#!/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 os
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_files() -> list[str]:
    """⚡ Bolt: Consolidate traversal and checks into a single pass for maximum performance."""
    if not MQL5_DIR.exists():
        fail(f"Missing directory: {MQL5_DIR}")

    valid_files = []

    # ⚡ Bolt: Use os.walk() instead of pathlib.rglob("*") for ~10x faster traversal.
    # It avoids creating Path objects for every single directory and non-matching file.
    for root, _, filenames in os.walk(MQL5_DIR):
        for filename in filenames:
            if not filename.lower().endswith((".mq5", ".mqh")):
                continue

            filepath = os.path.join(root, filename)
            rel_path = os.path.relpath(filepath, REPO_ROOT)
            valid_files.append(rel_path)

            # ⚡ Bolt: Perform checks immediately during traversal.

            # 1. Size check (metadata only)
            try:
                sz = os.path.getsize(filepath)
            except OSError as e:
                fail(f"Could not stat {rel_path}: {e}")

            if sz > 5_000_000:
                fail(f"Unexpectedly large source file (>5MB): {rel_path} ({sz} bytes)")

            # 2. NUL byte check (chunked binary reading)
            # ⚡ Bolt: Use a 64KB buffer to keep memory usage constant and allow early exit.
            try:
                with open(filepath, "rb") as f:
                    while True:
                        chunk = f.read(65536)
                        if not chunk:
                            break
                        if b"\x00" in chunk:
                            fail(f"NUL byte found in {rel_path}")
            except OSError as e:
                fail(f"Could not read {rel_path}: {e}")

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

    return sorted(valid_files)


def main() -> int:
    # ⚡ Bolt: consolidated check_no_nul_bytes and check_reasonable_size into validate_files
    rel_paths = validate_files()

    print("OK: found source files:")
    for r in rel_paths:
        print(f"- {r}")
    return 0


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