package agentcore

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

	"cloudipvalidator/internal/config"
)

// While the agent is busy with a slow assignment (an address whose outbound
// targets time out keeps it occupied for tens of seconds) it must keep sending
// heartbeats; control-api marks a validator that stays silent for
// heartbeat_timeout_seconds as unreachable.
func TestHeartbeatContinuesDuringSlowChecks(t *testing.T) {
	slowTarget := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		time.Sleep(3500 * time.Millisecond)
	}))
	defer slowTarget.Close()

	var heartbeats, assignments int32
	mux := http.NewServeMux()
	mux.HandleFunc("POST /api/v1/agents/register", func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprint(w, `{"ok":true}`)
	})
	mux.HandleFunc("POST /api/v1/agents/val-1/heartbeat", func(w http.ResponseWriter, r *http.Request) {
		atomic.AddInt32(&heartbeats, 1)
		fmt.Fprint(w, `{"ok":true}`)
	})
	mux.HandleFunc("GET /api/v1/agents/val-1/assignment", func(w http.ResponseWriter, r *http.Request) {
		if atomic.AddInt32(&assignments, 1) > 1 {
			w.WriteHeader(http.StatusNoContent)
			return
		}
		fmt.Fprintf(w, `{"ip_id":1,"ip_address":"1.1.1.1","phase":"checking","check_config":[{"type":"https","targets":[%q]}]}`, slowTarget.URL)
	})
	mux.HandleFunc("POST /api/v1/agents/val-1/results", func(w http.ResponseWriter, r *http.Request) { fmt.Fprint(w, `{"ok":true}`) })
	mux.HandleFunc("POST /api/v1/agents/val-1/complete", func(w http.ResponseWriter, r *http.Request) { fmt.Fprint(w, `{"ok":true}`) })
	capi := httptest.NewServer(mux)
	defer capi.Close()

	a := New(&config.ValidatorAgent{
		ValidatorID: "val-1", ControlAPIURL: capi.URL, PollIntervalSeconds: 1,
		Checks: config.AgentChecks{HTTPSTimeoutSeconds: 10, ICMPTimeoutSeconds: 1, ICMPCount: 1},
	}, testLogger())

	ctx, cancel := context.WithCancel(context.Background())
	done := make(chan struct{})
	go func() { _ = a.Run(ctx); close(done) }()

	time.Sleep(3 * time.Second) // the slow check (3.5 s) is still running
	during := atomic.LoadInt32(&heartbeats)
	cancel()
	select {
	case <-done:
	case <-time.After(10 * time.Second):
		t.Fatal("Run did not stop after the context was cancelled")
	}

	// One per second plus the first: 3-4 in 3 s. With heartbeats in the poll
	// loop there is exactly one, sent before the slow assignment started.
	if during < 3 {
		t.Fatalf("%d heartbeats in 3 s while a check was running, want at least 3", during)
	}
	if atomic.LoadInt32(&assignments) < 1 {
		t.Fatal("the assignment was never fetched, the test did not exercise a busy agent")
	}
}