context("Testing computation of distance")
# Brute force formula
check_dist <- function(n, fun) {
  # Generate all permutations
  perm <- permutations(n)

  apply(perm, 1, fun, r2 = 1:n)
}

# Loop over some n values
test_that("footrule distance is correct", {
  for (n in c(2, 3, 5)) {
    expect_equal(
      check_dist(n, fun = function(r1, r2) {
        get_rank_distance(r1, r2, "footrule")
      }),
      check_dist(n, fun = function(r1, r2) sum(abs(r1 - r2)))
    )
  }
})

# Loop over some n values
test_that("Spearman distance is correct", {
  for (n in c(2, 3, 5)) {
    expect_equal(
      check_dist(n, fun = function(r1, r2) {
        get_rank_distance(r1, r2, "spearman")
      }),
      check_dist(n, fun = function(r1, r2) sum((r1 - r2)^2))
    )
  }
})

# Loop over some n values
test_that("Kendall distance is correct", {
  ns <- c(2, 3, 5)
  correct <- list(c(0, 1), c(0, 1, 1, 2, 2, 3),
                  c(0, 1, 1, 2, 2, 3, 1, 2, 2, 3, 3, 4, 2, 3, 3, 4, 4, 5, 3, 4,
                    4, 5, 5, 6, 1, 2, 2, 3, 3, 4, 2, 3, 3, 4, 4, 5, 3, 4, 4, 5, 5,
                    6, 4, 5, 5, 6, 6, 7, 2, 3, 3, 4, 4, 5, 3, 4, 4, 5, 5, 6, 4, 5,
                    5, 6, 6, 7, 5, 6, 6, 7, 7, 8, 3, 4, 4, 5, 5, 6, 4, 5, 5, 6, 6,
                    7, 5, 6, 6, 7, 7, 8, 6, 7, 7, 8, 8, 9, 4, 5, 5, 6, 6, 7, 5, 6,
                    6, 7, 7, 8, 6, 7, 7, 8, 8, 9, 7, 8, 8, 9, 9, 10))
  for (i in seq_along(ns)) {
    expect_equal(
      check_dist(ns[[i]], fun = function(r1, r2) {
        get_rank_distance(r1, r2, "kendall")
      }),
      correct[[i]]
    )
  }
})


# Loop over some n values
test_that("Cayley distance is correct", {
  ns <- c(2, 3, 5)
  correct <- list(c(0, 1), c(0, 1, 1, 2, 2, 1),
                  c(0, 1, 1, 2, 2, 1, 1, 2, 2, 3, 3, 2, 2, 3, 1, 2, 2, 3, 3, 2,
                    2, 1, 3, 2, 1, 2, 2, 3, 3, 2, 2, 3, 3, 4, 4, 3, 3, 4, 2, 3, 3,
                    4, 4, 3, 3, 2, 4, 3, 2, 3, 3, 4, 4, 3, 1, 2, 2, 3, 3, 2, 2, 3,
                    3, 4, 4, 3, 3, 2, 4, 3, 3, 4, 3, 4, 2, 3, 3, 4, 2, 3, 1, 2, 2,
                    3, 3, 4, 2, 3, 3, 4, 4, 3, 3, 4, 2, 3, 4, 3, 3, 2, 4, 3, 3, 2,
                    2, 1, 3, 2, 4, 3, 3, 2, 4, 3, 3, 4, 4, 3, 3, 2))
  for (i in seq_along(ns)) {
    expect_equal(
      check_dist(ns[[i]], fun = function(r1, r2) {
        get_rank_distance(r1, r2, "cayley")
      }),
      correct[[i]]
    )
  }
})


# Loop over some n values
test_that("Hamming distance is correct", {
  ns <- c(2, 3, 5)
  correct <- list(c(0, 2), c(0, 2, 2, 3, 3, 2),
                  c(0, 2, 2, 3, 3, 2, 2, 4, 3, 4, 4, 3, 3, 4, 2, 3, 4, 4, 4, 3,
                    3, 2, 4, 4, 2, 4, 4, 5, 5, 4, 3, 5, 4, 5, 5, 4, 4, 5, 3, 4, 5,
                    5, 5, 4, 4, 3, 5, 5, 3, 5, 4, 5, 5, 4, 2, 4, 3, 4, 4, 3, 4, 5,
                    4, 5, 5, 5, 5, 4, 5, 4, 5, 5, 4, 5, 3, 4, 5, 5, 3, 4, 2, 3, 4,
                    4, 4, 5, 4, 5, 5, 5, 5, 5, 5, 5, 4, 4, 5, 4, 4, 3, 5, 5, 4, 3,
                    3, 2, 4, 4, 5, 4, 5, 4, 5, 5, 5, 5, 5, 5, 4, 4))
  for (i in seq_along(ns)) {
    expect_equal(
      check_dist(ns[[i]], fun = function(r1, r2) {
        get_rank_distance(r1, r2, "hamming")
      }),
      correct[[i]]
    )
  }
})


# Loop over some n values
test_that("Ulam distance is correct", {
  ns <- c(2, 3, 5)
  correct <- list(c(0, 1), c(0, 1, 1, 1, 1, 2),
                  c(0, 1, 1, 1, 1, 2, 1, 2, 1, 1, 2, 2, 1, 2, 2, 2, 2, 2, 1, 2,
                    2, 2, 2, 3, 1, 2, 2, 2, 2, 3, 1, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2,
                    2, 2, 3, 2, 2, 3, 3, 1, 2, 2, 2, 2, 3, 2, 3, 2, 2, 3, 3, 2, 2,
                    2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 1, 2, 2, 2, 2, 3, 2, 3, 2, 2, 3,
                    3, 2, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 1, 2, 2, 2, 2, 3, 2, 3,
                    2, 2, 3, 3, 2, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 4))
  for (i in seq_along(ns)) {
    expect_equal(
      check_dist(ns[[i]], fun = function(r1, r2) {
        get_rank_distance(r1, r2, "ulam")
      }),
      correct[[i]]
    )
  }
})


test_that("Exported rank_distance is correct", {
  # Distance between two vectors of rankings:
  expect_equal(rank_distance(1:5, 5:1, metric = "kendall"), 10)
  expect_equal(
    rank_distance(c(2, 4, 3, 6, 1, 7, 5), c(3, 5, 4, 7, 6, 2, 1), metric = "cayley"),
    6
  )
  expect_equal(
    rank_distance(c(4, 2, 3, 1), c(3, 4, 1, 2), metric = "hamming"),
    4
  )
  expect_equal(
    rank_distance(c(1, 3, 5, 7, 9, 8, 6, 4, 2), c(1, 2, 3, 4, 9, 8, 7, 6, 5), "ulam"),
    4
  )
  expect_equal(
    rank_distance(c(8, 7, 1, 2, 6, 5, 3, 4), c(1, 2, 8, 7, 3, 4, 6, 5), "footrule"),
    32
  )
  expect_equal(
    rank_distance(c(1, 6, 2, 5, 3, 4), c(4, 3, 5, 2, 6, 1), "spearman"),
    54
  )

  expect_error(rank_distance(c(1, 6, 2, 5, 3, 4), c(4, 3, 5, 2, 6, 1), "spearman", obs_freq = 1:3))

  expect_equal(
    rank_distance(
      potato_visual, potato_true_ranking, "footrule"
    ),
    c(22, 24, 32, 14, 36, 24, 14, 28, 34, 24, 30, 24)
  )
})