lovr = require 'lovr'

-- Note: Cannot be overloaded
function lovr.boot()
  local conf = {
    version = '0.16.0',
    identity = 'default',
    saveprecedence = true,
    modules = {
      audio = true,
      data = true,
      event = true,
      graphics = true,
      headset = true,
      math = true,
      physics = true,
      system = true,
      thread = true,
      timer = true
    },
    audio = {
      start = true,
      spatializer = nil
    },
    graphics = {
      debug = false,
      vsync = true,
      stencil = false,
      antialias = true,
      shadercache = true
    },
    headset = {
      drivers = { 'openxr', 'webxr', 'desktop' },
      supersample = false,
      offset = 1.7,
      stencil = false,
      antialias = true,
      submitdepth = true,
      overlay = false
    },
    math = {
      globals = true
    },
    window = {
      width = 720,
      height = 800,
      fullscreen = false,
      resizable = false,
      title = 'LÖVR',
      icon = nil
    }
  }

  lovr.filesystem = require('lovr.filesystem')
  local main = arg[0] and arg[0]:match('[^\\/]-%.lua$') or 'main.lua'
  local hasConf, hasMain = lovr.filesystem.isFile('conf.lua'), lovr.filesystem.isFile(main)
  if not lovr.filesystem.getSource() or not (hasConf or hasMain) then require('nogame') end

  -- Shift args up in fused mode, instead of consuming one for the source path
  if lovr.filesystem.isFused() then
    for i = 1, #arg + 1 do
      arg[i] = arg[i - 1]
    end
    arg[0] = lovr.filesystem.getSource()
  end

  local confOk, confError = true
  if hasConf then confOk, confError = pcall(require, 'conf') end
  if confOk and lovr.conf then confOk, confError = pcall(lovr.conf, conf) end

  lovr._setConf(conf)
  lovr.filesystem.setIdentity(conf.identity, conf.saveprecedence)

  for module in pairs(conf.modules) do
    if conf.modules[module] then
      local ok, result = pcall(require, 'lovr.' .. module)
      if not ok then
        print(string.format('Warning: Could not load module %q: %s', module, result))
      else
        lovr[module] = result
      end
    end
  end

  if lovr.system and conf.window then
    lovr.system.openWindow(conf.window)
  end

  if lovr.graphics then
    lovr.graphics.initialize()
  end

  if lovr.headset and lovr.graphics and conf.window then
    lovr.headset.start()

    if lovr.headset.getDriver() == 'desktop' then
      lovr.mirror = nil
    end
  end

  lovr.handlers = setmetatable({}, { __index = lovr })
  if not confOk then error(confError) end
  if hasMain then require(main:gsub('%.lua$', '')) end
  return lovr.run()
end

function lovr.run()
  if lovr.timer then lovr.timer.step() end
  if lovr.load then lovr.load(arg) end
  return function()
    if lovr.event then
      lovr.event.pump()
      for name, a, b, c, d in lovr.event.poll() do
        if name == 'restart' then
          local cookie = lovr.restart and lovr.restart()
          return 'restart', cookie
        elseif name == 'quit' and (not lovr.quit or not lovr.quit(a)) then
          return a or 0
        end
        if lovr.handlers[name] then lovr.handlers[name](a, b, c, d) end
      end
    end
    local dt = 0
    if lovr.timer then dt = lovr.timer.step() end
    if lovr.headset then dt = lovr.headset.update() end
    if lovr.update then lovr.update(dt) end
    if lovr.graphics then
      if lovr.headset then
        local pass = lovr.headset.getPass()
        if pass then
          local skip = lovr.draw and lovr.draw(pass)
          if not skip then lovr.graphics.submit(pass) end
        end
      end
      if lovr.system.isWindowOpen() then
        if lovr.mirror then
          local pass = lovr.graphics.getWindowPass()
          local skip = lovr.mirror(pass)
          if not skip then lovr.graphics.submit(pass) end
        end
        lovr.graphics.present()
      end
    end
    if lovr.headset then lovr.headset.submit() end
    if lovr.math then lovr.math.drain() end
  end
end

function lovr.mirror(pass)
  if lovr.headset then
    local texture = lovr.headset.getTexture()
    if texture then
      pass:fill(texture)
    else
      return true
    end
  else
    return lovr.draw and lovr.draw(pass)
  end
end

local function formatTraceback(s)
  return s:gsub('\n[^\n]+$', ''):gsub('\t', ''):gsub('stack traceback', '\nStack')
end

function lovr.errhand(message)
  message = tostring(message) .. formatTraceback(debug.traceback('', 4))
  print('Error:\n' .. message)

  if not lovr.graphics then return function() return 1 end end

  if lovr.audio then lovr.audio.stop() end

  local scale = .35
  local font = lovr.graphics.getDefaultFont()
  local wrap = .7 * font:getPixelDensity()
  local lines = font:getLines(message, wrap)
  local width = math.min(font:getWidth(message), wrap) * scale
  local height = .8 + #lines * font:getHeight() * scale
  local x = -width / 2
  local y = math.min(height / 2, 10)
  local z = -10

  lovr.graphics.setBackgroundColor(.11, .10, .14)
  font:setPixelDensity()

  local function render(pass)
    pass:setColor(.95, .95, .95)
    pass:text('Error', x, y, z, scale * 1.6, 0, 0, 0, 0, nil, 'left', 'top')
    pass:text(message, x, y - .8, z, scale, 0, 0, 0, 0, wrap, 'left', 'top')
  end

  return function()
    lovr.event.pump()

    for name, a in lovr.event.poll() do
      if name == 'quit' then return a or 1
      elseif name == 'restart' then return 'restart', lovr.restart and lovr.restart()
      elseif name == 'keypressed' and a == 'f5' then lovr.event.restart() end
    end

    if lovr.headset and lovr.headset.getDriver() ~= 'desktop' then
      lovr.headset.update()
      local pass = lovr.headset.getPass()
      if pass then
        render(pass)
        lovr.graphics.submit(pass)
        lovr.headset.submit()
      end
    end

    if lovr.system.isWindowOpen() then
      local pass = lovr.graphics.getWindowPass()
      render(pass)
      lovr.graphics.submit(pass)
      lovr.graphics.present()
    end
  end
end

function lovr.threaderror(thread, err)
  error('Thread error\n\n' .. err, 0)
end

function lovr.log(message, level, tag)
  print(message:gsub('\n$', ''))
end

return function()
  local errored = false

  local function onerror(...)
    if not errored then
      errored = true -- Ensure errhand is only called once
      return lovr.errhand(...) or function() return 1 end
    else
      local message = tostring(...) .. formatTraceback(debug.traceback('', 2))
      print('Error occurred while trying to display another error:\n' .. message)
      return function() return 1 end
    end
  end

  -- thread will be either lovr.run's step function, or the result of errhand
  local _, thread = xpcall(lovr.boot, onerror)

  while true do
    local ok, result, cookie = xpcall(thread, onerror)

    -- If step function returned something, exit coroutine and return to C
    if result and ok then
      return result, cookie
    elseif not ok then -- Switch to errhand loop
      thread = result
      if type(thread) ~= 'function' then
        print('Error occurred while trying to display another error:\n' .. tostring(result))
        return 1
      end
    end

    coroutine.yield()
  end
end