#!/usr/bin/env python3
"""
Lightweight repository sanity checks suitable for GitHub Actions.
This is intentionally NOT a compiler for MQL5 (MetaEditor isn't available on CI).
"""

from __future__ import annotations

import sys
from pathlib import Path


REPO_ROOT = Path(__file__).resolve().parents[1]
MQL5_DIR = REPO_ROOT / "mt5" / "MQL5"


def fail(msg: str) -> None:
    print(f"ERROR: {msg}", file=sys.stderr)
    raise SystemExit(1)


def iter_source_files() -> list[Path]:
    if not MQL5_DIR.exists():
        fail(f"Missing directory: {MQL5_DIR}")
    files: list[Path] = []
    # ⚡ Bolt: rglob('*') followed by suffix filtering is more efficient than
    # multiple targeted globs (like rglob('*.mq5') and rglob('*.mqh'))
    # as it avoids repeated traversals of the file system tree.
    for p in MQL5_DIR.rglob("*"):
        if p.is_file() and p.suffix.lower() in {".mq5", ".mqh"}:
            files.append(p)
    if not files:
        fail(f"No .mq5/.mqh files found under {MQL5_DIR}")
    return sorted(files)


def validate_files(files: list[Path]) -> None:
    """⚡ Bolt: Single-pass validation for performance and memory efficiency."""
    for p in files:
        # ⚡ Bolt: Use stat() for early size check before reading file content.
        # This prevents loading unexpectedly large files into memory.
        stat = p.stat()
        if stat.st_size > 5_000_000:
            fail(f"Unexpectedly large source file (>5MB): {p.relative_to(REPO_ROOT)} ({stat.st_size} bytes)")

        # ⚡ Bolt: Use chunked binary reading (64KB) to detect NUL bytes efficiently.
        # This minimizes memory overhead compared to full file reads.
        with p.open("rb") as f:
            while chunk := f.read(65536):
                if b"\x00" in chunk:
                    fail(f"NUL byte found in {p.relative_to(REPO_ROOT)}")


def main() -> int:
    files = iter_source_files()
    validate_files(files)

    rel = [str(p.relative_to(REPO_ROOT)) for p in files]
    print("OK: found source files:")
    for r in rel:
        print(f"- {r}")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())