#!/bin/bash
set -euo pipefail

DOCKER_CONFIG="/etc/docker/daemon.json"
JQ=$(command -v jq || true)

if [[ -z "$JQ" ]]; then
  echo "❌ jq is required but not installed."
  exit 1
fi

# Step 1: Check if default-address-pools exists and extract current second octet
DEFAULT_OCTET=""
if [[ -f "$DOCKER_CONFIG" ]] && grep -q '"default-address-pools"' "$DOCKER_CONFIG"; then
  BASE=$(jq -r '.["default-address-pools"][0].base' "$DOCKER_CONFIG")
  if [[ "$BASE" =~ ^10\.([0-9]+)\. ]]; then
    DEFAULT_OCTET="${BASH_REMATCH[1]}"
    echo "Found existing default-address-pools base: $BASE"
  fi
fi

# Step 2: Ask for second octet (suggest default if available)
USE_EXISTING_CONFIG=false

if [[ -n "$DEFAULT_OCTET" ]]; then
  read -rp "Use existing second octet ($DEFAULT_OCTET)? [Y/n]: " confirm
  confirm=${confirm:-Y}
  if [[ "$confirm" =~ ^[Nn]$ ]]; then
    read -rp "Enter new second octet (e.g. 102): " OCTET
  else
    OCTET="$DEFAULT_OCTET"
    USE_EXISTING_CONFIG=true
  fi
else
  read -rp "Enter second octet for Docker address pool (e.g. 102): " OCTET
fi

# Validate input
if ! [[ "$OCTET" =~ ^[0-9]+$ ]] || ((OCTET < 1 || OCTET > 254)); then
  echo "❌ Invalid octet: $OCTET"
  exit 1
fi

# Step 3: Write daemon.json (overwrite or create) only if needed
if [[ "$USE_EXISTING_CONFIG" == false ]]; then
  echo "Writing Docker daemon config with base: 10.${OCTET}.0.0/16"
  sudo mkdir -p /etc/docker
  cat <<EOF | sudo tee "$DOCKER_CONFIG" > /dev/null
{
    "default-address-pools": [
        {
            "base": "10.${OCTET}.0.0/16",
            "size": 24
        }
    ]
}
EOF

  echo "Restarting Docker..."
  sudo systemctl restart docker
else
  echo "🟡 Skipping daemon config update and Docker restart (using existing settings)"
fi

# Step 4: Create standard networks
declare -A networks
networks[internet]="10.${OCTET}.100.0/24"
networks[pangolin_transport]="10.${OCTET}.200.0/24"

for name in "${!networks[@]}"; do
  subnet="${networks[$name]}"
  if docker network inspect "$name" >/dev/null 2>&1; then
    echo "✅ Network '$name' already exists."
  else
    echo "Creating network '$name' with subnet $subnet"

    if [[ "$name" == "internet" ]]; then
      docker network create \
        --driver=bridge \
        --subnet="$subnet" \
        "$name"
    else
      docker network create \
        --driver=bridge \
        --subnet="$subnet" \
        --internal \
        "$name"
    fi
  fi
done

echo "✅ Done. Docker daemon configured and standard networks created."