module OhlohScm::Adapters
	class GitAdapter < AbstractAdapter

		#---------------------------------------------------------------------------
		# COMMIT-RELATED CODE
		#-------------------------------------------------------------------------

		# Commit all changes in the working directory, using metadata from the passed commit.
		def commit_all(commit=Commit.new)
			init_db
			ensure_gitignore
			write_token(commit.token)

			# Establish the author, email, message, etc. for the git-commit.
			message_filename = set_commit_metadata(commit)

			run "cd '#{self.url}' && git add ."
			if anything_to_commit?
				run "cd '#{self.url}' && git commit -a -F #{message_filename}"
			else
				logger.info { "nothing to commit" }
			end
		end

		# Store all of the commit metadata in the GIT environment variables
		# where they will be picked up by the git-commit command.
		#
		# Commit info is required.
		# Author info is optional, and defaults to committer info.
		def set_commit_metadata(commit)

			ENV['GIT_COMMITTER_NAME'] = commit.committer_name || '[anonymous]'
			ENV['GIT_AUTHOR_NAME'] = commit.author_name || ENV['GIT_COMMITTER_NAME']

			ENV['GIT_COMMITTER_EMAIL'] = commit.committer_email || ENV['GIT_COMMITTER_NAME']
			ENV['GIT_AUTHOR_EMAIL'] = commit.author_email || ENV['GIT_AUTHOR_NAME']

			ENV['GIT_COMMITTER_DATE'] = commit.committer_date.to_s
			ENV['GIT_AUTHOR_DATE'] = (commit.author_date || commit.committer_date).to_s

			# This is a one-off fix for DrJava, which includes some escape characters
			# in one of its Subversion messages. This might lead to a more generalized
			# cleanup of message text, but for now...
			commit.message.gsub!(/\\027/,'') if commit.message

			# Git requires a non-empty message
			if commit.message.nil? || commit.message =~ /\A\s*\z/
				commit.message = '[no message]'
			end

			# We need to store the message in a file in case it contains crazy characters
			#    that would corrupt a bash command line.
			File.open(message_filename, 'w') do |f|
				f.write commit.message
			end
			message_filename
		end

		# By hiding the message file inside the .git directory, we
		#    avoid it being found by the commit-all.
		def message_filename
			File.expand_path(File.join(git_path, 'ohloh_message'))
		end

		# True if there are pending changes to commit.
		def anything_to_commit?
			run("cd '#{self.url}' && git status | tail -1") =~ /nothing to commit/ ? false : true
		end

		# Ensures that the repository directory exists, and that the git database has been initialized.
		def init_db
			unless FileTest.exist? url
				run "mkdir -p '#{url}'"
			end
			unless FileTest.exist? git_path
				run "cd '#{url}' && git init-db"
			end
		end


		#-------------------------------------------------------------------------
		# GIT IGNORE CODE
		# Ensures that we do not waste storage space on non-source code files
		#-------------------------------------------------------------------------

		unless defined?(IGNORE)
			IGNORE = [
				".svn",
				"CVS",
				"*.jar",
				"*.tar",
				"*.gz",
				"*.tgz",
				"*.zip",
				"*.gif",
				"*.jpg",
				"*.jpeg",
				"*.bmp",
				"*.png",
				"*.tif",
				"*.tiff",
				"*.ogg",
				"*.aiff",
				"*.wav",
				"*.mp3",
				"*.au",
				"*.ra",
				"*.m4a",
				"*.pdf",
				"*.mpg",
				"*.mov",
				"*.qt",
				"*.avi",
				"*.xbm"
			]
		end

		# The .gitignore file will be created if it does not exist.
		# If our desired filespec is not found in .gitignore, it will be appended
		# to the end of .gitignore.
		def ensure_gitignore
			IGNORE.each do |ignore|
				gitignore_filename = File.join(self.url, '.gitignore')
				found = false
				File.open(gitignore_filename, File::CREAT | File::RDONLY) do |io|
					io.readlines.each do |l|
						if l.chomp == ignore
							found = true
							break
						end
					end
				end
				unless found
					File.open(gitignore_filename, File::APPEND | File::WRONLY) do |io|
						io.puts ignore
					end
				end
			end
		end
	end
end