange -:an, vgname  rescue Object
		sh.sync                   rescue Object
		departx dest.image        rescue Object
		departx base.image        rescue Object
		sh.sync                   rescue Object
		STDERR.puts "\e[1;#{nok ? 31: 36}m#{">"*80}\e[0m"
	end

	def activate_vg vgname
		return nil  if @activated_vgs.include? vgname
		@activated_vgs.unshift vgname
		sh.vgchange -:ae, vgname
	end

	def deactivate_vg vgname
		return nil  unless @activated_vgs.include? vgname
		sh.vgchange -:an, vgname
		@activated_vgs.delete vgname
	end

	def deactivate_all_vgs ignore_exceptions: nil
		until @activated_vgs.empty?
			if ignore_exceptions
				capsulated_rescue { sh.vgchange -:an, @activated_vgs.pop }
			else
				sh.umount @activated_vgs.pop
			end
		end
	end

	def mount dev, mp, *opts, &exe
		@mounted[mp] += 1
		sh.mount *opts, dev, mp
		if block_given?
			begin
				yield
			ensure
				umount mp
			end
		end
	end

	def umount mp, *opts
		if 0 < @mounted[mp]
			@mounted[mp] -= 1
			if 0 == @mounted[mp]
				r = sh.umount *opts, mp
				@mounted.delete mp
				r
			end
		end
	end

	def umount_all ignore_exceptions: nil
		until @mounted.empty?
			m = @mounted.keys.first
			if ignore_exceptions
				capsulated_rescue { sh.umount m }
			else
				sh.umount m
			end
			@mounted.delete m
		end
	end

	def mkmppaths
		[base, dest].each do |mp|
			mp.dir.mkpath
			mp.root.mkpath
		end
	end

	def ssh_copy_id_local src, home, uid, gid = nil
		akfile = home+'.ssh/authorized_keys'
		akdir = akfile.dirname
		akdir. mkdir
		akdir. chown uid, gid
		akdir. chmod 0700
		akfile.copy  src
		akfile.chown uid, gid
		akfile.chmod 0600
	end

	def install_authorized_keys
		ssh_copy_id_local @authorized_keys, dest.root+'home/pi', 1000, 1000  if @authorized_keys
		ssh_copy_id_local @root_authorized_keys, dest.root+'root', 0, 0  if @root_authorized_keys
	end

	def rename_user username = nil, password: nil, old: nil
		username ||= @username
		old ||= 'pi'
		password ||= @password

		if username and old != username
			dest.root.join( 'etc/passwd').sed_i do |l|
				user, pwd, uid, gid, name, home, shell = l.split( ':', 7)
				user, home = username, "/home/#{username}"  if old == user
				[user, pwd, uid, gid, name, home, shell].join ':'
			end

			dest.root.join( 'etc/group').sed_i do |l|
				group, pwd, gid, users = l.split( ':', 4)
				group = username  if old == group
				users = users.split( ',').map {|user| old == user ? username : user }
				[group, pwd, gid, users.join( ',')].join ':'
			end

			dest.root.join( 'home', old).rename dest.root.join( 'home', username)
		end

		if password or username
			dest.root.join( 'etc/shadow').sed_i do |l|
				user, crypt, lastchange, minage, maxage, warn, inact, expiry, reserved = l.split( ':', 9)
				if old == user
					crypt = password  if password
					user  = username  if username
				end
				[user, crypt, lastchange, minage, maxage, warn, inact, expiry, reserved].join ':'
			end
		end
	end

	def set_hostname hostname = nil
		hostname ||= @hostname
		return  if hostname.nil? or hostname.empty?
		msg "setting hostname", hostname
		dest.root.join( 'etc/hosts').sed_i {|l| l.gsub /\<raspberrypi\>/, hostname }
		dest.root.join( 'etc/hostname').write "#{hostname}\n"
	end

	FSTabMountEntry =
		Struct.new :spec, :file, :type, :ops, :freq, :passno do
			def to_a() [spec, file, type, ops, freq||0, passno||0] end
			def to_s() to_a.join ' ' end
		end

	def update_fstab content
		cnt = {}
		content = content.each do |ent|
			cnt[ent.file.to_s] = ent.to_s
		end
		dest.root.join( 'etc/fstab').replace_i do |f|
			f.each_line.flat_map do |l|
				mp = l.split( /\s+/)[1]
				cnt.delete( mp) || l
			end + cnt.values
		end
	end

	def install_packages_from_dir *paths
		paths.each do |pkgs|
			next  unless pkgs.directory?
			pkgs.each_child do |pn|
				next  if /\A\./ =~ pn.basename.to_s # no dot-files.
				install_package pn
			end
		end
	end

	def install_package path
		case path.basename.to_s
		when /\.deb\z/
			install_deb path
		when /\.tar\z/, /\.t(?:ar\.|)(?:xz|bzip2|gz|lzma|Z)\z/
			sh.tar -:C, dest.root, -:xf, path
		else
			warn :ignore, path
		end
	end

	def install_deb path
		#sh.dpkg '--unpack', '--force-architecture', pn, chroot: dest.root
		adeb = XPathname.new( 'var/cache/apt/archives')+path.basename.to_s
		dest.root.join( adeb.to_s).copy path
		sh.dpkg -:i, adeb, chroot: dest.root
		#msg :unpack, path
		# sometimes, you have to use system to do something.  but it is ok, if you know, how to do it.
		# this command should be safe.
		#d "unpacking failed: #{path}",
		#		system( "ar p #{path.to_s.shellescape} data.tar.xz | tar -JxC #{dest.root.to_s.shellescape}")
	end
end