package transfer

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

	"github.com/gogo/protobuf/grpc"

	"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"
	cdctypes "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/client/rest"
	"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 20-transfer appmodulebasic
type AppModuleBasic struct{}

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

// RegisterCodec implements AppModuleBasic interface
func (AppModuleBasic) RegisterCodec(cdc *codec.Codec) {
	types.RegisterCodec(cdc)
}

// 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, 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) {
	rest.RegisterRoutes(clientCtx, rtr)
}

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

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

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

// 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
}

// NewQuerierHandler implements the AppModule interface
func (am AppModule) NewQuerierHandler() sdk.Querier {
	return nil
}

func (am AppModule) RegisterQueryService(grpc.Server) {}

// 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)

	// TODO: check if the IBC transfer module account is set
	InitGenesis(ctx, am.keeper, genesisState)
	return []abci.ValidatorUpdate{}
}

func (am AppModule) ExportGenesis(ctx sdk.Context, cdc codec.JSONMarshaler) json.RawMessage {
	gs := ExportGenesis(ctx, am.keeper)
	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 returns nil.
func (AppModule) RandomizedParams(_ *rand.Rand) []simtypes.ParamChange {
	return nil
}

// RegisterStoreDecoder registers a decoder for transfer module's types
func (am AppModule) RegisterStoreDecoder(_ sdk.StoreDecoderRegistry) {
}

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

//____________________________________________________________________________

// Implement IBCModule callbacks
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 {
	// TODO: Enforce ordering, currently relayers use ORDERED channels

	// 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(porttypes.ErrInvalidPort, "invalid version: %s, expected %s", version, "ics20-1")
	}

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

	// TODO: escrow
	return nil
}

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 {
	// TODO: Enforce ordering, currently relayers use ORDERED channels

	// 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(porttypes.ErrInvalidPort, "invalid version: %s, expected %s", version, "ics20-1")
	}

	if counterpartyVersion != types.Version {
		return sdkerrors.Wrapf(porttypes.ErrInvalidPort, "invalid counterparty version: %s, expected %s", counterpartyVersion, "ics20-1")
	}

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

	// TODO: escrow
	return nil
}

func (am AppModule) OnChanOpenAck(
	ctx sdk.Context,
	portID,
	channelID string,
	counterpartyVersion string,
) error {
	if counterpartyVersion != types.Version {
		return sdkerrors.Wrapf(porttypes.ErrInvalidPort, "invalid counterparty version: %s, expected %s", counterpartyVersion, "ics20-1")
	}
	return nil
}

func (am AppModule) OnChanOpenConfirm(
	ctx sdk.Context,
	portID,
	channelID string,
) error {
	return nil
}

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")
}

func (am AppModule) OnChanCloseConfirm(
	ctx sdk.Context,
	portID,
	channelID string,
) error {
	return nil
}

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 := types.FungibleTokenPacketAcknowledgement{
		Success: true,
		Error:   "",
	}
	if err := am.keeper.OnRecvPacket(ctx, packet, data); err != nil {
		acknowledgement = types.FungibleTokenPacketAcknowledgement{
			Success: false,
			Error:   err.Error(),
		}
	}

	ctx.EventManager().EmitEvent(
		sdk.NewEvent(
			types.EventTypePacket,
			sdk.NewAttribute(sdk.AttributeKeyModule, types.ModuleName),
			sdk.NewAttribute(types.AttributeKeyReceiver, data.Receiver),
			sdk.NewAttribute(types.AttributeKeyValue, data.Amount.String()),
		),
	)

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

func (am AppModule) OnAcknowledgementPacket(
	ctx sdk.Context,
	packet channeltypes.Packet,
	acknowledgement []byte,
) (*sdk.Result, error) {
	var ack types.FungibleTokenPacketAcknowledgement
	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.AttributeKeyValue, data.Amount.String()),
			sdk.NewAttribute(types.AttributeKeyAckSuccess, fmt.Sprintf("%t", ack.Success)),
		),
	)

	if !ack.Success {
		ctx.EventManager().EmitEvent(
			sdk.NewEvent(
				types.EventTypePacket,
				sdk.NewAttribute(types.AttributeKeyAckError, ack.Error),
			),
		)
	}

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

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(types.AttributeKeyRefundReceiver, data.Sender),
			sdk.NewAttribute(types.AttributeKeyRefundValue, data.Amount.String()),
			sdk.NewAttribute(sdk.AttributeKeyModule, types.ModuleName),
		),
	)

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