package override

import (
	"net"

	"github.com/coredns/caddy"
	"github.com/coredns/coredns/core/dnsserver"
	"github.com/coredns/coredns/plugin"
	clog "github.com/coredns/coredns/plugin/pkg/log"
)

var log = clog.NewWithPlugin("overide")

func init() {
	plugin.Register("override", setup)
}

func setup(c *caddy.Controller) error {
	rules, err := parseRules(c)

	if err != nil {
		return plugin.Error("override", err)
	}

	dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
		return Override{Next: next, Rules: rules}
	})

	return nil
}

func parseRules(c *caddy.Controller) ([]Rule, error) {
	var rules []Rule

	for c.Next() {
		for c.NextBlock() {
			searchIP := net.ParseIP(c.Val())
			if searchIP == nil {
				return nil, c.Errf("invalid search IP: %s", c.Val())
			}

			if !c.NextArg() {
				return nil, c.ArgErr()
			}

			overrideIP := net.ParseIP(c.Val())
			if overrideIP == nil {
				return nil, c.Errf("invalid override IP: %s", c.Val())
			}

			rules = append(rules, Rule{Search: searchIP, Override: overrideIP})
		}
	}

	return rules, nil
}