#
# Copyright (c) 2006-2019 Wade Alcorn - wade@bindshell.net
# Browser Exploitation Framework (BeEF) - http://beefproject.com
# See the file 'doc/COPYING' for copying permission
#

module BeEF
  module Core
    class Configuration
      attr_accessor :config

      # antisnatchor: still a singleton, but implemented by hand because we want to have only one instance
      # of the Configuration object while having the possibility to specify a parameter to the constructor.
      # This is  why we don't use anymore the default Ruby implementation -> include Singleton
      def self.instance
        @@instance
      end

      # Loads the default configuration system
      # @param [String] configuration_file Configuration file to be loaded,
      #        by default loads $root_dir/config.yaml
      def initialize(config)
        raise TypeError, "'config' needs to be a string" unless config.string?
        raise TypeError, "Configuration file '#{config}' cannot be found" unless File.exist? config

        begin
          #open base config
          @config = load(config)
          # set default value if key? does not exist
          @config.default = nil
          @@config = config
        rescue => e
          print_error "Fatal Error: cannot load configuration file '#{config}' : #{e.message}"
          print_error e.backtrace
        end

        @@instance = self
      end

      # Loads yaml file
      # @param [String] file YAML file to be loaded
      # @return [Hash] YAML formatted hash
      def load(file)
        return nil unless File.exist? file
        raw = File.read file
        YAML.safe_load raw
      rescue => e
        print_debug "Unable to load configuration file '#{file}' : #{e.message}"
        print_error e.backtrace
      end

      #
      # @note balidate the configuration file
      #
      def validate
        if @config.empty?
          print_error 'Configuration file is empty'
          return
	end

        if @config['beef'].nil?
          print_error "Configuration file is malformed: 'beef' is nil"
          return
        end

        if @config['beef']['credentials'].nil?
          print_error "Configuration file is malformed: 'beef.credentials' is nil"
          return
        end

        if @config['beef']['http'].nil?
          print_error "Configuration file is malformed: 'beef.http' is nil"
          return
        end

        true
      end

      #
      # Returns the value of a selected key in the configuration file.
      # @param [String] key Key of configuration item
      # @return [Hash|String] The resulting value stored against the 'key'
      #
      def get(key)
        subkeys = key.split('.')
        lastkey = subkeys.pop
        subhash = subkeys.inject(@config) do |hash, k|
          hash[k]
        end
        return nil if subhash.nil?
        subhash.key?(lastkey) ? subhash[lastkey] : nil
      end

      #
      # Sets the give key value pair to the config instance
      # @param [String] key The configuration key
      # @param value The value to be stored against the 'key'
      # @return [Boolean] If the store procedure was successful
      #
      def set(key, value)
        subkeys = key.split('.').reverse
        return false if subkeys.empty?

        hash = { subkeys.shift.to_s => value }
        subkeys.each { |v| hash = {v.to_s => hash} }
        @config = @config.deep_merge hash
        true
      end

      #
      # Clears the given key hash
      # @param [String] key Configuration key to be cleared
      # @return [Boolean] If the configuration key was cleared
      #
      def clear(key)
        subkeys = key.split('.')
        return false if subkeys.empty?

        lastkey = subkeys.pop
        hash = @config
        subkeys.each {|v| hash = hash[v] }
        hash.delete(lastkey).nil? ? false : true
      end

      #
      # Load extensions configurations
      #
      def load_extensions_config
        set('beef.extension', {})
        Dir.glob("#{$root_dir}/extensions/*/config.yaml") do |cf|
          y = load(cf)
          if y.nil?
            print_error "Unable to load extension configuration '#{cf}'"
            next
          end

          y['beef']['extension'][y['beef']['extension'].keys.first]['path'] = cf.gsub(/config\.yaml/, '').gsub(%r{#{$root_dir}/}, '')
          @config = y.deep_merge(@config)
        end
      end

      #
      # Load module configurations
      #
      def load_modules_config
        set('beef.module', {})
        # support nested sub-categories, like browser/hooked_domain/ajax_fingerprint
        module_configs = File.join("#{$root_dir}/modules/**", "config.yaml")
        Dir.glob(module_configs) do |cf|
          y = load(cf)
          if y.nil?
            print_error "Unable to load module configuration '#{cf}'"
            next
          end

          y['beef']['module'][y['beef']['module'].keys.first]['path'] = cf.gsub('config.yaml', '').gsub(%r{#{$root_dir}/}, '')
          @config = y.deep_merge @config
          # API call for post module config load
          BeEF::API::Registrar.instance.fire(
            BeEF::API::Configuration,
            'module_configuration_load',
            y['beef']['module'].keys.first
          )
        end
      end
    end
  end
end