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

port_in_use() {
  lsof -nP -iTCP:"$1" -sTCP:LISTEN &>/dev/null
}

find_port() {
  local port=$1
  while port_in_use "$port"; do
    ((port++))
  done
  echo "$port"
}

if [[ -z "${WM_SLOT:-}" ]]; then
  # Auto-assign: find the first slot (1-99) where both ports are free
  # Slot 0 (8000/3000) is reserved for the main worktree
  for slot in $(seq 1 99); do
    bp=$((8000 + slot * 10))
    fp=$((3000 + slot * 10))
    if ! port_in_use "$bp" && ! port_in_use "$fp"; then
      WM_SLOT=$slot
      break
    fi
  done
  if [[ -z "${WM_SLOT:-}" ]]; then
    echo "ERROR: No available slot found (tried 1-99)" >&2
    exit 1
  fi
  echo "Auto-assigned slot $WM_SLOT"
fi

# Slot-based: predictable ports for SSH forwarding
# Slot 0 = 8000/3000, slot 1 = 8010/3010, slot 2 = 8020/3020, etc.
backend_port=$((8000 + WM_SLOT * 10))
frontend_port=$((3000 + WM_SLOT * 10))

if port_in_use "$backend_port" || port_in_use "$frontend_port"; then
  echo "ERROR: Slot $WM_SLOT ports ($backend_port/$frontend_port) already in use" >&2
  exit 1
fi

# Generate .env.local with port overrides
cat > .env.local <<EOF
BACKEND_PORT=$backend_port
FRONTEND_PORT=$frontend_port
REMOTE=http://localhost:$backend_port
EOF

echo "Created .env.local with ports: backend=$backend_port, frontend=$frontend_port"