From 4e641dea1eb29978f1fa78a3c235250d52d1d31f Mon Sep 17 00:00:00 2001
From: Kamil Trzcinski <ayufan@ayufan.eu>
Date: Tue, 12 Jul 2022 21:59:02 +0200
Subject: [PATCH] Open default camera of a given type

---
 cmd/camera-streamer.c        |  6 +++---
 device/camera/camera_input.c |  8 +++++++-
 device/libcamera/device.cc   | 39 +++++++++++++++++++++++++-----------
 3 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/cmd/camera-streamer.c b/cmd/camera-streamer.c
index c405f13..dd82157 100644
--- a/cmd/camera-streamer.c
+++ b/cmd/camera-streamer.c
@@ -90,7 +90,7 @@ http_method_t http_methods[] = {
 };
 
 camera_options_t camera_options = {
-  .path = "/dev/video0",
+  .path = "",
   .width = 1920,
   .height = 1080,
   .format = 0,
@@ -154,12 +154,12 @@ option_value_t camera_type[] = {
 };
 
 option_t all_options[] = {
-  DEFINE_OPTION_PTR(camera, path, string, "Chooses the camera to use."),
+  DEFINE_OPTION_PTR(camera, path, string, "Chooses the camera to use. If empty connect to default."),
+  DEFINE_OPTION_VALUES(camera, type, camera_type, "Select camera type."),
   DEFINE_OPTION(camera, width, uint, "Set the camera capture width."),
   DEFINE_OPTION(camera, height, uint, "Set the camera capture height."),
   DEFINE_OPTION_VALUES(camera, format, camera_formats, "Set the camera capture format."),
   DEFINE_OPTION(camera, nbufs, uint, "Set number of capture buffers. Preferred 2 or 3."),
-  DEFINE_OPTION_VALUES(camera, type, camera_type, "Select camera capture."),
   DEFINE_OPTION(camera, fps, uint, "Set the desired capture framerate."),
   DEFINE_OPTION_DEFAULT(camera, allow_dma, bool, "1", "Prefer to use DMA access to reduce memory copy."),
   DEFINE_OPTION(camera, high_res_factor, float, "Set the desired high resolution output scale factor."),
diff --git a/device/camera/camera_input.c b/device/camera/camera_input.c
index c4e44a3..c283048 100644
--- a/device/camera/camera_input.c
+++ b/device/camera/camera_input.c
@@ -9,7 +9,13 @@
 
 static int camera_configure_input_v4l2(camera_t *camera)
 {
-  camera->camera = device_v4l2_open(camera->name, camera->options.path);
+  const char *path = camera->options.path;
+
+  if (!*path) {
+    path = "/dev/video0";
+  }
+
+  camera->camera = device_v4l2_open(camera->name, path);
   if (!camera->camera) {
     LOG_INFO(camera, "Listing available v4l2 devices:");
     system("v4l2-ctl --list-devices");
diff --git a/device/libcamera/device.cc b/device/libcamera/device.cc
index 6686d86..68c279a 100644
--- a/device/libcamera/device.cc
+++ b/device/libcamera/device.cc
@@ -58,6 +58,19 @@ void libcamera_device_dump_options(device_t *dev, FILE *stream)
   fprintf(stream, "\n");
 }
 
+void libcamera_print_cameras(device_t *dev)
+{
+  if (dev->libcamera->camera_manager->cameras().size()) {
+    LOG_INFO(dev, "Available cameras (%zu)", dev->libcamera->camera_manager->cameras().size());
+
+    for (auto const &camera : dev->libcamera->camera_manager->cameras()) {
+      LOG_INFO(dev, "- %s", camera->id().c_str());
+    }
+  } else {
+    LOG_INFO(dev, "No available cameras");
+  }
+}
+
 int libcamera_device_open(device_t *dev)
 {
   dev->libcamera = new device_libcamera_t{};
@@ -68,25 +81,27 @@ int libcamera_device_open(device_t *dev)
     LOG_ERROR(dev, "Cannot start camera_manager.");
   }
 
-  dev->libcamera->camera = dev->libcamera->camera_manager->get(dev->path);
-  if (!dev->libcamera->camera) {
-    if (dev->libcamera->camera_manager->cameras().size()) {
-      LOG_INFO(dev, "Available cameras (%zu)", dev->libcamera->camera_manager->cameras().size());
-
-      for (auto const &camera : dev->libcamera->camera_manager->cameras()) {
-        LOG_INFO(dev, "- %s", camera->id().c_str());
-      }
-    } else {
-      LOG_INFO(dev, "No available cameras");
+  if (strlen(dev->path) == 0) {
+    if (dev->libcamera->camera_manager->cameras().size() != 1) {
+      libcamera_print_cameras(dev);
+      LOG_ERROR(dev, "Too many cameras was found. Cannot select default.");
     }
+
+    dev->libcamera->camera = dev->libcamera->camera_manager->cameras().front();
+  } else {
+    dev->libcamera->camera = dev->libcamera->camera_manager->get(dev->path);
+  }
+
+  if (!dev->libcamera->camera) {
+    libcamera_print_cameras(dev);
     LOG_ERROR(dev, "Camera `%s` was not found.", dev->path);
   }
 
   if (dev->libcamera->camera->acquire()) {
-    LOG_ERROR(dev, "Failed to acquire `%s` camera.", dev->path);
+    LOG_ERROR(dev, "Failed to acquire `%s` camera.", dev->libcamera->camera->id().c_str());
   }
 
-	LOG_INFO(dev, "Device path=%s opened", dev->path);
+	LOG_INFO(dev, "Device path=%s opened", dev->libcamera->camera->id().c_str());
   return 0;
 
 error: