#!/usr/bin/env ruby

require 'pathname'
$: << Pathname.new($0).expand_path.dirname+'lib'
require 'base'
require 'active_support/all'

Sector = Sectors = 512

class Armbian2LVM_XFS < Base
	def initialize vgname = nil
		super
		chs = [?a..?z, ?A..?Z].map(&:to_a).flatten
		@vgname = vgname || "armbian_#{5.times.map{chs[rand(chs.length)]}.join}"
	end

	def remove_all_partitions_from image
		o = `parted -ms #{image.to_s.shellescape} print`
		d "Cannot determine partitions in dest-image #{image}", 0 == $?
		o.split( "\n")[2..-1].each do
			sh.parted image, :rm, 1
		end
	end

	def run
		mkmppaths

		d "Base image does not exist", base.image.exist?
		base_parts = kpartx base.image
		d "two (root-)partition in base expected, got: #{base_parts.inspect}", 1 == base_parts.length

		mount -:oro, base_parts[0], base.root

		# creates an image
		dest.image.open 'w' do |f|
			#f.pos = 1*Sector
			## copy first 4mb from base-image because of u-boot
			#f.write base.image.read( 4.megabytes-Sector, Sector)
			f.pos = 1.6.gigabytes-1
			f.putc 0.chr
		end
		# partitions for: /boot (128MiBi), LVM
		sh.parted dest.image, *%w[--
			mklabel msdos
			mkpart primary ext2    4MB 132MB
			mkpart primary ext2  132MB   -1s
			set 2 LVM on
			print]
		
		sh.bash -:ec, <<-EOF.gsub( /^\t{3}/, '').sub( /\n$/m, '')
			BRANCH=dev
			source ./build/config/sources/odroidxu4.conf
			write_uboot_platform base/root/usr/lib/linux-u-boot-dev-odroidxu4_5.34.171103_armhf dest/base
		EOF

		dest_parts = kpartx dest.image
		d "two partitions in destination expected", 2 == dest_parts.length
		vgpath = Pathname.new( '/dev') + vgname
		sh.pvcreate dest_parts[1]
		sh.vgcreate vgname, dest_parts[1]
		sh.lvcreate -:nroot, '-L1.1G', vgname
		sh.lvcreate -:nhome, '-L100M', vgname
		sh.vgchange -:ae, vgname
		sh.mkext4fs dest_parts[0]
		sh.mkxfs vgpath+'root'
		sh.mkxfs vgpath+'home'

		mount vgpath+'root', dest.root
		addmp = {}
		%i[home boot].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]

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

		(addmp[:boot]+'boot').make_symlink '.' # boot -> .
		(addmp[:boot]+'boot.ini').open 'r+' do |f|
			replace = {
				rootdev: "setenv rootdev \"#{vgpath+'root'}\"",
				rootfstype: "setenv rootfstype \"xfs\"",
			}
			lines =
				f.each_line.map do |l|
					l.chomp!
					case l
					when /^setenv rootdev /
						replace.delete :rootdev
					when /^setenv rootfstype /
						replace.delete :rootfstype
					else
						l.gsub ' /boot/', ' /'
					end
				end
			f.truncate 0
			f.pos = 0
			f.puts *lines
			d "boot.ini had no entry for: #{replace.keys}", replace.empty?
		end

		(dest.root+'etc'+'fstab').open 'r+' do |f|
			replace = {
				'/' => "#{vgpath+'root'} / xfs defaults,noatime 0 0",
				'/boot' => "#{dest_parts[0]} /boot ext4 defaults,noatime 0 0",
				'/home' => "#{vgpath+'home'} /home xfs defaults,noatime 0 0",
			}
			lines =
				f.each_line.flat_map do |l|
					mp = l.split( /\s+/)[1]
					replace.delete( mp) || l
				end
			lines += replace.values
			f.truncate 0
			f.pos = 0
			f.puts lines
		end

		(dest.root+'etc'+'initramfs-tools'+'initramfs.conf').open 'r+' do |f|
			lines = 
				f.each_line.flat_map do |l|
					l.chomp!
					case l
					when /^COMPRESS=/
						'COMPRESS=xz'
					when /^# *COMPRESS=/
						[l, 'COMPRESS=xz']
					else
						l
					end
				end
			f.truncate 0
			f.pos = 0
			f.puts lines
		end

		sh.tar -:C, dest.root, -:xf, 'files.tar'  if File.exists? 'files.tar'

	rescue ProgrammError
		err $!
		raise
	ensure
		STDERR.puts "="*80
		umount_all ignore_exceptions: true
		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 "="*80
	end
end

Armbian2LVM_XFS.new(*ARGV).run