From 27cf23445769829c4a116717433787d8b5cc810b Mon Sep 17 00:00:00 2001
From: Daniel Kempkens <daniel+git@kempkens.io>
Date: Thu, 17 Aug 2023 01:12:58 +0200
Subject: [PATCH] fix: Chat image IDs

---
 lib/bdfr_browser/http/plug.ex | 11 ++++++---
 lib/bdfr_browser/importer.ex  | 44 +++++++++++++++++++++++++++++++++--
 lib/bdfr_browser/message.ex   | 14 +++++++++++
 3 files changed, 64 insertions(+), 5 deletions(-)

diff --git a/lib/bdfr_browser/http/plug.ex b/lib/bdfr_browser/http/plug.ex
index d9d098e..3566e0a 100644
--- a/lib/bdfr_browser/http/plug.ex
+++ b/lib/bdfr_browser/http/plug.ex
@@ -1,7 +1,7 @@
 defmodule BdfrBrowser.HTTP.Plug do
   use Plug.Router
 
-  alias BdfrBrowser.{Chat, Comment, Message, Repo, Post, Subreddit}
+  alias BdfrBrowser.{Chat, Comment, Importer, Message, Repo, Post, Subreddit}
 
   plug :match
   plug :dispatch
@@ -150,15 +150,20 @@ defmodule BdfrBrowser.HTTP.Plug do
   end
 
   post "/_import" do
-    :ok = BdfrBrowser.Importer.background_import()
+    :ok = Importer.background_import()
     send_resp(conn, 200, "IMPORTING")
   end
 
   post "/_import_changes" do
-    :ok = BdfrBrowser.Importer.background_import_changes()
+    :ok = Importer.background_import_changes()
     send_resp(conn, 200, "IMPORTING CHANGES")
   end
 
+  post "/_cleanup" do
+    :ok = Importer.cleanup_messages()
+    send_resp(conn, 200, "CLEANED UP")
+  end
+
   get "/_ping" do
     send_resp(conn, 200, "PONG")
   end
diff --git a/lib/bdfr_browser/importer.ex b/lib/bdfr_browser/importer.ex
index c1885cb..c846813 100644
--- a/lib/bdfr_browser/importer.ex
+++ b/lib/bdfr_browser/importer.ex
@@ -5,6 +5,8 @@ defmodule BdfrBrowser.Importer do
 
   alias BdfrBrowser.{Chat, Comment, Message, Post, Repo, Subreddit}
 
+  @image_extensions [".jpg", ".jpeg", ".gif", ".png", ".webp"]
+
   defmodule State do
     use TypedStruct
 
@@ -77,6 +79,29 @@ defmodule BdfrBrowser.Importer do
     List.flatten(result)
   end
 
+  def cleanup_messages do
+    all_images = Message.images() |> Repo.all()
+
+    dupes =
+      for image <- all_images, uniq: true do
+        incorrect_id =
+          :sha3_256
+          |> :crypto.hash([image.chat_id, DateTime.to_iso8601(image.posted_at)])
+          |> Base.encode16(case: :lower)
+
+        potential_dupes = Message.potential_duplicates(image) |> Repo.all()
+
+        Enum.filter(potential_dupes, fn msg ->
+          msg.message == "Image" or
+            msg.message == "image" or
+            (msg.id == incorrect_id and String.starts_with?(msg.message, ["mxc://", "https://i.redd.it/"])) or
+            (String.starts_with?(msg.message, "image") and String.ends_with?(msg.message, @image_extensions))
+        end)
+      end
+
+    for dupe <- List.flatten(dupes), do: Repo.delete(dupe)
+  end
+
   def background_import do
     GenServer.cast(__MODULE__, :background_import)
   end
@@ -326,7 +351,7 @@ defmodule BdfrBrowser.Importer do
   end
 
   defp import_message(message, chat) when not is_nil(chat) do
-    id = :sha3_256 |> :crypto.hash([chat.id, message["timestamp"]]) |> Base.encode16(case: :lower)
+    id = calculate_message_id(message, chat.id)
     message_content = message["content"]["Message"]
     {:ok, posted_at, 0} = DateTime.from_iso8601(message["timestamp"])
 
@@ -343,7 +368,11 @@ defmodule BdfrBrowser.Importer do
         conflict_target: :id
       )
 
-    existing_image = message_record.message == "Image" or String.starts_with?(message_record.message, "image")
+    existing_image =
+      message_record.message == "Image" or
+        message_record.message == "image" or
+        (String.starts_with?(message_record.message, "image") and
+           String.ends_with?(message_record.message, @image_extensions))
 
     message_record =
       if existing_image and String.starts_with?(message_content, "mxc://") do
@@ -355,4 +384,15 @@ defmodule BdfrBrowser.Importer do
 
     message_record
   end
+
+  defp calculate_message_id(message, chat_id) do
+    message_content = message["content"]["Message"]
+    is_img = String.starts_with?(message_content, ["mxc://", "https://i.redd.it/"])
+
+    if is_img do
+      :sha3_256 |> :crypto.hash([chat_id, message["timestamp"], message_content]) |> Base.encode16(case: :lower)
+    else
+      :sha3_256 |> :crypto.hash([chat_id, message["timestamp"]]) |> Base.encode16(case: :lower)
+    end
+  end
 end
diff --git a/lib/bdfr_browser/message.ex b/lib/bdfr_browser/message.ex
index 326a7bc..83480a3 100644
--- a/lib/bdfr_browser/message.ex
+++ b/lib/bdfr_browser/message.ex
@@ -22,4 +22,18 @@ defmodule BdfrBrowser.Message do
       order_by: [asc: m.posted_at]
     )
   end
+
+  def images do
+    from(m in __MODULE__,
+      where: like(m.message, "mxc://%") or like(m.message, "https://i.redd.it/%"),
+      order_by: [asc: m.posted_at]
+    )
+  end
+
+  def potential_duplicates(other_m) do
+    from(m in __MODULE__,
+      where: m.id != ^other_m.id and m.chat_id == ^other_m.chat_id and m.posted_at == ^other_m.posted_at,
+      order_by: [asc: m.posted_at]
+    )
+  end
 end