From a85dca5b3da94dbe54a781eedf66d6fddc99c7c8 Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Sat, 28 Aug 2021 12:17:16 -0400
Subject: [PATCH] Add filtering by item content

---
 lib/frenzy/pipeline/filter_engine.ex          | 29 ++++++++++++++++---
 .../live/filter/filter_rule_live.ex           |  4 ++-
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/lib/frenzy/pipeline/filter_engine.ex b/lib/frenzy/pipeline/filter_engine.ex
index 0de7c51..e1f7034 100644
--- a/lib/frenzy/pipeline/filter_engine.ex
+++ b/lib/frenzy/pipeline/filter_engine.ex
@@ -45,18 +45,24 @@ defmodule Frenzy.Pipeline.FilterEngine do
 
   def validate_rules(_rules), do: {:error, "rules must be a list"}
 
+  @rule_modes ~W[contains_string contains_string_case_sensitive matches_regex]
+  @rule_properties ~W[url title author content]
+
   def validate_rule(rule) do
     cond do
       not is_map(rule) ->
         {:error, "rule must be a map"}
 
       not (Map.has_key?(rule, "mode") and is_binary(rule["mode"]) and
-               rule["mode"] in ["contains_string", "matches_regex"]) ->
-        {:error, "mode property must be a string, either 'contains_string' or 'matches_regex'"}
+               rule["mode"] in @rule_modes) ->
+        rule_modes_text = Enum.map_join(@rule_modes, ", ", &"'#{&1}'")
+        {:error, "mode property must be a string, one of #{rule_modes_text}"}
 
       not (Map.has_key?(rule, "property") and is_binary(rule["property"]) and
-               rule["property"] in ["url", "title", "author"]) ->
-        {:error, "property property must be a string, either 'url', 'title', or 'author'"}
+               rule["property"] in @rule_properties) ->
+        rule_props_text = Enum.map_join(@rule_properties, ", ", &"'#{&1}'")
+
+        {:error, "property property must be a string, one of #{rule_props_text}"}
 
       not (Map.has_key?(rule, "param") and is_binary(rule["param"])) ->
         {:error, "param property must be a string"}
@@ -105,6 +111,10 @@ defmodule Frenzy.Pipeline.FilterEngine do
   end
 
   defp matches(value, "contains_string", param) do
+    String.contains?(String.downcase(value), String.downcase(param))
+  end
+
+  defp matches(value, "contains_string_case_sensitive", param) do
     String.contains?(value, param)
   end
 
@@ -116,5 +126,16 @@ defmodule Frenzy.Pipeline.FilterEngine do
   defp get_property(item_params, "url"), do: item_params.url
   defp get_property(item_params, "title"), do: item_params.title
   defp get_property(item_params, "author"), do: item_params.author
+
+  defp get_property(%{content: content, content_type: type}, "content")
+       when type in ["text/plain", "text/gemini"],
+       do: content
+
+  defp get_property(%{content: content, content_type: "text/html"}, "content") do
+    content
+    |> Floki.parse()
+    |> Floki.text()
+  end
+
   defp get_property(_item_params, _property), do: {:error, "invalid property"}
 end
diff --git a/lib/frenzy_web/live/filter/filter_rule_live.ex b/lib/frenzy_web/live/filter/filter_rule_live.ex
index b33b274..90b1a7f 100644
--- a/lib/frenzy_web/live/filter/filter_rule_live.ex
+++ b/lib/frenzy_web/live/filter/filter_rule_live.ex
@@ -3,13 +3,15 @@ defmodule FrenzyWeb.FilterRuleLive do
 
   @modes [
     {"Contains Substring", "contains_string"},
+    {"Contains Substring (case sensitive)", "contains_string_case_sensitive"},
     {"Matches Regex", "matches_regex"}
   ]
 
   @properties [
     {"Title", "title"},
     {"URL", "url"},
-    {"Author", "author"}
+    {"Author", "author"},
+    {"Content", "content"}
   ]
 
   @impl true