From 1b73e42756a8a2588bfb94a4270a068d663a3afb Mon Sep 17 00:00:00 2001
From: matlag <matlag@chtisurel.net>
Date: Sun, 21 Jul 2024 00:08:11 -0400
Subject: [PATCH] swap_link first working version

---
 swap_link.py             | 32 ++++++++++++++++++++++++++++++++
 test/test_search_file.py |  1 -
 test/test_swap_link.py   | 20 ++++++++++++++++++++
 3 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 swap_link.py
 create mode 100644 test/test_swap_link.py

diff --git a/swap_link.py b/swap_link.py
new file mode 100644
index 0000000..2292645
--- /dev/null
+++ b/swap_link.py
@@ -0,0 +1,32 @@
+# swap_link.py
+# Replace a link file with another one pointing to a new target
+#
+
+from pathlib import Path
+from os.path import relpath # won't be necessary with Python 3.12 thanks to walk_up arg in relative_to()
+
+def swap_link(lnk, tgt):
+    #lnk: symbolic link to swap
+    #tgt: target for new link
+    lnpath = Path(lnk)
+    if not lnpath.is_symlink():
+        raise Exception("First argument is not a symbolic link")
+    elif lnpath.exists():
+        raise Exception("Link is not broken")
+
+    tpath = Path(tgt)
+    if tpath.is_symlink():
+        if not tpath.exists():
+            raise Exception("Target is also a broken link!")
+        elif tpath.readlink().resolve() == lnpath.resolve() :
+            raise Exception("Target is a link to link to be fixed...")
+    
+    try:
+        lnpath.unlink()
+    except Exception(e):
+        raise Exception("Failed to unlink lnk. Check permissions!")
+
+    lnpath = Path(lnk)
+
+    sym_path = relpath(tgt, lnk)[3:]
+    lnpath.symlink_to(sym_path)
\ No newline at end of file
diff --git a/test/test_search_file.py b/test/test_search_file.py
index 1a512f5..67b6448 100644
--- a/test/test_search_file.py
+++ b/test/test_search_file.py
@@ -4,7 +4,6 @@ import io
 from search_file import print_num_list, search_all_match, select_path
 import search_file
 
-# TODO: gros TODO icitte. Presque rien de fait!
 
 class TestSearchFile(unittest.TestCase):
 
diff --git a/test/test_swap_link.py b/test/test_swap_link.py
new file mode 100644
index 0000000..b24127f
--- /dev/null
+++ b/test/test_swap_link.py
@@ -0,0 +1,20 @@
+import unittest
+
+class TestSwapLink(unittest.TestCase):
+    
+    data_dir = "test/data/search_test"
+
+    def test_wrong_lnk_file(self):
+        with self.assertRaises(Exception):
+            swap_link(data_dir+"inexistent.txt", data_dir+"/subdir/match1.txt") # inexistent file
+        with self.assertRaises(Exception):
+            swap_link(data_dir+"/subdir1/match1.txt", data_dir+"/subdir/match1.txt") # non link file
+        with self.assertRaises(Exception):
+            swap_link(data_dir+"lnk_dir/ln_valid", data_dir+"/subdir/match1.txt") # not broken link
+        # TODO: no writing permission on file
+    
+    def test_wrong_tgt_file(self):
+        # TODO: non-existing target
+        # TODO: target is link to lnk file (can't have 2 symlinks pointing at one another)
+        True
+