package main

import (
	"context"
	"errors"
	"net/http"
	"net/http/httptest"
	"net/netip"
	"testing"

	"github.com/go-gost/plugin/bypass/proto"
)

func TestBypass(t *testing.T) {
	for _, tc := range []struct {
		name string
		addr string
		ips  []netip.Addr
		err  error
		deny bool
	}{
		{name: "listed IPv4", addr: "203.0.113.1:443"},
		{name: "foreign IPv4", addr: "198.51.100.1:443", deny: true},
		{name: "listed IPv6", addr: "[2001:db8::1]:443"},
		{name: "bare IPv6", addr: "2001:db8::1"},
		{name: "foreign IPv6", addr: "[2001:db9::1]:443", deny: true},
		{name: "mapped IPv4", addr: "[::ffff:203.0.113.1]:443"},
		{name: "listed domain", addr: "allowed.test:443", ips: []netip.Addr{netip.MustParseAddr("203.0.113.2")}},
		{name: "mixed answers", addr: "mixed.test:443", ips: []netip.Addr{netip.MustParseAddr("203.0.113.2"), netip.MustParseAddr("198.51.100.2")}, deny: true},
		{name: "no addresses", addr: "empty.test:443", deny: true},
		{name: "DNS failure", addr: "error.test:443", err: errors.New("DNS unavailable"), deny: true},
	} {
		t.Run(tc.name, func(t *testing.T) {
			s := &server{
				list: []netip.Prefix{netip.MustParsePrefix("203.0.113.0/24"), netip.MustParsePrefix("2001:db8::/32")},
				lookup: func(ctx context.Context, _, _ string) ([]netip.Addr, error) {
					if _, ok := ctx.Deadline(); !ok {
						t.Error("DNS lookup has no deadline")
					}
					return tc.ips, tc.err
				},
			}
			reply, err := s.Bypass(context.Background(), &proto.BypassRequest{Addr: tc.addr})
			if err != nil || reply.Ok != tc.deny {
				t.Fatalf("Bypass = %v, %v; want deny=%v", reply, err, tc.deny)
			}
		})
	}
}

func TestRefresh(t *testing.T) {
	status, body := 200, "# list\n203.0.113.7/24 # normalize\n2001:db8::/32\n"
	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(status)
		_, _ = w.Write([]byte(body))
	}))
	defer upstream.Close()
	s := &server{}
	if err := s.refresh(upstream.URL); err != nil {
		t.Fatal(err)
	}
	for _, tc := range []struct {
		name   string
		status int
		body   string
	}{
		{"HTTP failure", 503, "unavailable"},
		{"empty list", 200, "# empty\n"},
		{"malformed list", 200, "198.51.100.0/24\n<html>error</html>"},
	} {
		t.Run(tc.name, func(t *testing.T) {
			status, body = tc.status, tc.body
			if err := s.refresh(upstream.URL); err == nil {
				t.Fatal("accepted invalid list")
			}
			reply, _ := s.Bypass(context.Background(), &proto.BypassRequest{Addr: "203.0.113.1:443"})
			if reply.Ok || len(s.list) != 2 {
				t.Fatal("failed refresh discarded previous rules")
			}
		})
	}
	status, body = 200, "198.51.100.0/24\n"
	if err := s.refresh(upstream.URL); err != nil {
		t.Fatal(err)
	}
	old, _ := s.Bypass(context.Background(), &proto.BypassRequest{Addr: "203.0.113.1:443"})
	updated, _ := s.Bypass(context.Background(), &proto.BypassRequest{Addr: "198.51.100.1:443"})
	if !old.Ok || updated.Ok {
		t.Fatal("refresh did not replace rules")
	}
}