#!/usr/bin/env ruby

require "optparse"

ROOT = File.expand_path("../../", __FILE__)


# Break a repository URL into its separate components
def parse_url(input)
	hosts = "github\.com|bitbucket\.org|gitlab\.com"
	
	# HTTPS/HTTP link pointing to recognised hosts
	if input =~ /^(?:https?:\/\/)?(?:[^.@]+@)?(?:www\.)?(#{hosts})\/([^\/]+)\/([^\/]+)/i
		{ host: $1.downcase(), user: $2, repo: $3.sub(/\.git$/, "") }
	# SSH
	elsif input =~ /^git@(#{hosts}):([^\/]+)\/([^\/]+)\.git$/i
		{ host: $1.downcase(), user: $2, repo: $3 }
	# provider:user/repo
	elsif input =~ /^(github|bitbucket|gitlab):\/?([^\/]+)\/([^\/]+)\/?$/i
		{ host: $1.downcase(), user: $2, repo: $3 }
	# user/repo - Common GitHub shorthand
	elsif input =~ /^\/?([^\/]+)\/([^\/]+)\/?$/
		{ host: "github.com", user: $1, repo: $2 }
	else
		raise "Unsupported URL: #{input}"
	end
end

# Isolate the vendor-name component of a submodule path
def parse_submodule(name)
	name =~ /^(?:.*(?:vendor\/)?grammars\/)?([^\/]+)/i
	path = "vendor/grammars/#{$1}"
	unless File.exist?("#{ROOT}/" + path)
		warn "Submodule '#{path}' does not exist. Aborting."
		exit 1
	end
	path
end

usage = """Usage:
  #{$0} [--replace grammar] url
Examples:
  #{$0} https://github.com/Alhadis/language-roff
  #{$0} --replace sublime-apl https://github.com/Alhadis/language-apl
"""


$replace = nil
$verbose = false

OptionParser.new do |opts|
	opts.banner = usage
	opts.on("-v", "--verbose", "Print verbose feedback to STDOUT") do
		$verbose = true
	end
	opts.on("-rSUBMODULE", "--replace=SUBMODDULE", "Replace an existing grammar submodule.") do |name|
		$replace = name
	end
end.parse!


$url = ARGV[0]

# No URL? Print a usage message and bail.
unless $url
	warn usage
	exit 1;
end


# Ensure the given URL is an HTTPS link
parts = parse_url $url
https = "https://#{parts[:host]}/#{parts[:user]}/#{parts[:repo]}"
path  = "vendor/grammars/#{parts[:repo]}"
repl  = parse_submodule($replace) if $replace

if $verbose
	puts "Adding grammar"
	puts "\tFrom:      #{https}"
	puts "\tInto:      #{path}"
	puts "\tReplacing: #{repl}" if repl
	puts "\nRegistering submodule..."
end

#`git submodule add #{https} #{path}`