#!/usr/bin/env bash
set -euo pipefail

cd "$(dirname "$0")"

PORT=7777

echo
echo "================================================================================"
echo " Commonwealth Online - Port ${PORT} in Use"
echo "================================================================================"
echo
echo "Port ${PORT} is currently in use by another process."
echo
echo "Options:"
echo "  1. Kill the process using port ${PORT} and restart server"
echo "  2. Use a different port (you will be prompted to enter one)"
echo "  3. Cancel and exit"
echo

read -r -p "Select option (1-3): " choice

find_pids_on_port() {
    local port="$1"
    local pids=""

    if command -v lsof >/dev/null 2>&1; then
        pids=$(lsof -tiTCP:"$port" -sTCP:LISTEN 2>/dev/null || true)
    fi

    if [[ -z "$pids" ]] && command -v fuser >/dev/null 2>&1; then
        # fuser prints "7777/tcp: 1234 5678"
        pids=$(fuser "${port}/tcp" 2>/dev/null | tr -s '[:space:]' '\n' | grep -E '^[0-9]+$' || true)
    fi

    if [[ -z "$pids" ]] && command -v ss >/dev/null 2>&1; then
        pids=$(ss -lptn "sport = :${port}" 2>/dev/null | sed -n 's/.*pid=\([0-9]\+\).*/\1/p' | sort -u || true)
    fi

    echo "$pids"
}

# Prefer local venv, then python3, then python.
if [[ -x ".venv/bin/python" ]]; then
    PYTHON=".venv/bin/python"
elif command -v python3 >/dev/null 2>&1; then
    PYTHON=python3
elif command -v python >/dev/null 2>&1; then
    PYTHON=python
else
    echo "ERROR: Python is not installed or not in PATH."
    exit 1
fi

case "$choice" in
    1)
        echo
        echo "Finding process using port ${PORT}..."
        pids=$(find_pids_on_port "$PORT")

        if [[ -z "$pids" ]]; then
            echo "Could not determine which process is using port ${PORT}."
            echo "Try:"
            echo "  - Restarting your computer"
            echo "  - Running with elevated permissions"
            echo "  - Or choose option 2 to use a different port"
            echo
            echo "Manual tip: lsof -i :${PORT}   or   ss -lptn 'sport = :${PORT}'"
            exit 1
        fi

        echo "Killing process(es): $pids"
        # shellcheck disable=SC2086
        if ! kill -9 $pids 2>/dev/null; then
            echo "ERROR: Could not kill process. Try running this script with sudo."
            exit 1
        fi
        echo "Process killed successfully."
        echo
        echo "Waiting for port to be released..."
        sleep 2
        echo
        echo "Restarting server..."
        exec bash ./start.sh
        ;;
    2)
        echo
        read -r -p "Enter desired port (1024-65535, default is ${PORT}): " NEW_PORT
        if [[ -z "${NEW_PORT}" ]]; then
            NEW_PORT=$PORT
        fi

        if ! [[ "$NEW_PORT" =~ ^[0-9]+$ ]]; then
            echo "ERROR: Port must be a number."
            exit 1
        fi

        if [[ "$NEW_PORT" -lt 1024 ]]; then
            echo "ERROR: Port must be 1024 or higher."
            exit 1
        fi

        if [[ "$NEW_PORT" -gt 65535 ]]; then
            echo "ERROR: Port must be 65535 or lower."
            exit 1
        fi

        echo
        echo "Updating commonwealth-server.json to use port ${NEW_PORT}..."

        "$PYTHON" - <<PY
import json
from pathlib import Path

path = Path("commonwealth-server.json")
if path.exists():
    with path.open("r", encoding="utf-8") as f:
        cfg = json.load(f)
else:
    cfg = {
        "host": "0.0.0.0",
        "port": ${NEW_PORT},
        "server_name": "Commonwealth Online Server",
        "max_players": 16,
        "log_verbosity": "info",
    }

cfg["port"] = ${NEW_PORT}
with path.open("w", encoding="utf-8") as f:
    json.dump(cfg, f, indent=2)
    f.write("\n")
PY

        echo "Config updated. Restarting server on port ${NEW_PORT}..."
        echo
        exec bash ./start.sh
        ;;
    3)
        echo
        echo "Cancelled."
        exit 0
        ;;
    *)
        echo
        echo "Invalid option."
        exit 1
        ;;
esac