class Terminal::Table::UnicodeBorder

def horizontal(type)
  raise ArgumentError, "Border type is #{type.inspect}, must be one of #{ALLOWED_SEPARATOR_BORDER_STYLES.inspect}" unless ALLOWED_SEPARATOR_BORDER_STYLES.include?(type)
  lookup = case type
           when :top
             [:nw, :nx, :n, :ne, :n, nil]
           when :bot
             [:sw, :sx, :s, :se, nil, :s]
           when :double
             # typically used for the separator below the heading row or above a footer row)
             [:aw, :ax, :ai, :ae, :ad, :au]
           when :thick, :thick_dash, :thick_dot3, :thick_dot4,
                :heavy, :heavy_dash, :heavy_dot3, :heavy_dot4,
                :bold, :bold_dash, :bold_dot3, :bold_dot4
             # alternate thick/bold border
             xref = type.to_s.sub(/^(thick|heavy|bold)/,'bx').to_sym
             [:bw, xref, :bi, :be, :bd, :bu]
           when :dash, :dot3, :dot4
             # alternate thin dividers
             xref = "x_#{type}".to_sym
             [:w, xref, :i, :e, :dn, :up]
           else  # :div (center, non-emphasized)
             [:w, :x, :i, :e, :dn, :up]
           end
  rval = lookup.map { |key| @data.fetch(key) }
  rval[0] = '' unless @left
  rval[3] = '' unless @right
  rval
end

def initialize
  super
  @data = {
    nil => nil,
    nw: "┌", nx: "─", n:  "┬", ne: "┐",
    yw: "│",          y:  "│", ye: "│", 
    aw: "╞", ax: "═", ai: "╪", ae: "╡", ad: '╤', au: "╧", # double
    bw: "┝", bx: "━", bi: "┿", be: "┥", bd: '┯', bu: "┷", # heavy/bold/thick
    w:  "├", x:  "─", i:  "┼", e:  "┤", dn: "┬", up: "┴", # normal div
    sw: "└", sx: "─", s:  "┴", se: "┘",
    # alternative dots/dashes
    x_dot4:  '┈', x_dot3:  '┄', x_dash:  '╌',
    bx_dot4: '┉', bx_dot3: '┅', bx_dash: '╍',
  }
end

def vertical
  [maybeleft(:yw), @data[:y], mayberight(:ye)] 
end