local system = require 'pandoc.system'

local function get_file(filename)
    local sysdir = system.get_working_directory()
    for k,v in pairs(PANDOC_STATE.resource_path) do
      local path = sysdir.."/"..v.."/"..filename
      local f = io.open(path, "r")
      if f ~= nil then
        return f
      else
        io.stderr:write(string.format("file not found, content of code block not replaced: %s", filename))
        return nil
      end
    end
end

local function get_content(file, ranges)
  if ranges == nil then
    return file:read "*a"
  end
  print(ranges)

  local intervals = {}
  for interval in ranges:gmatch('[^,%s]+') do
    table.insert(intervals, interval)
  end

  local current_line = 0
  for k, interval in pairs(intervals) do
    print("handling interval", interval)
    local first = 0
    local last  = 0
    -- inspect interval
      if string.find(interval, '-') then
        -- we have an interval
        first, last = interval:match("([0-9]+)-([0-9]+)")
        print(first, last)
      end
  end

  return ""
end


function CodeBlock(elem)
  if (elem.attributes['include'] ~= nil) then
    local filename = elem.attributes['include']
    local f = get_file(filename)

    if (f == nil) then
      return elem
    end

    elem.text = get_content(f, elem.attributes['ranges'])
    io.close(f)
  end
  return elem
end