package ibc

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"
	"github.com/cosmos/cosmos-sdk/types/module"
	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
	client2 "github.com/cosmos/cosmos-sdk/x/ibc/02-client"
	host "github.com/cosmos/cosmos-sdk/x/ibc/24-host"
	"github.com/cosmos/cosmos-sdk/x/ibc/client/cli"
	"github.com/cosmos/cosmos-sdk/x/ibc/client/rest"
	"github.com/cosmos/cosmos-sdk/x/ibc/keeper"
	"github.com/cosmos/cosmos-sdk/x/ibc/simulation"
	"github.com/cosmos/cosmos-sdk/x/ibc/types"
)

var (
	_ module.AppModule           = AppModule{}
	_ module.AppModuleBasic      = AppModuleBasic{}
	_ module.AppModuleSimulation = AppModule{}
)

// AppModuleBasic defines the basic application module used by the ibc module.
type AppModuleBasic struct{}

var _ module.AppModuleBasic = AppModuleBasic{}

// Name returns the ibc module's name.
func (AppModuleBasic) Name() string {
	return host.ModuleName
}

// RegisterCodec registers the ibc module's types for the given codec.
func (AppModuleBasic) RegisterCodec(cdc *codec.Codec) {
	types.RegisterCodec(cdc)
}

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

// ValidateGenesis performs genesis state validation for the ibc 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", host.ModuleName, err)
	}

	return gs.Validate()
}

// RegisterRESTRoutes registers the REST routes for the ibc module.
func (AppModuleBasic) RegisterRESTRoutes(clientCtx client.Context, rtr *mux.Router) {
	rest.RegisterRoutes(clientCtx, rtr, host.StoreKey)
}

// GetTxCmd returns the root tx command for the ibc module.
func (AppModuleBasic) GetTxCmd(clientCtx client.Context) *cobra.Command {
	return cli.GetTxCmd(clientCtx)
}

// GetQueryCmd returns no root query command for the ibc module.
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 implements an application module for the ibc module.
type AppModule struct {
	AppModuleBasic
	keeper *keeper.Keeper

	// create localhost by default
	createLocalhost bool
}

// NewAppModule creates a new AppModule object
func NewAppModule(k *keeper.Keeper) AppModule {
	return AppModule{
		keeper: k,
	}
}

// Name returns the ibc module's name.
func (AppModule) Name() string {
	return host.ModuleName
}

// RegisterInvariants registers the ibc module invariants.
func (am AppModule) RegisterInvariants(ir sdk.InvariantRegistry) {
	// TODO:
}

// Route returns the message routing key for the ibc module.
func (am AppModule) Route() sdk.Route {
	return sdk.NewRoute(host.RouterKey, NewHandler(*am.keeper))
}

// QuerierRoute returns the ibc module's querier route name.
func (AppModule) QuerierRoute() string {
	return host.QuerierRoute
}

// NewQuerierHandler returns the ibc module sdk.Querier.
func (am AppModule) NewQuerierHandler() sdk.Querier {
	return keeper.NewQuerier(*am.keeper)
}

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

// InitGenesis performs genesis initialization for the ibc module. It returns
// no validator updates.
func (am AppModule) InitGenesis(ctx sdk.Context, cdc codec.JSONMarshaler, bz json.RawMessage) []abci.ValidatorUpdate {
	var gs types.GenesisState
	err := cdc.UnmarshalJSON(bz, &gs)
	if err != nil {
		panic(fmt.Sprintf("failed to unmarshal %s genesis state: %s", host.ModuleName, err))
	}
	InitGenesis(ctx, *am.keeper, am.createLocalhost, gs)
	return []abci.ValidatorUpdate{}
}

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

// BeginBlock returns the begin blocker for the ibc module.
func (am AppModule) BeginBlock(ctx sdk.Context, req abci.RequestBeginBlock) {
	client2.BeginBlocker(ctx, am.keeper.ClientKeeper)
}

// EndBlock returns the end blocker for the ibc module. It returns no validator
// updates.
func (am AppModule) EndBlock(ctx sdk.Context, req abci.RequestEndBlock) []abci.ValidatorUpdate {
	return []abci.ValidatorUpdate{}
}

//____________________________________________________________________________

// AppModuleSimulation functions

// GenerateGenesisState creates a randomized GenState of the ibc 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 since IBC doesn't register parameter changes.
func (AppModule) RandomizedParams(_ *rand.Rand) []simtypes.ParamChange {
	return nil
}

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

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