"""GET /api/logs — tail log files."""

import os

from flask import Blueprint, jsonify, request

from ..config import LOG_DIR

bp = Blueprint("logs", __name__)

ALLOWED_LOGS = {"poller", "liquidsoap", "icecast_access", "icecast_error"}


@bp.route("/logs")
def get_logs():
    log_name = request.args.get("file", "poller")
    lines_count = request.args.get("lines", 50, type=int)
    lines_count = min(lines_count, 500)

    if log_name not in ALLOWED_LOGS:
        return jsonify({"error": f"Unknown log file. Allowed: {ALLOWED_LOGS}"}), 400

    log_path = LOG_DIR / f"{log_name}.log"

    if not log_path.exists():
        return jsonify({"lines": [], "file": log_name, "exists": False})

    # Read last N lines efficiently
    try:
        with open(log_path, "rb") as f:
            f.seek(0, os.SEEK_END)
            size = f.tell()
            # Read up to 1MB from the end
            read_size = min(size, 1024 * 1024)
            f.seek(max(0, size - read_size))
            content = f.read().decode("utf-8", errors="replace")

        all_lines = content.splitlines()
        tail = all_lines[-lines_count:]
    except Exception as e:
        return jsonify({"error": str(e)}), 500

    return jsonify({
        "lines": tail,
        "file": log_name,
        "exists": True,
        "total_lines": len(all_lines),
    })