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

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

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

local function color(name, s)
  return colors[name] .. s .. colors.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 })
  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 })

  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 = string.format("%s %s %s", group.name, icons.chevron, name) end
    group = group.parent
  end
  return name
end

local function trace(msg)
  return color("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("", color("pass", "PASS") .. " " .. name_test(test))
  else
    test.state = "fail"
    print("", color("fail", "FAIL") .. " " .. name_test(test) .. "\n")
    print(res .. "\n")
  end
  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 main(item)
  local cx = { tasks = {} }
  local pass, fail = 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
  if fail == 0 then
    print("", color("pass", string.format("%s %d tests passed", icons.check, pass)))
    return 0
  end
  print(
    "",
    color("pass", string.format("%s %d tests passed", icons.check, pass))
      .. ", "
      .. color("fail", string.format("%s %d tests failed", icons.cross, fail))
  )
  return 1 -- report error to cargo
end

return main(create_group("", function()
  local function glob(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

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