Description: >
    This template deploys a VPC, with a pair of public and private subnets spread
    across two Availabilty Zones. It deploys an Internet Gateway, with a default
    route on the public subnets. It deploys a pair of NAT Gateways (one in each AZ),
    and default routes for them in the private subnets.

Parameters:

    EnvironmentName:
        Description: An environment name that will be prefixed to resource names
        Type: String

    VpcCIDR:
        Description: Please enter the IP range (CIDR notation) for this VPC
        Type: String
        Default: 10.192.0.0/16

    PublicSubnet1CIDR:
        Description: Please enter the IP range (CIDR notation) for the public subnet in the first Availability Zone
        Type: String
        Default: 10.192.10.0/24

    PublicSubnet2CIDR:
        Description: Please enter the IP range (CIDR notation) for the public subnet in the second Availability Zone
        Type: String
        Default: 10.192.11.0/24

    PrivateSubnet1CIDR:
        Description: Please enter the IP range (CIDR notation) for the private subnet in the first Availability Zone
        Type: String
        Default: 10.192.20.0/24

    PrivateSubnet2CIDR:
        Description: Please enter the IP range (CIDR notation) for the private subnet in the second Availability Zone
        Type: String
        Default: 10.192.21.0/24

Resources:

    VPC:
        Type: AWS::EC2::VPC
        Properties:
            CidrBlock: !Ref VpcCIDR
            Tags:
                - Key: Name
                  Value: !Ref EnvironmentName

    InternetGateway:
        Type: AWS::EC2::InternetGateway
        Properties:
            Tags:
                - Key: Name
                  Value: !Ref EnvironmentName

    InternetGatewayAttachment:
        Type: AWS::EC2::VPCGatewayAttachment
        Properties:
            InternetGatewayId: !Ref InternetGateway
            VpcId: !Ref VPC

    PublicSubnet1:
        Type: AWS::EC2::Subnet
        Properties:
            VpcId: !Ref VPC
            AvailabilityZone: !Select [ 0, !GetAZs ]
            CidrBlock: !Ref PublicSubnet1CIDR
            MapPublicIpOnLaunch: true
            Tags:
                - Key: Name
                  Value: !Sub ${EnvironmentName} Public Subnet (AZ1)

    PublicSubnet2:
        Type: AWS::EC2::Subnet
        Properties:
            VpcId: !Ref VPC
            AvailabilityZone: !Select [ 1, !GetAZs ]
            CidrBlock: !Ref PublicSubnet2CIDR
            MapPublicIpOnLaunch: true
            Tags:
                - Key: Name
                  Value: !Sub ${EnvironmentName} Public Subnet (AZ2)

    PrivateSubnet1:
        Type: AWS::EC2::Subnet
        Properties:
            VpcId: !Ref VPC
            AvailabilityZone: !Select [ 0, !GetAZs ]
            CidrBlock: !Ref PrivateSubnet1CIDR
            MapPublicIpOnLaunch: false
            Tags:
                - Key: Name
                  Value: !Sub ${EnvironmentName} Private Subnet (AZ1)

    PrivateSubnet2:
        Type: AWS::EC2::Subnet
        Properties:
            VpcId: !Ref VPC
            AvailabilityZone: !Select [ 1, !GetAZs ]
            CidrBlock: !Ref PrivateSubnet2CIDR
            MapPublicIpOnLaunch: false
            Tags:
                - Key: Name
                  Value: !Sub ${EnvironmentName} Private Subnet (AZ2)


    PublicRouteTable:
        Type: AWS::EC2::RouteTable
        Properties:
            VpcId: !Ref VPC
            Tags:
                - Key: Name
                  Value: !Sub ${EnvironmentName} Public Routes

    DefaultPublicRoute:
        Type: AWS::EC2::Route
        Properties:
            RouteTableId: !Ref PublicRouteTable
            DestinationCidrBlock: 0.0.0.0/0
            GatewayId: !Ref InternetGateway

    PublicSubnet1RouteTableAssociation:
        Type: AWS::EC2::SubnetRouteTableAssociation
        Properties:
            RouteTableId: !Ref PublicRouteTable
            SubnetId: !Ref PublicSubnet1

    PublicSubnet2RouteTableAssociation:
        Type: AWS::EC2::SubnetRouteTableAssociation
        Properties:
            RouteTableId: !Ref PublicRouteTable
            SubnetId: !Ref PublicSubnet2


    PrivateRouteTable1:
        Type: AWS::EC2::RouteTable
        Properties:
            VpcId: !Ref VPC
            Tags:
                - Key: Name
                  Value: !Sub ${EnvironmentName} Private Routes (AZ1)


    PrivateSubnet1RouteTableAssociation:
        Type: AWS::EC2::SubnetRouteTableAssociation
        Properties:
            RouteTableId: !Ref PrivateRouteTable1
            SubnetId: !Ref PrivateSubnet1

    PrivateRouteTable2:
        Type: AWS::EC2::RouteTable
        Properties:
            VpcId: !Ref VPC
            Tags:
                - Key: Name
                  Value: !Sub ${EnvironmentName} Private Routes (AZ2)

    PrivateSubnet2RouteTableAssociation:
        Type: AWS::EC2::SubnetRouteTableAssociation
        Properties:
            RouteTableId: !Ref PrivateRouteTable2
            SubnetId: !Ref PrivateSubnet2

Outputs:

    VPC:
        Description: A reference to the created VPC
        Value: !Ref VPC

    PublicSubnets:
        Description: A list of the public subnets
        Value: !Join [ ",", [ !Ref PublicSubnet1, !Ref PublicSubnet2 ]]

    PrivateSubnets:
        Description: A list of the private subnets
        Value: !Join [ ",", [ !Ref PrivateSubnet1, !Ref PrivateSubnet2 ]]

    PublicSubnet1:
        Description: A reference to the public subnet in the 1st Availability Zone
        Value: !Ref PublicSubnet1

    PublicSubnet2:
        Description: A reference to the public subnet in the 2nd Availability Zone
        Value: !Ref PublicSubnet2

    PrivateSubnet1:
        Description: A reference to the private subnet in the 1st Availability Zone
        Value: !Ref PrivateSubnet1

    PrivateSubnet2:
        Description: A reference to the private subnet in the 2nd Availability Zone
        Value: !Ref PrivateSubnet2