package backend

import (
	"context"
	"encoding/json"
	"errors"
	"strings"
	"testing"
	"time"

	"github.com/eclipse/paho.golang/paho"
	"robot-market/test-mqtt-5/internal/events"
)

func TestReceiptRawPayloadRoutingAndCorrelation(t *testing.T) {
	b := testBackend()
	b.Client.Config.Topics.ObserveAll = true
	for _, payload := range []string{"hello", "", "[1,2]", `{"device_id":"different","timestamp":"{{$isoTimestamp}}","message_id":"msg-1"}`} {
		reply := b.receipt(&paho.Publish{Topic: "robot-market/test/v1/real-device/telemetry", Payload: []byte(payload)})
		if reply == nil || reply.Topic != "robot-market/test/v1/real-device/acks" || reply.Retain || reply.QoS != 1 {
			t.Fatal("missing/routed/retained reply")
		}
		var ack ReceiptAck
		if json.Unmarshal(reply.Payload, &ack) != nil || !ack.OK || ack.Type != "receipt_ack" || ack.PayloadBytes != len(payload) || len(ack.PayloadSHA256) != 64 {
			t.Fatal("invalid receipt")
		}
	}
	p := &paho.Publish{Topic: "robot-market/test/v1/device/telemetry", Payload: []byte("x"), Properties: &paho.PublishProperties{ResponseTopic: "robot-market/test/v1/replies/custom", CorrelationData: []byte{0, 255, 1}}}
	reply := b.receipt(p)
	p.Properties.CorrelationData[0] = 99
	if reply.Topic != "robot-market/test/v1/replies/custom" || reply.Properties.CorrelationData[0] != 0 || reply.Properties.ResponseTopic != "" {
		t.Fatal("native response/correlation lost or aliased")
	}
	p.Properties.ResponseTopic = "outside/test"
	if b.receipt(p).Topic != "robot-market/test/v1/device/acks" {
		t.Fatal("unusable response topic should use default receipt topic")
	}
}

func TestReceiptLoopAndRetainedReplayPrevention(t *testing.T) {
	b := testBackend()
	b.Client.Config.Topics.ObserveAll = true
	for _, topic := range []string{"acks", "commands", "receipts"} {
		if b.receipt(&paho.Publish{Topic: "robot-market/test/v1/device/" + topic, Payload: []byte("hello")}) != nil {
			t.Fatal("ACK loop possible")
		}
	}
	for _, p := range []*paho.Publish{
		{Topic: "robot-market/test/v1/device/status", Retain: true, Payload: []byte("online")},
		{Topic: "robot-market/test/v1/custom/topic", Payload: []byte(`{"type":"receipt_ack","ok":true}`)},
		{Topic: "outside/device/topic", Payload: []byte("hello")},
	} {
		if b.receipt(p) != nil {
			t.Fatal("reply created for replay, receipt or external topic")
		}
	}
}

func TestReceiptDuplicateDeliveryRepliesWithoutCommandExecution(t *testing.T) {
	b := testBackend()
	b.Client.Config.Topics.ObserveAll = true
	b.Client.Config.Receipts.Enabled = true
	p := &paho.Publish{Topic: "robot-market/test/v1/device/telemetry", Payload: []byte("same message")}
	b.Handle(p)
	b.Handle(p)
	if len(b.receipts) != 2 || len(b.pending) != 0 {
		t.Fatal("duplicate receipt handling must not execute commands")
	}
}

func TestReceiptQueueFailureAndShutdown(t *testing.T) {
	b := testBackend()
	b.Client.Config.Topics.ObserveAll = true
	b.Client.Config.Receipts.Enabled = true
	b.receipts = make(chan *paho.Publish, 1)
	p := &paho.Publish{Topic: "robot-market/test/v1/device/telemetry", Payload: []byte("hello")}
	b.Handle(p)
	b.Handle(p)
	_, counts := b.Client.Events.Snapshot()
	if counts[events.Kind("receipt_ack_dropped")] != 1 {
		t.Fatal("queue overflow invisible")
	}
	b.PublishReceipt = func(context.Context, *paho.Publish) error { return errors.New("test disconnect") }
	ctx, cancel := context.WithCancel(context.Background())
	done := make(chan struct{})
	go func() { b.receiptWorker(ctx); close(done) }()
	deadline := time.Now().Add(time.Second)
	for {
		_, counts = b.Client.Events.Snapshot()
		if counts[events.Kind("receipt_ack_failed")] == 1 {
			break
		}
		if time.Now().After(deadline) {
			t.Fatal("failure not recorded")
		}
		time.Sleep(time.Millisecond)
	}
	cancel()
	select {
	case <-done:
	case <-time.After(time.Second):
		t.Fatal("worker shutdown blocked")
	}
	history, _ := b.Client.Events.Snapshot()
	if !strings.Contains(history[len(history)-1].Outcome, "not confirmed") {
		t.Fatal("failure claims success")
	}
}