package link

import (
	"encoding/json"
	"testing"
	"time"
)

// The drain picked the last to arrive. A backlog longer than the batch, or a broker that split a
// burst, delivered a superseded declaration last (novox/hq 04-ISSUES/107).

func sequenced(t *testing.T, n int64) *said {
	t.Helper()
	inner, err := json.Marshal(map[string]any{"declaration": 1, "resources": []any{}, "sequence": n})
	if err != nil {
		t.Fatal(err)
	}
	body, err := json.Marshal(Signed{Declaration: inner, Signature: []byte("s")})
	if err != nil {
		t.Fatal(err)
	}
	return &said{body: body}
}

func TestTheDrainKeepsTheHighestSequenceNotTheLastToArrive(t *testing.T) {
	waiting := make(chan Declaration, 8)
	waiting <- sequenced(t, 9)
	waiting <- sequenced(t, 4) // arrived last, composed earlier
	latest, aside := newest(waiting, sequenced(t, 8), 30*time.Millisecond)
	if got := sequenceOf(latest.Body()); got != 9 {
		t.Fatalf("the drain kept sequence %d, and 9 was waiting", got)
	}
	if len(aside) != 2 {
		t.Fatalf("%d set aside, wanted 2 (the 8 and the late 4)", len(aside))
	}
}

func TestWithoutSequencesTheLastToArriveStillWins(t *testing.T) {
	// The behaviour this had before, kept for a controller that sends no order.
	apply, aside := newest(arriving("two", "three"), &said{body: []byte("one")}, 30*time.Millisecond)
	if string(apply.Body()) != "three" || len(aside) != 2 {
		t.Fatalf("applied %q with %d set aside", apply.Body(), len(aside))
	}
}

func TestAnUnreadableBodyClaimsNoOrder(t *testing.T) {
	if got := sequenceOf([]byte("not json")); got != 0 {
		t.Fatalf("garbage claimed sequence %d", got)
	}
}