require 'active_support/core_ext/hash/keys'
require 'active_support/core_ext/string/output_safety'
require 'active_support/number_helper'

module ActionView
  # = Action View Number Helpers
  module Helpers #:nodoc:

    # Provides methods for converting numbers into formatted strings.
    # Methods are provided for phone numbers, currency, percentage,
    # precision, positional notation, file size and pretty printing.
    #
    # Most methods expect a +number+ argument, and will return it
    # unchanged if can't be converted into a valid number.
    module NumberHelper

      # Raised when argument +number+ param given to the helpers is invalid and
      # the option :raise is set to  +true+.
      class InvalidNumberError < StandardError
        attr_accessor :number
        def initialize(number)
          @number = number
        end
      end

      # Formats a +number+ into a phone number (US by default e.g., (555)
      # 123-9876). You can customize the format in the +options+ hash.
      #
      # ==== Options
      #
      # * <tt>:area_code</tt> - Adds parentheses around the area code.
      # * <tt>:delimiter</tt> - Specifies the delimiter to use
      #   (defaults to "-").
      # * <tt>:extension</tt> - Specifies an extension to add to the
      #   end of the generated number.
      # * <tt>:country_code</tt> - Sets the country code for the phone
      #   number.
      # * <tt>:pattern</tt> - Specifies how the number is divided into three
      #   groups with the custom regexp to override the default format.
      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
      #   the argument is invalid.
      #
      # ==== Examples
      #
      #   number_to_phone(5551234)                                           # => 555-1234
      #   number_to_phone("5551234")                                         # => 555-1234
      #   number_to_phone(1235551234)                                        # => 123-555-1234
      #   number_to_phone(1235551234, area_code: true)                       # => (123) 555-1234
      #   number_to_phone(1235551234, delimiter: " ")                        # => 123 555 1234
      #   number_to_phone(1235551234, area_code: true, extension: 555)       # => (123) 555-1234 x 555
      #   number_to_phone(1235551234, country_code: 1)                       # => +1-123-555-1234
      #   number_to_phone("123a456")                                         # => 123a456
      #   number_to_phone("1234a567", raise: true)                           # => InvalidNumberError
      #
      #   number_to_phone(1235551234, country_code: 1, extension: 1343, delimiter: ".")
      #   # => +1.123.555.1234 x 1343
      #
      #   number_to_phone(75561234567, pattern: /(\d{1,4})(\d{4})(\d{4})$/, area_code: true)
      #   # => "(755) 6123-4567"
      #   number_to_phone(13312345678, pattern: /(\d{3})(\d{4})(\d{4})$/))
      #   # => "133-1234-5678"
      def number_to_phone(number, options = {})
        return unless number
        options = options.symbolize_keys

        parse_float(number, true) if options.delete(:raise)
        ERB::Util.html_escape(ActiveSupport::NumberHelper.number_to_phone(number, options))
      end

      # Formats a +number+ into a currency string (e.g., $13.65). You
      # can customize the format in the +options+ hash.
      #
      # The currency unit and number formatting of the current locale will be used
      # unless otherwise specified in the provided options. No currency conversion
      # is performed. If the user is given a way to change their locale, they will
      # also be able to change the relative value of the currency displayed with
      # this helper. If your application will ever support multiple locales, you
      # may want to specify a constant <tt>:locale</tt> option or consider
      # using a library capable of currency conversion.
      #
      # ==== Options
      #
      # * <tt>:locale</tt> - Sets the locale to be used for formatting
      #   (defaults to current locale).
      # * <tt>:precision</tt> - Sets the level of precision (defaults
      #   to 2).
      # * <tt>:unit</tt> - Sets the denomination of the currency
      #   (defaults to "$").
      # * <tt>:separator</tt> - Sets the separator between the units
      #   (defaults to ".").
      # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
      #   to ",").
      # * <tt>:format</tt> - Sets the format for non-negative numbers
      #   (defaults to "%u%n").  Fields are <tt>%u</tt> for the
      #   currency, and <tt>%n</tt> for the number.
      # * <tt>:negative_format</tt> - Sets the format for negative
      #   numbers (defaults to prepending an hyphen to the formatted
      #   number given by <tt>:format</tt>).  Accepts the same fields
      #   than <tt>:format</tt>, except <tt>%n</tt> is here the
      #   absolute value of the number.
      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
      #   the argument is invalid.
      #
      # ==== Examples
      #
      #   number_to_currency(1234567890.50)                    # => $1,234,567,890.50
      #   number_to_currency(1234567890.506)                   # => $1,234,567,890.51
      #   number_to_currency(1234567890.506, precision: 3)     # => $1,234,567,890.506
      #   number_to_currency(1234567890.506, locale: :fr)      # => 1 234 567 890,51 €
      #   number_to_currency("123a456")                        # => $123a456
      #
      #   number_to_currency("123a456", raise: true)           # => InvalidNumberError
      #
      #   number_to_currency(-1234567890.50, negative_format: "(%u%n)")
      #   # => ($1,234,567,890.50)
      #   number_to_currency(1234567890.50, unit: "R$", separator: ",", delimiter: "")
      #   # => R$1234567890,50
      #   number_to_currency(1234567890.50, unit: "R$", separator: ",", delimiter: "", format: "%n %u")
      #   # => 1234567890,50 R$
      def number_to_currency(number, options = {})
        delegate_number_helper_method(:number_to_currency, number, options)
      end

      # Formats a +number+ as a percentage string (e.g., 65%). You can
      # customize the format in the +options+ hash.
      #
      # ==== Options
      #
      # * <tt>:locale</tt> - Sets the locale to be used for formatting
      #   (defaults to current locale).
      # * <tt>:precision</tt> - Sets the precision of the number
      #   (defaults to 3).
      # * <tt>:significant</tt> - If +true+, precision will be the number
      #   of significant_digits. If +false+, the number of fractional
      #   digits (defaults to +false+).
      # * <tt>:separator</tt> - Sets the separator between the
      #   fractional and integer digits (defaults to ".").
      # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
      #   to "").
      # * <tt>:strip_insignificant_zeros</tt> - If +true+ removes
      #   insignificant zeros after the decimal separator (defaults to
      #   +false+).
      # * <tt>:format</tt> - Specifies the format of the percentage
      #   string The number field is <tt>%n</tt> (defaults to "%n%").
      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
      #   the argument is invalid.
      #
      # ==== Examples
      #
      #   number_to_percentage(100)                                        # => 100.000%
      #   number_to_percentage("98")                                       # => 98.000%
      #   number_to_percentage(100, precision: 0)                          # => 100%
      #   number_to_percentage(1000, delimiter: '.', separator: ',')       # => 1.000,000%
      #   number_to_percentage(302.24398923423, precision: 5)              # => 302.24399%
      #   number_to_percentage(1000, locale: :fr)                          # => 1 000,000%
      #   number_to_percentage("98a")                                      # => 98a%
      #   number_to_percentage(100, format: "%n  %")                       # => 100.000  %
      #
      #   number_to_percentage("98a", raise: true)                         # => InvalidNumberError
      def number_to_percentage(number, options = {})
        delegate_number_helper_method(:number_to_percentage, number, options)
      end

      # Formats a +number+ with grouped thousands using +delimiter+
      # (e.g., 12,324). You can customize the format in the +options+
      # hash.
      #
      # ==== Options
      #
      # * <tt>:locale</tt> - Sets the locale to be used for formatting
      #   (defaults to current locale).
      # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
      #   to ",").
      # * <tt>:separator</tt> - Sets the separator between the
      #   fractional and integer digits (defaults to ".").
      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
      #   the argument is invalid.
      #
      # ==== Examples
      #
      #   number_with_delimiter(12345678)                        # => 12,345,678
      #   number_with_delimiter("123456")                        # => 123,456
      #   number_with_delimiter(12345678.05)                     # => 12,345,678.05
      #   number_with_delimiter(12345678, delimiter: ".")        # => 12.345.678
      #   number_with_delimiter(12345678, delimiter: ",")        # => 12,345,678
      #   number_with_delimiter(12345678.05, separator: " ")     # => 12,345,678 05
      #   number_with_delimiter(12345678.05, locale: :fr)        # => 12 345 678,05
      #   number_with_delimiter("112a")                          # => 112a
      #   number_with_delimiter(98765432.98, delimiter: " ", separator: ",")
      #   # => 98 765 432,98
      #
      #  number_with_delimiter("112a", raise: true)              # => raise InvalidNumberError
      def number_with_delimiter(number, options = {})
        delegate_number_helper_method(:number_to_delimited, number, options)
      end

      # Formats a +number+ with the specified level of
      # <tt>:precision</tt> (e.g., 112.32 has a precision of 2 if
      # +:significant+ is +false+, and 5 if +:significant+ is +true+).
      # You can customize the format in the +options+ hash.
      #
      # ==== Options
      #
      # * <tt>:locale</tt> - Sets the locale to be used for formatting
      #   (defaults to current locale).
      # * <tt>:precision</tt> - Sets the precision of the number
      #   (defaults to 3).
      # * <tt>:significant</tt> - If +true+, precision will be the number
      #   of significant_digits. If +false+, the number of fractional
      #   digits (defaults to +false+).
      # * <tt>:separator</tt> - Sets the separator between the
      #   fractional and integer digits (defaults to ".").
      # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
      #   to "").
      # * <tt>:strip_insignificant_zeros</tt> - If +true+ removes
      #   insignificant zeros after the decimal separator (defaults to
      #   +false+).
      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
      #   the argument is invalid.
      #
      # ==== Examples
      #
      #   number_with_precision(111.2345)                                         # => 111.235
      #   number_with_precision(111.2345, precision: 2)                           # => 111.23
      #   number_with_precision(13, precision: 5)                                 # => 13.00000
      #   number_with_precision(389.32314, precision: 0)                          # => 389
      #   number_with_precision(111.2345, significant: true)                      # => 111
      #   number_with_precision(111.2345, precision: 1, significant: true)        # => 100
      #   number_with_precision(13, precision: 5, significant: true)              # => 13.000
      #   number_with_precision(111.234, locale: :fr)                             # => 111,234
      #
      #   number_with_precision(13, precision: 5, significant: true, strip_insignificant_zeros: true)
      #   # => 13
      #
      #   number_with_precision(389.32314, precision: 4, significant: true)       # => 389.3
      #   number_with_precision(1111.2345, precision: 2, separator: ',', delimiter: '.')
      #   # => 1.111,23
      def number_with_precision(number, options = {})
        delegate_number_helper_method(:number_to_rounded, number, options)
      end

      # Formats the bytes in +number+ into a more understandable
      # representation (e.g., giving it 1500 yields 1.5 KB). This
      # method is useful for reporting file sizes to users. You can
      # customize the format in the +options+ hash.
      #
      # See <tt>number_to_human</tt> if you want to pretty-print a
      # generic number.
      #
      # ==== Options
      #
      # * <tt>:locale</tt> - Sets the locale to be used for formatting
      #   (defaults to current locale).
      # * <tt>:precision</tt> - Sets the precision of the number
      #   (defaults to 3).
      # * <tt>:significant</tt> - If +true+, precision will be the number
      #   of significant_digits. If +false+, the number of fractional
      #   digits (defaults to +true+)
      # * <tt>:separator</tt> - Sets the separator between the
      #   fractional and integer digits (defaults to ".").
      # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
      #   to "").
      # * <tt>:strip_insignificant_zeros</tt> - If +true+ removes
      #   insignificant zeros after the decimal separator (defaults to
      #   +true+)
      # * <tt>:prefix</tt> - If +:si+ formats the number using the SI
      #   prefix (defaults to :binary)
      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
      #   the argument is invalid.
      #
      # ==== Examples
      #
      #   number_to_human_size(123)                                          # => 123 Bytes
      #   number_to_human_size(1234)                                         # => 1.21 KB
      #   number_to_human_size(12345)                                        # => 12.1 KB
      #   number_to_human_size(1234567)                                      # => 1.18 MB
      #   number_to_human_size(1234567890)                                   # => 1.15 GB
      #   number_to_human_size(1234567890123)                                # => 1.12 TB
      #   number_to_human_size(1234567890123456)                             # => 1.1 PB
      #   number_to_human_size(1234567890123456789)                          # => 1.07 EB
      #   number_to_human_size(1234567, precision: 2)                        # => 1.2 MB
      #   number_to_human_size(483989, precision: 2)                         # => 470 KB
      #   number_to_human_size(1234567, precision: 2, separator: ',')        # => 1,2 MB
      #   number_to_human_size(1234567890123, precision: 5)                  # => "1.1228 TB"
      #   number_to_human_size(524288000, precision: 5)                      # => "500 MB"
      def number_to_human_size(number, options = {})
        delegate_number_helper_method(:number_to_human_size, number, options)
      end

      # Pretty prints (formats and approximates) a number in a way it
      # is more readable by humans (eg.: 1200000000 becomes "1.2
      # Billion"). This is useful for numbers that can get very large
      # (and too hard to read).
      #
      # See <tt>number_to_human_size</tt> if you want to print a file
      # size.
      #
      # You can also define your own unit-quantifier names if you want
      # to use other decimal units (eg.: 1500 becomes "1.5
      # kilometers", 0.150 becomes "150 milliliters", etc). You may
      # define a wide range of unit quantifiers, even fractional ones
      # (centi, deci, mili, etc).
      #
      # ==== Options
      #
      # * <tt>:locale</tt> - Sets the locale to be used for formatting
      #   (defaults to current locale).
      # * <tt>:precision</tt> - Sets the precision of the number
      #   (defaults to 3).
      # * <tt>:significant</tt> - If +true+, precision will be the number
      #   of significant_digits. If +false+, the number of fractional
      #   digits (defaults to +true+)
      # * <tt>:separator</tt> - Sets the separator between the
      #   fractional and integer digits (defaults to ".").
      # * <tt>:delimiter</tt> - Sets the thousands delimiter (defaults
      #   to "").
      # * <tt>:strip_insignificant_zeros</tt> - If +true+ removes
      #   insignificant zeros after the decimal separator (defaults to
      #   +true+)
      # * <tt>:units</tt> - A Hash of unit quantifier names. Or a
      #   string containing an i18n scope where to find this hash. It
      #   might have the following keys:
      #   * *integers*: <tt>:unit</tt>, <tt>:ten</tt>,
      #     <tt>:hundred</tt>, <tt>:thousand</tt>, <tt>:million</tt>,
      #     <tt>:billion</tt>, <tt>:trillion</tt>,
      #     <tt>:quadrillion</tt>
      #   * *fractionals*: <tt>:deci</tt>, <tt>:centi</tt>,
      #     <tt>:mili</tt>, <tt>:micro</tt>, <tt>:nano</tt>,
      #     <tt>:pico</tt>, <tt>:femto</tt>
      # * <tt>:format</tt> - Sets the format of the output string
      #   (defaults to "%n %u"). The field types are:
      #   * %u - The quantifier (ex.: 'thousand')
      #   * %n - The number
      # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
      #   the argument is invalid.
      #
      # ==== Examples
      #
      #   number_to_human(123)                                          # => "123"
      #   number_to_human(1234)                                         # => "1.23 Thousand"
      #   number_to_human(12345)                                        # => "12.3 Thousand"
      #   number_to_human(1234567)                                      # => "1.23 Million"
      #   number_to_human(1234567890)                                   # => "1.23 Billion"
      #   number_to_human(1234567890123)                                # => "1.23 Trillion"
      #   number_to_human(1234567890123456)                             # => "1.23 Quadrillion"
      #   number_to_human(1234567890123456789)                          # => "1230 Quadrillion"
      #   number_to_human(489939, precision: 2)                         # => "490 Thousand"
      #   number_to_human(489939, precision: 4)                         # => "489.9 Thousand"
      #   number_to_human(1234567, precision: 4,
      #                           significant: false)                   # => "1.2346 Million"
      #   number_to_human(1234567, precision: 1,
      #                           separator: ',',
      #                           significant: false)                   # => "1,2 Million"
      #
      #   number_to_human(500000000, precision: 5)                      # => "500 Million"
      #   number_to_human(12345012345, significant: false)              # => "12.345 Billion"
      #
      # Non-significant zeros after the decimal separator are stripped
      # out by default (set <tt>:strip_insignificant_zeros</tt> to
      # +false+ to change that):
      #
      # number_to_human(12.00001)                                       # => "12"
      # number_to_human(12.00001, strip_insignificant_zeros: false)     # => "12.0"
      #
      # ==== Custom Unit Quantifiers
      #
      # You can also use your own custom unit quantifiers:
      #  number_to_human(500000, units: {unit: "ml", thousand: "lt"})  # => "500 lt"
      #
      # If in your I18n locale you have:
      #   distance:
      #     centi:
      #       one: "centimeter"
      #       other: "centimeters"
      #     unit:
      #       one: "meter"
      #       other: "meters"
      #     thousand:
      #       one: "kilometer"
      #       other: "kilometers"
      #     billion: "gazillion-distance"
      #
      # Then you could do:
      #
      #  number_to_human(543934, units: :distance)              # => "544 kilometers"
      #  number_to_human(54393498, units: :distance)            # => "54400 kilometers"
      #  number_to_human(54393498000, units: :distance)         # => "54.4 gazillion-distance"
      #  number_to_human(343, units: :distance, precision: 1)   # => "300 meters"
      #  number_to_human(1, units: :distance)                   # => "1 meter"
      #  number_to_human(0.34, units: :distance)                # => "34 centimeters"
      #
      def number_to_human(number, options = {})
        delegate_number_helper_method(:number_to_human, number, options)
      end

      private

      def delegate_number_helper_method(method, number, options)
        return unless number
        options = escape_unsafe_options(options.symbolize_keys)

        wrap_with_output_safety_handling(number, options.delete(:raise)) {
          ActiveSupport::NumberHelper.public_send(method, number, options)
        }
      end

      def escape_unsafe_options(options)
        options[:format]          = ERB::Util.html_escape(options[:format]) if options[:format]
        options[:negative_format] = ERB::Util.html_escape(options[:negative_format]) if options[:negative_format]
        options[:separator]       = ERB::Util.html_escape(options[:separator]) if options[:separator]
        options[:delimiter]       = ERB::Util.html_escape(options[:delimiter]) if options[:delimiter]
        options[:unit]            = ERB::Util.html_escape(options[:unit]) if options[:unit] && !options[:unit].html_safe?
        options[:units]           = escape_units(options[:units]) if options[:units] && Hash === options[:units]
        options
      end

      def escape_units(units)
        Hash[units.map do |k, v|
          [k, ERB::Util.html_escape(v)]
        end]
      end

      def wrap_with_output_safety_handling(number, raise_on_invalid, &block)
        valid_float = valid_float?(number)
        raise InvalidNumberError, number if raise_on_invalid && !valid_float

        formatted_number = yield

        if valid_float || number.html_safe?
          formatted_number.html_safe
        else
          formatted_number
        end
      end

      def valid_float?(number)
        !parse_float(number, false).nil?
      end

      def parse_float(number, raise_error)
        Float(number)
      rescue ArgumentError, TypeError
        raise InvalidNumberError, number if raise_error
      end
    end
  end
end
