package updateip

import (
	"fmt"
	"net"

	"github.com/hashicorp/hcl/v2/hclsimple"
	log "github.com/sirupsen/logrus"
)

func Load(name string) (*Config, error) {
	var (
		config Config
		err    error
	)

	log.WithField("config", name).Debug("loading configuration file")
	if err = hclsimple.DecodeFile(name, nil, &config); err != nil {
		return nil, err
	}

	providers := make(map[string]Provider)
	for _, v := range config.Provider {
		if providers[v.Name], err = NewProvider(v); err != nil {
			return nil, fmt.Errorf("error configuring provider %q: %w", v.Name, err)
		}
	}

	for _, v := range config.Domain {
		if p, ok := providers[v.ProviderName]; ok {
			v.Provider = p
		} else {
			return nil, fmt.Errorf("provider %q in domain %q is not configured", v.ProviderName, v.Name)
		}

		if len(v.Update) == 0 {
			v.Update = append(v.Update, "@")
		}
	}

	return &config, nil
}

type Config struct {
	Resolver ResolverConfig    `hcl:"resolver,block"`
	Domain   []*DomainConfig   `hcl:"domain,block"`
	Provider []*ProviderConfig `hcl:"provider,block"`
}

type ResolverConfig struct {
	Permit []string `hcl:"permit"`
}

func (r ResolverConfig) CurrentIP() (net.IP, error) {
	return NewResolver().CurrentIP()
}

func (r ResolverConfig) IsAllowed(ip net.IP) bool {
	if len(r.Permit) == 0 {
		// Fail open if no ACL is configured.
		log.WithField("ip", ip.String()).Debug("IP allowed by resolver; no ACL")
		return true
	}

	for _, v := range r.Permit {
		if _, ipnet, err := net.ParseCIDR(v); err == nil {
			if ipnet.Contains(ip) {
				log.WithFields(log.Fields{
					"ip":    ip.String(),
					"range": ipnet.String(),
				}).Debug("IP allowed by resolver ACL")
				return true
			}
		}
	}

	log.WithField("ip", ip.String()).Warn("IP not allowed by resolver ACL")
	return false
}

type DomainConfig struct {
	Name         string   `hcl:"name,label"`
	ProviderName string   `hcl:"provider"`
	Provider     Provider ``
	Update       []string `hcl:"update,optional"`
}

type ProviderConfig struct {
	Name       string `hcl:"name,label"`
	Type       string
	Username   string `hcl:"username"`
	PrivateKey string `hcl:"private_key"`
}