git status, diff ও log

# L30-এর ঠিক একই থ্রি-ট্রি Repo মডেল সম্প্রসারিত করা হচ্ছে -- বাস্তব git বাইনারি নেই,
# তাই status/diff/log নিজেরাই তিনটি dict তুলনা করে বাস্তবায়ন করা হলো।

def make_repo():
    return {"working_directory": {}, "staging_area": {}, "commits": {}, "head": None}

def git_add(repo, filename):
    repo["staging_area"][filename] = repo["working_directory"][filename]

def git_commit(repo, message):
    commit_hash = f"c{len(repo['commits']) + 1}"
    snapshot = dict(repo["staging_area"])
    repo["commits"][commit_hash] = {"message": message, "snapshot": snapshot, "parent": repo["head"]}
    repo["head"] = commit_hash
    repo["staging_area"] = {}
    return commit_hash


def git_status(repo):
    committed = repo["commits"][repo["head"]]["snapshot"] if repo["head"] else {}
    all_files = set(repo["working_directory"]) | set(repo["staging_area"]) | set(committed)
    status = {}
    for f in sorted(all_files):
        wd = repo["working_directory"].get(f)
        staged = repo["staging_area"].get(f)
        head = committed.get(f)
        if f not in repo["staging_area"] and f not in committed:
            status[f] = "untracked"
        elif wd != staged:
            status[f] = "modified (not staged)"
        elif staged != head:
            status[f] = "staged"
        else:
            status[f] = "no changes"
    return status

def git_diff(repo, filename, staged=False):
    committed = repo["commits"][repo["head"]]["snapshot"] if repo["head"] else {}
    if staged:
        old = committed.get(filename, "")
        new = repo["staging_area"].get(filename, "")
    else:
        old = repo["staging_area"].get(filename, committed.get(filename, ""))
        new = repo["working_directory"].get(filename, "")
    old_lines, new_lines = old.split("\n"), new.split("\n")
    added = [l for l in new_lines if l not in old_lines]
    removed = [l for l in old_lines if l not in new_lines]
    return {"added": added, "removed": removed}

def git_log(repo):
    entries = []
    current = repo["head"]
    while current:
        c = repo["commits"][current]
        entries.append((current, c["message"]))
        current = c["parent"]
    return entries


# --- একটি বাস্তব multi-file পরিস্থিতি তৈরি করা হচ্ছে ---
repo = make_repo()
repo["working_directory"]["staged.txt"] = "v1"
repo["working_directory"]["modified.txt"] = "লাইন এক\nলাইন দুই\nলাইন তিন"
git_add(repo, "staged.txt")
git_add(repo, "modified.txt")
git_commit(repo, "প্রাথমিক কমিট")

repo["working_directory"]["staged.txt"] = "v2 (পরের কমিটের জন্য স্টেজড)"
git_add(repo, "staged.txt")                      # staged.txt: staged

repo["working_directory"]["modified.txt"] = "লাইন এক\nলাইন দুই - সম্পাদিত\nলাইন তিন"  # modified, unstaged

repo["working_directory"]["untracked.txt"] = "একদম নতুন ফাইল"                       # untracked

print("== git status ==")
for f, s in git_status(repo).items():
    print(f"  {f}: {s}")

print()
print("== git diff (unstaged, modified.txt) ==")
d = git_diff(repo, "modified.txt")
print("  removed:", d["removed"])
print("  added:  ", d["added"])

print()
print("== git diff --staged (staged.txt) ==")
d2 = git_diff(repo, "staged.txt", staged=True)
print("  removed:", d2["removed"])
print("  added:  ", d2["added"])

print()
print("== git log ==")
for h, msg in git_log(repo):
    print(f"  {h}  {msg}")