#!/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)


# ⚡ Bolt: Consolidated file discovery and validation into a single pass for better performance.
def validate_files() -> list[Path]:
    if not MQL5_DIR.exists():
        fail(f"Missing directory: {MQL5_DIR}")

    files: list[Path] = []
    # ⚡ Bolt: Recursive globs like rglob('*') followed by suffix filtering are generally
    # more efficient as they avoid repeated traversals of the file system tree.
    for p in MQL5_DIR.rglob("*"):
        if p.is_file() and p.suffix.lower() in {".mq5", ".mqh"}:
            # ⚡ Bolt: Early size check using metadata only to avoid opening large files.
            sz = p.stat().st_size
            if sz > 5_000_000:
                fail(f"Unexpectedly large source file (>5MB): {p.relative_to(REPO_ROOT)} ({sz} bytes)")

            # ⚡ Bolt: Use chunked binary reading to detect NUL bytes with constant memory footprint.
            # This is significantly faster and more memory-efficient than reading the whole file.
            with open(p, "rb") as f:
                while chunk := f.read(65536): # 64KB chunks
                    if b"\x00" in chunk:
                        fail(f"NUL byte found in {p.relative_to(REPO_ROOT)}")

            files.append(p)

    if not files:
        fail(f"No .mq5/.mqh files found under {MQL5_DIR}")

    return sorted(files)


def main() -> int:
    # ⚡ Bolt: Replaced multi-pass check functions with a single-pass validator.
    files = validate_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())