# Tests for plot_ism()

test_that("plot_ism validates input", {
  expect_error(plot_ism(c(1, 2, 3)), "must be a matrix")
  expect_error(plot_ism(matrix(1:6, nrow = 2)), "must be square")
})

test_that("plot_ism returns list invisibly", {
  adj <- matrix(c(0, 1, 0, 0), nrow = 2, byrow = TRUE)
  reach <- compute_reachability(adj)

  # Suppress graphical output during testing
  pdf(NULL)
  result <- plot_ism(reach)
  dev.off()

  # plot_ism now returns a list invisibly
  expect_true(is.list(result))
  expect_true("levels" %in% names(result))
  expect_true("edges" %in% names(result))
})

test_that("plot_ism handles matrix with names", {
  adj <- matrix(c(0, 1, 0, 0), nrow = 2, byrow = TRUE)
  rownames(adj) <- colnames(adj) <- c("A", "B")
  reach <- compute_reachability(adj)

  # Should not error
  pdf(NULL)
  expect_no_error(plot_ism(reach))
  dev.off()
})

test_that("plot_ism with show_transitive option", {
  adj <- matrix(c(0, 1, 1, 0, 0, 1, 0, 0, 0), nrow = 3, byrow = TRUE)
  reach <- compute_reachability(adj)

  pdf(NULL)
  # Default: transitive edges removed
  result1 <- plot_ism(reach, show_transitive = FALSE)
  # Show all edges
  result2 <- plot_ism(reach, show_transitive = TRUE)
  dev.off()

  # With transitive removal, should have fewer edges
  expect_true(nrow(result1$edges) <= nrow(result2$edges))
})

test_that("plot_ism with igraph backend", {
  skip_if_not_installed("igraph")

  adj <- matrix(c(0, 1, 0, 0), nrow = 2, byrow = TRUE)
  rownames(adj) <- colnames(adj) <- c("A", "B")
  reach <- compute_reachability(adj)

  pdf(NULL)
  expect_no_error(plot_ism(reach, use_igraph = TRUE))
  dev.off()
})