From 3f49d9f7db40a64e967c28ba10479985aa0fadc9 Mon Sep 17 00:00:00 2001
From: Nathan McRae <nathanm@electroimpact.com>
Date: Thu, 11 Jul 2024 19:29:44 -0700
Subject: [PATCH] Add 'commit' command

---
 libwyag.py | 116 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 116 insertions(+)

diff --git a/libwyag.py b/libwyag.py
index 7d43d75..de56aa3 100644
--- a/libwyag.py
+++ b/libwyag.py
@@ -1342,3 +1342,119 @@ def add(repo, paths, delete=True, skip_missing=False):
             index.entries.append(entry)
 
     index_write(repo, index)
+
+argsp = argsubparsers.add_parser("commit", help="Record changes to the repository.")
+
+argsp.add_argument("-m",
+                   metavar="mesaage",
+                   dest="message",
+                   help="Message to associate with this commit.")
+
+def gitconfig_read():
+    xdg_config_home = os.environ["XDG_CONFIG_HOME"] if "XDG_CONFIG_HOME" in os.environ else "~/.config"
+    config_files = [
+        os.path.expanduser(join_path(xdg_config_home, "git/config")).replace("\\", "/"),
+        #os.path.expanduser("~/.gitconfig").replace("\\", "/")
+    ]
+
+    config = configparser.ConfigParser()
+    config.read(config_files)
+    return config
+
+def gitconfig_user_get(config):
+    if "user" in config:
+        if "name" in config["user"] and "email" in config["user"]:
+            return f"{config['user']['name']} <{config['user']['email']}>"
+    return None
+
+def tree_from_index(repo, index):
+    contents = dict()
+    contents[""] = list()
+
+    # Convert entries to dictionary where keys are directories, and values are
+    # lists of directory contents.
+    for entry in index.entries:
+        dirname = os.path.dirname(entry.name).replace("\\", "/")
+
+        # We create all dictionary entries up to root (""). We need them *all*
+        # because even if a directory holds no files it will contain at least
+        # a tree.
+        key = dirname
+        while key != "":
+            if not key in contents:
+                contents[key] = list()
+            key = os.path.dirname(key).replace("\\", "/")
+
+        contents[dirname].append(entry)
+
+    # Sort keys (= directories) by length, descending. This means that we'll
+    # always encounter a given path before its parent, which is all we need,
+    # since for each directory D we'll need to modify its parent P to add
+    # D's tree.
+    sorted_paths = sorted(contents.keys(), key=len, reverse=True)
+
+    sha = None
+
+    for path in sorted_paths:
+        tree = GitTree()
+
+        for entry in contents[path]:
+            # An entry can be a normal GitIndexEntry read from the index, or
+            # a tree we've created.
+            if isinstance(entry, GitIndexEntry):
+                leaf_mode = f"{entry.mode_type:02o}{entry.mode_perms:04o}".encode("ascii")
+                leaf = GitTreeLeaf(mode=leaf_mode, path=os.path.basename(entry.name), sha=entry.sha)
+            else: # Tree. We've stored it as a pair: (basename, SHA)
+                leaf = GitTreeLeaf(mode=b"040000", path=entry[0], sha=entry[1])
+
+            tree.items.append(leaf)
+
+        sha = object_write(tree, repo)
+
+        parent = os.path.dirname(path).replace("\\", "/")
+        base = os.path.basename(path)
+        contents[parent].append((base, sha))
+
+    return sha
+
+def commit_create(repo, tree, parent, author, timestamp, message):
+    commit = GitCommit()
+    commit.kvlm[b"tree"] = tree.encode("ascii")
+    if parent:
+        commit.kvlm[b'parent'] = parent.encode("ascii")
+
+    offset = int(timestamp.astimezone().utcoffset().total_seconds())
+    hours = offset // 3600
+    minutes = (offset & 3600) // 60
+    tz = f"{'+' if offset > 0 else '-'}{hours:02}{minutes:02}"
+
+    if author == None:
+        author = ""
+    author = author + timestamp.strftime(" %S ") + tz
+
+    commit.kvlm[b"author"] = author.encode("utf8")
+    commit.kvlm[b"committer"] = author.encode("utf8")
+    commit.kvlm[None] = message.encode("utf8")
+
+    return object_write(commit, repo)
+
+def cmd_commit(args):
+    repo = repo_find()
+    index = index_read(repo)
+    tree = tree_from_index(repo, index)
+
+    commit = commit_create(repo,
+                           tree,
+                           object_find(repo, "HEAD"),
+                           gitconfig_user_get(gitconfig_read()),
+                           datetime.now(),
+                           args.message)
+
+    # Update HEAD so our commit is now the tip of the active branch.
+    active_branch = branch_get_active(repo)
+    if active_branch: # If on a branch, update that branch
+        with open(GitRepository.repo_file(repo, join_path("refs/heads", active_branch)), "w") as fd:
+            fd.write(commit + "\n")
+    else: # Otherwise, we update HEAD itself.
+        with open(repo_file(repo, "HEAD"), "w") as fd:
+            fd.write(commit + "\n")