package contract_test

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

	"git.5iot.com/iotlcm-public/iotlcm-worker-svr/internal/fullsync/contract"
	"git.5iot.com/iotlcm-public/iotlcm-worker-svr/internal/queue/zset"
)

// Check every old field, including zero/omitempty behavior, so future adapters
// can adopt the contract without silently changing the persisted wire format.
func TestLegacyFieldSchemas(t *testing.T) {
	for _, pair := range []struct{ old, next any }{
		{zset.RunMeta{}, contract.RunMeta{}},
		{zset.FailureRecord{}, contract.FailureRecord{}},
		{zset.Task{}, contract.Task{}},
	} {
		old, next := reflect.TypeOf(pair.old), reflect.TypeOf(pair.next)
		for i := 0; i < old.NumField(); i++ {
			field := old.Field(i)
			replacement, ok := next.FieldByName(field.Name)
			if !ok || replacement.Tag.Get("json") != field.Tag.Get("json") || replacement.Type.Kind() != field.Type.Kind() {
				t.Errorf("%s.%s lost its legacy schema: old=%+v new=%+v", old.Name(), field.Name, field, replacement)
			}
		}
	}
}

func TestLegacyRunJSONRoundTrip(t *testing.T) {
	now := time.Date(2026, 9, 20, 1, 2, 3, 456, time.UTC)
	legacy := zset.RunMeta{
		RunID: "legacy", Operation: "current_month_usage_full_sync", QueryMonth: "202609",
		Status: "completed_with_failures", ProducerDone: true, CurrentRound: 5,
		SuccessCount: 9, FailedCount: 1, CreatedAt: now, ProducerCompletedAt: now, CompletedAt: now,
	}
	data := mustJSON(t, legacy)
	var decoded contract.RunMeta
	if err := json.Unmarshal(data, &decoded); err != nil {
		t.Fatal(err)
	}
	if err := decoded.Validate(); err != nil {
		t.Fatalf("legacy run rejected: %v", err)
	}
	if got := string(mustJSON(t, decoded)); got != string(data) {
		t.Fatalf("legacy wire format changed:\n%s\n%s", data, got)
	}
	// New fields do not prevent old readers from consuming the same metadata.
	decoded.SyncType = contract.SyncReplay
	decoded.SourceRunID = "source"
	decoded.ReplayCycle = 1
	decoded.EnqueuedCount = 10
	decoded.PendingFailureCount = 1
	var oldReader zset.RunMeta
	if err := json.Unmarshal(mustJSON(t, decoded), &oldReader); err != nil {
		t.Fatal(err)
	}
	oldReader.SyncType = ""
	oldReader.SourceRunID = ""
	oldReader.ReplayCycle = 0
	oldReader.EnqueuedCount = 0
	oldReader.PendingFailureCount = 0
	if !reflect.DeepEqual(oldReader, legacy) {
		t.Fatalf("old reader lost fields: %+v", oldReader)
	}
}

func TestLegacyFailureAndTaskJSON(t *testing.T) {
	legacy := zset.FailureRecord{
		Version: 1, TaskID: "source:op:42", OriginalRunID: "source", LatestRunID: "latest",
		QueryMonth: "202609", Operation: "op", CardID: 42, ICCID: "iccid", MSISDN: "msisdn", IMSI: "imsi",
		ChanKey: "chan", TempKey: "template", Carrier: "mobile", FailureType: "mobile_busy_exhausted",
		Round: 5, Attempts: 7, Code: 13000, ErrCode: "BUSY", Message: "try again",
		ReviewStatus: "pending", ReviewRemark: "remark", ReviewedBy: "operator", ReviewedAt: "2026-09-20",
		RetryCycle: 2, ReplayRunID: "replayed", FirstFailedAt: time.Unix(1, 0).UTC(), LastFailedAt: time.Unix(2, 0).UTC(),
	}
	var record contract.FailureRecord
	if err := json.Unmarshal(mustJSON(t, legacy), &record); err != nil {
		t.Fatal(err)
	}
	if string(mustJSON(t, record)) != string(mustJSON(t, legacy)) {
		t.Fatal("failure record wire format changed")
	}
	if summary := record.Summary(); summary.ErrorCategory != contract.ErrorRateLimited || summary.TaskID != legacy.TaskID || summary.FailedAt != legacy.LastFailedAt {
		t.Fatalf("incorrect failure projection: %+v", summary)
	}
	task := zset.Task{TaskID: "r:op:42", RunID: "r", Operation: "op", QueryMonth: "202609", ChanKey: "c", TempKey: "t", Operator: 2, CardID: 42, ICCID: "i", MSISDN: "m", IMSI: "s", NextExecuteAt: 1234}
	var newTask contract.Task
	if err := json.Unmarshal(mustJSON(t, task), &newTask); err != nil {
		t.Fatal(err)
	}
	newTask.NextExecuteAt = 9999
	if string(mustJSON(t, newTask)) != string(mustJSON(t, task)) {
		t.Fatal("task wire format or scheduling exclusion changed")
	}
}

func mustJSON(t *testing.T, value any) []byte {
	t.Helper()
	data, err := json.Marshal(value)
	if err != nil {
		t.Fatal(err)
	}
	return data
}