From 6e651a53fac84e86ab1fd788a6618494c348d48c Mon Sep 17 00:00:00 2001
From: Luka Vandervelden <lukc@upyum.com>
Date: Sat, 28 Nov 2020 21:21:01 +0100
Subject: [PATCH] Creates, saves and restores snapshots.

---
 src/main.cr | 79 +++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 61 insertions(+), 18 deletions(-)

diff --git a/src/main.cr b/src/main.cr
index 68f73a0..1d176e5 100644
--- a/src/main.cr
+++ b/src/main.cr
@@ -14,9 +14,7 @@ class Baguette::Configuration
 	end
 end
 
-module Baguette::Base
-	getter configuration : Configuration
-
+module Baguette::Log
 	def info(text)
 		STDOUT << (":: ".colorize :blue) << (text.colorize :white) << "\n"
 	end
@@ -26,10 +24,16 @@ module Baguette::Base
 	end
 
 	def error(text)
-		STDERR << (":: ".colorize :red) << (text.colorize :white) << "\n"
+		STDERR << (":: ".colorize :red) << (text.colorize :red) << "\n"
 	end
 end
 
+module Baguette::Base
+	getter configuration : Configuration
+
+	include Baguette::Log
+end
+
 Colorize.on_tty_only!
 
 # CAUTION
@@ -48,7 +52,15 @@ class RootFS::Context
 
 		commands = {
 			"new" => ->(args : Array(String)){
-			}
+				RootFS.new args[1], args[0]
+			},
+			"save" => ->(args : Array(String)){
+				RootFS.load(args[0]).save(args[1])
+			},
+			"restore" => ->(args : Array(String)){
+				RootFS.load(args[0]).restore(args[1])
+			},
+			# FIXME: This needs access to the list of commands.
 			"help" => ->(args : Array(String)){
 				STDOUT << options_parser << "\n"
 			}
@@ -64,6 +76,11 @@ class RootFS::Context
 				Colorize.enabled = true
 			end
 
+			parser.on "-h", "--help", "Displays this help message." do
+				STDOUT << parser << "\n"
+				exit 0
+			end
+
 			# FIXME: This leads to unusual behaviors when using the CLI.
 			#        Replace by dedicated executables.
 			parser.unknown_args do |args|
@@ -71,7 +88,7 @@ class RootFS::Context
 
 				raise "no command provided" if args.size < 1
 
-				command = args.pop
+				command = args.shift
 				arguments = args
 			end
 		end
@@ -91,6 +108,8 @@ class RootFS::Context
 end
 
 class RootFS::RootFS
+	include Baguette::Log
+
 	getter directory : String
 
 	def initialize(@directory)
@@ -103,13 +122,37 @@ class RootFS::RootFS
 		instance
 	end
 
+	protected def execute(command : String)
+		info "Executing: #{command}"
+		r = Process.new(
+			"sh", ["-c", command],
+			input:  Process::Redirect::Inherit,
+			output: Process::Redirect::Inherit,
+			error:  Process::Redirect::Inherit
+		).wait
+
+		raise "Command returned #{r.exit_status}." unless r.success?
+	end
+
+	# FIXME: Abstract process calls.
+	# FIXME: REmove the sudos.
+
 	protected def create!(template : String)
-		show!
-		puts "UNIMPLEMENTED: creating rootfs here"
+		# FIXME: Alternate backends.
+		# FIXME: template string parsing.
+		is_btrfs = true # FIXME: do the actual detection
+
+		unless is_btrfs
+			raise "can only create rootfs in a btrfs filesystem"
+		end
+
+		execute "btrfs subvolume create '#{@directory}'"
+
+		execute "debootstrap --arch amd64 '#{template}' '#{@directory}'"
 	end
 
 	def self.load(directory)
-		new directory, nil
+		new directory
 	end
 
 	def delete
@@ -117,28 +160,28 @@ class RootFS::RootFS
 		puts "UNIMPLEMENTED: removing rootfs directory here"
 	end
 
-	def save
-		show!
-		puts "UNIMPLEMENTED: updating snapshot here"
+	def save(snapshot_directory)
+		execute "btrfs subvolume snapshot '#{@directory}' '#{snapshot_directory}'"
 	end
 
-	def restore
-		show!
-		puts "UNIMPLEMENTED: restoring from snapshot here"
+	def restore(snapshot_directory)
+		unmount
+		execute "btrfs subvolume delete '#{@directory}'"
+		execute "btrfs subvolume snapshot '#{snapshot_directory}' '#{@directory}'"
 	end
 
-	def mount
+	def mount(directory = nil)
 		show!
 		puts "UNIMPLEMENTED: binding file systems here"
 	end
 
-	def unmount
+	def unmount(directory = nil)
 		show!
 		puts "UNIMPLEMENTED: unbinding file systems here"
 	end
 
 	def show!
-		puts "#{@template}, #{@directory}"
+		puts "#{@directory}"
 	end
 end