1 files changed, 111 insertions, 0 deletions
diff --git a/src/layout.nim b/src/layout.nim
new file mode 100644
index 0000000..14eebaa
--- /dev/null
+++ b/src/layout.nim
@@ -0,0 +1,111 @@
+import std/options
+import formats/html
+
+# const inline_elements = []
+
+const block_elements = [
+  "html", "body", "article", "section", "nav", "aside",
+  "h1", "h2", "h3", "h4", "h5", "h6", "hgroup", "header",
+  "footer", "address", "p", "hr", "pre", "blockquote",
+  "ol", "ul", "menu", "li", "dl", "dt", "dd", "figure",
+  "figcaption", "main", "div", "table", "form", "fieldset",
+  "legend", "details", "summary"
+]
+
+type LayoutKind = enum
+  Inline, Block, Document
+
+# Improve error messages: suggest a ref object when failing from recursion
+type Layout = ref object
+  case kind*: LayoutKind:
+    of Inline:
+      weight: int
+    of Block:
+      discard
+    of Document:
+      discard
+  node: Node
+  parent: Option[Layout]
+  previous: Option[Layout]
+  children: seq[Layout]
+  # x, y, width, height: float
+
+# Recursively construct the layout tree
+func layout(node: Node, parent: Option[Layout], previous: Option[Layout]): Layout =
+  result = Layout() # !!! ref types are nil by default :-(
+  var children: seq[Layout] = @[]
+  var prevchild: Option[Layout] = none(Layout)
+  var kind: LayoutKind = Inline
+  case node.kind:
+    of Element:
+      for child in node.children:
+        # FIXME: parent nodes are broken. we pass a ref to result, which is different from the returned layout.
+        let current = child.layout(parent=some(result), previous=prevchild)
+        children.add(current)
+        prevchild = some(current)
+        if kind == Inline and child.kind == Element and child.tag in block_elements:
+          kind = Block
+      if node.children.len == 0:
+        kind = Block
+    of Text:
+      discard
+  return Layout(node: node, parent: parent, previous: previous, children: children, kind: kind)
+
+# Assuming the first node of an HTML object is the <html> tag.
+# Right now, HTML generation is Bad so this will change in the future
+func layout(html: Html): Layout =
+  result = Layout(kind: Document, node: html[0], parent: none(Layout), previous: none(Layout), children: @[])
+  for child in html[0].children:
+    result.children.add(child.layout(none(Layout), none(Layout)))
+
+# TODO: change Html into a distinct Node and adjust layout accordingly
+
+#[type DocumentLayout = ref object
+  node: Node
+  children: seq[Layout]]#
+
+#[func layout_mode(node: Node): LayoutKind =
+  if node.kind == Text:
+    return Inline
+  elif node.children.len > 0:
+    for child in node.children:
+      if child.kind == Text: continue
+      if child.tag in block_elements:
+        return Block
+    return Inline
+  else:
+    return Block]#
+
+#[func layout(node: Node, parent: Layout, previous: Layout = nil): Layout =
+  if node.kind == Element and node.children.len > 0:
+    var previous: Layout = previous
+    var current: Layout
+    for child in node.children:
+      if previous == nil:
+        current = child.layout(result)
+        result.children.add(current)
+      else:
+        current = child.layout(result, previous)
+        result.children.add(current)
+      previous = current
+  else:
+    result = Layout(node: node, parent: parent, previous: previous, children: @[])]#
+
+when isMainModule:
+  import formats/uri, protocols/http, std/strutils, print
+
+  proc printLayout(layout: Layout, indentation=0) =
+    if layout.node.kind == Element:
+      stdout.write(" ".repeat(indentation))
+      stdout.write(layout.node.tag)
+      stdout.write(" ")
+      stdout.write(layout.kind)
+      stdout.write("\n")
+      print layout.parent
+      for child in layout.children:
+        child.printLayout(indentation + 2)
+
+  let text = parseHTML(httpRequest(parseURL("https://example.org:443/index.html")).body)
+  print layout(text)
+  for node in text:
+    printLayout node.layout(none(Layout), none(Layout))