From 522ec59c0eda51bb2bd2d653108b3bbd39a124ee Mon Sep 17 00:00:00 2001
From: "Zed A. Shaw" <zed.shaw@gmail.com>
Date: Sun, 3 May 2026 23:10:07 -0400
Subject: [PATCH] Move the change detector to a separate module.

---
 meson.build           |  1 +
 sample/about-bezos.md | 20 ++++++++++++++++++++
 src/changes.cpp       | 31 +++++++++++++++++++++++++++++++
 src/changes.hpp       | 15 +++++++++++++++
 src/main.cpp          | 40 +++++-----------------------------------
 5 files changed, 72 insertions(+), 35 deletions(-)
 create mode 100644 src/changes.cpp
 create mode 100644 src/changes.hpp

diff --git a/meson.build b/meson.build
index a54ab49..97e3b08 100644
--- a/meson.build
+++ b/meson.build
@@ -96,6 +96,7 @@ sources = [
   'src/parser.cpp',
   'src/backend.cpp',
   'src/control.cpp',
+  'src/changes.cpp',
 ]
 
 tests = [
diff --git a/sample/about-bezos.md b/sample/about-bezos.md
index 354bac5..7426712 100644
--- a/sample/about-bezos.md
+++ b/sample/about-bezos.md
@@ -26,6 +26,26 @@ PowerPoint
 }
 Can We Blame Him?
 ---
+{
+  "shader": "flame",
+  "bg_color": [80, 0, 0, 255],
+  "layout": "no_title",
+  "font_size": 200
+}
+I Made a
+PowerPoint
+Killer
+---
+{
+  "shader": "flame",
+  "bg_color": [80, 0, 0, 255],
+  "layout": "no_title",
+  "font_size": 300,
+  "title_size": 300
+}
+In
+C++
+---
 # I Hate PowerPoint Too
 * So I made an alternative.
 * Markdown Format
diff --git a/src/changes.cpp b/src/changes.cpp
new file mode 100644
index 0000000..e5334d5
--- /dev/null
+++ b/src/changes.cpp
@@ -0,0 +1,31 @@
+#include "changes.hpp"
+#include <fmt/core.h>
+#include <SFML/System/Time.hpp>
+
+using namespace std::chrono_literals;
+
+void ChangeDetector::watch(const std::string& name) {
+   auto last_mod_time = std::filesystem::last_write_time(name);
+   $watching.try_emplace(name, last_mod_time);
+}
+
+bool ChangeDetector::changed() {
+  if(timer.getElapsedTime().toDuration() > 500ms) {
+    for(auto& [fname, last_mod_time] : $watching) {
+      try {
+        auto mod_time = std::filesystem::last_write_time(fname);
+
+        if(last_mod_time < mod_time) {
+          last_mod_time = mod_time;
+          return true;
+        }
+      } catch(const std::filesystem::filesystem_error& err) {
+        fmt::println("failed to open {}: {}", err.path1().string(), err.what());
+        timer.restart();
+        return false;
+      }
+    }
+  }
+
+  return false;
+}
diff --git a/src/changes.hpp b/src/changes.hpp
new file mode 100644
index 0000000..701d9d9
--- /dev/null
+++ b/src/changes.hpp
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <SFML/System/Clock.hpp>
+#include <filesystem>
+#include <chrono>
+#include <unordered_map>
+
+struct ChangeDetector {
+  std::string input_md;
+  sf::Clock timer{};
+  std::unordered_map<std::string, std::filesystem::file_time_type> $watching;
+
+  void watch(const std::string& name);
+  bool changed();
+};
diff --git a/src/main.cpp b/src/main.cpp
index 49ba269..b00fc75 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -6,13 +6,9 @@
 #include "slides_ui.hpp"
 #include "control_ui.hpp"
 #include "parser.hpp"
-#include <filesystem>
-#include <chrono>
-#include <SFML/System/Clock.hpp>
 #include <memory>
 #include <unistd.h>
-
-using namespace std::chrono_literals;
+#include "changes.hpp"
 
 struct Options {
   std::string deck_file{};
@@ -41,32 +37,6 @@ std::shared_ptr<SlidesUI> load_slides(const std::string& input_md, std::shared_p
   }
 }
 
-struct ChangeDetector {
-  std::string input_md;
-  sf::Clock timer{};
-  std::filesystem::file_time_type last_mod_time = std::filesystem::last_write_time(input_md);
-
-  bool changed() {
-    if(timer.getElapsedTime().toDuration() > 500ms) {
-      try {
-        auto mod_time = std::filesystem::last_write_time(input_md);
-
-        if(last_mod_time < mod_time) {
-          last_mod_time = mod_time;
-          return true;
-        } else {
-          return false;
-        }
-      } catch(const std::filesystem::filesystem_error& err) {
-        fmt::println("failed to open {}: {}", err.path1().string(), err.what());
-        timer.restart();
-        return false;
-      }
-    }
-
-    return false;
-  }
-};
 
 void print_usage() {
   fmt::println("USAGE: bezos [-p PORT] [-h] -d deck.md");
@@ -140,11 +110,11 @@ int main(int argc, char *argv[]) {
   control_ui.init();
   control_ui.full_screen(false);
 
-  ChangeDetector slides_reloader{options.deck_file};
-  ChangeDetector layout_reloader{slides->$deck->config["layouts"]};
+  ChangeDetector reloader;
+  reloader.watch(options.deck_file);
+  reloader.watch(slides->$deck->config["layouts"]);
 
   while(controller.isOpen()) {
-
     while(const auto event = presenter.pollEvent()) {
       if(event) slides->handle_events(presenter, *event);
     }
@@ -157,7 +127,7 @@ int main(int argc, char *argv[]) {
     presenter.display();
     controller.display();
 
-    if(slides_reloader.changed() || layout_reloader.changed()) {
+    if(reloader.changed()) {
       // save the current slide
       auto current_slide = slides->$deck->current;
       // load the new one