require 'active_support/inflector'
require 'fanforce/errors'
require 'fanforce/utils'

module Fanforce::Validations
  include Fanforce::Utils
  extend Fanforce::Validations
  def self.included(base) base.extend(self) end

  def extract_validation_params(opts)
    return opts.delete(:params) if is_present?(opts[:params])
    return self.params if self.respond_to?(:params)
    Fanforce.env[:request_params] || {}
  end

  def parse_validation_field_name(field, i, opts, params)
    name = opts[:fields][i] if is_present?(opts[:fields])
    name = field if is_blank?(name) and field.is_a?(Symbol)
    name = :unknown if is_blank?(name)
    name.to_sym
  end

  def validates_presence_of(*args)
    opts = extract_options!(args)
    params = extract_validation_params(opts)
    fields_to_validate = args.is_a?(Array) ? args : [args]

    invalid_fields = []
    fields_to_validate.each_with_index do |field_to_validate, i|
      if !(field_to_validate.is_a?(Symbol) ? is_present?(params[field_to_validate]) : is_present?(field_to_validate))
        invalid_fields << parse_validation_field_name(field_to_validate, i, opts, params)
      end
    end
    return true if invalid_fields.size == 0

    errors = invalid_fields.inject([]) {|result, f| result << format_validation_error(opts, f, :missing_field) }
    raise_validation_error(opts, errors, Fanforce::Error::CorruptRequest)
  end

  def validates_presence_of_any(*args)
    opts = extract_options!(args)
    params = extract_validation_params(opts)
    fields_to_validate = args.is_a?(Array) ? args : [args]

    invalid_fields = []
    fields_to_validate.each_with_index do |field_to_validate, i|
      if !(field_to_validate.is_a?(Symbol) ? is_present?(params[field_to_validate]) : is_present?(field_to_validate))
        invalid_fields << parse_validation_field_name(field_to_validate, i, opts, params)
      end
    end
    return true if invalid_fields.size < fields_to_validate.size

    errors = [format_validation_error(opts, invalid_fields, :invalid_data)]
    raise_validation_error(opts, errors, Fanforce::Error::CorruptRequest)
  end

  def validates_presence_of_all(*args)
    validates_presence_of(args)
  end

  def validates_true(*args)
    opts = extract_options!(args)
    params = extract_validation_params(opts)
    bools_to_validate = args.is_a?(Array) ? args : [args]

    invalid_fields = []
    bools_to_validate.each_with_index do |bool_is_true, i|
      if !bool_is_true
        invalid_fields << parse_validation_field_name(nil, i, opts, nil)
      end
    end
    return true if invalid_fields.size == 0

    errors = invalid_fields.inject([]) {|result, f| result << format_validation_error(opts, f, :invalid_data) }
    raise_validation_error(opts, errors, Fanforce::Error::RequestFailed)
  end

  def raise_validation_error(opts, errors, default_error_class)
    raise (opts[:error_class] || default_error_class).new(errors)
  end

  def format_validation_error(opts, fields, default_error_code=nil)
    error = {
        resource: is_present?(opts[:resource]) ? opts[:resource] : self.class.name.demodulize.tableize.singularize,
        code: is_present?(opts[:code]) ? opts[:code] : default_error_code,
        message: opts[:message]
    }
    fields.is_a?(Array) ? error.update(fields: fields) : error.update(field: fields)
  end

  def extract_options!(args)
    if args.last.is_a?(::Hash)
      opts = args.pop.symbolize_keys
      if is_present?(opts[:field]) and opts[:fields].is_a?(Array)
        opts[:fields] << opts.delete(:field)
      elsif is_present?(opts[:field])
        opts[:fields] = [opts.delete(:field)]
      end
      return opts
    elsif args.last.is_a?(::String)
      {msg: args.pop.to_s}
    else
      {}
    end
  end

end