#!/usr/bin/env python3
"""Apply HEADER.txt blocks to all project sources."""
from __future__ import annotations

import argparse
import sys
from pathlib import Path

from header_lib import (
    REPO_ROOT,
    apply_header_to_content,
    has_valid_header,
    header_needs_identity_refresh,
    is_excluded_path,
    iter_source_files,
)


def main() -> int:
    parser = argparse.ArgumentParser(description="Apply project headers to source files")
    parser.add_argument("--check", action="store_true", help="Only report files missing headers")
    parser.add_argument(
        "--fix-identity",
        action="store_true",
        help="Re-apply headers where contributors lack email but git has one",
    )
    parser.add_argument("--path", type=str, default="", help="Limit to one file or directory")
    args = parser.parse_args()

    root = REPO_ROOT
    targets = list(iter_source_files(root))
    if args.path:
        p = Path(args.path)
        if not p.is_absolute():
            p = REPO_ROOT / p
        if p.is_file():
            targets = [p]
        else:
            targets = [f for f in iter_source_files(root) if str(f).startswith(str(p))]

    missing = []
    identity_fix = []
    changed = 0
    skipped_vendor = 0
    for path in sorted(targets):
        if is_excluded_path(path):
            skipped_vendor += 1
            continue
        text = path.read_text(encoding="utf-8", errors="replace")
        if args.check:
            if not has_valid_header(text):
                missing.append(path.relative_to(REPO_ROOT))
            elif header_needs_identity_refresh(text, path):
                identity_fix.append(path.relative_to(REPO_ROOT))
            continue
        if args.fix_identity:
            if not header_needs_identity_refresh(text, path) and has_valid_header(text):
                continue
        new_text = apply_header_to_content(path, text)
        if new_text != text:
            path.write_text(new_text, encoding="utf-8", newline="\n")
            changed += 1

    if args.check:
        if missing:
            print("Missing headers:", len(missing))
            for m in missing[:50]:
                print(" ", m)
            if len(missing) > 50:
                print("  ...")
        if identity_fix:
            print("Identity refresh suggested:", len(identity_fix))
            for m in identity_fix[:30]:
                print(" ", m)
        if not missing and not identity_fix:
            print("All", len(targets) - skipped_vendor, "tracked files OK (third-party skipped).")
            return 0
        return 1 if missing else 0

    note = f" (skipped {skipped_vendor} under third-party/vendor paths)" if skipped_vendor else ""
    print(f"Updated {changed} / {len(targets) - skipped_vendor} source files{note}.")
    return 0


if __name__ == "__main__":
    sys.exit(main())