# A unit test for re-fitting models
test_that("tests for re-fitting models", {
  # arima
  fit <- Arima(
    mdeaths,
    c(1, 0, 0),
    c(2, 0, 0),
    include.mean = FALSE,
    include.drift = TRUE
  )

  refit <- Arima(fdeaths, model = fit)
  expect_identical(fit$coef, refit$coef)
  expect_false(identical(fit$x, refit$x))
  expect_false(identical(fit$fitted, refit$fitted))
  expect_false(identical(fit$residuals, refit$residuals))

  refit_same <- Arima(mdeaths, model = fit)
  expect_identical(fit$coef, refit_same$coef)
  expect_identical(fit$x, refit_same$x)
  expect_true(all.equal(fit$fitted, refit_same$fitted))
  expect_true(all.equal(fit$residuals, refit_same$residuals))

  # arfima
  fit <- arfima(mdeaths)

  refit <- arfima(fdeaths, model = fit)
  expect_identical(fit$ar, refit$ar)
  expect_identical(fit$ma, refit$ma)
  expect_false(identical(fit$x, refit$x))
  expect_false(identical(fit$fitted, refit$fitted))
  expect_false(identical(fit$residuals, refit$residuals))

  refit_same <- arfima(mdeaths, model = fit)
  expect_identical(fit$ar, refit_same$ar)
  expect_identical(fit$ma, refit_same$ma)
  expect_identical(fit$x, refit_same$x)
  expect_identical(fit$fitted, refit_same$fitted)
  expect_identical(fit$residuals, refit_same$residuals)

  # dshw
  fit <- dshw(mdeaths, period1 = 4, period2 = 12)

  refit <- dshw(fdeaths, model = fit)
  expect_false(identical(fit$x, refit$x))
  expect_false(identical(fit$fitted, refit$fitted))
  expect_false(identical(fit$residuals, refit$residuals))

  refit_same <- dshw(mdeaths, model = fit)
  expect_identical(fit$model, refit_same$model)
  expect_identical(fit$x, refit_same$x)
  expect_identical(fit$fitted, refit_same$fitted)
  expect_identical(fit$residuals, refit_same$residuals)

  # ets
  fit <- ets(mdeaths)

  refit <- ets(fdeaths, model = fit, use.initial.values = TRUE)
  expect_identical(fit$fit, refit$fit)
  expect_false(identical(fit$x, refit$x))
  expect_false(identical(fit$fitted, refit$fitted))
  expect_false(identical(fit$residuals, refit$residuals))

  refit_same <- ets(mdeaths, model = fit, use.initial.values = TRUE)
  expect_identical(fit$x, refit_same$x)
  expect_identical(fit$fitted, refit_same$fitted)
  expect_identical(residuals(fit), residuals(refit_same))

  # stlm
  fit <- stlm(mdeaths)

  refit <- stlm(fdeaths, model = fit)
  expect_identical(fit$model$par, refit$model$par)
  expect_false(identical(fit$x, refit$x))
  expect_false(identical(fit$fitted, refit$fitted))
  expect_false(identical(fit$residuals, refit$residuals))

  refit_same <- stlm(mdeaths, model = fit)
  expect_identical(fit$model$par, refit_same$model$par)
  expect_identical(fit$x, refit_same$x)
  expect_identical(fit$fitted, refit_same$fitted)
  expect_identical(fit$residuals, refit_same$residuals)

  # bats
  fit <- bats(mdeaths)

  refit <- bats(fdeaths, model = fit)
  expect_identical(fit$parameters, refit$parameters)
  expect_false(identical(fit$x, refit$x))
  expect_false(identical(fit$fitted.values, refit$fitted.values))
  expect_false(identical(residuals(fit), residuals(refit)))

  refit_same <- bats(mdeaths, model = fit)
  expect_identical(fit$model$par, refit_same$model$par)
  expect_identical(fit$x, refit_same$x)
  expect_identical(fit$fitted.values, refit_same$fitted.values)
  expect_identical(residuals(fit), residuals(refit_same))

  # tbats
  fit <- tbats(mdeaths)

  refit <- tbats(fdeaths, model = fit)
  expect_identical(fit$parameters, refit$parameters)
  expect_false(identical(fit$x, refit$x))
  expect_false(identical(fit$fitted.values, refit$fitted.values))
  expect_false(identical(residuals(fit), residuals(refit)))

  refit_same <- tbats(mdeaths, model = fit)
  expect_identical(fit$model$par, refit_same$model$par)
  expect_identical(fit$x, refit_same$x)
  expect_identical(fit$fitted.values, refit_same$fitted.values)
  expect_identical(residuals(fit), residuals(refit_same))

  # nnetar
  fit <- nnetar(mdeaths)

  refit <- nnetar(fdeaths, model = fit)
  expect_false(identical(fit$x, refit$x))
  expect_false(identical(fit$fitted, refit$fitted))
  expect_false(identical(fit$residuals, refit$residuals))

  refit_same <- nnetar(mdeaths, model = fit)
  expect_identical(fit$x, refit_same$x)
  expect_identical(fit$fitted, refit_same$fitted)
  expect_identical(residuals(fit), residuals(refit_same))

  # forecast.ts
  fit <- forecast(mdeaths)

  refit <- forecast(fdeaths, model = fit, use.initial.values = TRUE)
  expect_false(identical(fit$x, refit$x))
  expect_false(identical(fit$fitted, refit$fitted))
  expect_false(identical(fit$residuals, refit$residuals))

  refit_same <- forecast(mdeaths, model = fit, use.initial.values = TRUE)
  expect_identical(fit$x, refit_same$x)
  expect_identical(fit$fitted, refit_same$fitted)
  expect_identical(residuals(fit), residuals(refit_same))
})