require 'active_support/core_ext/object/blank'
require 'active_support/core_ext/string/filters'
require 'action_view/helpers/tag_helper'
module ActionView
  # = Action View Text Helpers
  module Helpers #:nodoc:
    # The TextHelper module provides a set of methods for filtering, formatting
    # and transforming strings, which can reduce the amount of inline Ruby code in
    # your views. These helper methods extend Action View making them callable
    # within your template files.
    #
    # ==== Sanitization
    #
    # Most text helpers by default sanitize the given content, but do not escape it.
    # This means HTML tags will appear in the page but all malicious code will be removed.
    # Let's look at some examples using the +simple_format+ method:
    #
    #   simple_format('Example')
    #   # => "
Example
"
    #
    #   simple_format('Example')
    #   # => "Example
"
    #
    # If you want to escape all content, you should invoke the +h+ method before
    # calling the text helper.
    #
    #   simple_format h('Example')
    #   # => "<a href=\"http://example.com/\">Example</a>
"
    module TextHelper
      extend ActiveSupport::Concern
      include SanitizeHelper
      # The preferred method of outputting text in your views is to use the
      # <%= "text" %> eRuby syntax. The regular _puts_ and _print_ methods
      # do not operate as expected in an eRuby code block. If you absolutely must
      # output text within a non-output code block (i.e., <% %>), you can use the concat method.
      #
      # ==== Examples
      #   <%
      #       concat "hello"
      #       # is the equivalent of <%= "hello" %>
      #
      #       if logged_in
      #         concat "Logged in!"
      #       else
      #         concat link_to('login', :action => login)
      #       end
      #       # will either display "Logged in!" or a login link
      #   %>
      def concat(string)
        output_buffer << string
      end
      def safe_concat(string)
        output_buffer.respond_to?(:safe_concat) ? output_buffer.safe_concat(string) : concat(string)
      end
      # Truncates a given +text+ after a given :length if +text+ is longer than :length
      # (defaults to 30). The last characters will be replaced with the :omission (defaults to "...")
      # for a total length not exceeding :length.
      #
      # Pass a :separator to truncate +text+ at a natural break.
      #
      # The result is not marked as HTML-safe, so will be subject to the default escaping when
      # used in views, unless wrapped by raw(). Care should be taken if +text+ contains HTML tags
      # or entities, because truncation may produce invalid HTML (such as unbalanced or incomplete tags).
      #
      # ==== Examples
      #
      #   truncate("Once upon a time in a world far far away")
      #   # => "Once upon a time in a world..."
      #
      #   truncate("Once upon a time in a world far far away", :length => 17)
      #   # => "Once upon a ti..."
      #
      #   truncate("Once upon a time in a world far far away", :length => 17, :separator => ' ')
      #   # => "Once upon a..."
      #
      #   truncate("And they found that many people were sleeping better.", :length => 25, :omission => '... (continued)')
      #   # => "And they f... (continued)"
      #
      #   truncate("Once upon a time in a world far far away
")
      #   # => "Once upon a time in a wo..."
      def truncate(text, options = {})
        options.reverse_merge!(:length => 30)
        text.truncate(options.delete(:length), options) if text
      end
      # Highlights one or more +phrases+ everywhere in +text+ by inserting it into
      # a :highlighter string. The highlighter can be specialized by passing :highlighter
      # as a single-quoted string with \1 where the phrase is to be inserted (defaults to
      # '\1')
      #
      # ==== Examples
      #   highlight('You searched for: rails', 'rails')
      #   # => You searched for: rails
      #
      #   highlight('You searched for: ruby, rails, dhh', 'actionpack')
      #   # => You searched for: ruby, rails, dhh
      #
      #   highlight('You searched for: rails', ['for', 'rails'], :highlighter => '\1')
      #   # => You searched for: rails
      #
      #   highlight('You searched for: rails', 'rails', :highlighter => '\1')
      #   # => You searched for: rails
      #
      # You can still use highlight with the old API that accepts the
      # +highlighter+ as its optional third parameter:
      #   highlight('You searched for: rails', 'rails', '\1')     # => You searched for: rails
      def highlight(text, phrases, *args)
        options = args.extract_options!
        unless args.empty?
          options[:highlighter] = args[0] || '\1'
        end
        options.reverse_merge!(:highlighter => '\1')
        text = sanitize(text) unless options[:sanitize] == false
        if text.blank? || phrases.blank?
          text
        else
          match = Array(phrases).map { |p| Regexp.escape(p) }.join('|')
          text.gsub(/(#{match})(?!(?:[^<]*?)(?:["'])[^<>]*>)/i, options[:highlighter])
        end.html_safe
      end
      # Extracts an excerpt from +text+ that matches the first instance of +phrase+.
      # The :radius option expands the excerpt on each side of the first occurrence of +phrase+ by the number of characters
      # defined in :radius (which defaults to 100). If the excerpt radius overflows the beginning or end of the +text+,
      # then the :omission option (which defaults to "...") will be prepended/appended accordingly. The resulting string
      # will be stripped in any case. If the +phrase+ isn't found, nil is returned.
      #
      # ==== Examples
      #   excerpt('This is an example', 'an', :radius => 5)
      #   # => ...s is an exam...
      #
      #   excerpt('This is an example', 'is', :radius => 5)
      #   # => This is a...
      #
      #   excerpt('This is an example', 'is')
      #   # => This is an example
      #
      #   excerpt('This next thing is an example', 'ex', :radius => 2)
      #   # => ...next...
      #
      #   excerpt('This is also an example', 'an', :radius => 8, :omission => ' ')
      #   # =>  is also an example
      #
      # You can still use excerpt with the old API that accepts the
      # +radius+ as its optional third and the +ellipsis+ as its
      # optional forth parameter:
      #   excerpt('This is an example', 'an', 5)                   # => ...s is an exam...
      #   excerpt('This is also an example', 'an', 8, ' ')   # =>  is also an example
      def excerpt(text, phrase, *args)
        return unless text && phrase
        options = args.extract_options!
        unless args.empty?
          options[:radius] = args[0] || 100
          options[:omission] = args[1] || "..."
        end
        options.reverse_merge!(:radius => 100, :omission => "...")
        phrase = Regexp.escape(phrase)
        return unless found_pos = text.mb_chars =~ /(#{phrase})/i
        start_pos = [ found_pos - options[:radius], 0 ].max
        end_pos   = [ [ found_pos + phrase.mb_chars.length + options[:radius] - 1, 0].max, text.mb_chars.length ].min
        prefix  = start_pos > 0 ? options[:omission] : ""
        postfix = end_pos < text.mb_chars.length - 1 ? options[:omission] : ""
        prefix + text.mb_chars[start_pos..end_pos].strip + postfix
      end
      # Attempts to pluralize the +singular+ word unless +count+ is 1. If
      # +plural+ is supplied, it will use that when count is > 1, otherwise
      # it will use the Inflector to determine the plural form
      #
      # ==== Examples
      #   pluralize(1, 'person')
      #   # => 1 person
      #
      #   pluralize(2, 'person')
      #   # => 2 people
      #
      #   pluralize(3, 'person', 'users')
      #   # => 3 users
      #
      #   pluralize(0, 'person')
      #   # => 0 people
      def pluralize(count, singular, plural = nil)
        "#{count || 0} " + ((count == 1 || count =~ /^1(\.0+)?$/) ? singular : (plural || singular.pluralize))
      end
      # Wraps the +text+ into lines no longer than +line_width+ width. This method
      # breaks on the first whitespace character that does not exceed +line_width+
      # (which is 80 by default).
      #
      # ==== Examples
      #
      #   word_wrap('Once upon a time')
      #   # => Once upon a time
      #
      #   word_wrap('Once upon a time, in a kingdom called Far Far Away, a king fell ill, and finding a successor to the throne turned out to be more trouble than anyone could have imagined...')
      #   # => Once upon a time, in a kingdom called Far Far Away, a king fell ill, and finding\n a successor to the throne turned out to be more trouble than anyone could have\n imagined...
      #
      #   word_wrap('Once upon a time', :line_width => 8)
      #   # => Once upon\na time
      #
      #   word_wrap('Once upon a time', :line_width => 1)
      #   # => Once\nupon\na\ntime
      #
      # You can still use word_wrap with the old API that accepts the
      # +line_width+ as its optional second parameter:
      #   word_wrap('Once upon a time', 8)     # => Once upon\na time
      def word_wrap(text, *args)
        options = args.extract_options!
        unless args.blank?
          options[:line_width] = args[0] || 80
        end
        options.reverse_merge!(:line_width => 80)
        text.split("\n").collect do |line|
          line.length > options[:line_width] ? line.gsub(/(.{1,#{options[:line_width]}})(\s+|$)/, "\\1\n").strip : line
        end * "\n"
      end
      # Returns +text+ transformed into HTML using simple formatting rules.
      # Two or more consecutive newlines(\n\n) are considered as a
      # paragraph and wrapped in  tags. One newline (\n) is
      # considered as a linebreak and a 
 tag is appended. This
      # method does not remove the newlines from the +text+.
      #
      # You can pass any HTML attributes into html_options.  These
      # will be added to all created paragraphs.
      # ==== Examples
      #   my_text = "Here is some basic text...\n...with a line break."
      #
      #   simple_format(my_text)
      #   # => "
Here is some basic text...\n
...with a line break.
"
      #
      #   more_text = "We want to put a paragraph...\n\n...right there."
      #
      #   simple_format(more_text)
      #   # => "We want to put a paragraph...
\n\n...right there.
"
      #
      #   simple_format("Look ma! A class!", :class => 'description')
      #   # => "Look ma! A class!
"
      def simple_format(text, html_options={}, options={})
        text = ''.html_safe if text.nil?
        start_tag = tag('p', html_options, true)
        text = sanitize(text) unless options[:sanitize] == false
        text.gsub!(/\r\n?/, "\n")                    # \r\n and \r -> \n
        text.gsub!(/\n\n+/, "
\n\n#{start_tag}")  # 2+ newline  -> paragraph
        text.gsub!(/([^\n]\n)(?=[^\n])/, '\1
') # 1 newline   -> br
        text.insert 0, start_tag
        text.html_safe.safe_concat("")
      end
      # Turns all URLs and e-mail addresses into clickable links. The :link option
      # will limit what should be linked. You can add HTML attributes to the links using
      # :html. Possible values for :link are :all (default),
      # :email_addresses, and :urls. If a block is given, each URL and
      # e-mail address is yielded and the result is used as the link text.
      #
      # ==== Examples
      #   auto_link("Go to http://www.rubyonrails.org and say hello to david@loudthinking.com")
      #   # => "Go to http://www.rubyonrails.org and
      #   #     say hello to david@loudthinking.com"
      #
      #   auto_link("Visit http://www.loudthinking.com/ or e-mail david@loudthinking.com", :link => :urls)
      #   # => "Visit http://www.loudthinking.com/
      #   #     or e-mail david@loudthinking.com"
      #
      #   auto_link("Visit http://www.loudthinking.com/ or e-mail david@loudthinking.com", :link => :email_addresses)
      #   # => "Visit http://www.loudthinking.com/ or e-mail david@loudthinking.com"
      #
      #   post_body = "Welcome to my new blog at http://www.myblog.com/.  Please e-mail me at me@email.com."
      #   auto_link(post_body, :html => { :target => '_blank' }) do |text|
      #     truncate(text, :length => 15)
      #   end
      #   # => "Welcome to my new blog at http://www.m....
      #         Please e-mail me at me@email.com."
      #
      #
      # You can still use auto_link with the old API that accepts the
      # +link+ as its optional second parameter and the +html_options+ hash
      # as its optional third parameter:
      #   post_body = "Welcome to my new blog at http://www.myblog.com/. Please e-mail me at me@email.com."
      #   auto_link(post_body, :urls)     # => Once upon\na time
      #   # => "Welcome to my new blog at http://www.myblog.com.
      #         Please e-mail me at me@email.com."
      #
      #   auto_link(post_body, :all, :target => "_blank")     # => Once upon\na time
      #   # => "Welcome to my new blog at http://www.myblog.com.
      #         Please e-mail me at me@email.com."
      def auto_link(text, *args, &block)#link = :all, html = {}, &block)
        return ''.html_safe if text.blank?
        options = args.size == 2 ? {} : args.extract_options! # this is necessary because the old auto_link API has a Hash as its last parameter
        unless args.empty?
          options[:link] = args[0] || :all
          options[:html] = args[1] || {}
        end
        options.reverse_merge!(:link => :all, :html => {})
        case options[:link].to_sym
          when :all                         then auto_link_email_addresses(auto_link_urls(text, options[:html], options, &block), options[:html], &block)
          when :email_addresses             then auto_link_email_addresses(text, options[:html], &block)
          when :urls                        then auto_link_urls(text, options[:html], options, &block)
        end
      end
      # Creates a Cycle object whose _to_s_ method cycles through elements of an
      # array every time it is called. This can be used for example, to alternate
      # classes for table rows.  You can use named cycles to allow nesting in loops.
      # Passing a Hash as the last parameter with a :name key will create a
      # named cycle. The default name for a cycle without a +:name+ key is
      # "default". You can manually reset a cycle by calling reset_cycle
      # and passing the name of the cycle. The current cycle string can be obtained
      # anytime using the current_cycle method.
      #
      # ==== Examples
      #   # Alternate CSS classes for even and odd numbers...
      #   @items = [1,2,3,4]
      #   
      #   <% @items.each do |item| %>
      #     ">
      #       | item# | 
      #   <% end %>
      #   
      #
      #
      #   # Cycle CSS classes for rows, and text colors for values within each row
      #   @items = x = [{:first => 'Robert', :middle => 'Daniel', :last => 'James'},
      #                {:first => 'Emily', :middle => 'Shannon', :maiden => 'Pike', :last => 'Hicks'},
      #               {:first => 'June', :middle => 'Dae', :last => 'Jones'}]
      #   <% @items.each do |item| %>
      #      "row_class") -%>">
      #       | #         <% item.values.each do |value| %>
      #           <%# Create a named cycle "colors" %>
      #            "colors") -%>">
      #             <%= value %>
      #           
      #         <% end %>
      #         <% reset_cycle("colors") %>
      ## | 
      #  <% end %>
      def cycle(first_value, *values)
        if (values.last.instance_of? Hash)
          params = values.pop
          name = params[:name]
        else
          name = "default"
        end
        values.unshift(first_value)
        cycle = get_cycle(name)
        unless cycle && cycle.values == values
          cycle = set_cycle(name, Cycle.new(*values))
        end
        cycle.to_s
      end
      # Returns the current cycle string after a cycle has been started. Useful
      # for complex table highlighting or any other design need which requires
      # the current cycle string in more than one place.
      #
      # ==== Example
      #   # Alternate background colors
      #   @items = [1,2,3,4]
      #   <% @items.each do |item| %>
      #     ">
      #       <%= item %>
      #     
      #   <% end %>
      def current_cycle(name = "default")
        cycle = get_cycle(name)
        cycle.current_value if cycle
      end
      # Resets a cycle so that it starts from the first element the next time
      # it is called. Pass in +name+ to reset a named cycle.
      #
      # ==== Example
      #   # Alternate CSS classes for even and odd numbers...
      #   @items = [[1,2,3,4], [5,6,3], [3,4,5,6,7,4]]
      #   
      #   <% @items.each do |item| %>
      #     ">
      #         <% item.each do |value| %>
      #            "colors") -%>">
      #             <%= value %>
      #           
      #         <% end %>
      #
      #         <% reset_cycle("colors") %>
      #     
      #   <% end %>
      #   
      def reset_cycle(name = "default")
        cycle = get_cycle(name)
        cycle.reset if cycle
      end
      class Cycle #:nodoc:
        attr_reader :values
        def initialize(first_value, *values)
          @values = values.unshift(first_value)
          reset
        end
        def reset
          @index = 0
        end
        def current_value
          @values[previous_index].to_s
        end
        def to_s
          value = @values[@index].to_s
          @index = next_index
          return value
        end
        private
        def next_index
          step_index(1)
        end
        def previous_index
          step_index(-1)
        end
        def step_index(n)
          (@index + n) % @values.size
        end
      end
      private
        # The cycle helpers need to store the cycles in a place that is
        # guaranteed to be reset every time a page is rendered, so it
        # uses an instance variable of ActionView::Base.
        def get_cycle(name)
          @_cycles = Hash.new unless defined?(@_cycles)
          return @_cycles[name]
        end
        def set_cycle(name, cycle_object)
          @_cycles = Hash.new unless defined?(@_cycles)
          @_cycles[name] = cycle_object
        end
        AUTO_LINK_RE = %r{
            (?: ([\w+.:-]+:)// | www\. )
            [^\s<]+
          }x
        # regexps for determining context, used high-volume
        AUTO_LINK_CRE = [/<[^>]+$/, /^[^>]*>/, //i, /<\/a>/i]
        AUTO_EMAIL_RE = /[\w.!#\$%+-]+@[\w-]+(?:\.[\w-]+)+/
        BRACKETS = { ']' => '[', ')' => '(', '}' => '{' }
        # Turns all urls into clickable links.  If a block is given, each url
        # is yielded and the result is used as the link text.
        def auto_link_urls(text, html_options = {}, options = {})
          link_attributes = html_options.stringify_keys
          text.gsub(AUTO_LINK_RE) do
            scheme, href = $1, $&
            punctuation = []
            if auto_linked?($`, $')
              # do not change string; URL is already linked
              href
            else
              # don't include trailing punctuation character as part of the URL
              while href.sub!(/[^\w\/-]$/, '')
                punctuation.push $&
                if opening = BRACKETS[punctuation.last] and href.scan(opening).size > href.scan(punctuation.last).size
                  href << punctuation.pop
                  break
                end
              end
              link_text = block_given?? yield(href) : href
              href = 'http://' + href unless scheme
              unless options[:sanitize] == false
                link_text = sanitize(link_text)
                href      = sanitize(href)
              end
              content_tag(:a, link_text, link_attributes.merge('href' => href), !!options[:sanitize]) + punctuation.reverse.join('')
            end
          end.html_safe
        end
        # Turns all email addresses into clickable links.  If a block is given,
        # each email is yielded and the result is used as the link text.
        def auto_link_email_addresses(text, html_options = {}, options = {})
          text.gsub(AUTO_EMAIL_RE) do
            text = $&
            if auto_linked?($`, $')
              text.html_safe
            else
              display_text = (block_given?) ? yield(text) : text
              unless options[:sanitize] == false
                text         = sanitize(text)
                display_text = sanitize(display_text) unless text == display_text
              end
              mail_to text, display_text, html_options
            end
          end
        end
        # Detects already linked context or position in the middle of a tag
        def auto_linked?(left, right)
          (left =~ AUTO_LINK_CRE[0] and right =~ AUTO_LINK_CRE[1]) or
            (left.rindex(AUTO_LINK_CRE[2]) and $' !~ AUTO_LINK_CRE[3])
        end
    end
  end
end