From 23410cf4edeeeadb3295e2d371b3f97f2fe29a86 Mon Sep 17 00:00:00 2001
From: Amar Raja <amaryraja@gmail.com>
Date: Fri, 14 Sep 2018 16:09:51 +0100
Subject: [PATCH] Start on rendering blocks

---
 .gitignore                                    |   2 +
 lib/fragment/image.ex                         |   6 +-
 .../structured_text/block/text/paragraph.ex   |  39 ++++++-
 lib/fragment/structured_text/span.ex          |   2 +
 lib/fragment/structured_text/span/em.ex       |   2 +
 .../structured_text/span/hyperlink.ex         |   9 +-
 lib/fragment/structured_text/span/label.ex    |   2 +
 lib/fragment/structured_text/span/strong.ex   |   2 +
 test/frag_test.exs                            | 107 ++++++++++++++++++
 9 files changed, 166 insertions(+), 5 deletions(-)
 create mode 100644 test/frag_test.exs

diff --git a/.gitignore b/.gitignore
index 12179ea..46123ac 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,3 +18,5 @@ erl_crash.dump
 
 # Also ignore archive artifacts (built via "mix archive.build").
 *.ez
+
+.elixir_ls
diff --git a/lib/fragment/image.ex b/lib/fragment/image.ex
index d024f6b..633c45d 100644
--- a/lib/fragment/image.ex
+++ b/lib/fragment/image.ex
@@ -9,5 +9,9 @@ end
 
 defimpl Prismic.Fragment, for: Prismic.Fragment.Image do
   # TODO
-  def as_html(_, _, _), do: ""
+  def as_html(img, _link_resolver, _html_serializer) do
+    main = img.main
+    %{url: url, height: h, width: w} = main
+    ~s[<img src="#{url}" height="#{h}" width="#{w}" />]
+  end
 end
diff --git a/lib/fragment/structured_text/block/text/paragraph.ex b/lib/fragment/structured_text/block/text/paragraph.ex
index caf67b7..3230393 100644
--- a/lib/fragment/structured_text/block/text/paragraph.ex
+++ b/lib/fragment/structured_text/block/text/paragraph.ex
@@ -7,5 +7,42 @@ defmodule Block.Text.Paragraph do
 end
 
 defimpl Block, for: Block.Text.Paragraph do
-  def as_html(_, _link_resolver, _html_serializer), do: ""
+  alias Prismic.Fragment.StructuredText.Span
+
+  def as_html(para, _link_resolver, _html_serializer) do
+    ~s(<p>#{process_spans(para)}</p>)
+  end
+
+  # TODO: All this should move out (unless paragraph is the only one with spans?)
+  defp process_spans(%{text: text, spans: []}), do: text
+
+  defp process_spans(%{text: text, spans: spans}) do
+    text_stream = String.codepoints(text)
+    do_process_spans(text_stream, 0, spans, [], [])
+  end
+
+  defp do_process_spans([], _pos, _spans, applied_spans, acc) do
+    [acc | Enum.map(applied_spans, &Span.close_tag/1)]
+  end
+
+  # TODO: Not sure how efficient this is, since it is one character at a time
+  # Could do something smarter by checking the next opening and chunk characters
+  # from there. Uses an IO list so we aren't creating too many intermediate strings
+  defp do_process_spans([h | t], pos, spans, applied_spans, acc) do
+    {ending_here, still_to_end} = Enum.split_with(applied_spans, &match?(%{end: ^pos}, &1))
+    starting_here = Enum.filter(spans, &match?(%{start: ^pos}, &1))
+
+    ending_tags = Enum.map(ending_here, &Span.close_tag/1)
+    starting_tags = Enum.map(starting_here, &Span.open_tag/1)
+
+    # TODO: h should be html encoded
+    acc = [acc | [ending_tags, starting_tags, h]]
+
+    applied_spans =
+      starting_here
+      |> Enum.reverse()
+      |> Enum.concat(still_to_end)
+
+    do_process_spans(t, pos + 1, spans, applied_spans, acc)
+  end
 end
diff --git a/lib/fragment/structured_text/span.ex b/lib/fragment/structured_text/span.ex
index 663aa2d..4d3447e 100644
--- a/lib/fragment/structured_text/span.ex
+++ b/lib/fragment/structured_text/span.ex
@@ -1,3 +1,5 @@
 defprotocol Prismic.Fragment.StructuredText.Span do
   def serialize(span, link_resolver)
+  def open_tag(span)
+  def close_tag(span)
 end
diff --git a/lib/fragment/structured_text/span/em.ex b/lib/fragment/structured_text/span/em.ex
index 028285c..56991e3 100644
--- a/lib/fragment/structured_text/span/em.ex
+++ b/lib/fragment/structured_text/span/em.ex
@@ -9,4 +9,6 @@ end
 defimpl Span, for: Span.Em do
   # TODO
   def serialize(_, _link_resolver), do: ""
+  def open_tag(_span), do: "<i>"
+  def close_tag(_span), do: "</i>"
 end
diff --git a/lib/fragment/structured_text/span/hyperlink.ex b/lib/fragment/structured_text/span/hyperlink.ex
index b9262e2..1dc1d32 100644
--- a/lib/fragment/structured_text/span/hyperlink.ex
+++ b/lib/fragment/structured_text/span/hyperlink.ex
@@ -5,12 +5,15 @@ defmodule Span.Hyperlink do
   defstruct [:start, :end, :link]
 
   @type t :: %__MODULE__{
-    start: Integer.t(),
-    end: Integer.t(),
-    link: WebLink.t() | DocumentLink.t() | ImageLink.t()}
+          start: Integer.t(),
+          end: Integer.t(),
+          link: WebLink.t() | DocumentLink.t() | ImageLink.t()
+        }
 end
 
 defimpl Span, for: Span.Hyperlink do
   # TODO
   def serialize(_, _link_resolver), do: ""
+  def open_tag(%Span.Hyperlink{link: link}), do: ~s(<a href="#{link}">)
+  def close_tag(_span), do: "</a>"
 end
diff --git a/lib/fragment/structured_text/span/label.ex b/lib/fragment/structured_text/span/label.ex
index 9960c5b..8b2e319 100644
--- a/lib/fragment/structured_text/span/label.ex
+++ b/lib/fragment/structured_text/span/label.ex
@@ -9,4 +9,6 @@ end
 defimpl Span, for: Span.Label do
   # TODO
   def serialize(_, _link_resolver), do: ""
+  def open_tag(_span), do: "<label>"
+  def close_tag(_span), do: "</label>"
 end
diff --git a/lib/fragment/structured_text/span/strong.ex b/lib/fragment/structured_text/span/strong.ex
index 8558e74..4f9283a 100644
--- a/lib/fragment/structured_text/span/strong.ex
+++ b/lib/fragment/structured_text/span/strong.ex
@@ -9,4 +9,6 @@ end
 defimpl Span, for: Span.Strong do
   # TODO
   def serialize(_, _link_resolver), do: ""
+  def open_tag(_span), do: "<b>"
+  def close_tag(_span), do: "</b>"
 end
diff --git a/test/frag_test.exs b/test/frag_test.exs
new file mode 100644
index 0000000..7bbf454
--- /dev/null
+++ b/test/frag_test.exs
@@ -0,0 +1,107 @@
+defmodule Prismic.FragText do
+  use ExUnit.Case
+  alias Prismic.Fragment.StructuredText.Block.Text.Paragraph
+  alias Prismic.Fragment.StructuredText.Span.{Em, Strong, Hyperlink}
+
+  describe "structured text render" do
+    defp render_para(spans, text \\ "abc") do
+      st = %Prismic.Fragment.StructuredText{
+        blocks: [
+          %Paragraph{
+            label: nil,
+            spans: spans,
+            text: text
+          }
+        ]
+      }
+
+      Prismic.Fragment.as_html(st, nil)
+    end
+
+    test "renders em" do
+      spans = [
+        %Em{end: 3, start: 0}
+      ]
+
+      assert ~s(<p><i>abc</i></p>) == render_para(spans)
+    end
+
+    test "renders strong" do
+      spans = [
+        %Strong{end: 3, start: 0}
+      ]
+
+      assert ~s(<p><b>abc</b></p>) == render_para(spans)
+    end
+
+    test "renders link" do
+      spans = [
+        %Hyperlink{end: 3, start: 0, link: "somelink"}
+      ]
+
+      assert ~s(<p><a href="somelink">abc</a></p>) == render_para(spans)
+    end
+
+    test "renders multiple" do
+      spans = [
+        %Em{end: 3, start: 0},
+        %Em{end: 6, start: 4}
+      ]
+
+      text = "abcdef"
+      assert ~s(<p><i>abc</i>d<i>ef</i></p>) == render_para(spans, text)
+    end
+
+    test "handles nesting" do
+      spans = [
+        %Em{end: 6, start: 0},
+        %Strong{end: 5, start: 3}
+      ]
+
+      text = "abcdef"
+      assert ~s(<p><i>abc<b>de</b>f</i></p>) == render_para(spans, text)
+    end
+
+    test "ignores starts longer than input" do
+      spans = [
+        %Em{end: 6, start: 999}
+      ]
+
+      assert ~s(<p>abc</p>) == render_para(spans)
+    end
+
+    test "closes tag if end greater than input" do
+      spans = [
+        %Em{end: 999, start: 0}
+      ]
+
+      assert ~s(<p><i>abc</i></p>) == render_para(spans)
+    end
+
+    test "can do single characters" do
+      spans = [
+        %Em{end: 2, start: 1}
+      ]
+
+      assert ~s(<p>a<i>b</i>c</p>) == render_para(spans)
+    end
+
+    test "can do middle" do
+      spans = [
+        %Em{end: 4, start: 2}
+      ]
+
+      text = "abcdef"
+      assert ~s(<p>ab<i>cd</i>ef</p>) == render_para(spans, text)
+    end
+
+    test "leaves tags balanced" do
+      spans = [
+        %Em{end: 3, start: 0},
+        %Strong{end: 3, start: 0}
+      ]
+
+      assert ~s(<p><i><b>abc</b></i></p>) == render_para(spans)
+    end
+  end
+end