# encoding: utf-8

# core/text/formatted/arranger.rb : Implements a data structure for 2-stage
#                                   processing of lines of formatted text
#
# Copyright February 2010, Daniel Nelson. All Rights Reserved.
#
# This is free software. Please see the LICENSE and COPYING files for details.

module Prawn
  module Text
    module Formatted #:nodoc:
      # @private

      class Arranger #:nodoc:
        attr_reader :max_line_height
        attr_reader :max_descender
        attr_reader :max_ascender
        attr_reader :finalized
        attr_accessor :consumed

        # The following present only for testing purposes
        attr_reader :unconsumed
        attr_reader :fragments
        attr_reader :current_format_state

        def initialize(document, options = {})
          @document = document
          @fragments = []
          @unconsumed = []
          @kerning = options[:kerning]
        end

        def space_count
          unless finalized
            fail "Lines must be finalized before calling #space_count"
          end

          @fragments.inject(0) do |sum, fragment|
            sum + fragment.space_count
          end
        end

        def line_width
          unless finalized
            fail "Lines must be finalized before calling #line_width"
          end

          @fragments.inject(0) do |sum, fragment|
            sum + fragment.width
          end
        end

        def line
          unless finalized
            fail "Lines must be finalized before calling #line"
          end

          @fragments.collect do |fragment|
            fragment.text.dup.force_encoding(::Encoding::UTF_8)
          end.join
        end

        def finalize_line
          @finalized = true

          omit_trailing_whitespace_from_line_width
          @fragments = []
          @consumed.each do |hash|
            text = hash[:text]
            format_state = hash.dup
            format_state.delete(:text)
            fragment = Prawn::Text::Formatted::Fragment.new(text,
                                                            format_state,
                                                            @document)
            @fragments << fragment
            set_fragment_measurements(fragment)
            set_line_measurement_maximums(fragment)
          end
        end

        def format_array=(array)
          initialize_line
          @unconsumed = []
          array.each do |hash|
            hash[:text].scan(/[^\n]+|\n/) do |line|
              @unconsumed << hash.merge(:text => line)
            end
          end
        end

        def initialize_line
          @finalized = false
          @max_line_height = 0
          @max_descender = 0
          @max_ascender = 0

          @consumed = []
          @fragments = []
        end

        def finished?
          @unconsumed.length == 0
        end

        def next_string
          if finalized
            fail "Lines must not be finalized when calling #next_string"
          end

          next_unconsumed_hash = @unconsumed.shift

          if next_unconsumed_hash
            @consumed << next_unconsumed_hash.dup
            @current_format_state = next_unconsumed_hash.dup
            @current_format_state.delete(:text)

            next_unconsumed_hash[:text]
          end
        end

        def preview_next_string
          next_unconsumed_hash = @unconsumed.first

          if next_unconsumed_hash
            next_unconsumed_hash[:text]
          end
        end

        def apply_color_and_font_settings(fragment, &block)
          if fragment.color
            original_fill_color = @document.fill_color
            original_stroke_color = @document.stroke_color
            @document.fill_color(*fragment.color)
            @document.stroke_color(*fragment.color)
            apply_font_settings(fragment, &block)
            @document.stroke_color = original_stroke_color
            @document.fill_color = original_fill_color
          else
            apply_font_settings(fragment, &block)
          end
        end

        def apply_font_settings(fragment = nil, &block)
          if fragment.nil?
            font = current_format_state[:font]
            size = current_format_state[:size]
            character_spacing = current_format_state[:character_spacing] ||
                                @document.character_spacing
            styles = current_format_state[:styles]
            font_style = font_style(styles)
          else
            font = fragment.font
            size = fragment.size
            character_spacing = fragment.character_spacing
            styles = fragment.styles
            font_style = font_style(styles)
          end

          @document.character_spacing(character_spacing) do
            if font || font_style != :normal
              fail "Bad font family" unless @document.font.family
              @document.font(font || @document.font.family, :style => font_style) do
                apply_font_size(size, styles, &block)
              end
            else
              apply_font_size(size, styles, &block)
            end
          end
        end

        def update_last_string(printed, unprinted, normalized_soft_hyphen = nil)
          return if printed.nil?
          if printed.empty?
            @consumed.pop
          else
            @consumed.last[:text] = printed
            if normalized_soft_hyphen
              @consumed.last[:normalized_soft_hyphen] = normalized_soft_hyphen
            end
          end

          unless unprinted.empty?
            @unconsumed.unshift(@current_format_state.merge(:text => unprinted))
          end

          load_previous_format_state if printed.empty?
        end

        def retrieve_fragment
          unless finalized
            fail "Lines must be finalized before fragments can be retrieved"
          end

          @fragments.shift
        end

        def repack_unretrieved
          new_unconsumed = []
          while fragment = retrieve_fragment
            fragment.include_trailing_white_space!
            new_unconsumed << fragment.format_state.merge(:text => fragment.text)
          end
          @unconsumed = new_unconsumed.concat(@unconsumed)
        end

        def font_style(styles)
          if styles.nil?
            :normal
          elsif styles.include?(:bold) && styles.include?(:italic)
            :bold_italic
          elsif styles.include?(:bold)
            :bold
          elsif styles.include?(:italic)
            :italic
          else
            :normal
          end
        end

        private

        def load_previous_format_state
          if @consumed.empty?
            @current_format_state = {}
          else
            hash = @consumed.last
            @current_format_state = hash.dup
            @current_format_state.delete(:text)
          end
        end

        def apply_font_size(size, styles)
          if subscript?(styles) || superscript?(styles)
            relative_size = 0.583
            if size.nil?
              size = @document.font_size * relative_size
            else
              size = size * relative_size
            end
          end
          if size.nil?
            yield
          else
            @document.font_size(size) { yield }
          end
        end

        def subscript?(styles)
          if styles.nil? then false
          else styles.include?(:subscript)
          end
        end

        def superscript?(styles)
          if styles.nil? then false
          else styles.include?(:superscript)
          end
        end

        def omit_trailing_whitespace_from_line_width
          @consumed.reverse_each do |hash|
            if hash[:text] == "\n"
              break
            elsif hash[:text].strip.empty? && @consumed.length > 1
              # this entire fragment is trailing white space
              hash[:exclude_trailing_white_space] = true
            else
              # this fragment contains the first non-white space we have
              # encountered since the end of the line
              hash[:exclude_trailing_white_space] = true
              break
            end
          end
        end

        def set_fragment_measurements(fragment)
          apply_font_settings(fragment) do
            fragment.width = @document.width_of(fragment.text,
                                                :kerning => @kerning)
            fragment.line_height = @document.font.height
            fragment.descender = @document.font.descender
            fragment.ascender = @document.font.ascender
          end
        end

        def set_line_measurement_maximums(fragment)
          @max_line_height = [defined?(@max_line_height) && @max_line_height, fragment.line_height].compact.max
          @max_descender = [defined?(@max_descender) && @max_descender, fragment.descender].compact.max
          @max_ascender = [defined?(@max_ascender) && @max_ascender, fragment.ascender].compact.max
        end
      end
    end
  end
end