#!/usr/bin/env ruby
 
# A Ruby script that generates a bash script which automates the opening
# of terminals in Gnome.
 
def assemble_script 
	script =  $script1 + $listing + $script2 + 
		"echo #{$commands} \n\n#{$commands}" +
		$error_message
	File.open(ARGV[0], 'w') do |f|
		f.puts script
	end
end
 
def display_help_and_exit
	puts <<-EOF
	Gnome Terminals 4 Rails. 
 
	USAGE: terminals4rails file_name command1 command2 ... "title":"exec"
 
	file_name: File name of the generated bash script.
	tilte: Title of the terminal tab.
	exec: bash command. GIGO
 
	Built-in commands:
		bash         The Bash
		vim          Vim editor
		vimNERD      Vim with NERDTree, if pre-installed
		server       Start script/server
		autospec     Start autospect
	EOF
 
	exit
end
 
# Display helf if there are less than 2 arguments.
display_help_and_exit if ARGV.length < 2 
ARGV.each { |arg| display_help_and_exit if arg == "--help" or arg == "-h" }
 
 
# Start the core script 
 
$script1 = <<-EOF
#!/bin/bash
 
# Rails Terminals for Rails and Gnome
# A simple script that opens a Gnome terminal with titled tabs.
 
# Tabs with following bash commands:
EOF
 
$script2 = <<-EOF
 
# USAGE: terminal4rails.sh working_dir
 
dir=$1	# The first argument is the path of the working directory.
err=0	# If err becomes negative, an error message is generated in the end. 
 
if [ -z $dir ] || [ ! -d $dir ]; then
	echo "Please specify a working directory as the argument"
	exit
fi
 
# If the argument is a relative path, then augment it with 
# the current dir.
if [ ${dir:0:1} != '~' ] && [ ${dir:0:1} != '/' ]; then
	dir=`pwd`'/'$dir
fi
 
echo "Working directory: $dir"
 
EOF
 
$error_message =<<-EOF
 
if [ $err -lt 0 ]; then
	echo "WARNING: Some tabs could not be opened."
fi
EOF
 
$commands="gnome-terminal --working-directory=$dir --geometry=112x30 "
 
execs = Array.new 
 
ARGV[1..-1].each do |arg|
	case arg
	when "bash" then exec="bash"; title="Bash"
	when "vim" then exec="vim"; title="Vim"
	when "vimNERD" then exec='vim +NERDTree'; title="Vim"
	when "server" then exec="script/server && bash" 
		title="script/server"
	when "autospec" then exec='autospec'; title="autospec"
	else 
		if arg =~ /.+:.+/ 
			title, exec = arg.split(":")
		else raise "ERROR: Input is not recognised."
		end
	end
 
	first_exec = exec.split(" ")[0]
	if first_exec[0] == '"' or first_exec[0] == "'"
		first_exec = first_exec[1..-1]
	end
	script_title = title.downcase.gsub(/\W/, "_" )
 
	$script2 += <<-EOF
	#{script_title}_t="#{title}"
	command_path=$( type -P #{first_exec} | sed -e 's/^ *//g;s/ *$//g')
	executable_path=$( type -P ${dir}#{first_exec} | \\
		sed -e 's/^ *//g;s/ *$//g')
 
	if [ $command_path > /dev/null ]; then
		echo "#{title} found in $command_path."
		#{script_title}_e="bash -c '#{exec}'"
	elif [ $executable_path > /dev/null ]; then
		echo "#{title} found in $executable_path."
		#{script_title}_e="bash -c '#{exec}'"
	else
		#{script_title}_e="echo"	# Closes the tab w/o action.
		err=$(( $err - 1 ))
		echo "#{first_exec} not found."
	fi
 
	EOF
 
	execs << [exec, script_title] 
end
 
$listing = ""
 
execs.each do |exec, title|
	$commands += "--tab -t $#{title}_t -e \"$#{title}_e\" "
	$listing += "# * #{exec}\n"  
end	
 
# Ask for permission to overwrite an existing file.
if File.exists? ARGV[0] then 
	print "Do you want to overwrite the file #{ARGV[0]} (y/n): "
	answer = $stdin.gets
	if answer.downcase[0] == "y" then 
		puts "Script is assembled."
		assemble_script
	else 
		puts "Script terminates without writing."
		exit
	end
else 
	puts "Script is assembled."
	assemble_script
end