#-- encoding: UTF-8
#-- copyright
# OpenProject is a project management system.
# Copyright (C) 2012-2018 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) 2006-2017 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 docs/COPYRIGHT.rdoc for more details.
#++

class Setting < ActiveRecord::Base
  DATE_FORMATS = [
    '%Y-%m-%d',
    '%d/%m/%Y',
    '%d.%m.%Y',
    '%d-%m-%Y',
    '%m/%d/%Y',
    '%d %b %Y',
    '%d %B %Y',
    '%b %d, %Y',
    '%B %d, %Y'
  ]

  TIME_FORMATS = [
    '%H:%M',
    '%I:%M %p'
  ]

  ENCODINGS = %w(US-ASCII
                 windows-1250
                 windows-1251
                 windows-1252
                 windows-1253
                 windows-1254
                 windows-1255
                 windows-1256
                 windows-1257
                 windows-1258
                 windows-31j
                 ISO-2022-JP
                 ISO-2022-KR
                 ISO-8859-1
                 ISO-8859-2
                 ISO-8859-3
                 ISO-8859-4
                 ISO-8859-5
                 ISO-8859-6
                 ISO-8859-7
                 ISO-8859-8
                 ISO-8859-9
                 ISO-8859-13
                 ISO-8859-15
                 KOI8-R
                 UTF-8
                 UTF-16
                 UTF-16BE
                 UTF-16LE
                 EUC-JP
                 Shift_JIS
                 CP932
                 GB18030
                 GBK
                 ISCII91
                 EUC-KR
                 Big5
                 Big5-HKSCS
                 TIS-620)

  cattr_accessor :available_settings

  def self.create_setting(name, value = nil)
    @@available_settings[name] = value
  end

  def self.create_setting_accessors(name)
    # Defines getter and setter for each setting
    # Then setting values can be read using: Setting.some_setting_name
    # or set using Setting.some_setting_name = "some value"
    src = <<-END_SRC
      def self.#{name}
        # when running too early, there is no settings table. do nothing
        self[:#{name}] if settings_table_exists_yet?
      end

      def self.#{name}?
        # when running too early, there is no settings table. do nothing
        self[:#{name}].to_i > 0 if settings_table_exists_yet?
      end

      def self.#{name}=(value)
        if settings_table_exists_yet?
          self[:#{name}] = value
        else
          logger.warn "Trying to save a setting named '#{name}' while there is no 'setting' table yet. This setting will not be saved!"
          nil # when runnung too early, there is no settings table. do nothing
        end
      end
    END_SRC
    class_eval src, __FILE__, __LINE__
  end

  @@available_settings = YAML::load(File.open(Rails.root.join('config/settings.yml')))

  # Defines getter and setter for each setting
  # Then setting values can be read using: Setting.some_setting_name
  # or set using Setting.some_setting_name = "some value"
  @@available_settings.each do |name, _params|
    create_setting_accessors(name)
  end

  validates_uniqueness_of :name
  validates_inclusion_of :name, in: lambda { |_setting| @@available_settings.keys } # lambda, because @available_settings changes at runtime
  validates_numericality_of :value, only_integer: true, if: Proc.new { |setting| @@available_settings[setting.name]['format'] == 'int' }

  def value
    self.class.deserialize(name, read_attribute(:value))
  end

  def value=(v)
    if v && @@available_settings[name] && @@available_settings[name]['serialized']
      v = v.to_yaml
    end

    write_attribute(:value, v.to_s)
  end

  # Returns the value of the setting named name
  def self.[](name)
    cached_or_default(name)
  end

  def self.[]=(name, v)
    old_setting = cached_or_default(name)
    new_setting = find_or_initialize_by(name: name)
    new_setting.value = v

    # Keep the current cache key,
    # since updated_on will change after .save
    old_cache_key = cache_key

    if new_setting.save
      new_value = new_setting.value

      # Delete the cache
      clear_cache(old_cache_key)

      # fire callbacks for name and pass as much information as possible
      fire_callbacks(name, new_value, old_setting)

      new_value
    else
      old_setting
    end
  end

  # Check whether a setting was defined
  def self.exists?(name)
    @@available_settings.has_key?(name)
  end

  [:emails_header, :emails_footer].each do |mail|
    src = <<-END_SRC
    def self.localized_#{mail}
      I18n.fallbacks[I18n.locale].each do |lang|
        text = self[:#{mail}][lang.to_s]
        return text unless text.blank?
      end
      ''
    end
    END_SRC
    class_eval src, __FILE__, __LINE__
  end

  # Helper that returns an array based on per_page_options setting
  def self.per_page_options_array
    per_page_options.split(%r{[\s,]}).map(&:to_i).select { |n| n > 0 }.sort
  end

  def self.clear_cache(key = cache_key)
    Rails.cache.delete(key)
    RequestStore.delete :cached_settings
    RequestStore.delete :settings_updated_on
  end

  private

  # Returns the Setting instance for the setting named name
  # (record found in cache or default value)
  def self.cached_or_default(name)
    name = name.to_s
    raise "There's no setting named #{name}" unless exists? name

    value = cached_settings.fetch(name) { @@available_settings[name]['default'] }
    deserialize(name, value)
  end

  # Returns the settings from two levels of cache
  # 1. The current rack request using RequestStore
  # 2. Rails.cache serialized settings hash
  #
  # Unless one cache hits, it plucks from the database
  # Returns a hash of setting => (possibly serialized) value
  def self.cached_settings
    RequestStore.fetch(:cached_settings) {
      Rails.cache.fetch(cache_key) {
        Hash[Setting.pluck(:name, :value)]
      }
    }
  end

  def self.cache_key
    RequestStore.store[:settings_updated_on] ||= Setting.maximum(:updated_on)
    most_recent_settings_change = (RequestStore.store[:settings_updated_on] || Time.now.utc).to_i
    "/openproject/settings/all/#{most_recent_settings_change}"
  end

  def self.settings_table_exists_yet?
    # Check whether the settings table already exists. This makes plugins
    # patching core classes not break things when settings are accessed.
    # I'm not sure this is a good idea, but that's the way it is right now,
    # and caching this improves performance significantly for actions
    # accessing settings a lot.
    @settings_table_exists_yet ||= connection.data_source_exists?(table_name)
  end

  # Unserialize a serialized settings value
  def self.deserialize(name, v)
    default = @@available_settings[name]

    v = YAML::load(v) if default['serialized'] && v.is_a?(String)

    unless v.blank?
      v = v.to_sym if default['format'] == 'symbol'
      v = v.to_i if default['format'] == 'int'
    end

    v
  end

  require_dependency 'setting/callbacks'
  extend Callbacks
end