From 8735974d1267dfa6134fe56fc3c828101da75d2f Mon Sep 17 00:00:00 2001
From: Dudemanguy <random342@airmail.cc>
Date: Thu, 13 Feb 2025 17:39:31 -0600
Subject: [PATCH] test/libmpv_test_track_selection: add a test for os languages

This test requires that the OS language settings be English so the
--subs-match-os-language option is actually testable. In Linux, this can
be done by just setting LANG and it always will work. For macOS and
Windows, we use the OS APIs to get the languages and let the test
proceed if we find English. Gracefully fail and skip otherwise.
---
 test/libmpv_test_track_selection.c | 71 ++++++++++++++++++++++++++++++
 test/samples/meson.build           |  8 +++-
 2 files changed, 78 insertions(+), 1 deletion(-)

diff --git a/test/libmpv_test_track_selection.c b/test/libmpv_test_track_selection.c
index 87c77d7cf4..8d4e1f42a9 100644
--- a/test/libmpv_test_track_selection.c
+++ b/test/libmpv_test_track_selection.c
@@ -16,8 +16,65 @@
  */
 
 #include <unistd.h>
+
+#ifdef __APPLE__
+#include <CoreFoundation/CoreFoundation.h>
+#endif
+
+#ifdef _WIN32
+#include <windows.h>
+#endif
+
 #include "libmpv_common.h"
 
+static bool have_english_locale(void)
+{
+#ifdef __APPLE__
+    CFArrayRef arr = CFLocaleCopyPreferredLanguages();
+    if (!arr)
+        return false;
+    CFIndex count = CFArrayGetCount(arr);
+    if (!count)
+        return false;
+
+    bool ret = false;
+    CFRange range = CFRangeMake(0, 2);
+    CFStringRef en = CFStringCreateWithCString(NULL, "en", kCFStringEncodingMacRoman);
+    for (CFIndex i = 0; i < count; i++) {
+        CFStringRef cfstr = CFArrayGetValueAtIndex(arr, i);
+        if (CFStringCompareWithOptions(cfstr, en, range, 0) == 0) {
+            ret = true;
+            break;
+        }
+    }
+    CFRelease(en);
+    return ret;
+#endif
+
+#ifdef _WIN32
+    ULONG count = 0;
+    ULONG size = 0;
+    wchar_t buf[1024];
+
+    if (GetUserPreferredUILanguages(MUI_LANGUAGE_NAME, &count, buf, &size)) {
+        for (ULONG pos = 0; buf[pos]; pos += wcslen(buf + pos) + 1) {
+            if (wcsncmp(buf + pos, L"en", 2) == 0)
+                return true;
+        }
+    }
+
+    if (GetSystemPreferredUILanguages(MUI_LANGUAGE_NAME, &count, buf, &size)) {
+        for (ULONG pos = 0; buf[pos]; pos += wcslen(buf + pos) + 1) {
+            if (wcsncmp(buf + pos, L"en", 2) == 0)
+                return true;
+        }
+    }
+
+    return false;
+#endif
+    return true;
+}
+
 static void check_string(const char *property, const char *expect)
 {
     char *result_string;
@@ -84,6 +141,15 @@ static void test_track_selection(char *file, char *path)
         check_api_error(mpv_set_property_string(ctx, "subs-fallback", "yes"));
         reload_file(path);
         check_string("current-tracks/sub/selected", "yes");
+    } else if (strcmp(file, "locale.mkv") == 0) {
+        // default english subs
+        reload_file(path);
+        check_string("current-tracks/sub/lang", "eng");
+
+        // default german subs
+        check_api_error(mpv_set_property_string(ctx, "subs-match-os-language", "no"));
+        reload_file(path);
+        check_string("current-tracks/sub/lang", "ger");
     } else if (strcmp(file, "multilang.mkv") == 0) {
         // --alang=jpn should select forced jpn subs
         check_api_error(mpv_set_property_string(ctx, "alang", "jpn"));
@@ -186,6 +252,11 @@ int main(int argc, char *argv[])
     if (argc < 3)
         return 1;
 
+    if (!strcmp(argv[1], "locale.mkv") && !have_english_locale()) {
+        printf("Non English language detected. Skipping locale test.\n");
+        return 77;
+    }
+
     ctx = mpv_create();
     if (!ctx)
         return 1;
diff --git a/test/samples/meson.build b/test/samples/meson.build
index ce0c3c7094..3842c22c52 100644
--- a/test/samples/meson.build
+++ b/test/samples/meson.build
@@ -32,6 +32,11 @@ samples = {
          '-disposition:s:0', 'forced', '@OUTPUT@'],
     'eng_no_default.mkv':
         [ffmpeg, common_args, '@OUTPUT@'],
+    'locale.mkv':
+        [ffmpeg, '-v', 'error', '-y', '-i', video, '-i', audio, '-f', 'srt', '-i', sub, '-i', sub,
+         '-c', 'copy', '-map', '0:0', '-map', '1:0', '-map', '2:0', '-map', '3:0', '-metadata:s:s:0',
+         'language=ger', '-metadata:s:s:1', 'language=eng', '-disposition:s:0', 'default',
+         '-disposition:s:1', 'default', '@OUTPUT@'],
     'multilang.mkv':
         [ffmpeg, '-v', 'error', '-y', '-i', video, '-i', audio, '-i', audio, '-i', audio, '-i', audio,
          '-f', 'srt', '-i', sub, '-i', sub, '-i', sub, '-i', sub, '-c', 'copy', '-map', '0:0',
@@ -57,9 +62,10 @@ foreach name, cmd: samples
         depends: [video, audio],
         command: cmd,
     )
+    env = name == 'locale.mkv' ? 'LANG=C' : []
     testname = 'libmpv-test-' + name
     exe = executable(testname, '../libmpv_test_track_selection.c',
                      include_directories: incdir, link_with: libmpv)
     test(testname, exe, args: [name, target.full_path()],
-         depends: target, suite: 'libmpv')
+         depends: target, env: env, suite: 'libmpv')
 endforeach