package main

import (
	"encoding/json"
	"fmt"
	"log"
	"strings"

	consul "github.com/hashicorp/consul/api"
)

func dnToConsul(dn string) (string, error) {
	if strings.Contains(dn, "/") {
		return "", fmt.Errorf("DN %s contains a /", dn)
	}

	rdns := strings.Split(dn, ",")

	// Reverse rdns
	for i, j := 0, len(rdns)-1; i < j; i, j = i+1, j-1 {
		rdns[i], rdns[j] = rdns[j], rdns[i]
	}

	return strings.Join(rdns, "/"), nil
}

func consulToDN(key string) (string, string) {
	path := strings.Split(key, "/")
	dn := ""
	for _, cpath := range path {
		if cpath == "" {
			continue
		}
		kv := strings.Split(cpath, "=")
		if len(kv) == 2 && kv[0] == "attribute" {
			return dn, kv[1]
		}
		if dn != "" {
			dn = "," + dn
		}
		dn = cpath + dn
	}
	// TODO don't panic, handle this
	log.Panicf("Consul key %s does not end with attribute=something", key)
	panic("unreachable")
}

func parseValue(value []byte) ([]string, error) {
	val := []string{}
	err := json.Unmarshal(value, &val)
	if err == nil {
		return val, nil
	}

	val2 := ""
	err = json.Unmarshal(value, &val2)
	if err == nil {
		return []string{val2}, nil
	}

	return nil, fmt.Errorf("Not a string or list of strings: %s", value)
}

func parseConsulResult(data []*consul.KVPair) (map[string]Entry, error) {
	aggregator := map[string]Entry{}

	for _, kv := range data {
		dn, attr := consulToDN(kv.Key)
		if _, exists := aggregator[dn]; !exists {
			aggregator[dn] = Entry{}
		}
		value, err := parseValue(kv.Value)
		if err != nil {
			return nil, err
		}
		aggregator[dn][attr] = value
	}

	return aggregator, nil
}

type DNComponent struct {
	Type  string
	Value string
}

func parseDN(dn string) ([]DNComponent, error) {
	rdns := strings.Split(dn, ",")

	ret := []DNComponent{}

	for _, rdn := range rdns {
		splits := strings.Split(rdn, "=")
		if len(splits) != 2 {
			return nil, fmt.Errorf("Wrong DN component: %s (expected type=value)", rdn)
		}
		ret = append(ret, DNComponent{
			Type:  splits[0],
			Value: splits[1],
		})
	}
	return ret, nil
}