testthat::test_that("pareto_2d identifies Pareto points when minimizing both", {

  x <- c(1,2,3,4)
  y <- c(4,3,2,1)

  res <- pareto_2d(x, y,
                   x_bigger_better = FALSE,
                   y_bigger_better = FALSE)

  # All points should be Pareto
  testthat::expect_true(all(res))
})



testthat::test_that("pareto_2d identifies Pareto points when maximizing both", {

  x <- c(1,2,3,4)
  y <- c(1,2,3,4)

  res <- pareto_2d(x, y,
                   x_bigger_better = TRUE,
                   y_bigger_better = TRUE)

  # Only the best point survives
  testthat::expect_equal(which(res), 4)
})



testthat::test_that("pareto_2d works with mixed optimization directions", {

  x <- c(1,2,3)
  y <- c(3,2,1)

  res <- pareto_2d(x, y,
                   x_bigger_better = FALSE,
                   y_bigger_better = TRUE)

  # first point should dominate others
  testthat::expect_true(res[1])
  testthat::expect_false(res[2])
  testthat::expect_false(res[3])
})



testthat::test_that("pareto_2d handles NA values", {

  x <- c(1,2,NA,3)
  y <- c(3,2,1,NA)

  res <- pareto_2d(x, y,
                   x_bigger_better = FALSE,
                   y_bigger_better = FALSE)

  # NAs should be treated as dominated
  testthat::expect_false(res[3])
  testthat::expect_false(res[4])
})



testthat::test_that("plot_pareto returns expected structure", {

  set.seed(123)

  df <- data.frame(
    obj1 = runif(20),
    obj2 = runif(20)
  )

  res <- plot_pareto(df,"obj1","obj2")

  testthat::expect_true(is.list(res))
  testthat::expect_s3_class(res$plot,"ggplot")
  testthat::expect_true(is.data.frame(res$pareto_points))
  testthat::expect_true(is.data.frame(res$all))
})



testthat::test_that("plot_pareto works with all direction combinations", {

  set.seed(42)

  df <- data.frame(
    x = runif(30),
    y = runif(30)
  )

  combos <- expand.grid(
    x_bigger_better = c(TRUE,FALSE),
    y_bigger_better = c(TRUE,FALSE)
  )

  for(i in seq_len(nrow(combos))){

    res <- plot_pareto(
      df,
      "x",
      "y",
      x_bigger_better = combos$x_bigger_better[i],
      y_bigger_better = combos$y_bigger_better[i]
    )

    testthat::expect_s3_class(res$plot,"ggplot")
    testthat::expect_true(nrow(res$pareto_points) >= 1)
  }

})