package watcher

import (
	"context"
	"testing"
	"time"

	"github.com/wangjia/pangolin/pay/internal/store"
	"github.com/wangjia/pangolin/pay/internal/tron"
)

const recvAddr = "TRecv00000000000000000000000000000A"

type mockFetcher struct{ transfers []tron.Transfer }

func (f *mockFetcher) IncomingTransfers(_ context.Context, _ string) ([]tron.Transfer, error) {
	return f.transfers, nil
}

func memStore(t *testing.T) *store.Store {
	t.Helper()
	st, err := store.Open(":memory:")
	if err != nil {
		t.Fatalf("store: %v", err)
	}
	t.Cleanup(func() { _ = st.Close() })
	return st
}

func seed(t *testing.T, st *store.Store, no string, amount int64, created time.Time) {
	t.Helper()
	o := &store.Order{
		OrderNo: no, UserRef: "u", SKU: "pro", ExpectAmount: amount, Address: recvAddr,
		Status: store.StatusPending, CreatedAt: created, ExpiresAt: created.Add(time.Hour),
	}
	if err := st.CreateOrder(context.Background(), o); err != nil {
		t.Fatalf("seed: %v", err)
	}
}

func TestWatcherMatchesByAmountAndTime(t *testing.T) {
	st := memStore(t)
	ctx := context.Background()
	now := time.Unix(1_700_000_100, 0)
	created := now.Add(-5 * time.Minute)
	seed(t, st, "PAY1", 5_000017, created)
	seed(t, st, "PAY2", 5_000018, created)

	fetch := &mockFetcher{transfers: []tron.Transfer{
		{TxID: "tx1", To: recvAddr, Value: 5_000017, BlockTs: created.Add(time.Minute).Unix()},
	}}
	w := New(st, fetch, recvAddr, nil)
	w.now = func() time.Time { return now }

	if err := w.Tick(ctx); err != nil {
		t.Fatalf("tick: %v", err)
	}
	o1, _ := st.GetOrder(ctx, "PAY1")
	if o1.Status != store.StatusPaid || o1.TxID != "tx1" {
		t.Fatalf("PAY1 %s/%s", o1.Status, o1.TxID)
	}
	o2, _ := st.GetOrder(ctx, "PAY2")
	if o2.Status != store.StatusPending {
		t.Fatalf("PAY2 should stay pending, got %s", o2.Status)
	}

	if err := w.Tick(ctx); err != nil { // idempotent
		t.Fatalf("tick2: %v", err)
	}
	o1, _ = st.GetOrder(ctx, "PAY1")
	if o1.Status != store.StatusPaid || o1.TxID != "tx1" {
		t.Fatal("idempotency broken")
	}
}

func TestWatcherWrongAmountIsOrphan(t *testing.T) {
	st := memStore(t)
	ctx := context.Background()
	now := time.Unix(1_700_000_100, 0)
	created := now.Add(-5 * time.Minute)
	seed(t, st, "PAY1", 5_000017, created)

	fetch := &mockFetcher{transfers: []tron.Transfer{
		{TxID: "tx-wrong", To: recvAddr, Value: 5_000000, BlockTs: created.Add(time.Minute).Unix()},
	}}
	w := New(st, fetch, recvAddr, nil)
	w.now = func() time.Time { return now }
	_ = w.Tick(ctx)

	o, _ := st.GetOrder(ctx, "PAY1")
	if o.Status != store.StatusPending {
		t.Fatalf("PAY1 should stay pending, got %s", o.Status)
	}
	if h, _ := st.TxHandled(ctx, "tx-wrong"); !h {
		t.Fatal("wrong-amount payment should be recorded as orphan")
	}
}

func TestWatcherLatePaymentDoesNotMatchNewOrder(t *testing.T) {
	// Order1 (amount 5_000017) expired; a NEW order (amount 5_000018) is now active
	// on the SAME address. A late payment of the OLD amount must NOT match the new
	// order (different amount) -> orphan.
	st := memStore(t)
	ctx := context.Background()
	now := time.Unix(1_700_000_500, 0)
	seed(t, st, "PAY2", 5_000018, now.Add(-time.Minute))

	fetch := &mockFetcher{transfers: []tron.Transfer{
		{TxID: "tx-late", To: recvAddr, Value: 5_000017, BlockTs: now.Unix()},
	}}
	w := New(st, fetch, recvAddr, nil)
	w.now = func() time.Time { return now }
	_ = w.Tick(ctx)

	o2, _ := st.GetOrder(ctx, "PAY2")
	if o2.Status != store.StatusPending {
		t.Fatalf("PAY2 must not be matched by a wrong-amount late payment, got %s", o2.Status)
	}
	if h, _ := st.TxHandled(ctx, "tx-late"); !h {
		t.Fatal("late payment should be orphan")
	}
}

func TestWatcherIgnoresPaymentBeforeOrder(t *testing.T) {
	// A payment whose block time is BEFORE the order was created must not match
	// (guards address reuse: prior balance / old tx).
	st := memStore(t)
	ctx := context.Background()
	now := time.Unix(1_700_000_500, 0)
	created := now.Add(-2 * time.Minute)
	seed(t, st, "PAY1", 5_000017, created)

	fetch := &mockFetcher{transfers: []tron.Transfer{
		{TxID: "tx-old", To: recvAddr, Value: 5_000017, BlockTs: created.Add(-time.Minute).Unix()},
	}}
	w := New(st, fetch, recvAddr, nil)
	w.now = func() time.Time { return now }
	_ = w.Tick(ctx)

	o, _ := st.GetOrder(ctx, "PAY1")
	if o.Status != store.StatusPending {
		t.Fatalf("payment before order must not match, got %s", o.Status)
	}
	if h, _ := st.TxHandled(ctx, "tx-old"); !h {
		t.Fatal("pre-order payment should be orphan")
	}
}

func TestWatcherExpires(t *testing.T) {
	st := memStore(t)
	ctx := context.Background()
	now := time.Unix(1_700_000_500, 0)
	o := &store.Order{
		OrderNo: "OLD", UserRef: "u", SKU: "pro", ExpectAmount: 1, Address: recvAddr,
		Status: store.StatusPending, CreatedAt: now.Add(-time.Hour), ExpiresAt: now.Add(-time.Minute),
	}
	_ = st.CreateOrder(ctx, o)

	w := New(st, &mockFetcher{}, recvAddr, nil)
	w.now = func() time.Time { return now }
	_ = w.Tick(ctx)

	got, _ := st.GetOrder(ctx, "OLD")
	if got.Status != store.StatusExpired {
		t.Fatalf("want expired, got %s", got.Status)
	}
}