-- Cribbed from http://czerasz.com/2015/07/19/wrk-http-benchmarking-tool-example

-- Module instantiation
local cjson = require "cjson"
local cjson2 = cjson.new()
local cjson_safe = require "cjson.safe"

-- Initialize the pseudo random number generator
-- Resource: http://lua-users.org/wiki/MathLibraryTutorial
math.randomseed(os.time())
math.random(); math.random(); math.random()

-- Shuffle array
-- Returns a randomly shuffled array
function shuffle(paths)
  local j, k
  local n = #paths

  for i = 1, n do
    j, k = math.random(n), math.random(n)
    paths[j], paths[k] = paths[k], paths[j]
  end

  return paths
end

-- Load URL paths from the file
function load_request_objects_from_file(file)
  local data = {}
  local content

  -- Check if the file exists
  -- Resource: http://stackoverflow.com/a/4991602/325852
  local f=io.open(file,"r")
  if f~=nil then
    content = f:read("*all")

    io.close(f)
  else
    -- Return the empty array
    return lines
  end

  -- Translate Lua value to/from JSON
  data = cjson.decode(content)


  return shuffle(data)
end

-- Load URL requests from file
requests = load_request_objects_from_file("requests.json")

-- Check if at least one path was found in the file
if #requests <= 0 then
  print("multiplerequests: No requests found.")
  os.exit()
end

print("multiplerequests: Found " .. #requests .. " requests")

-- Initialize the requests array iterator
counter = 1

request = function()
  -- Get the next requests array element
  local request_object = requests[counter]

  -- Increment the counter
  counter = counter + 1

  -- If the counter is longer than the requests array length then reset it
  if counter > #requests then
    counter = 1
  end

  -- Return the request object with the current URL path
  return wrk.format(request_object.method, request_object.path, request_object.headers, request_object.body)
end

done = function(summary, latency, requests)
   io.write("------------------------------\n")
   for _, p in pairs({ 10, 20, 30, 40, 50, 60, 70, 80, 90, 99 }) do
      n = latency:percentile(p)
      io.write(string.format("%g%%,%d\n", p, n))
   end
   io.write(string.format("duration (micros),%d\n", summary.duration))
   io.write(string.format("requests,%d\n", summary.requests))
   io.write(string.format("bytes,%d\n", summary.bytes))
   io.write(string.format("connect errors,%d\n", summary.errors.connect))
   io.write(string.format("read errors,%d\n", summary.errors.read))
   io.write(string.format("write errors,%d\n", summary.errors.write))
   io.write(string.format("status errors,%d\n", summary.errors.status))
   io.write(string.format("timeout errors,%d\n", summary.errors.timeout))
   io.write("------------------------------\n")
end