//go:build integration

package main

import (
	"context"
	"testing"
	"time"

	"github.com/nats-io/nats.go"
	"github.com/nats-io/nats.go/jetstream"
	"github.com/novox/mesh-controller/internal/broker"
	"github.com/novox/mesh-controller/internal/testbus"
)

func windowOnABus(t *testing.T) (*busWindow, <-chan string) {
	t.Helper()
	js, err := broker.Dial(testbus.URL(t))
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(js.Close)
	if err := js.EnsureControllerBuckets(); err != nil {
		t.Fatal(err)
	}
	conn, err := nats.Connect(testbus.URL(t))
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(conn.Close)
	api, err := jetstream.New(conn)
	if err != nil {
		t.Fatal(err)
	}
	heard := make(chan string, 16)
	ctx, stop := context.WithCancel(context.Background())
	t.Cleanup(stop)
	w, err := newBusWindow(ctx, api, func(batch string) { heard <- batch })
	if err != nil {
		t.Fatal(err)
	}
	return w, heard
}

func TestTheQuietKeyExpiresAndTheWatcherNamesTheBatch(t *testing.T) {
	w, heard := windowOnABus(t)
	if err := w.Arm(t.Context(), "plan-1", time.Second, time.Minute); err != nil {
		t.Fatal(err)
	}
	if b, ok := hears(t, heard, 10*time.Second); !ok || b != "plan-1" {
		t.Fatalf("heard %q (%v); want plan-1", b, ok)
	}
}

func TestAMergeRestartsTheQuietKeyAndTheMostKeyClosesAllTheSame(t *testing.T) {
	w, heard := windowOnABus(t)
	ctx := t.Context()
	if err := w.Arm(ctx, "plan-2", 2*time.Second, 5*time.Second); err != nil {
		t.Fatal(err)
	}
	time.Sleep(1200 * time.Millisecond)
	if err := w.Arm(ctx, "plan-2", 2*time.Second, 5*time.Second); err != nil { // a merge: quiet again, most as it was
		t.Fatal(err)
	}
	if b, ok := hears(t, heard, 1500*time.Millisecond); ok {
		t.Fatalf("heard %q before the restarted window was up", b)
	}
	// Another merge keeps the window open; the most (5 s from the first) closes it at about 5 s.
	start := time.Now()
	for time.Since(start) < 2500*time.Millisecond {
		if err := w.Arm(ctx, "plan-2", 2*time.Second, 5*time.Second); err != nil {
			t.Fatal(err)
		}
		time.Sleep(700 * time.Millisecond)
	}
	if b, ok := hears(t, heard, 8*time.Second); !ok || b != "plan-2" {
		t.Fatalf("the most did not close the batch: heard %q (%v)", b, ok)
	}
}

func TestForgettingABatchWakesNobody(t *testing.T) {
	w, heard := windowOnABus(t)
	if err := w.Arm(t.Context(), "plan-3", time.Second, time.Minute); err != nil {
		t.Fatal(err)
	}
	w.Forget(t.Context(), "plan-3")
	if b, ok := hears(t, heard, 3*time.Second); ok {
		t.Fatalf("a forgotten batch was heard expire: %q", b)
	}
}