From a419933e77c69ccf1c730fba303dcb1250c1c705 Mon Sep 17 00:00:00 2001
From: Bjoern Kerler <info@revskills.de>
Date: Sun, 18 Feb 2024 19:08:50 +0100
Subject: [PATCH] Update gcode M20 to fit common marlin behaviour

---
 src/marlin_stubs/host/M115.cpp              |  3 +
 src/marlin_stubs/sdcard/M20-M30_M32-M34.cpp | 65 +++++++++++++++++++--
 2 files changed, 63 insertions(+), 5 deletions(-)

diff --git a/src/marlin_stubs/host/M115.cpp b/src/marlin_stubs/host/M115.cpp
index dfade61623..7f3df434f0 100644
--- a/src/marlin_stubs/host/M115.cpp
+++ b/src/marlin_stubs/host/M115.cpp
@@ -214,5 +214,8 @@ void GcodeSuite::M115() {
     #endif
     );
 
+    // PARSE FILES ON USB (M20)
+    cap_line(PSTR("EXTENDED_M20"), true);
+
 #endif // EXTENDED_CAPABILITIES_REPORT
 }
diff --git a/src/marlin_stubs/sdcard/M20-M30_M32-M34.cpp b/src/marlin_stubs/sdcard/M20-M30_M32-M34.cpp
index 56b018f3f4..a0ecf87198 100644
--- a/src/marlin_stubs/sdcard/M20-M30_M32-M34.cpp
+++ b/src/marlin_stubs/sdcard/M20-M30_M32-M34.cpp
@@ -1,22 +1,77 @@
 #include <dirent.h>
 
 #include "../../lib/Marlin/Marlin/src/gcode/gcode.h"
+#include "libs/hex_print_routines.h"
 #include "marlin_server.hpp"
 #include "media.h"
 #include "marlin_vars.hpp"
 
-// M20 - List SD card
-void GcodeSuite::M20() {
-    SERIAL_ECHOLNPGM(MSG_BEGIN_FILE_LIST);
+static void print_file_size(const char *const filename) {
+    struct stat stat_buf;
+    int rc = stat(filename, &stat_buf);
+    if (rc == 0) {
+        SERIAL_ECHO(stat_buf.st_size);
+    }
+}
+
+static void print_file_info(const char *const dirname, const char *const long_dirname, bool timestamps, bool long_filenames) {
+    SERIAL_ECHO(&dirname[5]);
+    SERIAL_CHAR(' ');
+    print_file_size(dirname);
+    if (timestamps) {
+        struct stat stat_buf;
+        int rc = stat(dirname, &stat_buf);
+        if (rc == 0) {
+            time_t t = stat_buf.st_mtim.tv_sec;
+            struct tm lt;
+            localtime_r(&t, &lt);
+            uint16_t m20_date = (lt.tm_year + 1900 - 1980) << 9 | (lt.tm_mon + 1) << 5 | lt.tm_mday;
+            uint16_t m20_time = lt.tm_hour << 11 | lt.tm_min << 5;
+            m20_time |= int((lt.tm_sec - (lt.tm_sec % 2)) / 2);
+            SERIAL_ECHOPGM(" 0x");
+            print_hex_word(m20_date);
+            print_hex_word(m20_time);
+        }
+    }
+    if (long_filenames) {
+        SERIAL_CHAR(' ');
+        SERIAL_CHAR('"');
+        SERIAL_ECHO(&long_dirname[5]);
+        SERIAL_CHAR('"');
+    }
+    SERIAL_EOL();
+}
+
+static void print_listing(const char *const prepend, const char *const prepend_long, bool timestamps, bool long_filenames) {
     DIR *dir;
-    dir = opendir("/usb/");
+    dir = opendir(prepend);
     if (dir != NULL) {
         struct dirent *entry;
         while ((entry = readdir(dir)) != NULL && entry->d_name[0]) {
-            SERIAL_ECHOLN(entry->d_name);
+            char dirname[5 + 512];
+            char long_dirname[5 + 512];
+            snprintf(dirname, sizeof(dirname), "%s/%s", prepend, entry->d_name);
+            snprintf(long_dirname, sizeof(long_dirname), "%s/%s", prepend_long, entry->lfn);
+            if (entry->d_type != DT_DIR) {
+                print_file_info(dirname, long_dirname, timestamps, long_filenames);
+            }
         }
         closedir(dir);
     }
+}
+
+// M20 - List SD card
+void GcodeSuite::M20() {
+    bool longfilenames = false;
+    bool timestamps = false;
+    if (parser.seen('L')) {
+        longfilenames = true;
+    }
+    if (parser.seen('T')) {
+        timestamps = true;
+    }
+    SERIAL_ECHOLNPGM(MSG_BEGIN_FILE_LIST);
+    print_listing("/usb", "/usb", timestamps, longfilenames);
     SERIAL_ECHOLNPGM(MSG_END_FILE_LIST);
 }