"""Flask web layer for the syscall monitor."""

import json
import threading
from pathlib import Path

from flask import Flask, jsonify, redirect, render_template, request, url_for

from collector.syscall_tracer import get_tracer


BASE_DIR = Path(__file__).resolve().parent.parent
CONFIG_PATH = BASE_DIR / "config" / "monitors.json"
_config_lock = threading.Lock()


def _read_config() -> dict:
    if not CONFIG_PATH.exists():
        return {"syscalls": []}
    with CONFIG_PATH.open("r", encoding="utf-8") as f:
        return json.load(f)


def _write_config(data: dict) -> None:
    CONFIG_PATH.parent.mkdir(parents=True, exist_ok=True)
    tmp = CONFIG_PATH.with_suffix(".json.tmp")
    with tmp.open("w", encoding="utf-8") as f:
        json.dump(data, f, indent=2, ensure_ascii=False)
    tmp.replace(CONFIG_PATH)


def create_app() -> Flask:
    app = Flask(__name__, template_folder="templates", static_folder="static")
    tracer = get_tracer(CONFIG_PATH)

    @app.get("/")
    def index():
        cfg = _read_config()
        return render_template("index.html", syscalls=cfg.get("syscalls", []))

    @app.get("/api/counts")
    def api_counts():
        return jsonify(tracer.get_counts())

    @app.route("/config", methods=["GET", "POST"])
    def config_page():
        with _config_lock:
            cfg = _read_config()
            syscalls = list(cfg.get("syscalls", []))

            if request.method == "POST":
                action = request.form.get("action", "")
                name = (request.form.get("name") or "").strip()
                if action == "add" and name and name not in syscalls:
                    syscalls.append(name)
                elif action == "remove" and name in syscalls:
                    syscalls.remove(name)
                cfg["syscalls"] = syscalls
                _write_config(cfg)
                return redirect(url_for("config_page"))

        return render_template("config.html", syscalls=syscalls)

    return app