module Gig

# File lib/gig.rb, line 10
def make_task(name: 'gig', gemspec_filename: , ignore_files: )
  Rake.application.last_description = "check consistency of gemspec files with git and filesystem before building the gem"
  Rake::Task.define_task(name) do
    require 'shellwords'
    require 'set'

    git_files = `git ls-files -z --recurse-submodules`.split("\x0")

    fs_files = Dir.glob('**/*', File::FNM_DOTMATCH).reject { |f| File.lstat(f).ftype == 'directory' }

    spec = Gem::Specification.load(gemspec_filename) || abort("gemspec did not load: #{gemspec_filename}")

    files = Set.new + git_files + fs_files + spec.files + spec.test_files

    file_errors = []
    file_error = -> (msg) {
      file_errors << msg
      puts msg
    }

    files.each do |file|
      in_git = git_files.include?(file)
      in_fs = fs_files.include?(file)
      in_spec = spec.files.include?(file) || spec.test_files.include?(file)
      in_ignore = ignore_files.include?(file)

      if in_git
        if in_fs
          if in_spec
            if in_ignore
              file_error.("file is ignored, but present in gemspec: #{file}")
            end
            git_status = `git status --porcelain #{Shellwords.escape(file)}`
            if git_status.empty?
              # pass
            else
              file_error.("file modified from git: #{file}")
            end
          else
            if in_ignore
              # pass
            else
              file_error.("git file not in gemspec: #{file}")
            end
          end
        else
          file_error.("git file not in fs: #{file}")
        end
      else
        if in_spec
          file_error.("file in gemspec but not in git: #{file}")
        else
          # in fs but ignored by git and spec: pass
        end
      end
    end

    unless file_errors.empty?
      abort "aborting gem build due to file errors"
    end

    require 'rubygems/package'
    Gem::Package.build(spec)
  end
end