#!/usr/bin/ruby
#
# Templating program. Creates template files based on extensionm, with
# keyword expansion.
#
# Templates should be stored in ., ~/.templates, or /usr/share/templates,
# with the format template.ext, where ext is the extention the template is
# used on. For example 'template.cc' would be used for 'myfile.cc'.
#
# Some variables are obtained automatically. For those that have to be set
# specifically, like DESC, use "-s DESC=whatever".
#
# In templates, [%var FILE%] will be replaced with FILE, etc.
#
# See http://kapheine.hypa.net/archive/templates.tar.gz for example templates.

require 'etc'
require 'getoptlong'
require 'PageTemplate'
include Etc

def usage()
  puts "template"
  puts "Copyright (C) 2004 Zachary P. Landau"
  puts ""
  puts "Usage: template [options] <filename>\n"
  puts "\t-s, --set\t\tset a variable\n" +
    "\t-l, --list\t\tdisplay available tags\n" +
    "\t-d, --templatedir\tspecify template directory\n" +
    "\t-t, --template\t\tspecify template to use\n" +
    "\t-f, --flag\t\tset boolean flag to true\n"
end

ext = nil
flags = Hash.new
templatedir = nil
templatedirs = [ ".",
		 "#{ENV['HOME']}/.templates",
		 "/usr/share/templates"
		 ]
		
vars = { 'FILE_EXT' => nil,
	 'FILE' => nil,
	 'FILE_U' => nil,
	 'EMAIL' => nil,
	 'YEAR' => nil,
	 'NAME' => nil,
	 'DATE' => nil,
     }

# define from command line
cmdvars = Hash.new
opts = GetoptLong.new( ['--set', '-s', GetoptLong::REQUIRED_ARGUMENT],
		       ['--list', '-l', GetoptLong::NO_ARGUMENT],
		       ['--templatedir', '-d', GetoptLong::REQUIRED_ARGUMENT],
		       ['--template', '-t', GetoptLong::REQUIRED_ARGUMENT],
		       ['--flag', '-f', GetoptLong::REQUIRED_ARGUMENT]
		       )

opts.each do |opt, arg|
    case opt
	when '--list' || '-l'
	    puts "Available tags:"
	    vars.each_key do |key|
		puts "\t* #{key}"
	    end
	    exit 0
	when '--set' || '-s'
	    key, value = arg.split('=')
	    cmdvars[key] = value
	when '--templatedir' || '-d'
	    templatedir = arg
	when '--template' || '-t'
	    ext = arg
	when '--flag' || '-f'
	    flags[arg] = true
	else
	    raise "Invalid option '#{opt}'"
    end
end

newfile = ARGV.shift
if !newfile
    usage()
    exit 1
end

ext = newfile.split('.').last if !ext
#template = "#{templatedir}/template.#{ext}"
template = nil
found = false
if !templatedir
    templatedirs.each do |dir|
	if File.exists?("#{dir}/template.#{ext}")
	    template = "#{dir}/template.#{ext}"
	    found = true
	    break
	end
    end
    
    if !found 
	puts "Template #{ext} does not exist, exiting"
	exit 1
    end
end


# define the values we know
vars['FILE_EXT'] = newfile
vars['YEAR'] = Time.now.year
vars['NAME'] = getpwnam(getlogin()).gecos
vars['FILE'] = File.basename(newfile, '.'+ext)
vars['FILE_U'] = vars['FILE'].upcase
vars['DATE'] = Time.now.strftime("%m/%d/%Y")

# define from environmental variables
vars.each_key do |key|
    vars[key] = ENV[key] if ENV[key]
end

# update hash with command line variables
vars.update(cmdvars)

vars.default = ''

ptemplate = PageTemplate.new()
ptemplate.load(template)

vars.each do |key, value|
    ptemplate[key] = value if value
end

flags.each do |key, value|
  ptemplate[key] = value if value
end

if File.exists?(newfile)
    print "#{newfile} exists, overwrite? [y/N] "
    answer = gets
    if answer !~ /(y|yes)/i
	exit 1
    end
end

File.open(newfile, 'w') do |file|
    file.write(ptemplate.output)
end