require 'to_lvm_xfs'

class Raspbian < Base
	def initialize *args
		@vgname = "raspi_#{SecureRandom.urlsafe_base64 5}"
		super *args
	end

	def build
		ENV['LANG'] = 'C'
		mkmppaths

		case
		when !dest.image.exist?
		when dest.image.file?
			r = sh.losetup_list
			unless r.empty? or r['loopdevices']
				r['loopdevices'].each do |lo|
					d "File #{dest.image} used as loop-device back-file",
						+dest.image != +XPathname.new(lo['back-file'])
				end
			end
		when dest.image.blockdev?, dest.image.chardev?
			lsblk( dest.image).each do |l|
				d "Device #{l[:name]} mounted at #{l[:mountpoint]}", ! l[:mountpoint]
			end
		end

		sleep 5

		d "Base image does not exist", base.image.exist?
		base_parts = kpartx base.image
		d "two partitions in base expected, got: #{base_parts.inspect}", 2 == base_parts.length
		mount base_parts[1], base.root, -:oro
		mount base_parts[0], base.root+'boot', -:oro

		dest.image.open 'w' do |f|
			f << 0.chr*4096
			f.pos = 4.8*1024*1024*1024-1
			f.putc 0.chr
		end
		sh.parted dest.image, *%w[--
			mklabel msdos
			mkpart primary fat32   4MB 132MB
			mkpart primary ext2  132MB   -1s
			set 2 LVM on
			print]
		
		*dest_parts =
			begin
				lsblk( dest.image).select do |l|
					STDERR.puts l
					sh.dmsetup :remove, File.basename(l[:name])  if 'lvm' == l[:type]
					l[:name].start_with?( dest.image.to_s) and 'part' == l[:type]
				end.map {|l| XPathname.new l[:name] }.sort
			rescue Sh::ProcessError
				kpartx dest.image
			end
		d "two partitions in destination expected", 2 == dest_parts.length
		dest_parts[0].open( 'w') {|f| f << 0.chr*4*1024*1024 }
		dest_parts[1].open( 'w') {|f| f << 0.chr*4*1024*1024 }
		sh.vgscan '--cache'
		vgpath = XPathname.new( '/dev') + vgname
		sh.pvcreate -:ff, dest_parts[1]
		sh.vgcreate vgname, dest_parts[1]
		sh.lvcreate -:nroot, '-L4.2G', vgname
		sh.lvcreate -:nhome, '-L100M', vgname
		sh.vgchange -:ae, vgname
		sh.mkvfat -:nboot, dest_parts[0]
		sh.mkxfs -:Lroot, vgpath+'root'
		sh.mkxfs -:Lhome, vgpath+'home'
		mount vgpath+'root', dest.root
		addmp = {run_udev: dest.root+'run/udev'}
		%i[home boot dev proc sys].each do |n|
			d = addmp[n] = dest.root+n.to_s
			d.mkdir
		end
		mount vgpath+'home', addmp[:home]
		mount dest_parts[0], addmp[:boot]

		mount '/dev',  addmp[:dev],  --:bind
		mount 'proc',  addmp[:proc], -:tproc
		mount 'sysfs', addmp[:sys],  -:tsysfs

		sh.rsync_all "#{base.root}/", dest.root

		install_authorized_keys
		rename_user

		(dest.root+'etc'+'fstab').replace_i do |f|
			replace = {
				'/'     => "UUID=#{sh.fs_uuid vgpath+'root'}  /      xfs   defaults,noatime  0  0",
				'/boot' => "UUID=#{sh.fs_uuid dest_parts[0]}  /boot  vfat  defaults          1  1",
				'/home' => "UUID=#{sh.fs_uuid vgpath+'home'}  /home  xfs   defaults,noatime  1  1",
			}
			f.each_line.flat_map do |l|
				mp = l.split( /\s+/)[1]
				replace.delete( mp) || l
			end + replace.values
		end

		(addmp[:boot]+'config.txt').replace_i do |f|
			replace = {
				'pi4' => { initramfs: 'initramfs initrd7l.img followkernel', },
				'pi3' => { initramfs: 'initramfs initrd7.img followkernel', },
				'pi2' => { initramfs: 'initramfs initrd7.img followkernel', },
				'pi1' => { initramfs: 'initramfs initrd.img followkernel', },
				'pi0' => { initramfs: 'initramfs initrd.img followkernel', },
			}
			blocks = [nil]
			content =	Hash.new {|h,block| h[block] = [] }
			block = nil
			f.each_line do |l|
				l.chomp!
				case l
				when /\A\[([^\]]*)\]\z/
					block = $1
					blocks.push block
				when /\Ainitramfs /
					l = replace[block].delete :initramfs
				end
				content[block].push l
			end
			replace.each {|block, rpl| content[block] += rpl.values + ['']  unless rpl.empty? }
			blocks.flat_map {|block| content[block] }
		end

		(addmp[:boot]+'ssh').write ''

		(addmp[:boot]+'cmdline.txt').replace_i do |f|
			lines = f.readlines
			d "Only one line in cmdline.txt expected", 1 == lines.length
			opts = {}
			lines[0].split( ' ').each do |line|
				/^([^=]*)(?:=(.*))?/ =~ line
				opts[$1.to_sym] = $2
			end
			opts[:root] = vgpath+'root'
			opts[:rootfstype] = :xfs
			opts.delete :init
			opts.map {|k,v| v ? "#{k}=#{v}" : "#{k}" }.join(' ')
		end

		(dest.root+'etc').chdir do
			XPathname.glob( 'rc*.d/*resize2fs_once').each do |fn|
				fn.unlink
			end
		end

		qemu_bin = dest.root.join 'usr/bin/qemu-arm-static'
		qemu_bin.copy '/usr/bin/qemu-arm-static', preserve: true

		preload, preload_x = dest.root+'etc/ld.so.preload', dest.root+'etc/ld.so.preload.tp'
		preload.rename preload_x

		ish = sh.chroot( dest.root).chdir( '/')
		ish.apt :update
		ish.apt :upgrade, -:y
		ish.apt :update

		# We mount /run/udev for lvm-scanning - vgs / vgcfgbackup need it to connect to udev.
		addmp[:run_udev].mkdir
		mount '/run/udev',  addmp[:run_udev],  --:bind

		# prevent installing exim by installing nullmailer
		#ish.apt :install, -:y, :lvm2, :xfsprogs, :nullmailer, :dracut
		#dest.root.join( 'etc/dracut.conf.d/10-denkn.conf').open 'w' do |f|
		#	f.puts 'add_modules+="lvm"'
		#	f.puts 'add_drivers+="dm-mod xfs"'
		#	f.puts 'compress="xz"'
		#end

		ish.apt :install, -:y, :lvm2, :xfsprogs, 'initramfs-tools'
		dest.root.join( 'etc/initramfs-tools/initramfs.conf').replace_i do |f|
			replace = { compress: 'COMPRESS=xz', }
			f.each_line.flat_map do |l|
				case l.chomp!
				when /^COMPRESS=/    then replace.delete :compress
				when /^# *COMPRESS=/ then [l, replace.delete( :compress)]
				else l
				end
			end + replace.values
		end

		set_hostname

		install_packages_from_dir(
			XPathname.new( $0).expand_path.dirname + 'raspbian-files',
			XPathname.new( 'files')
		)

		# generates implicite initramfs
		ish.system *%w[dpkg-reconfigure raspberrypi-kernel]

		preload_x.rename preload
		qemu_bin.unlink
	end
end