package transfer

import (
	"context"
	"encoding/json"
	"fmt"
	"math/rand"

	"github.com/gogo/protobuf/grpc"
	"github.com/grpc-ecosystem/grpc-gateway/runtime"

	"github.com/gorilla/mux"
	"github.com/spf13/cobra"

	abci "github.com/tendermint/tendermint/abci/types"

	"github.com/cosmos/cosmos-sdk/client"
	"github.com/cosmos/cosmos-sdk/codec"
	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
	sdk "github.com/cosmos/cosmos-sdk/types"
	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
	"github.com/cosmos/cosmos-sdk/types/module"
	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
	capabilitytypes "github.com/cosmos/cosmos-sdk/x/capability/types"
	"github.com/cosmos/cosmos-sdk/x/ibc-transfer/client/cli"
	"github.com/cosmos/cosmos-sdk/x/ibc-transfer/keeper"
	"github.com/cosmos/cosmos-sdk/x/ibc-transfer/simulation"
	"github.com/cosmos/cosmos-sdk/x/ibc-transfer/types"
	channeltypes "github.com/cosmos/cosmos-sdk/x/ibc/04-channel/types"
	porttypes "github.com/cosmos/cosmos-sdk/x/ibc/05-port/types"
	host "github.com/cosmos/cosmos-sdk/x/ibc/24-host"
)

var (
	_ module.AppModule      = AppModule{}
	_ porttypes.IBCModule   = AppModule{}
	_ module.AppModuleBasic = AppModuleBasic{}
)

// AppModuleBasic is the IBC Transfer AppModuleBasic
type AppModuleBasic struct{}

// Name implements AppModuleBasic interface
func (AppModuleBasic) Name() string {
	return types.ModuleName
}

// RegisterLegacyAminoCodec implements AppModuleBasic interface
func (AppModuleBasic) RegisterLegacyAminoCodec(*codec.LegacyAmino) {}

// RegisterInterfaces registers module concrete types into protobuf Any.
func (AppModuleBasic) RegisterInterfaces(registry codectypes.InterfaceRegistry) {
	types.RegisterInterfaces(registry)
}

// DefaultGenesis returns default genesis state as raw bytes for the ibc
// transfer module.
func (AppModuleBasic) DefaultGenesis(cdc codec.JSONMarshaler) json.RawMessage {
	return cdc.MustMarshalJSON(types.DefaultGenesisState())
}

// ValidateGenesis performs genesis state validation for the ibc transfer module.
func (AppModuleBasic) ValidateGenesis(cdc codec.JSONMarshaler, config client.TxEncodingConfig, bz json.RawMessage) error {
	var gs types.GenesisState
	if err := cdc.UnmarshalJSON(bz, &gs); err != nil {
		return fmt.Errorf("failed to unmarshal %s genesis state: %w", types.ModuleName, err)
	}

	return gs.Validate()
}

// RegisterRESTRoutes implements AppModuleBasic interface
func (AppModuleBasic) RegisterRESTRoutes(clientCtx client.Context, rtr *mux.Router) {
}

// RegisterGRPCRoutes registers the gRPC Gateway routes for the ibc-transfer module.
func (AppModuleBasic) RegisterGRPCRoutes(clientCtx client.Context, mux *runtime.ServeMux) {
	types.RegisterQueryHandlerClient(context.Background(), mux, types.NewQueryClient(clientCtx))
}

// GetTxCmd implements AppModuleBasic interface
func (AppModuleBasic) GetTxCmd() *cobra.Command {
	return cli.NewTxCmd()
}

// GetQueryCmd implements AppModuleBasic interface
func (AppModuleBasic) GetQueryCmd() *cobra.Command {
	return cli.GetQueryCmd()
}

// AppModule represents the AppModule for this module
type AppModule struct {
	AppModuleBasic
	keeper keeper.Keeper
}

// NewAppModule creates a new 20-transfer module
func NewAppModule(k keeper.Keeper) AppModule {
	return AppModule{
		keeper: k,
	}
}

// RegisterInvariants implements the AppModule interface
func (AppModule) RegisterInvariants(ir sdk.InvariantRegistry) {
	// TODO
}

// Route implements the AppModule interface
func (am AppModule) Route() sdk.Route {
	return sdk.NewRoute(types.RouterKey, NewHandler(am.keeper))
}

// QuerierRoute implements the AppModule interface
func (AppModule) QuerierRoute() string {
	return types.QuerierRoute
}

// LegacyQuerierHandler implements the AppModule interface
func (am AppModule) LegacyQuerierHandler(*codec.LegacyAmino) sdk.Querier {
	return nil
}

// RegisterQueryService registers a GRPC query service to respond to the
// module-specific GRPC queries.
func (am AppModule) RegisterQueryService(server grpc.Server) {
	types.RegisterQueryServer(server, am.keeper)
}

// InitGenesis performs genesis initialization for the ibc-transfer module. It returns
// no validator updates.
func (am AppModule) InitGenesis(ctx sdk.Context, cdc codec.JSONMarshaler, data json.RawMessage) []abci.ValidatorUpdate {
	var genesisState types.GenesisState
	cdc.MustUnmarshalJSON(data, &genesisState)
	am.keeper.InitGenesis(ctx, genesisState)
	return []abci.ValidatorUpdate{}
}

// ExportGenesis returns the exported genesis state as raw bytes for the ibc-transfer
// module.
func (am AppModule) ExportGenesis(ctx sdk.Context, cdc codec.JSONMarshaler) json.RawMessage {
	gs := am.keeper.ExportGenesis(ctx)
	return cdc.MustMarshalJSON(gs)
}

// BeginBlock implements the AppModule interface
func (am AppModule) BeginBlock(ctx sdk.Context, req abci.RequestBeginBlock) {
}

// EndBlock implements the AppModule interface
func (am AppModule) EndBlock(ctx sdk.Context, req abci.RequestEndBlock) []abci.ValidatorUpdate {
	return []abci.ValidatorUpdate{}
}

//____________________________________________________________________________

// AppModuleSimulation functions

// GenerateGenesisState creates a randomized GenState of the transfer module.
func (AppModule) GenerateGenesisState(simState *module.SimulationState) {
	simulation.RandomizedGenState(simState)
}

// ProposalContents doesn't return any content functions for governance proposals.
func (AppModule) ProposalContents(_ module.SimulationState) []simtypes.WeightedProposalContent {
	return nil
}

// RandomizedParams creates randomized ibc-transfer param changes for the simulator.
func (AppModule) RandomizedParams(r *rand.Rand) []simtypes.ParamChange {
	return simulation.ParamChanges(r)
}

// RegisterStoreDecoder registers a decoder for transfer module's types
func (am AppModule) RegisterStoreDecoder(sdr sdk.StoreDecoderRegistry) {
	sdr[types.StoreKey] = simulation.NewDecodeStore(am.keeper)
}

// WeightedOperations returns the all the transfer module operations with their respective weights.
func (am AppModule) WeightedOperations(_ module.SimulationState) []simtypes.WeightedOperation {
	return nil
}

//____________________________________________________________________________

// OnChanOpenInit implements the IBCModule interface
func (am AppModule) OnChanOpenInit(
	ctx sdk.Context,
	order channeltypes.Order,
	connectionHops []string,
	portID string,
	channelID string,
	chanCap *capabilitytypes.Capability,
	counterparty channeltypes.Counterparty,
	version string,
) error {
	if order != channeltypes.UNORDERED {
		return sdkerrors.Wrapf(channeltypes.ErrInvalidChannelOrdering, "expected %s channel, got %s ", channeltypes.UNORDERED, order)
	}

	// Require portID is the portID transfer module is bound to
	boundPort := am.keeper.GetPort(ctx)
	if boundPort != portID {
		return sdkerrors.Wrapf(porttypes.ErrInvalidPort, "invalid port: %s, expected %s", portID, boundPort)
	}

	if version != types.Version {
		return sdkerrors.Wrapf(types.ErrInvalidVersion, "got %s, expected %s", version, types.Version)
	}

	// Claim channel capability passed back by IBC module
	if err := am.keeper.ClaimCapability(ctx, chanCap, host.ChannelCapabilityPath(portID, channelID)); err != nil {
		return err
	}

	return nil
}

// OnChanOpenTry implements the IBCModule interface
func (am AppModule) OnChanOpenTry(
	ctx sdk.Context,
	order channeltypes.Order,
	connectionHops []string,
	portID,
	channelID string,
	chanCap *capabilitytypes.Capability,
	counterparty channeltypes.Counterparty,
	version,
	counterpartyVersion string,
) error {
	if order != channeltypes.UNORDERED {
		return sdkerrors.Wrapf(channeltypes.ErrInvalidChannelOrdering, "expected %s channel, got %s ", channeltypes.UNORDERED, order)
	}

	// Require portID is the portID transfer module is bound to
	boundPort := am.keeper.GetPort(ctx)
	if boundPort != portID {
		return sdkerrors.Wrapf(porttypes.ErrInvalidPort, "invalid port: %s, expected %s", portID, boundPort)
	}

	if version != types.Version {
		return sdkerrors.Wrapf(types.ErrInvalidVersion, "got: %s, expected %s", version, types.Version)
	}

	if counterpartyVersion != types.Version {
		return sdkerrors.Wrapf(types.ErrInvalidVersion, "invalid counterparty version: got: %s, expected %s", counterpartyVersion, types.Version)
	}

	// Claim channel capability passed back by IBC module
	if err := am.keeper.ClaimCapability(ctx, chanCap, host.ChannelCapabilityPath(portID, channelID)); err != nil {
		return err
	}

	return nil
}

// OnChanOpenAck implements the IBCModule interface
func (am AppModule) OnChanOpenAck(
	ctx sdk.Context,
	portID,
	channelID string,
	counterpartyVersion string,
) error {
	if counterpartyVersion != types.Version {
		return sdkerrors.Wrapf(types.ErrInvalidVersion, "invalid counterparty version: %s, expected %s", counterpartyVersion, types.Version)
	}
	return nil
}

// OnChanOpenConfirm implements the IBCModule interface
func (am AppModule) OnChanOpenConfirm(
	ctx sdk.Context,
	portID,
	channelID string,
) error {
	return nil
}

// OnChanCloseInit implements the IBCModule interface
func (am AppModule) OnChanCloseInit(
	ctx sdk.Context,
	portID,
	channelID string,
) error {
	// Disallow user-initiated channel closing for transfer channels
	return sdkerrors.Wrap(sdkerrors.ErrInvalidRequest, "user cannot close channel")
}

// OnChanCloseConfirm implements the IBCModule interface
func (am AppModule) OnChanCloseConfirm(
	ctx sdk.Context,
	portID,
	channelID string,
) error {
	return nil
}

// OnRecvPacket implements the IBCModule interface
func (am AppModule) OnRecvPacket(
	ctx sdk.Context,
	packet channeltypes.Packet,
) (*sdk.Result, []byte, error) {
	var data types.FungibleTokenPacketData
	if err := types.ModuleCdc.UnmarshalJSON(packet.GetData(), &data); err != nil {
		return nil, nil, sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "cannot unmarshal ICS-20 transfer packet data: %s", err.Error())
	}

	acknowledgement := channeltypes.NewResultAcknowledgement([]byte{byte(1)})

	err := am.keeper.OnRecvPacket(ctx, packet, data)
	if err != nil {
		acknowledgement = channeltypes.NewErrorAcknowledgement(err.Error())
	}

	ctx.EventManager().EmitEvent(
		sdk.NewEvent(
			types.EventTypePacket,
			sdk.NewAttribute(sdk.AttributeKeyModule, types.ModuleName),
			sdk.NewAttribute(types.AttributeKeyReceiver, data.Receiver),
			sdk.NewAttribute(types.AttributeKeyDenom, data.Denom),
			sdk.NewAttribute(types.AttributeKeyAmount, fmt.Sprintf("%d", data.Amount)),
			sdk.NewAttribute(types.AttributeKeyAckSuccess, fmt.Sprintf("%t", err != nil)),
		),
	)

	return &sdk.Result{
		Events: ctx.EventManager().Events().ToABCIEvents(),
	}, acknowledgement.GetBytes(), nil
}

// OnAcknowledgementPacket implements the IBCModule interface
func (am AppModule) OnAcknowledgementPacket(
	ctx sdk.Context,
	packet channeltypes.Packet,
	acknowledgement []byte,
) (*sdk.Result, error) {
	var ack channeltypes.Acknowledgement
	if err := types.ModuleCdc.UnmarshalJSON(acknowledgement, &ack); err != nil {
		return nil, sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "cannot unmarshal ICS-20 transfer packet acknowledgement: %v", err)
	}
	var data types.FungibleTokenPacketData
	if err := types.ModuleCdc.UnmarshalJSON(packet.GetData(), &data); err != nil {
		return nil, sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "cannot unmarshal ICS-20 transfer packet data: %s", err.Error())
	}

	if err := am.keeper.OnAcknowledgementPacket(ctx, packet, data, ack); err != nil {
		return nil, err
	}

	ctx.EventManager().EmitEvent(
		sdk.NewEvent(
			types.EventTypePacket,
			sdk.NewAttribute(sdk.AttributeKeyModule, types.ModuleName),
			sdk.NewAttribute(types.AttributeKeyReceiver, data.Receiver),
			sdk.NewAttribute(types.AttributeKeyDenom, data.Denom),
			sdk.NewAttribute(types.AttributeKeyAmount, fmt.Sprintf("%d", data.Amount)),
			sdk.NewAttribute(types.AttributeKeyAck, fmt.Sprintf("%v", ack)),
		),
	)

	switch resp := ack.Response.(type) {
	case *channeltypes.Acknowledgement_Result:
		ctx.EventManager().EmitEvent(
			sdk.NewEvent(
				types.EventTypePacket,
				sdk.NewAttribute(types.AttributeKeyAckSuccess, string(resp.Result)),
			),
		)
	case *channeltypes.Acknowledgement_Error:
		ctx.EventManager().EmitEvent(
			sdk.NewEvent(
				types.EventTypePacket,
				sdk.NewAttribute(types.AttributeKeyAckError, resp.Error),
			),
		)
	}

	return &sdk.Result{
		Events: ctx.EventManager().Events().ToABCIEvents(),
	}, nil
}

// OnTimeoutPacket implements the IBCModule interface
func (am AppModule) OnTimeoutPacket(
	ctx sdk.Context,
	packet channeltypes.Packet,
) (*sdk.Result, error) {
	var data types.FungibleTokenPacketData
	if err := types.ModuleCdc.UnmarshalJSON(packet.GetData(), &data); err != nil {
		return nil, sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "cannot unmarshal ICS-20 transfer packet data: %s", err.Error())
	}
	// refund tokens
	if err := am.keeper.OnTimeoutPacket(ctx, packet, data); err != nil {
		return nil, err
	}

	ctx.EventManager().EmitEvent(
		sdk.NewEvent(
			types.EventTypeTimeout,
			sdk.NewAttribute(sdk.AttributeKeyModule, types.ModuleName),
			sdk.NewAttribute(types.AttributeKeyRefundReceiver, data.Sender),
			sdk.NewAttribute(types.AttributeKeyRefundDenom, data.Denom),
			sdk.NewAttribute(types.AttributeKeyRefundAmount, fmt.Sprintf("%d", data.Amount)),
		),
	)

	return &sdk.Result{
		Events: ctx.EventManager().Events().ToABCIEvents(),
	}, nil
}