require 'fileutils'

module Inspec
  #
  # Inspec::Cache manages an on-disk cache of inspec profiles.  The
  # cache can contain:
  #
  #  - .tar.gz profile archives
  #  - .zip profile archives
  #  - unpacked profiles
  #
  # Cache entries names include a hash of their source to prevent
  # conflicts between depenedencies with the same name from different
  # sources.
  #
  #
  class Cache
    attr_reader :path
    def initialize(path = nil)
      @path = path || File.join(Inspec.config_dir, 'cache')
      FileUtils.mkdir_p(@path) unless File.directory?(@path)
    end

    def prefered_entry_for(key)
      path = base_path_for(key)
      if File.directory?(path)
        path
      else
        archive_entry_for(key)
      end
    end

    def archive_entry_for(key)
      path = base_path_for(key)
      if File.exist?("#{path}.tar.gz")
        "#{path}.tar.gz"
      elsif File.exist?("#{path}.zip")
        "#{path}.zip"
      end
    end

    #
    # For a given name and source_url, return true if the
    # profile exists in the Cache.
    #
    # @param [String] name
    # @param [String] source_url
    # @return [Boolean]
    #
    def exists?(key)
      return false if key.nil? || key.empty?
      path = base_path_for(key)
      File.directory?(path) || File.exist?("#{path}.tar.gz") || File.exist?("#{path}.zip")
    end

    #
    # Return the path to given profile in the cache.
    #
    # The `source_url` parameter should be a URI-like string that
    # fully specifies the source of the exact version we want to pull
    # down.
    #
    # @param [String] name
    # @param [String] source_url
    # @return [String]
    #
    def base_path_for(cache_key)
      File.join(@path, cache_key)
    end
  end
end
