require "json"
require "skylight/util/logging"

module Skylight
  module Util
    module Deploy
      def self.build(config)
        DEPLOY_TYPES.each do |type|
          deploy = type.new(config)
          return deploy if deploy.id
        end
        nil
      end

      class EmptyDeploy
        attr_reader :config, :timestamp

        def initialize(config)
          @config = config
          @timestamp = Time.now.to_i
        end

        def id
          git_sha
        end

        def git_sha
          nil
        end

        def description
          nil
        end

        def to_query_hash
          hash = {
            timestamp: timestamp,
            deploy_id: id.to_s[0..100] # Keep this sane
          }
          hash[:git_sha] = git_sha.to_s[0..40] if git_sha # A valid SHA will never exceed 40
          hash[:description] = description[0..255] if description # Avoid massive descriptions
          hash
        end
      end

      class DefaultDeploy < EmptyDeploy
        include Util::Logging

        def initialize(*)
          super
          warn "The configured deploy will be ignored as an id or git_sha must be provided." if description && !id
        end

        def id
          config.get(:'deploy.id') || git_sha
        end

        def git_sha
          config.get(:'deploy.git_sha')
        end

        def description
          config.get(:'deploy.description')
        end
      end

      class HerokuDeploy < EmptyDeploy
        def initialize(*)
          super
          @info = get_info
        end

        def id
          @info ? @info["id"] : nil
        end

        def git_sha
          @info ? @info["commit"] : nil
        end

        def description
          @info ? @info["description"] : nil
        end

        private

        def get_info
          info_path = config[:'heroku.dyno_info_path']

          if File.exist?(info_path) && (info = JSON.parse(File.read(info_path)))
            info["release"]
          end
        end
      end

      class GitDeploy < EmptyDeploy
        attr_reader :git_sha, :description

        def initialize(*)
          super
          @git_sha, @description = get_info
        end

        private

        def get_info
          Dir.chdir(config.root) do
            info = `git log -1 --pretty="%H %s" 2>&1`
            info.split(" ", 2).map(&:strip) if $CHILD_STATUS.success?
          end
        end
      end

      DEPLOY_TYPES = [DefaultDeploy, HerokuDeploy, GitDeploy].freeze
    end
  end
end