#!/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 validate_repository() -> list[Path]:
    """
    ⚡ Bolt: Optimized repository validation.
    Performs discovery, size checks, and NUL byte detection in a single pass
    using chunked reading to minimize memory footprint and syscalls.
    """
    if not MQL5_DIR.exists():
        fail(f"Missing directory: {MQL5_DIR}")

    valid_files: list[Path] = []

    # ⚡ Bolt: Use a single-pass loop for all checks.
    # Recursive glob is efficient in Python 3.12.
    for p in MQL5_DIR.rglob("*"):
        if not p.is_file():
            continue

        suffix = p.suffix.lower()
        if suffix not in {".mq5", ".mqh"}:
            continue

        # ⚡ Bolt: Get metadata once.
        stat = p.stat()
        sz = stat.st_size

        # ⚡ Bolt: Early exit on size check before reading content.
        if sz > 5_000_000:
            fail(f"Unexpectedly large source file (>5MB): {p.relative_to(REPO_ROOT)} ({sz} bytes)")

        # ⚡ Bolt: Use chunked reading for NUL byte detection.
        # This keeps memory usage O(1) regardless of file size (up to 5MB).
        with open(p, 'rb') as f:
            has_nul = False
            while True:
                chunk = f.read(65536) # 64KB chunks
                if not chunk:
                    break
                if b"\x00" in chunk:
                    has_nul = True
                    break

            if has_nul:
                fail(f"NUL byte found in {p.relative_to(REPO_ROOT)}")

        valid_files.append(p)

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

    return sorted(valid_files)


def main() -> int:
    # ⚡ Bolt: Consolidated logic into validate_repository()
    files = validate_repository()

    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())