import os

from django.conf import settings
from django.core.management.base import BaseCommand


class Command(BaseCommand):
    help = (
        "Traverse all .po files under BASE_DIR (or a given base-dir), "
        "remove 'fuzzy' flags, drop '#| msgid' comments, and reset msgstr to empty."
    )

    def add_arguments(self, parser):
        parser.add_argument(
            "-b",
            "--base-dir",
            default=settings.BASE_DIR,
            help="Root directory to start searching for .po files (default: settings.BASE_DIR).",
        )

    def handle(self, *args, **options):
        base_dir = options["base_dir"]
        for root, _dirs, files in os.walk(base_dir):
            for fname in files:
                if not fname.endswith(".po"):
                    continue
                path = os.path.join(root, fname)
                self.stdout.write(f"→ Processing {path}")
                self._clean_po_file(path)

    def _clean_po_file(self, filepath):
        with open(filepath, encoding="utf-8") as f:
            lines = f.readlines()

        entries, curr = [], []
        for line in lines:
            if line.strip() == "":
                if curr:
                    entries.append(curr)
                    curr = []
            else:
                curr.append(line)
        if curr:
            entries.append(curr)

        new_lines = []
        changed = False

        for ent in entries:
            if ent and ent[0].startswith('msgid ""'):
                new_lines.extend(ent)
                new_lines.append("\n")
                continue

            if any(
                line.startswith("#~")
                or (line.startswith("#,") and line.lstrip("#, ").startswith("msgid "))
                for line in ent
            ):
                changed = True
                continue

            fuzzy_idx = next(
                (
                    i
                    for i, line in enumerate(ent)
                    if line.startswith("#,") and "fuzzy" in line
                ),
                None,
            )

            if fuzzy_idx is not None:
                flags = [
                    f.strip()
                    for f in ent[fuzzy_idx][2:].split(",")
                    if f.strip() != "fuzzy"
                ]
                if flags:
                    ent[fuzzy_idx] = "#, " + ", ".join(flags) + "\n"
                else:
                    del ent[fuzzy_idx]

                ent = [line for line in ent if not line.startswith("#| msgid")]

                ent = [
                    'msgstr ""\n' if line.startswith("msgstr") else line for line in ent
                ]

                changed = True

            new_lines.extend(ent)
            new_lines.append("\n")

        if changed:
            with open(filepath, "w", encoding="utf-8") as f:
                f.writelines(new_lines)
            self.stdout.write(self.style.SUCCESS(f"  → Updated {filepath}"))
        else:
            self.stdout.write("  (no changes)")