package modules

import (
	"fmt"
	"io"
	"os"

	"go.uber.org/fx"
	"golang.org/x/xerrors"

	"github.com/filecoin-project/lotus/build"
	"github.com/filecoin-project/lotus/chain/actors"
	"github.com/filecoin-project/lotus/node/modules/dtypes"
	"github.com/filecoin-project/lotus/node/modules/helpers"

	cbor "github.com/ipfs/go-ipld-cbor"
)

func LoadBultinActors(lc fx.Lifecycle, mctx helpers.MetricsCtx, bs dtypes.UniversalBlockstore) (result dtypes.BuiltinActorsLoaded, err error) {
	ctx := helpers.LifecycleCtx(mctx, lc)

	// TODO eventually we want this to start with bundle/manifest CIDs and fetch them from IPFS if
	//      not already loaded.
	//      For now, we just embed the v8 bundle and adjust the manifest CIDs for the migration/actor
	//      metadata.
	if len(build.BuiltinActorsV8Bundle()) > 0 {
		if err := actors.LoadBundle(ctx, bs, actors.Version8, build.BuiltinActorsV8Bundle()); err != nil {
			return result, err
		}
	}

	// for testing -- need to also set LOTUS_USE_FVM_CUSTOM_BUNDLE=1 to force the fvm to use it.
	if len(build.BuiltinActorsV7Bundle()) > 0 {
		if err := actors.LoadBundle(ctx, bs, actors.Version7, build.BuiltinActorsV7Bundle()); err != nil {
			return result, err
		}
	}

	cborStore := cbor.NewCborStore(bs)
	if err := actors.LoadManifests(ctx, cborStore); err != nil {
		return result, xerrors.Errorf("error loading actor manifests: %w", err)
	}

	return result, nil
}

// for itests
func LoadBuiltinActorsTesting(lc fx.Lifecycle, mctx helpers.MetricsCtx, bs dtypes.UniversalBlockstore) (result dtypes.BuiltinActorsLoaded, err error) {
	ctx := helpers.LifecycleCtx(mctx, lc)

	base := os.Getenv("LOTUS_SRC_DIR")
	if base == "" {
		base = "."
	}

	for _, ver := range []actors.Version{actors.Version8} {
		path := fmt.Sprintf("%s/build/builtin-actors/v%d/builtin-actors-testing.car", base, ver)

		file, err := os.Open(path)
		if err != nil {
			return result, xerrors.Errorf("error opening v%d bundle: %w", ver, err)
		}

		bundle, err := io.ReadAll(file)
		if err != nil {
			return result, xerrors.Errorf("error reading v%d bundle: %w", ver, err)
		}

		if err := actors.LoadBundle(ctx, bs, actors.Version8, bundle); err != nil {
			return result, xerrors.Errorf("error loading v%d bundle: %w", ver, err)
		}
	}

	cborStore := cbor.NewCborStore(bs)
	if err := actors.LoadManifests(ctx, cborStore); err != nil {
		return result, xerrors.Errorf("error loading actor manifests: %w", err)
	}

	return result, nil
}