require 'hanami/utils'
require 'hanami/utils/class_attribute'
require 'hanami/utils/escape'
require 'hanami/helpers/html_helper/empty_html_node'
require 'hanami/helpers/html_helper/html_node'
require 'hanami/helpers/html_helper/html_fragment'
require 'hanami/helpers/html_helper/text_node'

module Hanami
  module Helpers
    module HtmlHelper
      # HTML Builder
      #
      # @since 0.1.0
      class HtmlBuilder # rubocop:disable Metrics/ClassLength
        # HTML5 content tags
        #
        # @since 0.1.0
        # @api private
        #
        # @see Hanami::Helpers::HtmlHelper::HtmlNode
        # @see https://developer.mozilla.org/en-US/docs/Web/HTML/Element
        CONTENT_TAGS = %w(
          a
          abbr
          address
          article
          aside
          audio
          b
          bdi
          bdo
          blockquote
          body
          button
          canvas
          caption
          cite
          code
          colgroup
          data
          datalist
          del
          details
          dialog
          dfn
          div
          dl
          dt
          dd
          em
          fieldset
          figcaption
          figure
          footer
          form
          h1
          h2
          h3
          h4
          h5
          h6
          head
          header
          hgroup
          i
          iframe
          ins
          kbd
          label
          legend
          li
          main
          map
          mark
          math
          menu
          meter
          nav
          noscript
          object
          ol
          optgroup
          option
          output
          p
          pre
          progress
          q
          rp
          rt
          rtc
          ruby
          s
          samp
          script
          section
          select
          slot
          small
          span
          strong
          style
          sub
          summary
          sup
          svg
          table
          tbody
          td
          template
          textarea
          tfoot
          th
          thead
          time
          title
          tr
          u
          ul
          var
          video
        ).freeze

        # HTML5 empty tags
        #
        # @since 0.1.0
        # @api private
        #
        # @see Hanami::Helpers::HtmlHelper::EmptyHtmlNode
        # @see https://developer.mozilla.org/en-US/docs/Web/HTML/Element
        EMPTY_TAGS = %w(
          area
          base
          br
          col
          embed
          hr
          img
          input
          keygen
          link
          menuitem
          meta
          param
          source
          track
          wbr
        ).freeze

        # New line separator
        #
        # @since 0.1.0
        # @api private
        NEWLINE = "\n".freeze

        CONTENT_TAGS.each do |tag|
          class_eval %{
            def #{tag}(content = nil, attributes = nil, &blk)
              @nodes << self.class.html_node.new(:#{tag}, blk || content, attributes || content, options)
              self
            end
          }
        end

        EMPTY_TAGS.each do |tag|
          class_eval %{
            def #{tag}(attributes = nil)
              @nodes << EmptyHtmlNode.new(:#{tag}, attributes)
              self
            end
          }
        end

        include Utils::ClassAttribute

        class_attribute :html_node
        self.html_node = ::Hanami::Helpers::HtmlHelper::HtmlNode

        # Initialize a new builder
        #
        # @return [Hanami::Helpers::HtmlHelper::HtmlBuilder] the builder
        #
        # @since 0.1.0
        # @api private
        def initialize
          @nodes = []
        end

        # @api private
        def options
        end

        # Define a custom tag
        #
        # @param name [Symbol,String] the name of the tag
        # @param content [String,Hanami::Helpers::HtmlHelper::HtmlBuilder,NilClass] the optional content
        # @param attributes [Hash,NilClass] the optional tag attributes
        # @param blk [Proc] the optional nested content espressed as a block
        #
        # @return [self]
        #
        # @since 0.1.0
        # @api public
        #
        # @see Hanami::Helpers::HtmlHelper
        #
        # @example
        #   html.tag(:custom) # => <custom></custom>
        #
        #   html.tag(:custom, 'foo') # => <custom>foo</custom>
        #
        #   html.tag(:custom, html.p('hello')) # => <custom><p>hello</p></custom>
        #
        #   html.tag(:custom) { 'foo' }
        #   # =>
        #   #<custom>
        #   #  foo
        #   #</custom>
        #
        #   html.tag(:custom) do
        #     p 'hello'
        #   end
        #   # =>
        #   #<custom>
        #   #  <p>hello</p>
        #   #</custom>
        #
        #   html.tag(:custom, 'hello', id: 'foo', 'data-xyz': 'bar') # => <custom id="foo" data-xyz="bar">hello</custom>
        #
        #   html.tag(:custom, id: 'foo') { 'hello' }
        #   # =>
        #   #<custom id="foo">
        #   #  hello
        #   #</custom>
        def tag(name, content = nil, attributes = nil, &blk)
          @nodes << HtmlNode.new(name, blk || content, attributes || content, options)
          self
        end

        # Define a HTML fragment
        #
        # @param blk [Proc] the optional nested content espressed as a block
        #
        # @return [self]
        #
        # @since 0.2.6
        # @api public
        #
        # @see Hanami::Helpers::HtmlHelper
        #
        # @example
        #   html.fragment('Hanami') # => Hanami
        #
        #   html do
        #     p 'hello'
        #     p 'hanami'
        #   end
        #   # =>
        #     <p>hello</p>
        #     <p>hanami</p>
        def fragment(&blk)
          @nodes << HtmlFragment.new(&blk)
          self
        end

        # Defines a custom empty tag
        #
        # @param name [Symbol,String] the name of the tag
        # @param attributes [Hash,NilClass] the optional tag attributes
        #
        # @return [self]
        #
        # @since 0.1.0
        # @api public
        #
        # @see Hanami::Helpers::HtmlHelper
        #
        # @example
        #   html.empty_tag(:xr) # => <xr>
        #
        #   html.empty_tag(:xr, id: 'foo') # => <xr id="foo">
        #
        #   html.empty_tag(:xr, id: 'foo', 'data-xyz': 'bar') # => <xr id="foo" data-xyz="bar">
        def empty_tag(name, attributes = nil)
          @nodes << EmptyHtmlNode.new(name, attributes)
          self
        end

        # Defines a plain string of text. This particularly useful when you
        # want to build more complex HTML.
        #
        # @param content [String] the text to be rendered.
        #
        # @return [self]
        #
        # @see Hanami::Helpers::HtmlHelper
        # @see Hanami::Helpers::HtmlHelper::TextNode
        #
        # @example
        #
        #   <%=
        #     html.label do
        #       text "Option 1"
        #       radio_button :option, 1
        #     end
        #   %>
        #
        #   <!-- output -->
        #   <label>
        #     Option 1
        #     <input type="radio" name="option" value="1" />
        #   </label>
        def text(content)
          @nodes << TextNode.new(content)
          self
        end

        # @since 0.2.5
        # @api private
        alias + text

        # Resolves all the nodes and generates the markup
        #
        # @return [Hanami::Utils::Escape::SafeString] the output
        #
        # @since 0.1.0
        # @api private
        #
        # @see http://www.rubydoc.info/gems/hanami-utils/Hanami/Utils/Escape/SafeString
        def to_s
          Utils::Escape::SafeString.new(@nodes.map(&:to_s).join(NEWLINE))
        end

        # Encode the content with the given character encoding
        #
        # @param encoding [Encoding,String] the encoding or its string representation
        #
        # @return [String] the encoded string
        #
        # @since 0.2.5
        # @api private
        def encode(encoding)
          to_s.encode(encoding)
        end

        # Check if there are nested nodes
        #
        # @return [TrueClass,FalseClass] the result of the check
        #
        # @since 0.1.0
        # @api private
        def nested?
          @nodes.any?
        end

        if !Utils.jruby?
          # Resolve the context for nested contents
          #
          # @since 0.1.0
          # @api private
          def resolve(&blk)
            @context = blk.binding.receiver
            instance_exec(&blk)
          end
        else
          # Resolve the context for nested contents
          #
          # @since 0.1.0
          # @api private
          def resolve(&blk)
            @context = eval 'self', blk.binding
            instance_exec(&blk)
          end
        end

        # Forward missing methods to the current context.
        # This allows to access views local variables from nested content blocks.
        #
        # @since 0.1.0
        # @api private
        def method_missing(m, *args, &blk)
          @context.__send__(m, *args, &blk)
        end
      end
    end
  end
end