require 'money'
require 'iso8601'
require 'timezone'
require 'countries'

require_relative 'collection'

module Tickethub
  class Resource

    class << self

      def singleton?
        !! @singleton
      end

      def path(value = nil, singleton: false)        
        return @path || (superclass.respond_to?(:path) ? superclass.path : nil) if value.nil?
        @singleton = singleton
        @path = value
      end

      def registered_types
        @registered_types ||= {}
      end

      def scopes
        @scopes ||= {}
      end

      def attributes
        @attributes ||= {}
      end

      def descendants
        @descendants ||= []
      end

      def collection_methods
        @collection_methods ||= {}
      end
    end

    def self.collection_method(key, &block)
      collection_methods[key] = block
    end

    def self.inherited(descendant)
      if descendant.ancestors.member? Tickethub::Resource
        self.descendants.push descendant
      end
    end

    def self.all(params = {})
      Tickethub::Collection.new Tickethub.endpoint[self.path], self, params
    end

    def self.polymorphic(type, attribute = :type)
      self.superclass.register_type type, self, attribute
    end

    def self.register_type(type, klass, attribute = :type) # klass, attribute
      self.registered_types[type] = { klass: klass, attribute: attribute }
    end

    def self.attribute(key, options)
      self.attributes[key] = options

      self.descendants.each do |descendant|
        descendant.attributes[key] = options
      end
    end

    def self.scope(key, proc = -> (params = {}) { self.scope key, params })
      self.scopes[key] = proc
    end

    def self.load_value(key, value, object)
      return nil if value.nil? || (value.is_a?(String) && value.empty?)
      return value unless self.attributes.key? key

      case self.attributes[key][:type]
        when :date
          case value
            when String then ISO8601::Date.new(value)
            else raise ArgumentError, 'invalid date value: ' + value
          end
        when :datetime
          case value
            when String then ISO8601::DateTime.new(value)
            else raise ArgumentError, 'invalid datetime value: ' + value
          end
        when :time
          case value
            when String then ISO8601::Time.new(value)
            else raise ArgumentError, 'invalid time value: ' + value
          end
        when :duration
          case value
            when String then ISO8601::Duration.new(value)
            else raise ArgumentError, 'invalid time value: ' + value
          end
        when :money
          currency = Money::Currency.new(object.currency)
          raise ArgumentError, 'invalid money currency' if currency.blank?

          case value
            when Fixnum then Money.new(value, currency)
            when Numeric, String
              currency = Money::Currency.wrap(currency)
              Money.new(value.to_d * currency.subunit_to_unit, currency)
            else raise ArgumentError, 'invalid money value: ' + value
          end
        when :currency
          case value
            when String then Money::Currency.new(value)
            else raise ArgumentError, 'invalid currency value: ' + value
          end            
        when :timezone
          case value
            when String then Timezone::Zone.new(zone: value)
            else raise ArgumentError, 'invalid timezone value: ' + value
          end
        when :country
          case value
            when String then Country.new(value)
            else raise ArgumentError, 'invalid country value: ' + value
          end
        else value
      end
    end

    def self.dump_value(key, value)
      return value unless self.attributes.key? key
      case self.attributes[key][:type]
        when :date      then value.iso8601
        when :datetime  then value.iso8601
        when :time      then value.iso8601[10..-1]
        when :duration  then value.iso8601
        when :money     then value.fractional
        when :timezone  then value.zone
        when :country   then value.alpha2
        when :currency  then value.iso_code
        else value
      end
    end

    def self.serialize(attributes)
      attributes.collect do |key, value|
        [key, dump_value(key, value)]
      end.to_h
    end

    def self.call(endpoint, attributes = nil)
      attributes ||= endpoint.get

      klass = registered_types.find do |type, options|
        attributes[options[:attribute].to_s] == type
      end

      klass = klass ? klass[1][:klass] : self
      endpoint = if klass.singleton?
        endpoint[klass.path]
      elsif id = attributes['id']
        endpoint[klass.path, id]
      else # readonly
        endpoint[klass.path].freeze
      end

      klass.new endpoint, attributes
    end

    def self.association(key, klass)
      define_method key do
        @attributes.key?(key.to_sym) ? 
          (attrs = @attributes[key.to_sym]) &&
            klass.call(@endpoint[key], attrs) :
              klass.call(@endpoint[key])
      end
    end

    def self.collection(key, klass, &block)
      define_method key do |params = {}|
        Tickethub::Collection.new(@endpoint[key], klass, params).tap do |collection|
          collection.instance_eval &block if block
        end
      end
    end

    attr_accessor :endpoint

    def initialize(endpoint, attributes = nil)
      @endpoint = endpoint
      attributes ||= endpoint.get

      self.load attributes
    end

    def valid?
      errors.nil? || errors.valid?
    end

    def update(attributes)
      self.load @endpoint.patch(attributes).decoded
      return true
    rescue Tickethub::ResourceInvalid => err
      self.load Tickethub::Response.new(err.response).decoded
      return false
    end

    def destroy
      self.load @endpoint.delete.decoded
    end

    def respond_to?(method, include_priv = false)
      @attributes.key?(method.to_s.remove(/[=\?]\Z/).to_sym) || super
    end

    def reload!
      self.call @endpoint.get
    end

    def load(attributes)
      @attributes = {}
      attributes.each do |key, value|
        send "#{key}=", value
      end
      return self
    end

    def [](key)
      send key
    end

    def []=(key, value)
      send "#{key}=", value
    end

    def ==(other)
      self.hash == other.hash
    end

    def eql?(other)
      self == other
    end

    def hash
      id?? [self.class, id].hash : super
    end

    def to_param
      self.id
    end

    def errors
      @errors ||= Tickethub::Errors.new @attributes[:errors]
    end

    def to_h
      @attributes
    end

    def to_s
      self.id?? id : super
    end

    def inspect
      "#<#{self.class.name} #{to_h}>"
    end

    protected

    def method_missing(method, *arguments)
      if match = method.to_s.match(/^(.+)(=|\?)$/)
        key = match[1].to_sym

        case match[2]
          when '='
            @attributes[key] = self.class.load_value(key, arguments.first, self)
          when "?"
            !! @attributes[key]
        end
      else
        @attributes.key?(method) ? @attributes[method] : super
      end
    end
  end
end