# -*- coding: utf-8 -*-
module Axlsx
  
  # The Worksheet class represents a worksheet in the workbook. 
  class Worksheet
    
    # The name of the worksheet
    # @return [String]
    attr_accessor :name

    # The workbook that owns this worksheet
    # @return [Workbook]
    attr_reader :workbook

    # The worksheet relationships. This is managed automatically by the worksheet
    # @return [Relationships]
    attr_reader :relationships

    # The rows in this worksheet
    # @note The recommended way to manage rows is Worksheet#add_row
    # @return [SimpleTypedList]
    # @see Worksheet#add_row
    attr_reader :rows
    
    # The drawing associated with this worksheet.
    # @note the recommended way to work with drawings and charts is Worksheet#add_chart
    # @return [Drawing]
    # @see Worksheet#add_chart
    attr_reader :drawing

    # An array of content based calculated column widths.
    # @note a single auto fit data item is a hash with :longest => [String] and :sz=> [Integer] members.
    # @return [Array] of Hash 
    attr_reader :auto_fit_data

    # The part name of this worksheet
    # @return [String]
    attr_reader :pn

    # The relationship part name of this worksheet
    # @return [String]
    attr_reader :rels_pn

    # The relationship Id of thiw worksheet
    # @return [String]
    attr_reader :rId

    # The index of this worksheet in the owning Workbook's worksheets list.
    # @return [Integer]
    attr_reader :index

    # TODO Merge Cells
    # attr_reader :merge_cells
    
    # Creates a new worksheet.
    # @note the recommended way to manage worksheets is Workbook#add_worksheet
    # @see Workbook#add_worksheet
    # @option options [String] name The name of this sheet.
    def initialize(wb, options={})
      @rows = SimpleTypedList.new Row
      self.workbook = wb
      @workbook.worksheets << self
      @auto_fit_data = []
      self.name = options[:name] || "Sheet" + (index+1).to_s
      @magick_draw = Magick::Draw.new
    end

    
    def name=(v) DataTypeValidator.validate "Worksheet.name", String, v; @name=v end
    
    def pn
      "#{WORKSHEET_PN % (index+1)}"
    end

    def rels_pn
      "#{WORKSHEET_RELS_PN % (index+1)}"
    end

    def rId
      "rId#{index+1}"
    end
    
    def index
      @workbook.worksheets.index(self)
    end

    def drawing
      @drawing || @drawing = Axlsx::Drawing.new(self)
    end

    # Adds a row to the worksheet and updates auto fit data
    # @return [Row]
    # @option options [Array] values
    # @option options [Array, Symbol] types 
    # @option options [Array, Integer] style 
    def add_row(values=[], options={})
      Row.new(self, values, options)
      update_auto_fit_data @rows.last.cells
      yield @rows.last if block_given?
      @rows.last
    end

    # Adds a chart to this worksheets drawing.
    # @param [Class] chart_type
    # @option options [Array] start_at
    # @option options [Array] end_at
    # @option options [Cell, String] title
    def add_chart(chart_type, options={})
      chart = drawing.add_chart(chart_type, options)
      yield chart if block_given?
      chart
    end

    # Serializes the worksheet document
    # @return [String]
    def to_xml
      builder = Nokogiri::XML::Builder.new(:encoding => ENCODING) do |xml|
        xml.worksheet(:xmlns => XML_NS, :'xmlns:r' => XML_NS_R) {
          if @auto_fit_data.size > 0
            xml.cols {
              @auto_fit_data.each_with_index do |col, index|
                min_max = index+1
                xml.col(:min=>min_max, :max=>min_max, :width => auto_width(col), :customWidth=>"true")
              end
            }
          end
          xml.sheetData {
            @rows.each do |row|
              row.to_xml(xml)
            end
          }
          xml.drawing :"r:id"=>"rId1" if @drawing          
        }
      end
      builder.to_xml(:indent=>0, :save_with=>0)
    end

    # The worksheet's relationships.
    def relationships
        r = Relationships.new
        r << Relationship.new(DRAWING_R, "../#{@drawing.pn}") if @drawing
        r
    end

    private 

    # assigns the owner workbook for this worksheet
    def workbook=(v) DataTypeValidator.validate "Worksheet.workbook", Workbook, v; @workbook = v; end

    # Updates auto fit data. 
    # Autofit data attempts to determine the cell in a column that has the greatest width by comparing the length of the text multiplied by the size of the font.
    # @return [Array] of Cell objects
    # @param [Array] cells an array of cells
    def update_auto_fit_data(cells)
      styles = self.workbook.styles
      cellXfs, fonts = styles.cellXfs, styles.fonts
      sz = fonts[0].sz

      cells.each_with_index do |item, index|
        col = @auto_fit_data[index] || {:longest=>"", :sz=>sz} 
        cell_xf = cellXfs[item.style]
        font = fonts[cell_xf.fontId || 0]
        sz = font.sz || sz

        if (col[:longest].scan(/./mu).size * col[:sz]) < (item.value.to_s.scan(/./mu).size * sz)
          col[:sz] =  sz
          col[:longest] = item.value.to_s
        end
        @auto_fit_data[index] = col
      end
      cells
    end

    # Determines the proper width for a column based on content.
    # @note 
    #  From ECMA docs
    #   Column width measured as the number of characters of the maximum digit width of the numbers 0 .. 9 as 
    #   rendered in the normal style's font. There are 4 pixels of margin padding (two on each side), plus 1 pixel padding for the gridlines.
    #   width = Truncate([{Number of Characters} * {Maximum Digit Width} + {5 pixel padding}]/{Maximum Digit Width}*256)/256
    # @return [Float]
    # @param [Hash] A hash of auto_fit_data 
    def auto_width(col)
      mdw = 6.0 # maximum digit with is always 6.0 in testable fonts so instead of beating RMagick every time, I am hardcoding it here.
      mdw_count = 0 
      best_guess = 1.5  #direct testing shows the results of the documented formula to be a bit too small. This is a best guess scaling
      font_scale = col[:sz].to_f / (self.workbook.styles.fonts[0].sz.to_f || 11.0)
      col[:longest].scan(/./mu).each do |i|
        mdw_count +=1 if @magick_draw.get_type_metrics(i).width >= mdw 
      end
      ((mdw_count * mdw + 5) / mdw * 256) / 256.0 * best_guess * font_scale      
    end   
  end
end