package main

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

	"github.com/segmentio/kafka-go"

	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/metrics"
)

func TestProcessStatMessageUsesUncancelledContextForAppendAndCommit(t *testing.T) {
	parent, cancel := context.WithCancel(context.Background())
	cancel()

	env := envelope.FrameEnvelope{
		Protocol:     envelope.ProtocolJT808,
		MessageID:    "0x0200",
		Phone:        "13307795425",
		EventTimeMS:  1782918600000,
		ReceivedAtMS: 1782918600000,
		ParseStatus:  envelope.ParseOK,
	}
	payload, err := json.Marshal(env)
	if err != nil {
		t.Fatal(err)
	}
	appender := &contextCheckingStatAppender{}
	committer := &contextCheckingStatCommitter{}

	processStatMessage(parent, discardStatLogger{}, nil, appender, committer, kafka.Message{Value: payload})

	if appender.ctxErr != nil {
		t.Fatalf("appender saw cancelled context: %v", appender.ctxErr)
	}
	if committer.ctxErr != nil {
		t.Fatalf("committer saw cancelled context: %v", committer.ctxErr)
	}
	if appender.count != 1 || committer.count != 1 {
		t.Fatalf("appends=%d commits=%d", appender.count, committer.count)
	}
}

func TestProcessStatMessageRecordsMetrics(t *testing.T) {
	env := envelope.FrameEnvelope{Protocol: envelope.ProtocolJT808, Phone: "13307795425", MessageID: "0x0200"}
	payload, err := json.Marshal(env)
	if err != nil {
		t.Fatal(err)
	}
	registry := metrics.NewRegistry()

	processStatMessage(
		context.Background(),
		discardStatLogger{},
		registry,
		&contextCheckingStatAppender{},
		&contextCheckingStatCommitter{},
		kafka.Message{Topic: "vehicle.raw.jt808.v1", Partition: 4, Offset: 30, HighWaterMark: 41, Value: payload},
	)

	text := registry.Render()
	for _, want := range []string{
		`vehicle_stat_kafka_messages_total{status="received",topic="vehicle.raw.jt808.v1"} 1`,
		`vehicle_stat_writes_total{status="ok",topic="vehicle.raw.jt808.v1"} 1`,
		`vehicle_stat_kafka_commits_total{status="ok",topic="vehicle.raw.jt808.v1"} 1`,
		`vehicle_stat_kafka_lag{partition="4",topic="vehicle.raw.jt808.v1"} 10`,
		`vehicle_stat_write_duration_ms_histogram_bucket{le="+Inf",status="ok",topic="vehicle.raw.jt808.v1"} 1`,
		`vehicle_stat_write_duration_ms_histogram_count{status="ok",topic="vehicle.raw.jt808.v1"} 1`,
		`vehicle_stat_write_duration_ms_histogram_sum{status="ok",topic="vehicle.raw.jt808.v1"}`,
	} {
		if !strings.Contains(text, want) {
			t.Fatalf("metrics missing %s:\n%s", want, text)
		}
	}
}

func TestLoadConfigDefaultsToGoRawTopics(t *testing.T) {
	cfg := loadConfig()

	got := strings.Join(cfg.KafkaTopics, ",")
	want := "vehicle.fields.go.gb32960.v1,vehicle.fields.go.jt808.v1,vehicle.fields.go.yutong-mqtt.v1"
	if got != want {
		t.Fatalf("KafkaTopics = %q, want %q", got, want)
	}
}

type contextCheckingStatAppender struct {
	ctxErr error
	count  int
}

func (a *contextCheckingStatAppender) Append(ctx context.Context, _ envelope.FrameEnvelope) error {
	a.ctxErr = ctx.Err()
	a.count++
	return a.ctxErr
}

type contextCheckingStatCommitter struct {
	ctxErr error
	count  int
}

func (c *contextCheckingStatCommitter) CommitMessages(ctx context.Context, _ ...kafka.Message) error {
	c.ctxErr = ctx.Err()
	c.count++
	return c.ctxErr
}

type discardStatLogger struct{}

func (discardStatLogger) Error(string, ...any) {}
func (discardStatLogger) Warn(string, ...any)  {}