#-- encoding: UTF-8
#-- copyright
# OpenProject is a project management system.
# Copyright (C) 2012-2015 the OpenProject Foundation (OPF)
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License version 3.
#
# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
# Copyright (C) 2006-2013 Jean-Philippe Lang
# Copyright (C) 2010-2013 the ChiliProject Team
#
# 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; either version 2
# of the License, or (at your option) any later version.
#
# 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.
#
# See doc/COPYRIGHT.rdoc for more details.
#++

require_relative 'configuration/helpers'

module OpenProject
  module Configuration
    extend Helpers

    ENV_PREFIX = 'OPENPROJECT_'

    # Configuration default values
    @defaults = {
      'attachments_storage'     => 'file',
      'attachments_storage_path' => nil,
      'autologin_cookie_name'   => 'autologin',
      'autologin_cookie_path'   => '/',
      'autologin_cookie_secure' => false,
      'database_cipher_key'     => nil,
      'scm_git_command'         => nil,
      'scm_subversion_command'  => nil,
      'disable_browser_cache'   => true,
      # default cache_store is :file_store in production and :memory_store in development
      'rails_cache_store'       => :file_store,
      'cache_expires_in_seconds' => nil,
      'cache_namespace' => nil,
      # use dalli defaults for memcache
      'cache_memcache_server'   => nil,
      # where to store session data
      'session_store'           => :cache_store,
      # url-path prefix
      'rails_relative_url_root' => '',
      'rails_force_ssl' => false,

      # email configuration
      'email_delivery_method' => nil,
      'smtp_address' => nil,
      'smtp_port' => nil,
      'smtp_domain' => nil,  # HELO domain
      'smtp_authentication' => nil,
      'smtp_user_name' => nil,
      'smtp_password' => nil,
      'smtp_enable_starttls_auto' => nil,
      'smtp_openssl_verify_mode' => nil,  # 'none', 'peer', 'client_once' or 'fail_if_no_peer_cert'
      'sendmail_location' => '/usr/sbin/sendmail',
      'sendmail_arguments' => '-i',

      'disable_password_login' => false,
      'omniauth_direct_login_provider' => nil,

      'disable_password_choice' => false
    }

    @config = nil

    class << self
      # Loads the OpenProject configuration file
      # Valid options:
      # * <tt>:file</tt>: the configuration file to load (default: config/configuration.yml)
      # * <tt>:env</tt>: the environment to load the configuration for (default: Rails.env)
      def load(options = {})
        filename = options[:file] || File.join(Rails.root, 'config', 'configuration.yml')
        env = options[:env] || Rails.env

        @config = @defaults.dup

        load_config_from_file(filename, env, @config)

        convert_old_email_settings(@config)

        override_config!(@config)

        if @config['email_delivery_method']
          configure_action_mailer(@config)
        end

        define_config_methods

        @config
      end

      # Replace config values for which an environment variable with the same key in upper case
      # exists
      def override_config!(config, source = ENV)
        config.each do |key, value|
          config[key] = source.fetch(key.upcase, value)
        end

        config.deep_merge! merge_config(config, source)
      end

      def merge_config(config, source, prefix: ENV_PREFIX)
        new_config = config.dup.with_indifferent_access

        source.select { |k, _| k =~ /^#{prefix}/i }.each do |k, value|
          path = self.path prefix, k

          path_config = path_to_hash(*path, value)

          new_config.deep_merge! path_config
        end

        new_config
      end

      def path(prefix, env_var_name)
        path = []
        env_var_name = env_var_name.sub /^#{prefix}/, ''

        env_var_name.gsub(/([a-zA-Z0-9]|(__))+/) do |seg|
          path << unescape_underscores(seg.downcase).to_sym
        end

        path
      end

      # takes the path provided and transforms it into a deeply nested hash
      # where the last parameter becomes the value.
      #
      # e.g. path_to_hash(:a, :b, :c, :d) => { a: { b: { c: :d } } }

      def path_to_hash(*path)
        value = path.pop

        path.reverse.inject(value) do |path_hash, key|
          { key => path_hash }
        end
      end

      def get_value(value)
        value
      end

      def unescape_underscores(path_segment)
        path_segment.gsub '__', '_'
      end

      # Returns a configuration setting
      def [](name)
        load unless @config
        @config[name]
      end

      # Sets configuration setting
      def []=(name, value)
        load unless @config
        @config[name] = value
      end

      # Yields a block with the specified hash configuration settings
      def with(settings)
        settings.stringify_keys!
        load unless @config
        was = settings.keys.inject({}) { |h, v| h[v] = @config[v]; h }
        @config.merge! settings
        yield if block_given?
        @config.merge! was
      end

      def configure_cache(application_config)
        return unless @config['rails_cache_store']

        # rails defaults to :file_store, use :dalli when :memcaches is configured in configuration.yml
        cache_store = @config['rails_cache_store'].to_sym
        if cache_store == :memcache
          cache_config = [:dalli_store]
          cache_config << @config['cache_memcache_server'] \
            if @config['cache_memcache_server']
        elsif cache_store == :file_store
          cache_config = [:file_store, Rails.root.join('tmp/cache')]
        else
          cache_config = [cache_store]
        end
        parameters = cache_parameters(@config)
        cache_config << parameters if parameters.size > 0
        application_config.cache_store = cache_config
      end

      private

      def load_config_from_file(filename, env, config)
        if File.file?(filename)
          file_config = YAML::load(ERB.new(File.read(filename)).result)
          unless file_config.is_a? Hash
            warn "#{filename} is not a valid OpenProject configuration file, ignoring."
          else
            config.merge!(load_env_from_config(file_config, env))
          end
        end
      end

      def load_env_from_config(config, env)
        merged_config = {}

        if config['default']
          merged_config.merge!(config['default'])
        end
        if config[env]
          merged_config.merge!(config[env])
        end
        merged_config
      end

      def configure_action_mailer(config)
        ActionMailer::Base.perform_deliveries = true
        ActionMailer::Base.delivery_method = config['email_delivery_method'].to_sym

        ['smtp_', 'sendmail_'].each do |config_type|
          mail_delivery_config = filter_hash_by_key_prefix(config, config_type)

          unless mail_delivery_config.empty?
            mail_delivery_config.symbolize_keys! if mail_delivery_config.respond_to?(:symbolize_keys!)
            ActionMailer::Base.send("#{config_type + 'settings'}=", mail_delivery_config)
          end
        end
      end

      # Convert old mail settings
      #
      # SMTP Example:
      # mail_delivery.smtp_settings.<key> is converted to smtp_<key>
      # options:
      # disable_deprecation_message - used by testing
      def convert_old_email_settings(config, options = {})
        if config['email_delivery']
          unless options[:disable_deprecation_message]
            ActiveSupport::Deprecation.warn 'Deprecated mail delivery settings used. Please ' +
              'update them in config/configuration.yml or use ' +
              'environment variables. See doc/CONFIGURATION.md for ' +
              'more information.'
          end

          config['email_delivery_method'] = config['email_delivery']['delivery_method'] || :smtp

          ['sendmail', 'smtp'].each do |settings_type|
            settings_key = "#{settings_type}_settings"
            if config['email_delivery'][settings_key]
              config['email_delivery'][settings_key].each do |key, value|
                config["#{settings_type}_#{key}"] = value
              end
            end
          end
          config.delete('email_delivery')
        end
      end

      def cache_parameters(config)
        mapping = {
          'cache_expires_in_seconds' => [:expires_in, :to_i],
          'cache_namespace' => [:namespace, :to_s]
        }
        parameters = {}
        mapping.each_pair do |from, to|
          if config[from]
            to_key, method = to
            parameters[to_key] = config[from].method(method).call
          end
        end
        parameters
      end

      # Filters a hash with String keys by a key prefix and removes the prefix from the keys
      def filter_hash_by_key_prefix(hash, prefix)
        filtered_hash = {}
        hash.each do |key, value|
          if key.start_with? prefix
            filtered_hash[key[prefix.length..-1]] = value
          end
        end
        filtered_hash
      end

      def define_config_methods
        @config.keys.each do |setting|
          (class << self; self; end).class_eval do
            define_method setting do
              self[setting]
            end
          end unless respond_to? setting
        end
      end
    end
  end
end