module Oxidized
	class GitCrypt < Output
		class GitCryptError < OxidizedError; end
		begin
			require 'git'
		rescue LoadError
			raise OxidizedError, 'git not found: sudo gem install ruby-git'
		end

		attr_reader :commitref

		def initialize
			@cfg = Oxidized.config.output.gitcrypt
			@gitcrypt_cmd = "/usr/bin/git-crypt"
			@gitcrypt_init = @gitcrypt_cmd + " init"
			@gitcrypt_unlock = @gitcrypt_cmd + " unlock"
			@gitcrypt_lock = @gitcrypt_cmd + " lock"
			@gitcrypt_adduser = @gitcrypt_cmd + " add-gpg-user --trusted "
		end

		def setup
			if @cfg.empty?
				Oxidized.asetus.user.output.gitcrypt.user  = 'Oxidized'
				Oxidized.asetus.user.output.gitcrypt.email = 'o@example.com'
				Oxidized.asetus.user.output.gitcrypt.repo  =  File.join(Config::Root, 'oxidized.git')
				Oxidized.asetus.save :user
				raise NoConfig, 'no output git config, edit ~/.config/oxidized/config'
			end

			if @cfg.repo.respond_to?(:each)
				@cfg.repo.each do |group, repo|
					@cfg.repo["#{group}="] = File.expand_path repo
				end
			else
				@cfg.repo = File.expand_path @cfg.repo
			end
		end

		def crypt_init repo
			repo.chdir do
				system(@gitcrypt_init)
				@cfg.users.each do |user|
					system("#{@gitcrypt_adduser} #{user}")
				end
				File.write(".gitattributes", "* filter=git-crypt diff=git-crypt\n.gitattributes !filter !diff")
				repo.add(".gitattributes")
				repo.commit("Initial commit: crypt all config files")
			end
		end

		def lock repo
			repo.chdir do
				system(@gitcrypt_lock)
			end
		end

		def unlock repo
			repo.chdir do
				system(@gitcrypt_unlock)
			end
		end

		def store file, outputs, opt={}
			@msg   = opt[:msg]
			@user  = (opt[:user]  or @cfg.user)
			@email = (opt[:email] or @cfg.email)
			@opt   = opt
			@commitref = nil
			repo   = @cfg.repo

			outputs.types.each do |type|
				type_cfg = ''
				type_repo = File.join(File.dirname(repo), type + '.git')
				outputs.type(type).each do |output|
					(type_cfg << output; next) if not output.name
					type_file = file + '--' + output.name
					if @cfg.type_as_directory?
						type_file = type + '/' + type_file
						type_repo = repo
					end
					update type_repo, type_file, output
				end
				update type_repo, file, type_cfg
			end

			update repo, file, outputs.to_cfg
		end


		def fetch node, group
			begin
				repo, path = yield_repo_and_path(node, group)
				repo = Git.open repo
				unlock repo
				index = repo.index
				# Empty repo ?
				empty = File.exists? index.path
				if empty
					raise 'Empty git repo'
				else
					File.read path
				end
				lock repo
			rescue
				'node not found'
			end
		end

		# give a hash of all oid revision for the given node, and the date of the commit
		def version node, group
			begin
				repo, path = yield_repo_and_path(node, group)

				repo = Git.open repo
				unlock repo
				walker = repo.log.path(path)
				i = -1
				tab  = []
				walker.each do |commit|
					hash = {}
					hash[:date] = commit.date.to_s
					hash[:oid] = commit.objectish
					hash[:author] = commit.author
					hash[:message] = commit.message
					tab[i += 1] = hash
				end
				walker.reset
				tab
			rescue
				'node not found'
			end
		end

		#give the blob of a specific revision
		def get_version node, group, oid
			begin
				repo, path = yield_repo_and_path(node, group)
				repo = Git.open repo
				unlock repo
				repo.gtree(oid).files[path].contents
			rescue
				'version not found'
			ensure
				lock repo
			end
		end

		#give a hash with the patch of a diff between 2 revision and the stats (added and deleted lines)
		def get_diff node, group, oid1, oid2
			begin
				diff_commits = nil
				repo, path = yield_repo_and_path(node, group)
				repo = Git.open repo
				unlock repo
				commit = repo.gcommit(oid1)

				if oid2
					commit_old = repo.gcommit(oid2)
					diff = repo.diff(commit_old, commit)
					stats = [diff.stats[:files][node.name][:insertions], diff.stats[:files][node.name][:deletions]]
					diff.each do |patch|
						if /#{node.name}\s+/.match(patch.patch.to_s.lines.first)
							diff_commits = {:patch => patch.patch.to_s, :stat => stats}
							break
						end
					end
				else
					stat = commit.parents[0].diff(commit).stats
					stat = [stat[:files][node.name][:insertions],stat[:files][node.name][:deletions]]
					patch = commit.parents[0].diff(commit).patch
					diff_commits = {:patch => patch, :stat => stat}
				end
				lock repo
				diff_commits
			rescue
				'no diffs'
			ensure
				lock repo
			end
		end

		private

		def yield_repo_and_path(node, group)
			repo, path = node.repo, node.name

			if group and @cfg.single_repo?
				path = "#{group}/#{node.name}"
			end

			[repo, path]
		end

		def update repo, file, data
			return if data.empty?

			if @opt[:group]
				if @cfg.single_repo?
					file = File.join @opt[:group], file
				else
					repo = if repo.is_a?(::String)
						File.join File.dirname(repo), @opt[:group] + '.git'
					else
						repo[@opt[:group]]
					end
				end
			end

			begin
				update_repo repo, file, data, @msg, @user, @email
			rescue Git::GitExecuteError, ArgumentError => open_error
				Oxidized.logger.debug "open_error #{open_error} #{file}"
				begin
					grepo = Git.init repo
					crypt_init grepo
				rescue => create_error
					raise GitCryptError, "first '#{open_error.message}' was raised while opening git repo, then '#{create_error.message}' was while trying to create git repo"
				end
				retry
			end
		end

		def update_repo repo, file, data, msg, user, email
			grepo = Git.open repo
			grepo.config('user.name', user)
			grepo.config('user.email', email)
			grepo.chdir do
				unlock grepo
				File.write(file, data)
				grepo.add(file)
				if grepo.status[file].nil?
					grepo.commit(msg)
					@commitref = grepo.log(1).first.objectish
					true
				elsif !grepo.status[file].type.nil?
					grepo.commit(msg)
					@commitref = grepo.log(1).first.objectish
					true
				end
				lock grepo
			end
		end
	end
end