class KPM::Migrations

def decode(content, encoding)
  if encoding == 'base64'
    Base64.decode64(content)
  else
    content
  end
end

def for_version(version = @from_version, name_only = false, migrations_to_skip = Set.new)
  @logger.info("Looking for migrations repository=#{@repository}, version=#{version}")
  metadata = get_as_json("https://api.github.com/repos/#{@repository}/git/trees/#{version}?recursive=1")
  migrations = []
  metadata['tree'].each do |entry|
    match_data = KILLBILL_MIGRATION_PATH.match(entry['path']) || JAVA_PLUGIN_MIGRATION_PATH.match(entry['path']) || RUBY_PLUGIN_MIGRATION_PATH.match(entry['path'])
    next unless match_data
    migration_name = match_data[1]
    @logger.debug("Found migration #{migration_name}")
    next if migrations_to_skip.include?(migration_name)
    sql = nil
    unless name_only
      blob_metadata = get_as_json((entry['url']).to_s)
      sql = decode(blob_metadata['content'], blob_metadata['encoding'])
    end
    migrations << {
      name: migration_name,
      sql: sql
    }
  end
  migrations
end

def get_as_json(url)
  uri = URI.parse(url)
  http = Net::HTTP.new(uri.host, uri.port)
  http.use_ssl = uri.scheme == 'https'
  path = uri.path || '/'
  path = "#{path}?#{uri.query}" unless uri.query.nil?
  request = Net::HTTP::Get.new(path)
  request['Authorization'] = "token #{@oauth_token}" unless @oauth_token.nil?
  response = http.request(request)
  case response.code
  when '200'
    JSON.parse(response.body)
  else
    raise "Unable to download #{url}: #{response.code}"
  end
end

def initialize(from_version, to_version = nil, repository = 'killbill/killbill', oauth_token = nil, logger = Logger.new(STDOUT))
  @from_version = from_version
  @to_version = to_version
  @repository = repository
  @oauth_token = oauth_token
  @logger = logger
end

def migrations
  @migrations ||= begin
    if @to_version.nil?
      for_version(@from_version)
    else
      migrations_to_skip = Set.new
      for_version(@from_version, true).each { |migration| migrations_to_skip << migration[:name] }
      for_version(@to_version, false, migrations_to_skip)
    end
  end
end

def save(dir = nil)
  return nil if migrations.empty?
  dir ||= Dir.mktmpdir
  @logger.debug("Storing migrations to #{dir}")
  migrations.each do |migration|
    @logger.info("Migration to run: #{migration[:name]}")
    migration_path = Pathname.new(dir).join(migration[:name])
    File.open(migration_path, 'w') do |file|
      @logger.debug("Storing migration #{migration_path}")
      file.write(migration[:sql])
    end
  end
  dir
end