package pipeline

import (
	"context"
	"sync"
	"testing"
	"time"

	"mqqt-scrubber/internal/config"
	"mqqt-scrubber/internal/model"
)

type fakeWriter struct {
	mu      sync.Mutex
	batches [][]model.Record
	flushed chan struct{}
}

func newFakeWriter() *fakeWriter {
	return &fakeWriter{flushed: make(chan struct{}, 1)}
}

func (writer *fakeWriter) Write(_ context.Context, records []model.Record) error {
	writer.mu.Lock()
	copyBatch := append([]model.Record(nil), records...)
	writer.batches = append(writer.batches, copyBatch)
	writer.mu.Unlock()

	select {
	case writer.flushed <- struct{}{}:
	default:
	}

	return nil
}

func (writer *fakeWriter) firstBatch() []model.Record {
	writer.mu.Lock()
	defer writer.mu.Unlock()
	if len(writer.batches) == 0 {
		return nil
	}
	return writer.batches[0]
}

func TestServiceFlushesParsedRecords(t *testing.T) {
	fake := newFakeWriter()
	service := NewService(config.Config{
		DeviceAliases: map[string]string{
			"tasmota-896001": "Garage Plug",
			"Tasmota C88994": "Office Plug",
		},
		App: config.AppConfig{
			BatchSize:     2,
			BufferSize:    8,
			FlushInterval: config.DurationValue{Duration: time.Hour},
			FlushTimeout:  config.DurationValue{Duration: time.Second},
		},
	}, fake)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	errCh := make(chan error, 1)
	go func() {
		errCh <- service.Run(ctx)
	}()

	service.Enqueue(model.RawMessage{
		Topic:      "tele/tasmota_896001/LWT",
		Payload:    []byte("Online"),
		ReceivedAt: time.Date(2026, time.March, 12, 15, 21, 39, 0, time.UTC),
	})
	service.Enqueue(model.RawMessage{
		Topic:      "tele/tasmota_C88994/SENSOR",
		Payload:    []byte(`{"Time":"2026-03-12T16:23:13","ENERGY":{"TotalStartTime":"2026-02-04T19:13:40","Total":41.385,"Yesterday":1.124,"Today":0.799,"Period":0,"Power":1,"ApparentPower":4,"ReactivePower":4,"Factor":0.22,"Voltage":231,"Current":0.016}}`),
		ReceivedAt: time.Date(2026, time.March, 12, 16, 23, 13, 0, time.UTC),
	})

	select {
	case <-fake.flushed:
	case <-time.After(2 * time.Second):
		t.Fatal("timed out waiting for pipeline flush")
	}

	batch := fake.firstBatch()
	if len(batch) != 2 {
		t.Fatalf("expected 2 records in flushed batch, got %d", len(batch))
	}

	if batch[0].Measurement != "tasmota_lwt" {
		t.Fatalf("unexpected first measurement: %s", batch[0].Measurement)
	}
	if batch[0].Fields["online"] != true {
		t.Fatalf("unexpected lwt online field: %#v", batch[0].Fields["online"])
	}
	if batch[0].Fields["device_alias"] != "Garage Plug" {
		t.Fatalf("unexpected lwt device_alias field: %#v", batch[0].Fields["device_alias"])
	}

	if batch[1].Measurement != "tasmota_sensor" {
		t.Fatalf("unexpected second measurement: %s", batch[1].Measurement)
	}
	if batch[1].Fields["energy_total"] != float64(41.385) {
		t.Fatalf("unexpected sensor energy_total field: %#v", batch[1].Fields["energy_total"])
	}
	if batch[1].Fields["device_alias"] != "Office Plug" {
		t.Fatalf("unexpected sensor device_alias field: %#v", batch[1].Fields["device_alias"])
	}

	cancel()
	select {
	case err := <-errCh:
		if err != nil {
			t.Fatalf("service returned error: %v", err)
		}
	case <-time.After(2 * time.Second):
		t.Fatal("timed out waiting for service shutdown")
	}
}