package evidence

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

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

// ----------------------------------------------------------------------------
// AppModuleBasic
// ----------------------------------------------------------------------------

// AppModuleBasic implements the AppModuleBasic interface for the evidence module.
type AppModuleBasic struct {
	evidenceHandlers []eviclient.EvidenceHandler // eviclient evidence submission handlers
}

// NewAppModuleBasic crates a AppModuleBasic without the codec.
func NewAppModuleBasic(evidenceHandlers ...eviclient.EvidenceHandler) AppModuleBasic {
	return AppModuleBasic{
		evidenceHandlers: evidenceHandlers,
	}
}

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

// RegisterLegacyAminoCodec registers the evidence module's types to the LegacyAmino codec.
func (AppModuleBasic) RegisterLegacyAminoCodec(cdc *codec.LegacyAmino) {
	types.RegisterLegacyAminoCodec(cdc)
}

// DefaultGenesis returns the evidence module's default genesis state.
func (AppModuleBasic) DefaultGenesis(cdc codec.JSONMarshaler) json.RawMessage {
	return cdc.MustMarshalJSON(types.DefaultGenesisState())
}

// ValidateGenesis performs genesis state validation for the evidence 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 registers the evidence module's REST service handlers.
func (a AppModuleBasic) RegisterRESTRoutes(clientCtx client.Context, rtr *mux.Router) {
	evidenceRESTHandlers := make([]rest.EvidenceRESTHandler, len(a.evidenceHandlers))

	for i, evidenceHandler := range a.evidenceHandlers {
		evidenceRESTHandlers[i] = evidenceHandler.RESTHandler(clientCtx)
	}

	rest.RegisterRoutes(clientCtx, rtr, evidenceRESTHandlers)
}

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

// GetTxCmd returns the evidence module's root tx command.
func (a AppModuleBasic) GetTxCmd() *cobra.Command {
	evidenceCLIHandlers := make([]*cobra.Command, len(a.evidenceHandlers))

	for i, evidenceHandler := range a.evidenceHandlers {
		evidenceCLIHandlers[i] = evidenceHandler.CLIHandler()
	}

	return cli.GetTxCmd(evidenceCLIHandlers)
}

// GetQueryCmd returns the evidence module's root query command.
func (AppModuleBasic) GetQueryCmd() *cobra.Command {
	return cli.GetQueryCmd()
}

func (AppModuleBasic) RegisterInterfaces(registry codectypes.InterfaceRegistry) {
	types.RegisterInterfaces(registry)
}

// ----------------------------------------------------------------------------
// AppModule
// ----------------------------------------------------------------------------

// AppModule implements the AppModule interface for the evidence module.
type AppModule struct {
	AppModuleBasic

	keeper keeper.Keeper
}

func NewAppModule(keeper keeper.Keeper) AppModule {
	return AppModule{
		AppModuleBasic: AppModuleBasic{},
		keeper:         keeper,
	}
}

// Name returns the evidence module's name.
func (am AppModule) Name() string {
	return am.AppModuleBasic.Name()
}

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

// QuerierRoute returns the evidence module's query routing key.
func (AppModule) QuerierRoute() string {
	return types.QuerierRoute
}

// LegacyQuerierHandler returns the evidence module's 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))
	types.RegisterQueryServer(cfg.QueryServer(), am.keeper)
}

// RegisterInvariants registers the evidence module's invariants.
func (am AppModule) RegisterInvariants(ir sdk.InvariantRegistry) {}

// InitGenesis performs the evidence module's genesis initialization 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", types.ModuleName, err))
	}

	InitGenesis(ctx, am.keeper, &gs)
	return []abci.ValidatorUpdate{}
}

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

// ConsensusVersion implements AppModule/ConsensusVersion.
func (AppModule) ConsensusVersion() uint64 { return 1 }

// BeginBlock executes all ABCI BeginBlock logic respective to the evidence module.
func (am AppModule) BeginBlock(ctx sdk.Context, req abci.RequestBeginBlock) {
	BeginBlocker(ctx, req, am.keeper)
}

// EndBlock executes all ABCI EndBlock logic respective to the evidence module. It
// returns no validator updates.
func (am AppModule) EndBlock(ctx sdk.Context, _ abci.RequestEndBlock) []abci.ValidatorUpdate {
	return []abci.ValidatorUpdate{}
}

// AppModuleSimulation functions

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

// ProposalContents returns all the evidence content functions used to
// simulate governance proposals.
func (am AppModule) ProposalContents(simState module.SimulationState) []simtypes.WeightedProposalContent {
	return nil
}

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

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

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