package recon

import (
	"context"
	"net/http"
	"net/http/httptest"
	"sync/atomic"
	"testing"
	"time"
)

func newRobotsServer(body string, status int, counter *atomic.Int32) *httptest.Server {
	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if counter != nil {
			counter.Add(1)
		}
		if status >= 400 {
			http.Error(w, "boom", status)
			return
		}
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte(body))
	}))
}

func TestRobotsAllowed(t *testing.T) {
	srv := newRobotsServer("User-agent: *\nDisallow:\n", 200, nil)
	defer srv.Close()

	rc := NewRobotsCache()
	rc.Client = srv.Client()

	ok, err := rc.Allowed(context.Background(), srv.URL+"/public")
	if err != nil {
		t.Fatalf("unexpected err: %v", err)
	}
	if !ok {
		t.Fatalf("expected allowed, got disallowed")
	}
}

func TestRobotsDisallowed(t *testing.T) {
	srv := newRobotsServer("User-agent: *\nDisallow: /private\n", 200, nil)
	defer srv.Close()

	rc := NewRobotsCache()
	rc.Client = srv.Client()

	ok, err := rc.Allowed(context.Background(), srv.URL+"/private")
	if err != nil {
		t.Fatalf("unexpected err: %v", err)
	}
	if ok {
		t.Fatalf("expected disallowed, got allowed")
	}
}

func TestRobotsCacheHit(t *testing.T) {
	var counter atomic.Int32
	srv := newRobotsServer("User-agent: *\nDisallow:\n", 200, &counter)
	defer srv.Close()

	rc := NewRobotsCache()
	rc.Client = srv.Client()

	for i := 0; i < 3; i++ {
		if _, err := rc.Allowed(context.Background(), srv.URL+"/any"); err != nil {
			t.Fatalf("iter %d: %v", i, err)
		}
	}
	if got := counter.Load(); got != 1 {
		t.Fatalf("expected 1 http fetch for robots.txt, got %d", got)
	}
}

func TestRobotsNetworkError(t *testing.T) {
	srv := newRobotsServer("", 500, nil)
	defer srv.Close()

	rc := NewRobotsCache()
	rc.Client = srv.Client()

	ok, err := rc.Allowed(context.Background(), srv.URL+"/anything")
	if err != nil {
		t.Fatalf("unexpected err: %v", err)
	}
	if !ok {
		t.Fatalf("expected default-allow on 500, got disallowed")
	}
}

func TestRobotsUAKeyhunter(t *testing.T) {
	body := "User-agent: keyhunter\nDisallow: /blocked\n\nUser-agent: *\nDisallow:\n"
	srv := newRobotsServer(body, 200, nil)
	defer srv.Close()

	rc := NewRobotsCache()
	rc.Client = srv.Client()

	ok, err := rc.Allowed(context.Background(), srv.URL+"/blocked")
	if err != nil {
		t.Fatalf("unexpected err: %v", err)
	}
	if ok {
		t.Fatalf("expected /blocked disallowed for keyhunter UA")
	}

	ok, err = rc.Allowed(context.Background(), srv.URL+"/open")
	if err != nil {
		t.Fatalf("unexpected err: %v", err)
	}
	if !ok {
		t.Fatalf("expected /open allowed for keyhunter UA")
	}
}

// Compile-time assertion that TTL constant is exported usage-ready
var _ = time.Hour