#!/usr/bin/env ruby
# encoding: utf-8
# ruby 2.6.5
=begin
generates USB cables definitions

in usb_cables.c define USB cable template as follows:
static const uint8_t usb__a_host__b__abpower_pins[][2] = {
	{usb_a_host_pins[1], usb_b_device_pins[1]}, // VBUS
	{usb_a_host_pins[4], usb_b_device_pins[4]}, // GND
};

any following variable declarations like
static const uint8_t usb__a_device__b__abpower_pins[][2]
will copy the array content from the first declaration and replace a_host with a_device and b with b

this modified C file will be written to the path provided as argument
=end

class String
  # This method will return an array of MatchData's rather than the
  # array of strings returned by the vanilla `scan`.
  def match_all(regex)
    match_str = self
    match_datas = []
    while match_str.length > 0 do 
      md = match_str.match(regex)
      break unless md
      match_datas << md
      match_str = md.post_match
    end
    return match_datas
  end
end

# variable to process regexp
cable_regex = /static const uint8_t (?<variable>usb__(?<connector1>\w+)__(?<connector2>\w+)__(?<name>\w+)_(?<type>pins|opts))\[\]\[2\] = (?<array>\{[^;]+\});/m
# read C definitions file
usb_cables_text = IO.read("usb_cables.c")
output_text = usb_cables_text.dup
# get all variables to process
cables = usb_cables_text.match_all(cable_regex)
# go through variables
cables.each_index do |i|
  next if 0 == i
  cable = cables[i]
  # find if there was a previously matching definition
  template = cables[0, i].filter {|c| c[:name] == cable[:name] and c[:type] == cable[:type]}.first
  next unless template
  puts "generate #{cable[:variable]} usng #{template[:variable]}"
  array = template[:array]
  array.gsub!(template[:connector1], cable[:connector1])
  array.gsub!(template[:connector2], cable[:connector2])
  generated = cable[0]
  generated.gsub!(cable[:array], array)
  puts generated
  puts
  output_text.gsub!(cable[0], generated)
end

if ARGV[0] then
  puts "saving to #{ARGV[0]}"
  File.open(ARGV[0], "w") {|f| f.write output_text}
end