package services

import (
	"fmt"
	"net"
	"net/http"
	"net/http/httptest"
	"os"
	"strings"
	"testing"

	"agent-desk/internal/models"
)

// Service integration fixtures may enqueue outbound work asynchronously. Keep
// those clients inside this test process's loopback fixtures even when a test
// accidentally supplies an external URL. Production transports are unchanged.
type loopbackTestTransport struct {
	base http.RoundTripper
}

func (t loopbackTestTransport) RoundTrip(req *http.Request) (*http.Response, error) {
	host := req.URL.Hostname()
	ip := net.ParseIP(host)
	if host != "localhost" && (ip == nil || !ip.IsLoopback()) {
		return nil, fmt.Errorf("external HTTP transport disabled in service tests: %s", host)
	}
	return t.base.RoundTrip(req)
}

func TestMain(m *testing.M) {
	// These service fixtures do not contain AI-runtime tables/configuration.
	// Runtime behavior has its own suite; focused hook tests install their own
	// spies. Never let a transitive runtime init launch unowned background work.
	TriggerAIReplyAsyncHook = func(models.Conversation, models.Message) {}
	transport := http.DefaultTransport.(*http.Transport).Clone()
	transport.Proxy = nil
	http.DefaultTransport = loopbackTestTransport{base: transport}
	os.Exit(m.Run())
}

type testRoundTripper func(*http.Request) (*http.Response, error)

func (f testRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
	return f(req)
}

func TestServiceTransportRejectsExternalHostsBeforeDial(t *testing.T) {
	for _, address := range []string{"https://slack.com/api/chat.postMessage", "https://api.telegram.org/test", "http://example.invalid", "http://192.0.2.1", "http://[2001:db8::1]"} {
		t.Run(address, func(t *testing.T) {
			transport := loopbackTestTransport{base: testRoundTripper(func(*http.Request) (*http.Response, error) {
				t.Fatal("external request reached the underlying transport")
				return nil, nil
			})}
			req, err := http.NewRequest(http.MethodGet, address, nil)
			if err != nil {
				t.Fatal(err)
			}
			if _, err := transport.RoundTrip(req); err == nil {
				t.Fatal("external request was not blocked")
			}
		})
	}
}

func TestServiceTransportRejectsRedirectOutsideLoopback(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.Redirect(w, r, "https://example.invalid/forbidden", http.StatusFound)
	}))
	defer server.Close()
	response, err := http.Get(server.URL)
	if response != nil {
		response.Body.Close()
	}
	if err == nil || !strings.Contains(err.Error(), "external HTTP transport disabled") {
		t.Fatalf("redirect did not hit the loopback guard: %v", err)
	}
}