#!/usr/bin/env ruby
require 'gems'
require 'bundler/setup'
require 'json'
require 'rubygems'

# Find the current version of a gem you are using, then find the latest version of the
# gem and put in a reminder that theres been updates.
#
# gemnasium used to do this but then they got bought and that service is gone, I think
# it was bundled into github
#

# Scab returns a hash of the latest major versions of the gems in the hash
# which looks like { "gemname" : [array of gemspecs]}
def scab(gemhash)
    # This needs a sorted array -- you get it from Gems.versions anyway
    # so no need to do any sorts here directly, waste of time.

    # Should probably be able to do filters too, but eh that's not important
    results = {}
    gemhash.keys.each {|a|
        all_rails = Gems.versions(a).map{|r| r['number'] }
        release_versions = all_rails.select{|v| v =~ /^\d+.\d+(.\d+)*$/ }
        latest_versions = release_versions.inject([]) { |acc, i|
            if (acc.empty? || i[0] != acc.last[0])
                acc << i
            else
                acc
            end
        }
        results[a] = { vs: latest_versions, cv: gemhash[a].first.version}
    }
    results
end


if (ARGV.count > 0)
    # If list of gems on command line, discover versions of them, ignoring ones
    # that are not installed locally.
    # Yes, you could collapse all this into one line but let's be able to read it, ok?
    installed_gems = Gem::Specification.group_by{|g| g.name}
    arg_gems = ARGV.select{|g| installed_gems.keys.include?(g)}
    filtered_gems = installed_gems.select{|g| arg_gems.include?(g)}
    STDOUT.puts scab(filtered_gems).to_json
else
    # If no list of gems on command line, ask Bundler what's in use
    # according to the local Gemfile.lock
    STDOUT.puts scab(Bundler.load.specs.to_hash).to_json
end