///|
/// Demo for pathview module: KEGG pathway visualization.
fn main {
  println("=== pathview Demo: KEGG Pathway Visualization ===")
  println("")

  // Example 1: Build a simple pathway
  println("--- Step 1: Build Pathway ---")
  let pw0 = @src.pathview_new("hsa00010")
  let pw1 = @src.pathview_add_node(pw0, @src.PathviewNode::{
    node_id: "n1",
    label: "HK1",
    node_type: "gene",
    x: 20.0,
    y: 50.0,
    width: 50.0,
    height: 22.0,
  })
  let pw2 = @src.pathview_add_node(pw1, @src.PathviewNode::{
    node_id: "n2",
    label: "GPI",
    node_type: "gene",
    x: 100.0,
    y: 50.0,
    width: 50.0,
    height: 22.0,
  })
  let pw3 = @src.pathview_add_node(pw2, @src.PathviewNode::{
    node_id: "n3",
    label: "PFKP",
    node_type: "gene",
    x: 180.0,
    y: 50.0,
    width: 50.0,
    height: 22.0,
  })
  let pw4 = @src.pathview_add_edge(pw3, @src.PathviewEdge::{
    source: "n1",
    target: "n2",
    edge_type: "PPrel",
  })
  let pw5 = @src.pathview_add_edge(pw4, @src.PathviewEdge::{
    source: "n2",
    target: "n3",
    edge_type: "PPrel",
  })
  let pw6 = @src.pathview_map_gene(pw5, "HK1", "n1")
  let pw7 = @src.pathview_map_gene(pw6, "GPI", "n2")
  let pw = @src.pathview_map_gene(pw7, "PFKP", "n3")
  println(
    "Pathway: " +
    pw.pathway_id +
    ", nodes=" +
    pw.nodes.length().to_string() +
    ", edges=" +
    pw.edges.length().to_string(),
  )
  println("")

  // Example 2: Color mapping for logFC values
  println("--- Step 2: logFC Color Mapping ---")
  let up_color = @src.pathview_logfc_color(3.0)
  let down_color = @src.pathview_logfc_color(-3.0)
  let zero_color = @src.pathview_logfc_color(0.0)
  println(
    "logFC=+3.0 -> " +
    @src.pathview_color_hex(up_color) +
    " (rgb=" +
    @src.pathview_color_rgb(up_color) +
    ")",
  )
  println("logFC= 0.0 -> " + @src.pathview_color_hex(zero_color))
  println(
    "logFC=-3.0 -> " +
    @src.pathview_color_hex(down_color) +
    " (rgb=" +
    @src.pathview_color_rgb(down_color) +
    ")",
  )
  println("")

  // Example 3: Node statistics
  println("--- Step 3: Node Statistics ---")
  let vals = [("HK1", 2.5), ("GPI", -1.0), ("PFKP", 0.0)]
  let stats = @src.pathview_node_stats(pw, vals)
  println("Node stats: " + stats.length().to_string() + " nodes")
  for s in stats {
    println(
      "  " +
      s.node_id +
      " " +
      "mean=" +
      s.mean_value.to_string() +
      " up=" +
      s.num_up.to_string() +
      " down=" +
      s.num_down.to_string() +
      " genes=" +
      s.num_genes.to_string(),
    )
  }
  println("")

  // Example 4: Render SVG
  println("--- Step 4: Render SVG ---")
  let svg = @src.pathview_render_svg(pw, vals)
  println("SVG length: " + svg.length().to_string() + " chars")
  println("Contains