package types

import (
	"bytes"
	"database/sql/driver"
	"fmt"
	"net"
)

type (
	// Subnet is used to parse a subnet parameter.
	Subnet net.IPNet
	// IP is used to parse an IP parameter.
	IP net.IP
)

// UnmarshalJSON parses a value into a subnet.
//
// It is also checked if the provided IP matches the network address
// of the subnet.
func (s *Subnet) UnmarshalJSON(in []byte) error {
	in = bytes.Trim(in, `"`)

	ip, ipnet, err := net.ParseCIDR(string(in))
	if err != nil {
		return fmt.Errorf("not a valid subnet")
	}
	if !ipnet.IP.Equal(ip) {
		return fmt.Errorf("provided IP is not a subnet")
	}
	*s = Subnet(*ipnet)
	return nil
}

// String returns the string representation of the subnet.
//
// The subnet is returned as the subnet address and prefix separated by `/`
// as defined in RFC 4632 and RFC 4291.
func (s *Subnet) String() string {
	return (*net.IPNet)(s).String()
}

// Value implements the database Value interface.
//
// This function is needed so that a subnet can be inserted into
// the database without much casting.
func (s *Subnet) Value() (driver.Value, error) {
	return s.String(), nil
}

func (i *IP) UnmarshalJSON(in []byte) error {
	in = bytes.Trim(in, `"`)

	ip := net.ParseIP(string(in))
	if ip == nil {
		return fmt.Errorf("not a valid ip")
	}
	*i = IP(ip)
	return nil
}