test_that("caugi_layout works with simple DAG", {
  cg <- caugi(
    A %-->% B + C,
    B %-->% D,
    C %-->% D,
    class = "DAG"
  )

  layout <- caugi_layout(cg)

  expect_s3_class(layout, "data.frame")
  expect_equal(nrow(layout), 4L)
  expect_named(layout, c("name", "x", "y"))
  expect_equal(layout$name, c("A", "B", "C", "D"))
  expect_type(layout$x, "double")
  expect_type(layout$y, "double")
})

test_that("caugi_layout works with single node", {
  cg <- caugi(A, class = "DAG")

  layout <- caugi_layout(cg)

  expect_s3_class(layout, "data.frame")
  expect_equal(nrow(layout), 1L)
  expect_equal(layout$name, "A")
})

test_that("plot.caugi runs without error", {
  cg <- caugi(
    A %-->% B + C,
    B %-->% D,
    class = "DAG"
  )

  # Open a null graphics device to avoid opening windows during tests
  pdf(NULL)
  on.exit(dev.off())

  expect_s7_class(plot(cg), caugi_plot)
})

test_that("plot.caugi accepts node_style arguments", {
  cg <- caugi(A %-->% B)

  pdf(NULL)
  on.exit(dev.off())

  expect_s7_class(
    plot(
      cg,
      node_style = list(fill = "lightgreen", padding = 0.8)
    ),
    caugi_plot
  )
})

test_that("plot.caugi accepts local node_style arguments", {
  cg <- caugi(A %-->% B + C)

  pdf(NULL)
  on.exit(dev.off())

  expect_s7_class(
    plot(
      cg,
      node_style = list(
        by_node = list(
          A = list(fill = "lightblue", col = "darkblue", lwd = 2),
          B = list(fill = "red")
        )
      )
    ),
    caugi_plot
  )
})

test_that("plot.caugi accepts edge_style arguments", {
  cg <- caugi(A %-->% B)

  pdf(NULL)
  on.exit(dev.off())

  expect_s7_class(
    plot(
      cg,
      edge_style = list(col = "blue", arrow_size = 4)
    ),
    caugi_plot
  )
})

test_that("plot.caugi accepts local edge_style arguments", {
  cg <- caugi(A %-->% B + C)

  pdf(NULL)
  on.exit(dev.off())
  expect_s7_class(
    plot(
      cg,
      edge_style = list(
        by_edge = list(
          A = list(
            # Node-wide settings for A
            col = "red",
            lwd = 5
          )
        )
      )
    ),
    caugi_plot
  )

  expect_s7_class(
    plot(
      cg,
      edge_style = list(
        by_edge = list(
          A = list(
            # Node-wide settings for A
            col = "red",
            lwd = 5,
            B = list(
              # Specific edge overwrite A -> B
              col = "blue",
              lwd = 4
            )
          )
        )
      )
    ),
    caugi_plot
  )

  expect_s7_class(
    plot(
      cg,
      edge_style = list(
        by_edge = list(
          # Node-wide settings for A
          A = list(
            col = "red",
            lwd = 5
          ),
          # Specific edge overwrite also works for BA
          B = list(
            A = list(
              col = "blue",
              lwd = 4
            )
          )
        )
      )
    ),
    caugi_plot
  )
  expect_s7_class(
    plot(
      cg,
      edge_style = list(
        by_edge = list(
          # Node-wide settings for B, A -> C uses global settings
          B = list(
            col = "red",
            lwd = 5
          )
        )
      )
    ),
    caugi_plot
  )
})

test_that("plot.caugi works with single node", {
  cg <- caugi(A, class = "DAG")

  pdf(NULL)
  on.exit(dev.off())

  expect_s7_class(plot(cg), caugi_plot)
})

test_that("plot.caugi builds graph if needed", {
  cg <- caugi(A %-->% B)

  pdf(NULL)
  on.exit(dev.off())

  expect_s7_class(plot(cg), caugi_plot)
})

test_that("plot.caugi applies margins and title padding", {
  cg <- caugi(A %-->% B)

  pdf(NULL)
  on.exit(dev.off())

  p <- plot(cg, main = "Title")
  graph <- grid::getGrob(p@grob, "caugi.graph")
  layout <- graph$vp[[1]]$layout

  margin_widths <- grid::convertWidth(
    layout$widths[c(1, 3)],
    "mm",
    valueOnly = TRUE
  )
  expect_true(all(margin_widths > 0))
  expect_equal(margin_widths[1], margin_widths[2])

  top_bottom_margins <- grid::convertHeight(
    layout$heights[c(1, 5)],
    "mm",
    valueOnly = TRUE
  )
  expect_true(all(top_bottom_margins > 0))
  expect_equal(top_bottom_margins[1], top_bottom_margins[2])

  expect_gt(
    grid::convertHeight(layout$heights[[2]], "mm", valueOnly = TRUE),
    0
  )
  expect_gt(
    grid::convertHeight(layout$heights[[3]], "mm", valueOnly = TRUE),
    0
  )
})

test_that("plot.caugi omits title spacing when main is NULL", {
  cg <- caugi(A %-->% B)

  pdf(NULL)
  on.exit(dev.off())

  p <- plot(cg)
  graph <- grid::getGrob(p@grob, "caugi.graph")
  layout <- graph$vp[[1]]$layout

  expect_equal(
    grid::convertHeight(layout$heights[[2]], "mm", valueOnly = TRUE),
    0
  )
  expect_equal(
    grid::convertHeight(layout$heights[[3]], "mm", valueOnly = TRUE),
    0
  )
})

test_that("caugi_layout works with fruchterman-reingold method", {
  cg <- caugi(
    A %-->% B + C,
    B %-->% D,
    C %-->% D,
    class = "DAG"
  )

  layout <- caugi_layout(cg, method = "fruchterman-reingold")

  expect_s3_class(layout, "data.frame")
  expect_equal(nrow(layout), 4L)
  expect_named(layout, c("name", "x", "y"))
  expect_equal(layout$name, c("A", "B", "C", "D"))
  expect_type(layout$x, "double")
  expect_type(layout$y, "double")
  expect_true(all(is.finite(layout$x)))
  expect_true(all(is.finite(layout$y)))
})

test_that("fruchterman-reingold layout works with mixed edge types", {
  cg <- caugi(
    A %-->% B,
    B %---% C,
    C %<->% D
  )

  layout <- caugi_layout(cg, method = "fruchterman-reingold")

  expect_s3_class(layout, "data.frame")
  expect_equal(nrow(layout), 4L)
  expect_true(all(is.finite(layout$x)))
  expect_true(all(is.finite(layout$y)))
})

test_that("sugiyama layout rejects mixed edge types", {
  cg <- caugi(
    A %-->% B,
    B %---% C
  )

  expect_error(caugi_layout(cg, method = "sugiyama"))
})

test_that("plot.caugi works with fruchterman-reingold layout", {
  cg <- caugi(
    A %-->% B + C,
    B %-->% D,
    class = "DAG"
  )

  pdf(NULL)
  on.exit(dev.off())

  expect_s7_class(plot(cg, layout = "fruchterman-reingold"), caugi_plot)
})

test_that("auto method selects sugiyama for directed-only graphs", {
  cg <- caugi(
    A %-->% B %-->% C,
    class = "DAG"
  )

  layout_auto <- caugi_layout(cg, method = "auto")
  layout_sug <- caugi_layout(cg, method = "sugiyama")

  # Auto should produce same result as sugiyama for directed-only graphs
  expect_equal(layout_auto, layout_sug)
})

test_that("auto method selects fruchterman-reingold for mixed edge graphs", {
  cg <- caugi(
    A %-->% B,
    B %---% C
  )

  # Auto should work (selecting fruchterman-reingold internally)
  layout_auto <- caugi_layout(cg, method = "auto")
  expect_s3_class(layout_auto, "data.frame")
  expect_equal(nrow(layout_auto), 3L)

  # Sugiyama should fail
  expect_error(caugi_layout(cg, method = "sugiyama"))
})

test_that("plot with auto layout works", {
  # Test with directed-only
  cg_dir <- caugi(A %-->% B %-->% C, class = "DAG")

  pdf(NULL)
  on.exit(dev.off())

  expect_s7_class(plot(cg_dir, layout = "auto"), caugi_plot)

  # Test with mixed edges
  cg_mixed <- caugi(A %-->% B, B %---% C)
  expect_s7_class(plot(cg_mixed, layout = "auto"), caugi_plot)
})

test_that("auto is the default method", {
  cg <- caugi(A %-->% B, class = "DAG")

  # Default should work without specifying method
  layout_default <- caugi_layout(cg)
  expect_s3_class(layout_default, "data.frame")

  pdf(NULL)
  on.exit(dev.off())

  # Default should work for plot too
  expect_s7_class(plot(cg), caugi_plot)
})

test_that("kamada-kawai layout works with simple DAG", {
  cg <- caugi(
    A %-->% B + C,
    B %-->% D,
    C %-->% D,
    class = "DAG"
  )

  layout <- caugi_layout(cg, method = "kamada-kawai")

  expect_s3_class(layout, "data.frame")
  expect_equal(nrow(layout), 4L)
  expect_named(layout, c("name", "x", "y"))
  expect_equal(layout$name, c("A", "B", "C", "D"))
  expect_type(layout$x, "double")
  expect_type(layout$y, "double")
  expect_true(all(is.finite(layout$x)))
  expect_true(all(is.finite(layout$y)))
})

test_that("kamada-kawai layout is deterministic", {
  cg <- caugi(
    A %-->% B + C,
    B %-->% D,
    C %-->% D,
    class = "DAG"
  )

  layout1 <- caugi_layout(cg, method = "kamada-kawai")
  layout2 <- caugi_layout(cg, method = "kamada-kawai")
  layout3 <- caugi_layout(cg, method = "kamada-kawai")

  # All three should be identical
  expect_identical(layout1, layout2)
  expect_identical(layout2, layout3)
})

test_that("caugi_options can be queried", {
  opts <- caugi_options()

  expect_type(opts, "list")
  expect_true("plot" %in% names(opts))
  expect_type(opts$plot, "list")
})

test_that("caugi_options can set and get plot spacing", {
  old_opts <- caugi_options()
  on.exit(caugi_options(old_opts))

  # Set new spacing
  caugi_options(plot = list(spacing = grid::unit(2, "lines")))

  # Verify it was set
  opts <- caugi_options()
  expect_s3_class(opts$plot$spacing, "unit")
  expect_equal(as.numeric(opts$plot$spacing), 2)
})

test_that("caugi_options can set node_style defaults", {
  old_opts <- caugi_options()
  on.exit(caugi_options(old_opts))

  # Set node style
  caugi_options(
    plot = list(
      node_style = list(fill = "lightblue", padding = 3)
    )
  )

  opts <- caugi_options()
  expect_equal(opts$plot$node_style$fill, "lightblue")
  expect_equal(opts$plot$node_style$padding, 3)
})

test_that("caugi_options can set edge_style defaults", {
  old_opts <- caugi_options()
  on.exit(caugi_options(old_opts))

  # Set edge style
  caugi_options(
    plot = list(
      edge_style = list(arrow_size = 5, fill = "darkgray")
    )
  )

  opts <- caugi_options()
  expect_equal(opts$plot$edge_style$arrow_size, 5)
  expect_equal(opts$plot$edge_style$fill, "darkgray")
})

test_that("plot respects global node_style options", {
  old_opts <- caugi_options()
  on.exit(caugi_options(old_opts))

  # Set global node style
  caugi_options(
    plot = list(
      node_style = list(fill = "lightblue")
    )
  )

  cg <- caugi(A %-->% B)

  pdf(NULL)
  on.exit(dev.off(), add = TRUE)

  p <- plot(cg)
  expect_s7_class(p, caugi_plot)

  # Verify grob was created (basic check that options didn't break plotting)
  expect_true(!is.null(p@grob))
})

test_that("plot arguments override global options", {
  old_opts <- caugi_options()
  on.exit(caugi_options(old_opts))

  # Set global node style
  caugi_options(
    plot = list(
      node_style = list(fill = "lightblue")
    )
  )

  cg <- caugi(A %-->% B)

  pdf(NULL)
  on.exit(dev.off(), add = TRUE)

  # Override with argument
  p <- plot(cg, node_style = list(fill = "pink"))
  expect_s7_class(p, caugi_plot)
})

test_that("plot.caugi renders o-> edges with circles", {
  cg <- caugi(A %o->% B, class = "UNKNOWN")

  pdf(NULL)
  on.exit(dev.off())

  # Test that plot completes without error and renders circles
  expect_s7_class(plot(cg), caugi_plot)
})

test_that("plot.caugi renders o-o edges with circles on both ends", {
  cg <- caugi(A %o-o% B, class = "UNKNOWN")

  pdf(NULL)
  on.exit(dev.off())

  # Test that plot completes without error and renders circles
  expect_s7_class(plot(cg), caugi_plot)
})

test_that("plot.caugi accepts circle_size for partial edges", {
  cg <- caugi(A %o->% B, B %o-o% C, class = "UNKNOWN")

  pdf(NULL)
  on.exit(dev.off())

  # Test that custom circle_size is accepted
  p <- plot(
    cg,
    edge_style = list(
      partial = list(circle_size = 2.5)
    )
  )
  expect_s7_class(p, caugi_plot)
})

test_that("plot.caugi with mixed edge types including partial", {
  cg <- caugi(
    A %-->% B,
    B %o->% C,
    C %o-o% D,
    class = "UNKNOWN"
  )

  pdf(NULL)
  on.exit(dev.off())

  # Test that mixed edge types render correctly
  expect_s7_class(plot(cg), caugi_plot)
})

test_that("caugi_layout handles disconnected components", {
  # Single isolated node
  cg1 <- caugi(
    A %-->% B + C,
    D
  )

  layout1 <- caugi_layout(cg1, method = "fruchterman-reingold")
  expect_s3_class(layout1, "data.frame")
  expect_equal(nrow(layout1), 4L)
  expect_true(all(is.finite(layout1$x)))
  expect_true(all(is.finite(layout1$y)))

  # Multiple disconnected components
  cg2 <- caugi(
    A %-->% B,
    C %-->% D,
    E
  )

  layout2 <- caugi_layout(cg2, method = "kamada-kawai")
  expect_s3_class(layout2, "data.frame")
  expect_equal(nrow(layout2), 5L)
  expect_true(all(is.finite(layout2$x)))
  expect_true(all(is.finite(layout2$y)))

  # Sugiyama with disconnected components
  layout3 <- caugi_layout(cg1, method = "sugiyama")
  expect_s3_class(layout3, "data.frame")
  expect_equal(nrow(layout3), 4L)
  expect_true(all(is.finite(layout3$x)))
  expect_true(all(is.finite(layout3$y)))
})

test_that("plot.caugi renders disconnected components", {
  cg <- caugi(
    A %-->% B + C,
    D,
    E %-->% F
  )

  pdf(NULL)
  on.exit(dev.off())

  # Should work with all layout methods
  expect_s7_class(plot(cg, layout = "fruchterman-reingold"), caugi_plot)
  expect_s7_class(plot(cg, layout = "kamada-kawai"), caugi_plot)
  expect_s7_class(plot(cg, layout = "sugiyama"), caugi_plot)
  expect_s7_class(plot(cg, layout = "auto"), caugi_plot)
})

test_that("plot.caugi asp parameter works", {
  cg <- caugi(A %-->% B + C, B %-->% D, class = "DAG")

  pdf(NULL)
  on.exit(dev.off())

  # asp = NULL should work (automatic aspect ratio)
  expect_s7_class(plot(cg, asp = NULL), caugi_plot)

  # asp = NA should work (automatic aspect ratio)
  expect_s7_class(plot(cg, asp = NA), caugi_plot)

  # asp = 1 should work (equal aspect ratio)
  expect_s7_class(plot(cg, asp = 1), caugi_plot)

  # asp = 2 should work (y-axis twice as tall)
  expect_s7_class(plot(cg, asp = 2), caugi_plot)

  # asp = 0.5 should work (x-axis twice as wide)
  expect_s7_class(plot(cg, asp = 0.5), caugi_plot)
})

# ──────────────────────────────────────────────────────────────────────────────
# ─────────────────────────── Tiered plotting ──────────────────────────────────
# ──────────────────────────────────────────────────────────────────────────────

test_that("plot with tiers as data.frame works", {
  cg <- caugi(
    A %-->% B + C,
    B %-->% D,
    C %-->% D,
    class = "DAG"
  )

  tiers_df <- data.frame(
    name = c("A", "B", "C", "D"),
    tier = c(1, 2, 2, 3)
  )

  pdf(NULL)
  on.exit(dev.off())

  expect_s7_class(plot(cg, tiers = tiers_df), caugi_plot)
})

test_that("plot with tiers orientation='columns' works", {
  cg <- caugi(
    A %-->% B + C,
    B %-->% D,
    C %-->% D,
    class = "DAG"
  )

  tiers_list <- list(
    tier1 = "A",
    tier2 = c("B", "C"),
    tier3 = "D"
  )

  pdf(NULL)
  on.exit(dev.off())

  expect_s7_class(
    plot(cg, tiers = tiers_list, orientation = "columns"),
    caugi_plot
  )
})

test_that("plot with tier_style and label_style works", {
  cg <- caugi(
    A %-->% B + C,
    B %-->% D,
    C %-->% D,
    class = "DAG"
  )

  tiers_list <- list(
    tier1 = "A",
    tier2 = c("B", "C"),
    tier3 = "D"
  )

  tier_style <- list(
    global = list(
      labels = c("Input", "Middle", "Output"),
      label_style = list(col = "red", fontsize = 12)
    ),
    by_tier = list(
      tier1 = list(
        label_style = list(col = "blue", fontsize = 14)
      )
    )
  )

  pdf(NULL)
  on.exit(dev.off())

  expect_s7_class(
    plot(
      cg,
      tiers = tiers_list,
      tier_style = tier_style
    ),
    caugi_plot
  )
})

test_that("plot with tiers orientation='rows' and labels works", {
  cg <- caugi(
    A %-->% B + C,
    B %-->% D,
    C %-->% D,
    class = "DAG"
  )

  tiers_list <- list(
    tier1 = "A",
    tier2 = c("B", "C"),
    tier3 = "D"
  )

  tier_style <- list(
    global = list(
      labels = c("Input", "Middle", "Output")
    )
  )

  pdf(NULL)
  on.exit(dev.off())

  expect_s7_class(
    plot(
      cg,
      tiers = tiers_list,
      orientation = "rows",
      tier_style = tier_style
    ),
    caugi_plot
  )
})

test_that("plot nodes without labels uses nullGrob", {
  cg <- caugi(
    A %-->% B,
    class = "DAG"
  )

  pdf(NULL)
  on.exit(dev.off())

  # Plot without node labels
  p <- plot(cg, node_style = list(label = FALSE))
  expect_s7_class(p, caugi_plot)
})

test_that("plot renders o-> edge circles at tail", {
  cg <- caugi(A %o->% B, class = "UNKNOWN")

  pdf(NULL)
  on.exit(dev.off())

  # Test with custom circle size
  p <- plot(cg, edge_style = list(partial = list(circle_size = 3)))
  expect_s7_class(p, caugi_plot)
})

test_that("plot renders o-o edge circles at both ends", {
  cg <- caugi(A %o-o% B, class = "UNKNOWN")

  pdf(NULL)
  on.exit(dev.off())

  # Test that circles render at both ends
  p <- plot(cg)
  expect_s7_class(p, caugi_plot)

  # Test with custom circle size
  p2 <- plot(cg, edge_style = list(partial = list(circle_size = 2)))
  expect_s7_class(p2, caugi_plot)
})

test_that("plot handles self-loop edges for circle rendering", {
  # Create a graph with a self-loop (zero-length edge case)
  cg <- caugi(
    A %o->% A,
    class = "UNKNOWN",
    simple = FALSE
  )

  pdf(NULL)
  on.exit(dev.off())

  # This should trigger the zero-length edge path
  expect_s7_class(plot(cg), caugi_plot)
})

test_that("plot-grobs internal branches are covered", {
  # n_tiers == 0 branch
  coords0 <- data.frame(name = character(), x = numeric(), y = numeric())
  tier_style <- list(
    global = list(
      boxes = TRUE,
      labels = character(0),
      padding = grid::unit(1, "mm"),
      fill = "grey95",
      col = "grey70",
      lwd = 1,
      lty = 1,
      alpha = 1,
      label_style = list(col = "black", fontsize = 9)
    ),
    by_tier = list()
  )
  tiers0 <- caugi:::make_tiers(
    circle_grobs = grid::gList(),
    coords = coords0,
    tiers = list(),
    tier_style = tier_style,
    orientation = "rows"
  )
  expect_true(length(tiers0$grobs) >= 1L)

  # Recycled labels + empty tier skip branch
  coords <- data.frame(name = c("A", "B"), x = c(0.2, 0.8), y = c(0.5, 0.5))
  circles <- grid::gList(
    grid::circleGrob(
      x = grid::unit(0.2, "npc"),
      y = grid::unit(0.5, "npc"),
      r = grid::unit(1, "mm")
    ),
    grid::circleGrob(
      x = grid::unit(0.8, "npc"),
      y = grid::unit(0.5, "npc"),
      r = grid::unit(1, "mm")
    )
  )
  tier_style$global$labels <- c("Tier")
  tiers_gap <- c(A = 0L, B = 2L)
  tiers_gap_out <- caugi:::make_tiers(
    circle_grobs = circles,
    coords = coords,
    tiers = tiers_gap,
    tier_style = tier_style,
    orientation = "rows"
  )
  expect_true(length(tiers_gap_out$grobs) >= 1L)

  # make_nodes() branch where labels are omitted -> nullGrob labels
  node_style <- list(
    global = list(fill = "white", col = "black", lwd = 1, size = 1),
    by_node = list()
  )
  label_style <- list(col = "black", fontsize = 10)
  nodes_out <- caugi:::make_nodes(
    coords = data.frame(name = "A", x = 0.5, y = 0.5),
    labels = character(0),
    node_style = node_style,
    label_style = label_style
  )
  expect_s3_class(nodes_out$label_grobs[[1]], "null")

  # Zero-length edge branches (including o-> and o-o circles).
  pdf(NULL)
  on.exit(dev.off(), add = TRUE)
  grid::grid.newpage()
  grid::pushViewport(grid::viewport(xscale = c(0, 1), yscale = c(0, 1)))

  eg_o_to <- caugi:::make_edge_grob(
    x0 = 0.5,
    y0 = 0.5,
    x1 = 0.5,
    y1 = 0.5,
    r_from = grid::unit(1, "mm"),
    r_to = grid::unit(1, "mm"),
    edge_type = "o->",
    circle_size = 2
  )
  c1 <- caugi:::makeContent.caugi_edge_grob(eg_o_to)
  expect_equal(length(c1$children), 2L)

  eg_o_o <- caugi:::make_edge_grob(
    x0 = 0.5,
    y0 = 0.5,
    x1 = 0.5,
    y1 = 0.5,
    r_from = grid::unit(1, "mm"),
    r_to = grid::unit(1, "mm"),
    edge_type = "o-o",
    circle_size = 2
  )
  c2 <- caugi:::makeContent.caugi_edge_grob(eg_o_o)
  expect_equal(length(c2$children), 3L)
})

test_that("plotting empty graph gives clear error", {
  cg_empty <- caugi(class = "DAG")

  expect_error(
    plot(cg_empty),
    "Cannot plot an empty graph \\(0 nodes\\)\\."
  )
})

test_that("plot layout validation branch is covered", {
  cg <- caugi(
    from = LETTERS[1:7],
    edge = rep("-->", 7),
    to = LETTERS[2:8],
    class = "DAG"
  )
  bad_layout <- data.frame(
    name = rep("A", 8),
    x = seq(0, 1, length.out = 8),
    y = seq(0, 1, length.out = 8)
  )
  expect_error(
    plot(cg, layout = bad_layout),
    "and 2 more"
  )
})