if (...) ~= nil and (...).type == "group" then return end -- prevent recursive harness call

local ok = pcall(require, "lb:task")
if not ok then error("lua test harness requires 'lb:task'") end
local ok, time = pcall(require, "lb:time")
if not ok then error("lua test harness requires 'lb:time'") end
local ok, fs = pcall(require, "lb:fs")
if not ok then error("lua test harness requires 'lb:fs'") end

local global = _G
local color = {
  reset = "\x1b[0m",
  pass = "\x1b[32;1m", -- green
  fail = "\x1b[31;1m", -- red
}

local icon = {
  check = "\u{2713}",
  cross = "\u{00d7}",
  chevron = "\u{203a}",
}

local function style(name, s)
  return ("%s%s%s"):format(color[name], s, color.reset)
end

local function create_test(name, f, group)
  local test = { type = "test", name = name or "", group = group, state = "pending", f = f }
  local fenv = setmetatable({}, { __index = global, __newindex = global })
  setfenv(f, fenv)
  return test
end

local function create_group(name, f, parent)
  local group = { type = "group", name = name or "", parent = parent, items = {} }
  local fenv = setmetatable({
    describe = function(name, f)
      local item = create_group(name, f, group)
      table.insert(group.items, item)
      return item
    end,

    test = function(name, f)
      local item = create_test(name, f, group)
      table.insert(group.items, item)
      return item
    end,
  }, { __index = global, __newindex = global })

  setfenv(f, fenv)
  f(group)
  return group
end

local function name_test(test)
  local name = test.name
  local group = test.group
  while group ~= nil do
    if group.name ~= "" then name = ("%s %s %s"):format(group.name, icon.chevron, name) end
    group = group.parent
  end
  return name
end

local function trace(msg)
  return style("fail", msg) .. debug.traceback("", 2):sub(("\nstack traceback:"):len() + 1)
end

local function run_test(test)
  local ok, res = xpcall(test.f, trace, test)
  if ok then
    test.state = "pass"
    print("", ("%s %s"):format(style("pass", "PASS"), name_test(test)))
  else
    test.state = "fail"
    print("", ("%s %s\n\n%s\n"):format(style("fail", "FAIL"), name_test(test), res))
  end
  collectgarbage() -- gc after each test to test destructors
  return test
end

local function start(cx, item)
  if item.type == "test" then
    table.insert(cx.tasks, spawn(run_test, item))
  elseif item.type == "group" then
    for _, item in ipairs(item.items) do
      start(cx, item)
    end
  end
end

local function check_refs()
  -- ensure all refs were properly unref'ed
  local registry = debug.getregistry()
  local count = #registry
  local ref = 0 -- FREELIST_REF
  while type(registry[ref]) == "number" do
    local next = registry[ref]
    registry[ref], ref = nil, next
  end
  for i = 1, count do
    local value = registry[i]
    if type(value) ~= "thread" then -- ignore threads pinned by the runtime
      assert(rawequal(registry[i], nil), ("ref %d not unref'ed: %s"):format(i, registry[i]))
    end
  end
end

local function main(item)
  local cx = { tasks = {} }
  local time, pass, fail = time.instant(), 0, 0
  start(cx, item)
  for _, task in ipairs(cx.tasks) do
    if task:await().state == "pass" then
      pass = pass + 1
    else
      fail = fail + 1
    end
  end
  local elapsed = time:elapsed()
  local code = 1
  if fail == 0 then
    print("", style("pass", ("%s %d tests passed"):format(icon.check, pass)))
    code = 0
  else
    print(
      "",
      ("%s, %s"):format(
        style("pass", ("%s %d tests passed"):format(icon.check, pass)),
        style("fail", ("%s %d tests failed"):format(icon.cross, fail))
      )
    )
  end
  if elapsed < 1000 then
    print("", ("%s completed in %.2f ms"):format(icon.chevron, elapsed * 1000))
  else
    print("", ("%s completed in %.2f s"):format(icon.chevron, elapsed))
  end
  cx = nil
  collectgarbage()
  check_refs()
  return code -- report error to cargo
end

return main(create_group("", function()
  local function include(path, pat)
    for entry in fs.glob_dir(path, pat) do
      local path = entry:path()
      local f, err = loadfile(path)
      if not f then error(err) end
      describe(path, f)
    end
  end

  include("tests", "**/*.lua")
  include("crates", "*/tests/**/*.lua")
end))