class Filebeat < Formula
  desc "File harvester to ship log files to Elasticsearch or Logstash"
  homepage "https://www.elastic.co/products/beats/filebeat"
  # Pinned at 6.2.x because of a licencing issue
  # See: https://github.com/Homebrew/homebrew-core/pull/28995
  url "https://github.com/elastic/beats/archive/v6.2.4.tar.gz"
  sha256 "87d863cf55863329ca80e76c3d813af2960492f4834d4fea919f1d4b49aaf699"
  head "https://github.com/elastic/beats.git"

  bottle do
    cellar :any_skip_relocation
    rebuild 1
    sha256 "3e8ba2861a929174fe1fec21c8c957842ba64f75451984f5619f3d5956cecaf7" => :mojave
    sha256 "16df33929b7bed4480a78d6e7907f9e8eb3b35f90a1da8b8b88217e041da361f" => :high_sierra
    sha256 "c0887cf5e4842173b9bc286657755f19f03f4c025934f632efb6d90d24626a27" => :sierra
  end

  depends_on "go" => :build
  depends_on "python" => :build

  resource "virtualenv" do
    url "https://files.pythonhosted.org/packages/b1/72/2d70c5a1de409ceb3a27ff2ec007ecdd5cc52239e7c74990e32af57affe9/virtualenv-15.2.0.tar.gz"
    sha256 "1d7e241b431e7afce47e77f8843a276f652699d1fa4f93b9d8ce0076fd7b0b54"
  end

  def install
    ENV["GOPATH"] = buildpath
    (buildpath/"src/github.com/elastic/beats").install Dir["{*,.git,.gitignore}"]

    xy = Language::Python.major_minor_version "python3"
    ENV.prepend_create_path "PYTHONPATH", buildpath/"vendor/lib/python#{xy}/site-packages"

    resource("virtualenv").stage do
      system "python3", *Language::Python.setup_install_args(buildpath/"vendor")
    end

    ENV.prepend_path "PATH", buildpath/"vendor/bin"

    cd "src/github.com/elastic/beats/filebeat" do
      system "make"
      # prevent downloading binary wheels during python setup
      system "make", "PIP_INSTALL_COMMANDS=--no-binary :all", "python-env"
      system "make", "DEV_OS=darwin", "update"
      system "make", "modules"

      (etc/"filebeat").install Dir["filebeat.*", "fields.yml", "modules.d"]
      (etc/"filebeat"/"module").install Dir["_meta/module.generated/*"]
      (libexec/"bin").install "filebeat"
      prefix.install "_meta/kibana"
    end

    prefix.install_metafiles buildpath/"src/github.com/elastic/beats"

    (bin/"filebeat").write <<~EOS
      #!/bin/sh
      exec #{libexec}/bin/filebeat \
        --path.config #{etc}/filebeat \
        --path.data #{var}/lib/filebeat \
        --path.home #{prefix} \
        --path.logs #{var}/log/filebeat \
        "$@"
    EOS
  end

  plist_options :manual => "filebeat"

  def plist; <<~EOS
    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN"
    "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
    <plist version="1.0">
      <dict>
        <key>Label</key>
        <string>#{plist_name}</string>
        <key>Program</key>
        <string>#{opt_bin}/filebeat</string>
        <key>RunAtLoad</key>
        <true/>
      </dict>
    </plist>
  EOS
  end

  test do
    log_file = testpath/"test.log"
    touch log_file

    (testpath/"filebeat.yml").write <<~EOS
      filebeat:
        prospectors:
          -
            paths:
              - #{log_file}
            scan_frequency: 0.1s
      output:
        file:
          path: #{testpath}
    EOS

    (testpath/"log").mkpath
    (testpath/"data").mkpath

    filebeat_pid = fork do
      exec "#{bin}/filebeat", "-c", "#{testpath}/filebeat.yml",
           "-path.config", "#{testpath}/filebeat",
           "-path.home=#{testpath}",
           "-path.logs", "#{testpath}/log",
           "-path.data", testpath
    end

    begin
      sleep 1
      log_file.append_lines "foo bar baz"
      sleep 5

      assert_predicate testpath/"filebeat", :exist?
    ensure
      Process.kill("TERM", filebeat_pid)
    end
  end
end