package resolver

import (
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"testing"

	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/netbox"
)

// newIPServer returns a test server that always responds with the given IP list.
func newIPServer(t *testing.T, ips []string) *httptest.Server {
	t.Helper()
	type result struct {
		Address string `json:"address"`
	}
	type response struct {
		Count   int      `json:"count"`
		Results []result `json:"results"`
	}
	resp := response{Count: len(ips)}
	for _, ip := range ips {
		resp.Results = append(resp.Results, result{Address: ip})
	}
	body, _ := json.Marshal(resp)
	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		w.Write(body)
	}))
}

func TestManagementSubnetStrategy_MatchesSubnet(t *testing.T) {
	srv := newIPServer(t, []string{"10.0.1.5/24", "192.168.0.1/24"})
	defer srv.Close()

	s, _ := NewManagementSubnetStrategy([]string{"10.0.0.0/8"})
	client := netbox.NewClient(srv.URL, "token")

	ip, err := s.Resolve(context.Background(), &netbox.HostEntry{ID: 1, Kind: "device"}, client)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if ip != "10.0.1.5" {
		t.Errorf("got %q, want %q", ip, "10.0.1.5")
	}
}

func TestManagementSubnetStrategy_NoMatch(t *testing.T) {
	srv := newIPServer(t, []string{"192.168.0.1/24"})
	defer srv.Close()

	s, _ := NewManagementSubnetStrategy([]string{"10.0.0.0/8"})
	client := netbox.NewClient(srv.URL, "token")

	_, err := s.Resolve(context.Background(), &netbox.HostEntry{ID: 1, Kind: "device"}, client)
	if err != ErrNoIP {
		t.Errorf("no matching subnet should return ErrNoIP, got %v", err)
	}
}

func TestManagementSubnetStrategy_FirstMatchWins(t *testing.T) {
	srv := newIPServer(t, []string{"10.0.1.1/24", "10.0.1.2/24"})
	defer srv.Close()

	s, _ := NewManagementSubnetStrategy([]string{"10.0.0.0/8"})
	client := netbox.NewClient(srv.URL, "token")

	ip, err := s.Resolve(context.Background(), &netbox.HostEntry{ID: 1, Kind: "device"}, client)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if ip != "10.0.1.1" {
		t.Errorf("got %q, want first matching IP %q", ip, "10.0.1.1")
	}
}

func TestManagementSubnetStrategy_VMKind(t *testing.T) {
	srv := newIPServer(t, []string{"172.16.5.10/16"})
	defer srv.Close()

	s, _ := NewManagementSubnetStrategy([]string{"172.16.0.0/12"})
	client := netbox.NewClient(srv.URL, "token")

	ip, err := s.Resolve(context.Background(), &netbox.HostEntry{ID: 2, Kind: "vm"}, client)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if ip != "172.16.5.10" {
		t.Errorf("got %q, want %q", ip, "172.16.5.10")
	}
}

func TestManagementSubnetStrategy_IPv6Subnet(t *testing.T) {
	srv := newIPServer(t, []string{"fd00::1/64"})
	defer srv.Close()

	s, _ := NewManagementSubnetStrategy([]string{"fd00::/8"})
	client := netbox.NewClient(srv.URL, "token")

	ip, err := s.Resolve(context.Background(), &netbox.HostEntry{ID: 1, Kind: "device"}, client)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if ip != "fd00::1" {
		t.Errorf("got %q, want %q", ip, "fd00::1")
	}
}