#!/usr/bin/env ruby

require 'pathname'
require 'tmpdir'
require 'git'
require 'github_api'
require 'json'
require 'yaml'

YAML_FRONT_MATTER_REGEXP = /\A(---\s*\n.*?\n?)^((---|\.\.\.)\s*$\n?)/m

def fileitems(pattern = 'docs/**/README.md')
  Pathname.glob(pattern).select do |item|
    item if item.read =~ YAML_FRONT_MATTER_REGEXP
  end
end

def mktmpdir(prefix, &block)
  pwd = Dir.pwd
  Dir.mktmpdir(prefix) { |dir| Dir.chdir(dir, &block) }
ensure
  Dir.chdir(pwd)
end

def jsonify(keys, args)
  JSON.pretty_generate(Hash[keys.zip(args)])
end

def meta(data)
  front_matter = data.scan(YAML_FRONT_MATTER_REGEXP).flatten.join
  YAML.safe_load(front_matter)
end

def last_commit(git_dir)
  base = Git::Base.open(git_dir)
  last_commit = Git::Lib.new(base).full_log_commits.first
  klass = Struct.new(*last_commit.keys.map(&:to_sym))
  klass.new(*last_commit.values)
end

def remote_vars(git_dir)
  git = Git.open(git_dir)
  r = git.remote
  [r.name, r.url]
end


if __FILE__ == $PROGRAM_NAME
  metas = []

  commit =  last_commit('.')
  items = fileitems.map(&:dirname).map(&:basename)

  fileitems.each do |file|
    m = meta(file.read)
    m['last_commit'] = commit.sha
    m['tree'] = commit.tree
    m['remote'] = remote_vars('.')
    metas << m
  end

  puts jsonify(items, metas)
end