#!/usr/bin/env ruby
#
# Create a chunk morphology to build Omnibus software in Baserock
#
# Copyright (C) 2014  Codethink Limited
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

require_relative 'importer_base'
require_relative 'importer_omnibus_extensions'

BANNER = "Usage: omnibus.to_chunk PROJECT_DIR PROJECT_NAME SOURCE_DIR SOFTWARE_NAME"

DESCRIPTION = <<-END
Generate a .morph file for a given Omnibus software component.
END

class OmnibusChunkMorphologyGenerator < Importer::Base
  def parse_options(arguments)
    opts = create_option_parser(BANNER, DESCRIPTION)

    parsed_arguments = opts.parse!(arguments)

    if parsed_arguments.length != 4 and parsed_arguments.length != 5
      STDERR.puts "Expected 4 or 5 arguments, got #{parsed_arguments}."
      opts.parse(['-?'])
      exit 255
    end

    project_dir, project_name, source_dir, software_name, expected_version = \
      parsed_arguments
    # Not yet implemented
    #if expected_version != nil
    #  expected_version = Gem::Version.new(expected_version)
    #end
    [project_dir, project_name, source_dir, software_name, expected_version]
  end

  class SubprocessError < RuntimeError
  end

  def run_tool_capture_output(tool_name, *args)
    scripts_dir = File.dirname(__FILE__)
    tool_path = File.join(scripts_dir, tool_name)

    # FIXME: something breaks when we try to share this FD, it's not
    # ideal that the subprocess doesn't log anything, though.
    env_changes = {'MORPH_LOG_FD' => nil}

    command = [[tool_path, tool_name], *args]
    log.info("Running #{command.join(' ')} in #{scripts_dir}")

    text = IO.popen(
      env_changes, command, :chdir => scripts_dir, :err => [:child, :out]
    ) do |io|
      io.read
    end

    if $? == 0
      text
    else
      raise SubprocessError, text
    end
  end

  def generate_chunk_morph_for_rubygems_software(software, source_dir)
    # This is a better heuristic for getting the name of the Gem
    # than the software name, it seems ...
    gem_name = software.relative_path

    text = run_tool_capture_output('rubygems.to_chunk', source_dir, gem_name)
    log.debug("Text from output: #{text}, result #{$?}")

    morphology = YAML::load(text)
    return morphology
  rescue SubprocessError => e
    error "Tried to import #{software.name} as a RubyGem, got the " \
          "following error from rubygems.to_chunk: #{e.message}"
    exit 1
  end

  def generate_chunk_morph_for_software(project, software, source_dir)
    if software.builder.built_gemspec != nil
      morphology = generate_chunk_morph_for_rubygems_software(software,
                                                              source_dir)
    else
      morphology = {
        "name" => software.name,
        "kind" => "chunk",
        "description" => "Automatically generated by omnibus.to_chunk"
      }
    end

    # Possibly this tool should look at software.build and
    # generate suitable configure, build and install-commands.
    # For now: don't bother!

    if software.description
      morphology['description'] = software.description + '\n\n' +
        morphology['description']
    end

    morphology
  end

  def run
    project_dir, project_name, source_dir, software_name = parse_options(ARGV)

    log.info("Creating chunk morph for #{software_name} from project " +
             "#{project_name}, defined in #{project_dir}")

    Dir.chdir(project_dir)

    project = Omnibus::Project.load(project_name)

    software = Omnibus::Software.load(@project, software_name)

    morph = generate_chunk_morph_for_software(project, software, source_dir)
    write_morph(STDOUT, morph)
  end
end

OmnibusChunkMorphologyGenerator.new.run