require "bigdecimal"
require "set"

module Lace

  extend self

  def en(series, sigfigs, n)
    return BigDecimal((10.0**Math.log10(n.to_f**series.to_f).round.to_f)**(1.0/series.to_f), sigfigs).round
  end

  HISTORIC_E24_FIX_TABLE = {
    Math.log10(2.6)  => Math.log10(2.7),
    Math.log10(2.9)  => Math.log10(3.0),
    Math.log10(3.2)  => Math.log10(3.3),
    Math.log10(3.5)  => Math.log10(3.6),
    Math.log10(3.8)  => Math.log10(3.9),
    Math.log10(4.2)  => Math.log10(4.3),
    Math.log10(4.6)  => Math.log10(4.7),
    }
  def historic_e24_fix(n)
    exp, rem = Math.log10(n).divmod(1)
    HISTORIC_E24_FIX_TABLE.each do | accurate, historic |
      rem = historic if (rem - accurate).abs <= 0.0001
    end
    return (10 ** (exp + rem)).round
  end

  def e3(n)
    return historic_e24_fix(en(3, 2, n))
  end

  def e6(n)
    return historic_e24_fix(en(6, 2, n))
  end

  def e12(n)
    return historic_e24_fix(en(12, 2, n))
  end

  def e24(n)
    return historic_e24_fix(en(24, 2, n))
  end

  def e48(n)
    return en(48, 3, n)
  end

  def e96(n)
    return en(96, 3, n)
  end

  def e192(n)
    return en(192, 3, n)
  end

  class Netlist

    attr_reader :components
    attr_reader :nets

    def initialize(&p)
      @components = {}
      @nets = {}

      edit(&p) if p
    end

    def merge_nets(a, b)
      into = @nets[[a.object_id, b.object_id].min]
      if a.name
        raise "Nets #{into.name} and #{a.name} merged!" if into.name and into.name != a.name
        into.name = a.name
      end
      if b.name
        raise "Nets #{into.name} and #{b.name} merged!" if into.name and into.name != b.name
        into.name = b.name
      end
      @nets[a.object_id] = into
      @nets[b.object_id] = into
      return into
    end

    def edit(&p)
      instance_eval &p
    end

    def comp(*args)
      c = Component.new(self, *args)
      @components[c.object_id] = c
    end

    def net(*args)
      n = Net.new(self, *args)
      @nets[n.object_id] = n
    end

    def real_refs
      refs = {}
      counters = {}
      seen = Set.new
      @components.each do | id, comp |
        next if seen.member?(comp.object_id)
        seen.add(comp.object_id)
        counter = counters[comp.refbase] || 1
        counters[comp.refbase] = counter + 1
        ref = "#{comp.refbase}#{counter}"
        refs[ref] = comp
      end
      return refs
    end

    def real_nets(refs)
      n = 1
      nets = {}
      seen = Set.new
      @nets.each do | id, net |
        next if seen.member?(net.object_id)
        seen.add(net.object_id)
        name = net.name
        unless name
          name = "$unnamed#{n}"
          n += 1
        end
        raise "Multiple disconnected nets named #{name}" if nets.member?(name)
        nodes = []
        refs.each do | ref, comp |
          comp.pins.each do | pin, pinnet |
            nodes << {:ref => ref, :pin => pin} if @nets[pinnet].object_id == net.object_id
          end
        end
        nets[name] = nodes if nodes.size > 1
      end
      return nets
    end

    def real
      refs = real_refs
      nets = real_nets(refs)
      return [refs, nets]
    end

    def kicad(stream=$stdout)
      refs, nets = real
      stream.write(<<END)
(export
  (version D)
  (components
END
      refs.each do | ref, comp |
        stream.write(<<END)
    (comp
      (ref #{ref.inspect})
      (footprint #{comp.footprint.inspect})
      (value #{comp.value.inspect})
      (libsource (lib NO_LIB) (part #{comp.name.inspect}))
    )
END
      end
      stream.write(<<END)
  )
  (nets
END
      n = 1
      nets.each do | name, nodes |
        stream.write(<<END)
    (net
      (code #{n})
      (name #{name.inspect})
END
        nodes.each do | node |
          stream.write(<<END)
      (node
        (ref #{node[:ref].inspect})
        (pin #{node[:pin]})
      )
END
        end
        stream.write(<<END)
    )
END
        n += 1
      end
      stream.write(<<END)
  )
)
END
    end

    def summary(stream=$stdout)
      refs, nets = real
      refs.each do | ref, comp |
        stream.write("#{ref} is a #{comp.footprint} #{comp.desc}\n")
      end
      nets.each do | name, nodes |
        stream.write("Net #{name}:\n")
        nodes.each do | node |
          stream.write("  #{node[:ref]}[#{node[:pin]}]\n")
        end
      end
    end

    def bom
      bom = {}
      real_refs.each do | ref, comp |
        desc = "#{comp.footprint} #{comp.desc}"
        bom[desc] = 0 unless bom.member?(desc)
        bom[desc] += 1
      end
      return bom
    end
  end

  class Wireable

    attr_reader :netlist

    attr_reader :left
    attr_reader :right

    def initialize(netlist, left=nil, right=nil)
      @netlist = netlist

      @left = left
      @right = right || left
    end

    def -(that)
      @netlist.merge_nets(@right, that.left)
      return Wireable.new(@netlist, @left, that.right)
    end

  end

  class Component < Wireable

    attr_reader :refbase
    attr_reader :footprint
    attr_reader :name
    attr_reader :value

    attr_reader :pins

    def initialize(netlist, refbase, footprint, name, value=nil)
      super(netlist)

      @refbase = refbase
      @footprint = footprint
      @name = name
      @value = value || name

      @pins = {}
    end

    def left
      return self[1]
    end

    def right
      return self[2]
    end

    def [](pin)
      unless pins.member?(pin)
        n = @netlist.net
        pins[pin] = n.object_id
      end
      return @netlist.nets[pins[pin]]
    end

    def desc
      return "#{@value} #{@name}" if @name != @value
      return @name
    end

  end

  class Net < Wireable

    attr_accessor :name

    def initialize(netlist, name=nil)
      super(netlist, self)

      @name = name
    end

  end

end