feat(feemarket): add interface and basic mock (#2)

* add interface

* mock

* md

* md

* md

* lint fix

* move files

* nit fix

x/feemarket/plugins/mock/feemarket.go

@@ -0,0 +1,83 @@
+package mock
+
+import (
+	"encoding/json"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+
+	"github.com/skip-mev/feemarket/x/feemarket/types"
+)
+
+var _ types.FeeMarketImplementation = &MockFeeMarket{}
+
+type MockFeeMarket struct{} //nolint
+
+// ValidateBasic is a no-op.
+func (fm *MockFeeMarket) ValidateBasic() error {
+	return nil
+}
+
+// Init which initializes the fee market (in InitGenesis)
+func (fm *MockFeeMarket) Init(_ sdk.Context) error {
+	return nil
+}
+
+// Export which exports the fee market (in ExportGenesis)
+func (fm *MockFeeMarket) Export(_ sdk.Context) (json.RawMessage, error) {
+	return nil, nil
+}
+
+// BeginBlockUpdateHandler allows the fee market to be updated
+// after every block. This will be added to the BeginBlock chain.
+func (fm *MockFeeMarket) BeginBlockUpdateHandler(_ sdk.Context) types.UpdateHandler {
+	return func(ctx sdk.Context) error {
+		return nil
+	}
+}
+
+// EndBlockUpdateHandler allows the fee market to be updated
+// after every block. This will be added to the EndBlock chain.
+func (fm *MockFeeMarket) EndBlockUpdateHandler(_ sdk.Context) types.UpdateHandler {
+	return func(ctx sdk.Context) error {
+		return nil
+	}
+}
+
+// GetFeeMarketInfo retrieves the fee market's information about
+// how to pay for a transaction (min gas price, min tip,
+// where the fees are being distributed, etc.).
+func (fm *MockFeeMarket) GetFeeMarketInfo(_ sdk.Context) map[string]string {
+	return nil
+}
+
+// GetID returns the identifier of the fee market
+func (fm *MockFeeMarket) GetID() string {
+	return "mock"
+}
+
+// FeeAnteHandler will be called in the module AnteHandler.
+// Performs no actions.
+func (fm *MockFeeMarket) FeeAnteHandler(
+	_ sdk.Context,
+	_ sdk.Tx,
+	_ bool,
+	next sdk.AnteHandler,
+) sdk.AnteHandler {
+	return func(ctx sdk.Context, tx sdk.Tx, simulate bool) (newCtx sdk.Context, err error) {
+		return next(ctx, tx, simulate)
+	}
+}
+
+// FeePostHandler will be called in the module PostHandler
+// if PostHandlers are implemented. Performs no actions.
+func (fm *MockFeeMarket) FeePostHandler(
+	_ sdk.Context,
+	_ sdk.Tx,
+	_,
+	_ bool,
+	next sdk.PostHandler,
+) sdk.PostHandler {
+	return func(ctx sdk.Context, tx sdk.Tx, simulate, success bool) (newCtx sdk.Context, err error) {
+		return next(ctx, tx, simulate, success)
+	}
+}

x/feemarket/types/feemarket.go

@@ -0,0 +1,70 @@
+package types
+
+import (
+	"encoding/json"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+)
+
+// FeeMarketImplementation represents the interface of various FeeMarket types implemented
+// by other modules or packages.
+type FeeMarketImplementation interface {
+	// proto.Message TODO: add
+
+	// ValidateBasic does a simple validation check that
+	// doesn't require access to any other information.
+	ValidateBasic() error
+
+	// ------------------- Fee Market Parameters ------------------- //
+
+	// Init which initializes the fee market (in InitGenesis)
+	Init(ctx sdk.Context) error
+
+	// Export which exports the fee market (in ExportGenesis)
+	Export(ctx sdk.Context) (json.RawMessage, error)
+
+	// BeginBlockUpdateHandler allows the fee market to be updated
+	// after every block. This will be added to the BeginBlock chain.
+	BeginBlockUpdateHandler(ctx sdk.Context) UpdateHandler
+
+	// EndBlockUpdateHandler allows the fee market to be updated
+	// after every block. This will be added to the EndBlock chain.
+	EndBlockUpdateHandler(ctx sdk.Context) UpdateHandler
+
+	// ------------------- Fee Market Queries ------------------- //
+
+	// GetFeeMarketInfo retrieves the fee market's information about
+	// how to pay for a transaction (min gas price, min tip,
+	// where the fees are being distributed, etc.).
+	GetFeeMarketInfo(ctx sdk.Context) map[string]string
+
+	// GetID returns the identifier of the fee market
+	GetID() string
+
+	// ------------------- Fee Market Extraction ------------------- //
+
+	// FeeAnteHandler will be called in the module AnteHandler,
+	// this is where the fee market would extract and distribute
+	// fees from a given transaction
+	FeeAnteHandler(
+		ctx sdk.Context,
+		tx sdk.Tx,
+		simulate bool,
+		next sdk.AnteHandler,
+	) sdk.AnteHandler
+
+	// FeePostHandler will be called in the module PostHandler
+	// if PostHandlers are implemented. This is another place
+	// the fee market might refund users
+	FeePostHandler(
+		ctx sdk.Context,
+		tx sdk.Tx,
+		simulate,
+		success bool,
+		next sdk.PostHandler,
+	) sdk.PostHandler
+}
+
+// UpdateHandler is responsible for updating the parameters of the
+// fee market plugin. Fees can optionally also be extracted here.
+type UpdateHandler func(ctx sdk.Context) error