test_that("Verify Input Formats", {
  dfts(dfts(electricity))
  if (requireNamespace("fda", quietly = TRUE)) {
    tmp <- dfts(fda::Data2fd(1:24, electricity$data))
    expect_equal(tmp$data[2, 7], electricity$data[2, 7])
  }
  if (requireNamespace("fda.usc", quietly = TRUE)) {
    tmp <- dfts(fda.usc::fdata(t(electricity$data)))
    expect_equal(tmp$data[2, 7], electricity$data[2, 7])
  }
  if (requireNamespace("rainbow", quietly = TRUE)) {
    tmp <- dfts(suppressWarnings(rainbow::fts(x = 1:nrow(electricity$data), y = electricity$data)))
    expect_equal(tmp$data[2, 7], electricity$data[2, 7])
    tmp <- dfts(rainbow::fds(1:nrow(electricity$data), electricity$data))
    expect_equal(tmp$data[2, 7], electricity$data[2, 7])
  }
  if (requireNamespace("funData", quietly = TRUE)) {
    tmp <- dfts(funData::funData(1:24, t(electricity$data)))
    expect_equal(tmp$data[2, 7], electricity$data[2, 7])
  }

  tmp <- dfts(electricity)
  expect_equal(tmp$data[2, 7], electricity$data[2, 7])
})

test_that("Check inheritance of dfts", {
  expect_false(is.dfts(electricity$data))
  expect_true(is.dfts(electricity))
})

test_that("Check math of dfts", {
  elec <- dfts(electricity)

  expect_equal((elec + elec)$data[8, 7], electricity$data[8, 7] * 2)
  expect_equal(sum((elec - elec)$data), 0)
  expect_equal(round(sqrt(elec)$data[8, 9], 5), 6.64605)

  expect_equal(min(elec)$data[1:3], c(0.2, 0.0, 0.0))
  expect_equal(max(elec)$data[1:3], c(67.2, 64.6, 62.68))

  expect_equal(mean(elec)[15], mean(electricity$data[15, ]))
  expect_equal(median(elec)[8], median(electricity$data[8, ]))
  expect_equal(
    quantile(elec, probs = 0.95)[1, ],
    quantile(electricity$data[1, ], prob = 0.95)[[1]]
  )
})

test_that("Check lag of dfts", {
  elec <- dfts(electricity)

  expect_equal(dim(lag(elec, 1)), c(24, 364))
  expect_equal(lag(elec, lag = 1, difference = 2)$data[22, 42], 18.69)
})


test_that("Check [ or [<-", {
  expect_equal(electricity[8, 10]$data[[1]], 51.3)
  expect_equal(electricity[1]$data[5], 0.5)

  # All 4 indices replacement
  tmp <- dfts(matrix(1:9, 3, 3))
  tmp[1, 2] <- 1
  expect_equal(tmp[1, 2]$data[1], 1)
  tmp[, 2] <- 2
  expect_equal(sum(tmp$data[, 2]), 6)
  tmp[1, ] <- 3
  expect_equal(sum(tmp$data[1, ]), 9)
  tmp[2:3, 1:2] <- 5
  expect_equal(sum(tmp$data[2:3, 1:2]), 20)
  tmp[1, ] <- 1:3
  expect_equal(sum(tmp$data[1, ]), 6)
  tmp[c(1, 3), ] <- 1
  expect_equal(sum(tmp$data[c(1, 3), ]), 6)

  # 3 indices replacement
  tmp <- dfts(matrix(1:9, 3, 3))
  tmp[2] <- 1
  expect_equal(sum(tmp$data[, 2]), 3)
  tmp[2] <- 1:3
  expect_equal(sum(tmp$data[, 2]), 6)
  tmp[c(1, 3)] <- 1
  expect_equal(sum(tmp$data[, c(1, 3)]), 6)

  # dfts addition
  tmp <- dfts(matrix(1:9, 3, 3))
  tmp[, 2:3] <- tmp[, 2:3] + 1
  expect_equal(sum(tmp$data[, 2:3]), 6 + sum(4:9))

  tmp <- dfts(matrix(1:9, 3, 3))
  tmp[1, ] <- tmp[1, ] + 1
  expect_equal(sum(tmp$data[1, ]), 3 + sum(c(1, 4, 7)))

  tmp <- dfts(matrix(1:9, 3, 3))
  tmp[c(1, 3), ] <- tmp[c(1, 3), ] + 1
  expect_equal(sum(tmp$data[c(1, 3), ]), 2 * 3 + sum(c(1, 3, 4, 6, 7, 9)))

  tmp <- dfts(matrix(1:9, 3, 3))
  tmp[3] <- tmp[3] + 1
  expect_equal(sum(tmp$data[, 3]), 3 + sum(c(7, 8, 9)))

  tmp <- dfts(matrix(1:9, 3, 3))
  tmp[c(1, 3)] <- tmp[c(1, 3)] + 1
  expect_equal(sum(tmp$data[, c(1, 3)]), 2 * 3 + sum(c(1:3, 7:9)))
})