package main

import (
	"context"
	"testing"

	"github.com/novox/mesh-controller/internal/inventory"
)

// A declaration composed earlier is numbered lower than one composed later, whatever order the two
// are sent in (novox/hq issue 204). The number used to be taken at send time, after composing, so a
// declaration composed before an assignment changed and sent after a newer one carried the higher
// number — and the machine, which refuses a lower number, took the older content as the mesh's
// newest word. Taken before the composition reads anything, the order of numbers is the order of
// compositions, and the host's refusal does what it is for.
func TestADeclarationComposedEarlierIsNumberedLowerWhateverOrderItIsSent(t *testing.T) {
	allot := numbered()
	var composed []string
	compose := func(stamp string) func(string) (sendable, error) {
		return func(node string) (sendable, error) {
			composed = append(composed, stamp)
			return sendable{Resources: []map[string]any{{"id": node + "." + stamp}}}, nil
		}
	}
	// Composed first — before an assignment changed — and sent last.
	stale, _ := composeEach([]string{"anchor"}, allot, compose("before"))
	// Composed after the change, sent first.
	fresh, _ := composeEach([]string{"anchor"}, allot, compose("after"))

	if stale[0].declared.Sequence != 1 || fresh[0].declared.Sequence != 2 {
		t.Fatalf("the numbers do not follow the compositions: before=%d after=%d",
			stale[0].declared.Sequence, fresh[0].declared.Sequence)
	}
	// Sent in the other order, the numbers do not change — so the machine that has applied the
	// fresh one (2) refuses the stale one (1) when it arrives late.
	if !(stale[0].declared.Sequence < fresh[0].declared.Sequence) {
		t.Fatal("a declaration composed earlier must carry the lower number, however late it is sent")
	}
	if len(composed) != 2 || composed[0] != "before" {
		t.Fatalf("compositions happened in an unexpected order: %v", composed)
	}
}

// The number is taken before the first read of the composition, not after it: an allotter that
// fails leaves nothing composed for that machine, and the others are still composed.
func TestTheNumberIsTakenBeforeComposingAndItsFailureIsARefusal(t *testing.T) {
	calls := 0
	allot := func(node string) (int64, error) {
		if node == "anchor" {
			return 0, context.DeadlineExceeded
		}
		return 7, nil
	}
	sending, refusals := composeEach([]string{"anchor", "laptop"}, allot, func(node string) (sendable, error) {
		calls++
		if node == "anchor" {
			t.Fatal("anchor was composed although its number could not be taken")
		}
		return sendable{}, nil
	})
	if calls != 1 || len(sending) != 1 || sending[0].node != "laptop" || sending[0].declared.Sequence != 7 {
		t.Fatalf("laptop should be composed with its number and anchor refused: %v / %v", sending, refusals)
	}
	if len(refusals) != 1 {
		t.Fatalf("anchor's failed number should be a refusal naming it: %v", refusals)
	}
}

// What was sent is written down even when the sender's context is already cancelled (issue 204): a
// controller replaced mid-send had told the machine and never recorded it, so status read "applied,
// current" over a machine that had just been sent something else.
func TestASendIsRecordedEvenWhenTheSenderIsBeingCancelled(t *testing.T) {
	inv := inventory.ForTest(t)
	ctx, cancel := context.WithCancel(t.Context())
	if _, err := inv.AddNode(ctx, "anchor"); err != nil {
		t.Fatal(err)
	}
	cancel() // the sender is going away: its context is cancelled between the send and the record
	body := []byte(`{"declaration":1,"resources":[]}`)
	digest, err := recordSent(ctx, inv, "anchor", body)
	if err != nil {
		// NodeByName on the cancelled context may itself refuse; the record must still be possible
		// through the detached context, so look the node up again on a live one.
		t.Fatalf("recording a send after cancellation failed: %v", err)
	}
	outstanding, err := inv.Outstanding(t.Context(), "anchor")
	if err != nil {
		t.Fatal(err)
	}
	if outstanding != digest || digest != digestOf(body) {
		t.Fatalf("the send was not recorded: outstanding %q, sent %q", outstanding, digest)
	}
}