package staking

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

	"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"
	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"
	"github.com/cosmos/cosmos-sdk/x/staking/client/cli"
	"github.com/cosmos/cosmos-sdk/x/staking/client/rest"
	"github.com/cosmos/cosmos-sdk/x/staking/keeper"
	"github.com/cosmos/cosmos-sdk/x/staking/simulation"
	"github.com/cosmos/cosmos-sdk/x/staking/types"
)

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

// AppModuleBasic defines the basic application module used by the staking module.
type AppModuleBasic struct {
	cdc codec.Marshaler
}

var _ module.AppModuleBasic = AppModuleBasic{}

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

// RegisterLegacyAminoCodec registers the staking module's types on the given LegacyAmino codec.
func (AppModuleBasic) RegisterLegacyAminoCodec(cdc *codec.LegacyAmino) {
	types.RegisterLegacyAminoCodec(cdc)
}

// RegisterInterfaces registers the module's interface types
func (b AppModuleBasic) RegisterInterfaces(registry cdctypes.InterfaceRegistry) {
	types.RegisterInterfaces(registry)
}

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

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

	return ValidateGenesis(&data)
}

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

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

// GetTxCmd returns the root tx command for the staking module.
func (AppModuleBasic) GetTxCmd() *cobra.Command {
	return cli.NewTxCmd()
}

// GetQueryCmd returns no root query command for the staking module.
func (AppModuleBasic) GetQueryCmd() *cobra.Command {
	return cli.GetQueryCmd()
}

// AppModule implements an application module for the staking module.
type AppModule struct {
	AppModuleBasic

	keeper        keeper.Keeper
	accountKeeper types.AccountKeeper
	bankKeeper    types.BankKeeper
}

// NewAppModule creates a new AppModule object
func NewAppModule(cdc codec.Marshaler, keeper keeper.Keeper, ak types.AccountKeeper, bk types.BankKeeper) AppModule {
	return AppModule{
		AppModuleBasic: AppModuleBasic{cdc: cdc},
		keeper:         keeper,
		accountKeeper:  ak,
		bankKeeper:     bk,
	}
}

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

// RegisterInvariants registers the staking module invariants.
func (am AppModule) RegisterInvariants(ir sdk.InvariantRegistry) {
	keeper.RegisterInvariants(ir, am.keeper)
}

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

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

// LegacyQuerierHandler returns the staking module sdk.Querier.
func (am AppModule) LegacyQuerierHandler(legacyQuerierCdc *codec.LegacyAmino) sdk.Querier {
	return keeper.NewQuerier(am.keeper, legacyQuerierCdc)
}

// RegisterServices registers module services.
func (am AppModule) RegisterServices(cfg module.Configurator) {
	types.RegisterMsgServer(cfg.MsgServer(), keeper.NewMsgServerImpl(am.keeper))
	querier := keeper.Querier{Keeper: am.keeper}
	types.RegisterQueryServer(cfg.QueryServer(), querier)

	m := keeper.NewMigrator(am.keeper)
	cfg.RegisterMigration(types.ModuleName, 1, m.Migrate1to2)
}

// InitGenesis performs genesis initialization for the staking 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)

	return InitGenesis(ctx, am.keeper, am.accountKeeper, am.bankKeeper, &genesisState)
}

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

// ConsensusVersion implements AppModule/ConsensusVersion.
func (AppModule) ConsensusVersion() uint64 { return 2 }

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

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

// AppModuleSimulation functions

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

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

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

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

// WeightedOperations returns the all the staking module operations with their respective weights.
func (am AppModule) WeightedOperations(simState module.SimulationState) []simtypes.WeightedOperation {
	return simulation.WeightedOperations(
		simState.AppParams, simState.Cdc, am.accountKeeper, am.bankKeeper, am.keeper,
	)
}
