Start refactor

The Page class is getting complicated, so extract out
the tree structure into its own class, and introduce a simple
struct to represent the pages themselves.

lib/obsidian/parser/page.rb

@@ -2,8 +2,25 @@
 
 # TODO: remove this dependency
 require "tilt/erb"
+require_relative "tree"
 
 module Obsidian
+  # WIP
+  PageNode = Struct.new(
+    :title,
+    :slug,
+    :last_modified,
+    :source_path,
+    :content_type,
+    keyword_init: true
+  ) do
+    def raw_content
+    end
+
+    def html
+    end
+  end
+
   # A page in the vault corresponding to either a markdown document,
   # or a directory containing other documents.
   #
@@ -71,7 +88,7 @@ def hash
     # Call this method on the root page.
     # When calling this method, you must ensure that anscestor pages
     # are added before their descendents.
-    def add_page(slug, last_modified: nil, content: nil, content_type: nil, media_root: nil, source_path: nil)
+    def add_page(slug, last_modified: nil, content: nil, content_type: nil, media_root: nil, source_path: nil, strip_numeric_prefix: true)
       path_components = slug.split("/")
 
       if path_components.empty?
@@ -80,10 +97,13 @@ def add_page(slug, last_modified: nil, content: nil, content_type: nil, media_ro
       end
 
       title = path_components.pop
+      if strip_numeric_prefix
+        title = title.sub(/^\d+ - /, "")
+      end
 
       parent = path_components.reduce(self) do |index, anscestor_title|
         anscestor_slug = Obsidian.build_slug(anscestor_title, index.slug)
-        index.get_or_create_child(slug: anscestor_slug, title: anscestor_title)
+        index.get_or_create_child(slug: anscestor_slug, title: anscestor_title.sub(/^\d+ - /, ""))
       end
 
       parent.get_or_create_child(
@@ -120,7 +140,7 @@ def update_content(content:, last_modified:)
     end
 
     def children
-      @children.values.sort_by { |c| [c.is_index? ? 0 : 1, c.title] }
+      @children.values.sort_by { |c| [c.is_index? ? 0 : 1, c.slug] }
     end
 
     def walk_tree(&block)

lib/obsidian/parser/tree.rb

@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+module Obsidian
+  class Tree
+    def initialize(value)
+      @value = value
+      @children = []
+    end
+
+    attr_reader :children
+    attr_reader :value
+
+    def inspect
+      "Tree(#{value.inspect}) [#{children.length} children]"
+    end
+
+    def add_child(value)
+      node = Tree.new(value)
+      children << node
+      node
+    end
+
+    def remove_child(value)
+      children.delete_if { |node| node.value == value }
+    end
+
+    def is_index?
+      children.length > 0
+    end
+
+    def find(&block)
+      walk_tree do |page|
+        return page if block.call(page)
+      end
+
+      nil
+    end
+
+    def walk_tree(&block)
+      block.call(self)
+
+      children.each do |page|
+        page.walk_tree(&block)
+      end
+    end
+  end
+end

spec/obsidian/parser/tree_spec.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+RSpec.describe Obsidian::Tree do
+  subject(:root) { described_class.new(:root) }
+
+  describe("creating, retrieving, and removing nodes") do
+    before do
+      foo = root.add_child(:foo)
+      foo.add_child(:bar)
+      foo.add_child(:baz)
+    end
+
+    it "can find a node from the root" do
+      a = root.find { |node| node.value == :baz }
+
+      expect(a&.value).to eq(:baz)
+    end
+
+    it "can list the children of a node" do
+      foo = root.children.first
+
+      expect(root.children.map(&:value)).to eq([:foo])
+      expect(foo.children.map(&:value)).to eq([:bar, :baz])
+    end
+
+    it "can remove nodes" do
+      root.remove_child(:foo)
+      expect(root.children).to be_empty
+    end
+
+    it "can tell if a node is non-terminal" do
+      foo = root.children.first
+      bar = foo.children.first
+      expect(root.is_index?).to eq(true)
+      expect(foo.is_index?).to eq(true)
+      expect(bar.is_index?).to eq(false)
+    end
+  end
+end