require 'net/scp'

module Evrone
  module CI
    module Worker

      DockerWebdavCache = Struct.new(:app) do

        include Helper::Config
        include Helper::Logger

        CASHER_URL = "https://raw.github.com/travis-ci/casher/master/bin/casher"
        CASHER_BIN = "$HOME/.casher/bin/casher"

        def call(env)
          if env.ssh && config.webdav_cache_url
            assign_url(env) &&
            prepare(env) &&
            fetch(env) &&
            add(env)
          end

          rs = app.call env

          if env.ssh && env.webdav_cache_url
            push(env)
          end

          rs
        end

        private

          def assign_url(env)
            release = nil

            env.ssh.spawn "lsb_release -s -c" do |out|
              release ||= out.gsub(/[^a-z0-9]/, '')
            end
            release = 'unknown' unless release

            name = env.job.message.name.dup
            name << "-#{release}"
            name << "-#{env.job.message.matrix_keys.join("_")}.tgz"
            name = name.gsub(/[^a-z0-9_\-.]/, '')

            env.webdav_cache_url = "#{config.webdav_cache_url.dup}/#{name}"
            true
          end

          def push(env)
            cmd = %{
              #{CASHER_BIN} push #{env.webdav_cache_url}
            }.compact

            logger.debug "push cache to #{env.webdav_cache_url.inspect}"
            env.ssh.spawn cmd, &env.job.method(:add_trace_to_output)
            true
          end

          def add(env)
            cmd = %{
              #{CASHER_BIN} add $HOME/cached
            }.compact
            env.ssh.spawn cmd, &env.job.method(:add_trace_to_output)
            true
          end

          def fetch(env)
            logger.debug "fetch cache from #{env.webdav_cache_url.inspect}"
            cmd = %{
              #{CASHER_BIN} fetch #{env.webdav_cache_url}
            }.compact
            env.ssh.spawn cmd, &env.job.method(:add_trace_to_output)
            true
          end

          def prepare(env)
            cmd = %{
              export CASHER_DIR=$HOME/.casher &&
              mkdir -p $CASHER_DIR/bin &&
              curl #{CASHER_URL} -s -o #{CASHER_BIN} &&
              chmod +x #{CASHER_BIN} &&
              echo casher successfuly downloaded
            }.compact
            code = env.ssh.spawn cmd, &env.job.method(:add_trace_to_output)
            code == 0
          end

      end
    end
  end
end