# src/web/api/routers/events.py
from fastapi import APIRouter, Query
from pathlib import Path
from collections import deque

router = APIRouter(prefix="/events", tags=["events"])


def _tail_file(path: Path, n: int) -> list[str]:
    if not path.exists():
        return []
    dq = deque(maxlen=n)
    with path.open("r", encoding="utf-8", errors="ignore") as f:
        for line in f:
            dq.append(line.rstrip())
    return list(dq)


@router.get("")
def events(
    limit: int = Query(200, ge=1, le=2000),
    kind: str = Query("trading", pattern="^(trading|errors)$"),
):
    logs_dir = Path("logs")
    pattern = "trading_bot_*.log" if kind == "trading" else "errors_*.log"

    files = sorted(
        logs_dir.glob(pattern),
        key=lambda p: p.stat().st_mtime,
        reverse=True,
    )

    if not files:
        return {"items": []}

    lines = _tail_file(files[0], limit)
    return {
        "items": lines,
        "file": files[0].name,
    }