package bnwasm

import (
	"context"
	"errors"
	"testing"

	abiv1 "git.dev.alexdunmow.com/block/pluginsdk/abi/v1"
	"google.golang.org/protobuf/proto"
)

// fakeHostErr mirrors *wasmguest.HostError's AbiErrorCode() method so the
// transport's cross-boundary classification (mapTransportErr) can be exercised
// natively, without importing the wasip1-only wasmguest package.
type fakeHostErr struct {
	code abiv1.AbiErrorCode
	msg  string
}

func (e *fakeHostErr) Error() string                    { return e.msg }
func (e *fakeHostErr) AbiErrorCode() abiv1.AbiErrorCode { return e.code }

// transportReturning builds a Transport whose every call fails with err.
func transportReturning(err error) Transport {
	return func(_ string, _, _ proto.Message) error { return err }
}

func TestTransportMapsTxExpiredToSentinel(t *testing.T) {
	hostErr := &fakeHostErr{code: abiv1.AbiErrorCode_ABI_ERROR_CODE_TX_EXPIRED, msg: "host: tx handle expired"}
	tr := transportReturning(hostErr)
	ctx := context.Background()

	// Every db.* verb that crosses the transport must classify TX_EXPIRED.
	t.Run("query", func(t *testing.T) {
		_, err := tr.query(ctx, "SELECT 1", 7, nil)
		if !errors.Is(err, ErrTxExpired) {
			t.Fatalf("query err = %v, want ErrTxExpired", err)
		}
	})
	t.Run("exec", func(t *testing.T) {
		_, err := tr.exec(ctx, "DELETE FROM t", 7, nil)
		if !errors.Is(err, ErrTxExpired) {
			t.Fatalf("exec err = %v, want ErrTxExpired", err)
		}
	})
	t.Run("txBegin", func(t *testing.T) {
		_, err := tr.txBegin(ctx)
		if !errors.Is(err, ErrTxExpired) {
			t.Fatalf("txBegin err = %v, want ErrTxExpired", err)
		}
	})
	t.Run("txCommit", func(t *testing.T) {
		if err := tr.txCommit(ctx, 7); !errors.Is(err, ErrTxExpired) {
			t.Fatalf("txCommit err = %v, want ErrTxExpired", err)
		}
	})
	t.Run("txRollback", func(t *testing.T) {
		if err := tr.txRollback(ctx, 7); !errors.Is(err, ErrTxExpired) {
			t.Fatalf("txRollback err = %v, want ErrTxExpired", err)
		}
	})
}

func TestTransportLeavesOtherAbiErrorsUntouched(t *testing.T) {
	hostErr := &fakeHostErr{code: abiv1.AbiErrorCode_ABI_ERROR_CODE_INTERNAL, msg: "boom"}
	tr := transportReturning(hostErr)
	_, err := tr.query(context.Background(), "SELECT 1", 0, nil)
	if errors.Is(err, ErrTxExpired) {
		t.Fatalf("non-tx-expired error was misclassified as ErrTxExpired: %v", err)
	}
	if !errors.Is(err, error(hostErr)) {
		t.Fatalf("original host error not preserved: %v", err)
	}
}