byom-core-infra-api/handlers/dns_handler.go

package handlers

import (
	"bufio"
	"byom-infra-api/config"
	"encoding/json"
	"fmt"
	"log"
	"math/rand"
	"net/http"
	"os"
	"regexp"
	"strings"

	"github.com/gorilla/mux"
)

type DNSRecord struct {
	FieldType string `json:"fieldType"`
	SubDomain string `json:"subDomain"`
	Target    string `json:"target"`
	TTL       int    `json:"ttl"`
}

type DNSHandler struct {
	Zone string
}

func NewDNSHandler() *DNSHandler {
	zone, exists := config.GetConfig("dns_zone")
	log.Printf("DNS Handler initialized - zone = %s (exists: %v)\n", zone, exists)

	return &DNSHandler{
		Zone: zone,
	}
}

// generateRandomWord generates a random 6-letter word from /usr/share/dict/words
func (h *DNSHandler) generateRandomWord() (string, error) {
	file, err := os.Open("/usr/share/dict/words")
	if err != nil {
		return "", err
	}
	defer file.Close()

	var words []string
	scanner := bufio.NewScanner(file)
	regex := regexp.MustCompile(`^[a-zA-Z]{6}$`)

	for scanner.Scan() {
		word := strings.ToLower(scanner.Text())
		if regex.MatchString(word) {
			words = append(words, word)
		}
	}

	if len(words) == 0 {
		return "", fmt.Errorf("no suitable words found")
	}

	return words[rand.Intn(len(words))], nil
}

// CreateDNSRecord handles the creation of a new DNS record
func (h *DNSHandler) CreateDNSRecord(w http.ResponseWriter, r *http.Request) {
	log.Printf("Handling POST request for new DNS record from %s", r.RemoteAddr)

	// Parse request body for target IP
	var request struct {
		Target string `json:"target"`
	}

	if err := json.NewDecoder(r.Body).Decode(&request); err != nil {
		log.Printf("Error decoding request body: %v", err)
		http.Error(w, "Invalid request body", http.StatusBadRequest)
		return
	}

	// Generate random subdomain
	word1, err := h.generateRandomWord()
	if err != nil {
		log.Printf("Error generating first word: %v", err)
		http.Error(w, "Failed to generate subdomain", http.StatusInternalServerError)
		return
	}

	word2, err := h.generateRandomWord()
	if err != nil {
		log.Printf("Error generating second word: %v", err)
		http.Error(w, "Failed to generate subdomain", http.StatusInternalServerError)
		return
	}

	// Create DNS record
	record := DNSRecord{
		FieldType: "A",
		SubDomain: word1 + "-" + word2,
		Target:    request.Target,
		TTL:       0,
	}

	var response DNSRecord
	err = config.OVHClient.Post("/domain/zone/"+h.Zone+"/record", record, &response)
	if err != nil {
		log.Printf("Error creating DNS record: %v", err)
		http.Error(w, "Failed to create DNS record: "+err.Error(), http.StatusInternalServerError)
		return
	}

	// Refresh the zone
	err = h.refreshZone()
	if err != nil {
		log.Printf("Warning: zone refresh failed: %v", err)
	}

	log.Printf("Successfully created DNS record: %s.%s", response.SubDomain, h.Zone)

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusCreated)
	if err := json.NewEncoder(w).Encode(response); err != nil {
		log.Printf("Error encoding response: %v", err)
		http.Error(w, "Failed to encode response", http.StatusInternalServerError)
		return
	}
}

// DeleteDNSRecord handles the deletion of a DNS record
func (h *DNSHandler) DeleteDNSRecord(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	recordID := vars["id"]
	log.Printf("Handling DELETE request for DNS record: %s from %s", recordID, r.RemoteAddr)

	err := config.OVHClient.Delete("/domain/zone/"+h.Zone+"/record/"+recordID, nil)
	if err != nil {
		log.Printf("Error deleting DNS record %s: %v", recordID, err)
		http.Error(w, "Failed to delete DNS record: "+err.Error(), http.StatusInternalServerError)
		return
	}

	// Refresh the zone
	err = h.refreshZone()
	if err != nil {
		log.Printf("Warning: zone refresh failed: %v", err)
	}

	log.Printf("Successfully deleted DNS record: %s", recordID)
	w.WriteHeader(http.StatusNoContent)
}

// refreshZone refreshes the DNS zone
func (h *DNSHandler) refreshZone() error {
	return config.OVHClient.Post("/domain/zone/"+h.Zone+"/refresh", nil, nil)
}

// ListDNSRecords handles listing all A records in the DNS zone
func (h *DNSHandler) ListDNSRecords(w http.ResponseWriter, r *http.Request) {
	log.Printf("Handling GET request for DNS records from %s", r.RemoteAddr)
	//log.Printf("Loading DNS Zone : %s", h.Zone)

	var recordIDs []int
	err := config.OVHClient.Get("/domain/zone/"+h.Zone+"/record", &recordIDs)
	if err != nil {
		log.Printf("Error getting DNS record IDs: %v", err)
		http.Error(w, "Failed to get DNS records: "+err.Error(), http.StatusInternalServerError)
		return
	}

	var records []DNSRecord
	for _, id := range recordIDs {
		var record DNSRecord
		err := config.OVHClient.Get(fmt.Sprintf("/domain/zone/%s/record/%d", h.Zone, id), &record)
		if err != nil {
			log.Printf("Error getting DNS record %d: %v", id, err)
			continue
		}

		// Only include A records
		if record.FieldType == "A" {
			records = append(records, record)
		}
	}

	w.Header().Set("Content-Type", "application/json")
	if err := json.NewEncoder(w).Encode(records); err != nil {
		log.Printf("Error encoding response: %v", err)
		http.Error(w, "Failed to encode response", http.StatusInternalServerError)
		return
	}
}

// GetDNSRecordID retrieves the record ID for a specific subdomain
func (h *DNSHandler) GetDNSRecordID(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	subdomain := vars["subdomain"]
	log.Printf("Handling GET request for DNS record ID with subdomain: %s from %s", subdomain, r.RemoteAddr)

	// Get all record IDs
	var recordIDs []int
	err := config.OVHClient.Get("/domain/zone/"+h.Zone+"/record", &recordIDs)
	if err != nil {
		log.Printf("Error getting DNS record IDs: %v", err)
		http.Error(w, "Failed to get DNS records: "+err.Error(), http.StatusInternalServerError)
		return
	}

	// Search through records to find matching subdomain
	for _, id := range recordIDs {
		var record DNSRecord
		err := config.OVHClient.Get(fmt.Sprintf("/domain/zone/%s/record/%d", h.Zone, id), &record)
		if err != nil {
			log.Printf("Error getting DNS record %d: %v", id, err)
			continue
		}

		if record.FieldType == "A" && record.SubDomain == subdomain {
			response := struct {
				ID int `json:"id"`
			}{
				ID: id,
			}

			w.Header().Set("Content-Type", "application/json")
			if err := json.NewEncoder(w).Encode(response); err != nil {
				log.Printf("Error encoding response: %v", err)
				http.Error(w, "Failed to encode response", http.StatusInternalServerError)
				return
			}
			return
		}
	}

	// If we get here, no matching record was found
	http.Error(w, "Record not found", http.StatusNotFound)
}