from flask import Flask, render_template, request, redirect, url_for, flash
import json
import os
import re
import subprocess
from pathlib import Path

APP_TITLE = "RelayDock"
CONFIG_PATH = Path(os.environ.get("RELAYDOCK_CONFIG", "./config.json"))
RECONCILE_CMD = os.environ.get("RELAYDOCK_RECONCILE", "./relaydock-reconcile.sh")
SERVICE_PREFIX = os.environ.get("RELAYDOCK_PREFIX", "relaydock")
app = Flask(__name__)
app.secret_key = os.environ.get("FLASK_SECRET_KEY", "change-me")

NAME_RE = re.compile(r"^[a-zA-Z0-9._-]+$")
PROTO_SET = {"udp", "tcp"}
ROLE_SET = {"oracle", "pi"}


def default_config():
    return {"role": "oracle", "rules": []}


def load_config():
    if not CONFIG_PATH.exists():
        return default_config()
    with CONFIG_PATH.open("r", encoding="utf-8") as f:
        return json.load(f)


def save_config(data):
    CONFIG_PATH.parent.mkdir(parents=True, exist_ok=True)
    with CONFIG_PATH.open("w", encoding="utf-8") as f:
        json.dump(data, f, indent=2)
        f.write("\n")


def validate_rule(rule, config):
    errors = []
    name = rule.get("name", "").strip()
    proto = rule.get("proto", "").strip().lower()
    target_host = rule.get("target_host", "").strip()
    try:
        listen_port = int(rule.get("listen_port", 0))
        target_port = int(rule.get("target_port", 0))
    except ValueError:
        errors.append("Ports müssen Zahlen sein.")
        return errors

    if not NAME_RE.match(name):
        errors.append("Name darf nur Buchstaben, Zahlen, Punkt, Unterstrich und Bindestrich enthalten.")
    if proto not in PROTO_SET:
        errors.append("Proto muss udp oder tcp sein.")
    if not (1 <= listen_port <= 65535 and 1 <= target_port <= 65535):
        errors.append("Ports müssen zwischen 1 und 65535 liegen.")
    if not target_host:
        errors.append("Target Host darf nicht leer sein.")

    existing = [r["name"] for r in config.get("rules", [])]
    if name in existing:
        errors.append("Name existiert bereits.")
    return errors


def run_cmd(cmd):
    return subprocess.run(cmd, text=True, capture_output=True)


def unit_name(name):
    return f"{SERVICE_PREFIX}@{name}.service"


@app.route("/")
def index():
    config = load_config()
    rules = []
    for rule in config.get("rules", []):
        svc = unit_name(rule["name"])
        state = run_cmd(["systemctl", "is-active", svc])
        enabled = run_cmd(["systemctl", "is-enabled", svc])
        rules.append({
            **rule,
            "service": svc,
            "active": state.stdout.strip() if state.returncode == 0 else state.stdout.strip() or "inactive",
            "enabled": enabled.stdout.strip() if enabled.returncode == 0 else enabled.stdout.strip() or "disabled",
        })
    return render_template("index.html", title=APP_TITLE, config=config, rules=rules)


@app.post("/role")
def set_role():
    config = load_config()
    role = request.form.get("role", "").strip().lower()
    if role not in ROLE_SET:
        flash("Ungültige Rolle.", "error")
        return redirect(url_for("index"))
    config["role"] = role
    save_config(config)
    flash("Rolle gespeichert.", "success")
    return redirect(url_for("index"))


@app.post("/rules/add")
def add_rule():
    config = load_config()
    rule = {
        "name": request.form.get("name", ""),
        "proto": request.form.get("proto", ""),
        "listen_port": request.form.get("listen_port", "0"),
        "target_host": request.form.get("target_host", ""),
        "target_port": request.form.get("target_port", "0"),
    }
    errors = validate_rule(rule, config)
    if errors:
        for err in errors:
            flash(err, "error")
        return redirect(url_for("index"))
    rule["listen_port"] = int(rule["listen_port"])
    rule["target_port"] = int(rule["target_port"])
    config.setdefault("rules", []).append(rule)
    save_config(config)
    flash("Regel hinzugefügt.", "success")
    return redirect(url_for("index"))


@app.post("/rules/<name>/delete")
def delete_rule(name):
    config = load_config()
    before = len(config.get("rules", []))
    config["rules"] = [r for r in config.get("rules", []) if r["name"] != name]
    save_config(config)
    if len(config["rules"]) < before:
        flash(f"Regel {name} gelöscht.", "success")
    else:
        flash("Regel nicht gefunden.", "error")
    return redirect(url_for("index"))


@app.post("/rules/<name>/toggle")
def toggle_rule(name):
    svc = unit_name(name)
    state = run_cmd(["systemctl", "is-active", svc])
    if state.returncode == 0 and state.stdout.strip() == "active":
        result = run_cmd(["sudo", "systemctl", "stop", svc])
        flash(result.stderr.strip() or result.stdout.strip() or f"{svc} gestoppt.", "success" if result.returncode == 0 else "error")
    else:
        result = run_cmd(["sudo", "systemctl", "start", svc])
        flash(result.stderr.strip() or result.stdout.strip() or f"{svc} gestartet.", "success" if result.returncode == 0 else "error")
    return redirect(url_for("index"))


@app.post("/rules/<name>/restart")
def restart_rule(name):
    svc = unit_name(name)
    result = run_cmd(["sudo", "systemctl", "restart", svc])
    flash(result.stderr.strip() or result.stdout.strip() or f"{svc} neugestartet.", "success" if result.returncode == 0 else "error")
    return redirect(url_for("index"))


@app.post("/reconcile")
def reconcile():
    result = run_cmd(["sudo", RECONCILE_CMD, str(CONFIG_PATH)])
    flash(result.stderr.strip() or result.stdout.strip() or "Synchronisierung ausgeführt.", "success" if result.returncode == 0 else "error")
    return redirect(url_for("index"))


@app.post("/daemon-reload")
def daemon_reload():
    result = run_cmd(["sudo", "systemctl", "daemon-reload"])
    flash(result.stderr.strip() or result.stdout.strip() or "systemd daemon-reload ausgeführt.", "success" if result.returncode == 0 else "error")
    return redirect(url_for("index"))


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=8080, debug=True)