wip: cdp params and types

x/cdp/app_test.go

@@ -2,10 +2,12 @@ package cdp
 
 import (
 	"testing"
+	"time"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/x/mock"
 	abci "github.com/tendermint/tendermint/abci/types"
+	tmtime "github.com/tendermint/tendermint/types/time"
 
 	"github.com/kava-labs/kava/x/pricefeed"
 )
@@ -19,7 +21,7 @@ func TestApp_CreateModifyDeleteCDP(t *testing.T) {
 	mock.SetGenesis(mapp, genAccs)
 	mock.CheckBalance(t, mapp, testAddr, cs(c("xrp", 100)))
 	// setup pricefeed, TODO can this be shortened a bit?
-	header := abci.Header{Height: mapp.LastBlockHeight() + 1}
+	header := abci.Header{Height: mapp.LastBlockHeight() + 1, Time: tmtime.Now()}
 	mapp.BeginBlock(abci.RequestBeginBlock{Header: header})
 	ctx := mapp.BaseApp.NewContext(false, header)
 	params := CdpParams{
@@ -35,15 +37,19 @@ func TestApp_CreateModifyDeleteCDP(t *testing.T) {
 	}
 	keeper.SetParams(ctx, params)
 	keeper.SetGlobalDebt(ctx, sdk.NewInt(0))
-	ap := pricefeed.AssetParams{
+	ap := pricefeed.Params{
-		Assets: []pricefeed.Asset{pricefeed.Asset{AssetCode: "xrp", Description: ""}},
+		Assets: []pricefeed.Asset{
+			pricefeed.Asset{
+				AssetCode: "xrp", BaseAsset: "xrp",
+				QuoteAsset: "usd", Oracles: pricefeed.Oracles{}, Active: true},
+		},
 	}
-	pfKeeper.SetAssetParams(ctx, ap)
+	pfKeeper.SetParams(ctx, ap)
 	pfKeeper.SetPrice(
 		ctx, sdk.AccAddress{}, "xrp",
 		sdk.MustNewDecFromStr("1.00"),
-		sdk.NewInt(10))
+		header.Time.Add(time.Hour*1))
-	pfKeeper.SetCurrentPrices(ctx)
+	pfKeeper.SetCurrentPrices(ctx, "xrp")
 	mapp.EndBlock(abci.RequestEndBlock{})
 	mapp.Commit()
 

x/cdp/genesis.go

@@ -9,7 +9,7 @@ import (
 func InitGenesis(ctx sdk.Context, k Keeper, pk PricefeedKeeper, data GenesisState) {
 	// validate denoms - check that any collaterals in the CdpParams are in the pricefeed, pricefeed needs to initgenesis before cdp
 	collateralMap := make(map[string]int)
-	ap := pk.GetAssetParams(ctx)
+	ap := pk.GetParams(ctx)
 	for _, a := range ap.Assets {
 		collateralMap[a.AssetCode] = 1
 	}

x/cdp/keeper/keeper_test.go

@@ -3,6 +3,7 @@ package keeper
 import (
 	"fmt"
 	"testing"
+	"time"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/x/auth"
@@ -12,6 +13,7 @@ import (
 	"github.com/kava-labs/kava/x/pricefeed"
 	"github.com/stretchr/testify/require"
 	abci "github.com/tendermint/tendermint/abci/types"
+	tmtime "github.com/tendermint/tendermint/types/time"
 )
 
 // How could one reduce the number of params in the test cases. Create a table driven test for each of the 4 add/withdraw collateral/debt?
@@ -103,27 +105,29 @@ func TestKeeper_ModifyCDP(t *testing.T) {
 			}
 			mock.SetGenesis(mapp, []authexported.Account{&genAcc})
 			// create a new context
-			header := abci.Header{Height: mapp.LastBlockHeight() + 1}
+			header := abci.Header{Height: mapp.LastBlockHeight() + 1, Time: tmtime.Now()}
 			mapp.BeginBlock(abci.RequestBeginBlock{Header: header})
 			ctx := mapp.BaseApp.NewContext(false, header)
 			keeper.SetParams(ctx, defaultParamsSingle())
 			// setup store state
-			ap := pricefeed.AssetParams{
+			ap := pricefeed.Params{
 				Assets: []pricefeed.Asset{
-					pricefeed.Asset{AssetCode: "xrp", Description: ""},
+					pricefeed.Asset{
+						AssetCode: "xrp", BaseAsset: "xrp",
+						QuoteAsset: "usd", Oracles: pricefeed.Oracles{}, Active: true},
 				},
 			}
-			keeper.pricefeedKeeper.SetAssetParams(ctx, ap)
+			keeper.pricefeedKeeper.SetParams(ctx, ap)
 			_, err := keeper.pricefeedKeeper.SetPrice(
 				ctx, ownerAddr, "xrp",
 				sdk.MustNewDecFromStr(tc.price),
-				sdk.NewInt(ctx.BlockHeight()+10))
+				header.Time.Add(time.Hour*1))
 			if err != nil {
 				t.Log("test context height", ctx.BlockHeight())
 				t.Log(err)
 				t.Log(tc.name)
 			}
-			err = keeper.pricefeedKeeper.SetCurrentPrices(ctx)
+			err = keeper.pricefeedKeeper.SetCurrentPrices(ctx, "xrp")
 			if err != nil {
 				t.Log("test context height", ctx.BlockHeight())
 				t.Log(err)
@@ -144,9 +148,6 @@ func TestKeeper_ModifyCDP(t *testing.T) {
 
 			// get new state for verification
 			actualCDP, found := keeper.GetCDP(ctx, tc.args.owner, tc.args.collateralDenom)
-			if tc.name == "removeTooMuchCollateral" {
-				t.Log(actualCDP.String())
-			}
 
 			// check for err
 			if tc.expectPass {
@@ -180,21 +181,23 @@ func TestKeeper_PartialSeizeCDP(t *testing.T) {
 	testAddr := addrs[0]
 	mock.SetGenesis(mapp, genAccs)
 	// setup pricefeed
-	header := abci.Header{Height: mapp.LastBlockHeight() + 1}
+	header := abci.Header{Height: mapp.LastBlockHeight() + 1, Time: tmtime.Now()}
 	mapp.BeginBlock(abci.RequestBeginBlock{Header: header})
 	ctx := mapp.BaseApp.NewContext(false, header)
 	keeper.SetParams(ctx, defaultParamsSingle())
-	ap := pricefeed.AssetParams{
+	ap := pricefeed.Params{
 		Assets: []pricefeed.Asset{
-			pricefeed.Asset{AssetCode: "xrp", Description: ""},
+			pricefeed.Asset{
+				AssetCode: "xrp", BaseAsset: "xrp",
+				QuoteAsset: "usd", Oracles: pricefeed.Oracles{}, Active: true},
 		},
 	}
-	keeper.pricefeedKeeper.SetAssetParams(ctx, ap)
+	keeper.pricefeedKeeper.SetParams(ctx, ap)
 	keeper.pricefeedKeeper.SetPrice(
 		ctx, sdk.AccAddress{}, collateral,
 		sdk.MustNewDecFromStr("1.00"),
-		i(10))
+		header.Time.Add(time.Hour*1))
-	keeper.pricefeedKeeper.SetCurrentPrices(ctx)
+	keeper.pricefeedKeeper.SetCurrentPrices(ctx, collateral)
 	// Create CDP
 	keeper.SetGlobalDebt(ctx, i(0))
 	err := keeper.ModifyCDP(ctx, testAddr, collateral, i(10), i(5))
@@ -203,8 +206,8 @@ func TestKeeper_PartialSeizeCDP(t *testing.T) {
 	keeper.pricefeedKeeper.SetPrice(
 		ctx, sdk.AccAddress{}, collateral,
 		sdk.MustNewDecFromStr("0.90"),
-		i(10))
+		header.Time.Add(time.Hour*1))
-	keeper.pricefeedKeeper.SetCurrentPrices(ctx)
+	keeper.pricefeedKeeper.SetCurrentPrices(ctx, collateral)
 
 	// Seize entire CDP
 	err = keeper.PartialSeizeCDP(ctx, testAddr, collateral, i(10), i(5))

x/cdp/keeper/test_common.go

@@ -30,7 +30,7 @@ func setUpMockAppWithoutGenesis() (*mock.App, Keeper, []sdk.AccAddress, []crypto
 	keyCDP := sdk.NewKVStoreKey("cdp")
 	keyPriceFeed := sdk.NewKVStoreKey(pricefeed.StoreKey)
 	pk := mapp.ParamsKeeper
-	priceFeedKeeper := pricefeed.NewKeeper(keyPriceFeed, mapp.Cdc, pk.Subspace(pricefeed.DefaultParamspace).WithKeyTable(pricefeed.ParamKeyTable()), pricefeed.DefaultCodespace)
+	priceFeedKeeper := pricefeed.NewKeeper(keyPriceFeed, mapp.Cdc, pk.Subspace(pricefeed.DefaultParamspace), pricefeed.DefaultCodespace)
 	blacklistedAddrs := make(map[string]bool)
 	bankKeeper := bank.NewBaseKeeper(mapp.AccountKeeper, pk.Subspace(bank.DefaultParamspace), bank.DefaultCodespace, blacklistedAddrs)
 	cdpKeeper := NewKeeper(mapp.Cdc, keyCDP, pk.Subspace(types.DefaultParamspace), priceFeedKeeper, bankKeeper)

x/cdp/test_common.go

@@ -28,7 +28,7 @@ func setUpMockAppWithoutGenesis() (*mock.App, Keeper, PricefeedKeeper) {
 	keyCDP := sdk.NewKVStoreKey("cdp")
 	keyPriceFeed := sdk.NewKVStoreKey(pricefeed.StoreKey)
 	pk := mapp.ParamsKeeper
-	priceFeedKeeper := pricefeed.NewKeeper(keyPriceFeed, mapp.Cdc, pk.Subspace(pricefeed.DefaultParamspace).WithKeyTable(pricefeed.ParamKeyTable()), pricefeed.DefaultCodespace)
+	priceFeedKeeper := pricefeed.NewKeeper(keyPriceFeed, mapp.Cdc, pk.Subspace(pricefeed.DefaultParamspace), pricefeed.DefaultCodespace)
 	blacklistedAddrs := make(map[string]bool)
 	bankKeeper := bank.NewBaseKeeper(mapp.AccountKeeper, pk.Subspace(bank.DefaultParamspace), bank.DefaultCodespace, blacklistedAddrs)
 	cdpKeeper := NewKeeper(mapp.Cdc, keyCDP, pk.Subspace(DefaultParamspace), priceFeedKeeper, bankKeeper)

x/cdp/types/expected_keepers.go

@@ -1,6 +1,8 @@
 package types
 
 import (
+	"time"
+
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	pftypes "github.com/kava-labs/kava/x/pricefeed/types"
 )
@@ -14,9 +16,9 @@ type BankKeeper interface {
 
 type PricefeedKeeper interface {
 	GetCurrentPrice(sdk.Context, string) pftypes.CurrentPrice
-	GetAssetParams(sdk.Context) pftypes.AssetParams
+	GetParams(sdk.Context) pftypes.Params
 	// These are used for testing TODO replace mockApp with keeper in tests to remove these
-	SetAssetParams(sdk.Context, pftypes.AssetParams)
+	SetParams(sdk.Context, pftypes.Params)
-	SetPrice(sdk.Context, sdk.AccAddress, string, sdk.Dec, sdk.Int) (pftypes.PostedPrice, sdk.Error)
+	SetPrice(sdk.Context, sdk.AccAddress, string, sdk.Dec, time.Time) (pftypes.PostedPrice, sdk.Error)
-	SetCurrentPrices(sdk.Context) sdk.Error
+	SetCurrentPrices(sdk.Context, string) sdk.Error
 }

x/cdp/types/genesis.go

@@ -1,16 +1,11 @@
 package types
 
-import (
-	sdk "github.com/cosmos/cosmos-sdk/types"
-)
-
 // GenesisState is the state that must be provided at genesis.
 // TODO What is globaldebt and is is separate from the global debt limit in CdpParams
 
 type GenesisState struct {
-	Params     CdpParams `json:"params" yaml:"params"`
+	Params Params `json:"params" yaml:"params"`
-	GlobalDebt sdk.Int   `json:"global_debt" yaml:"global_debt"`
+	CDPs   CDPs   `json:"cdps" yaml:"cdps"`
-	CDPs       CDPs      `json:"cdps" yaml:"cdps"`
 	// don't need to setup CollateralStates as they are created as needed
 }
 
@@ -18,9 +13,8 @@ type GenesisState struct {
 // TODO make this empty, load test values independent
 func DefaultGenesisState() GenesisState {
 	return GenesisState{
-		Params:     DefaultParams(),
+		Params: DefaultParams(),
-		GlobalDebt: sdk.ZeroInt(),
+		CDPs:   CDPs{},
-		CDPs:       CDPs{},
 	}
 }
 

x/cdp/types/params.go

@@ -4,135 +4,166 @@ import (
 	"fmt"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
-	"github.com/cosmos/cosmos-sdk/x/params/subspace"
+	"github.com/cosmos/cosmos-sdk/x/params"
 )
 
-/*
-How this uses the sdk params module:
- - Put all the params for this module in one struct `CDPModuleParams`
- - Store this in the keeper's paramSubspace under one key
- - Provide a function to load the param struct all at once `keeper.GetParams(ctx)`
-It's possible to set individual key value pairs within a paramSubspace, but reading and setting them is awkward (an empty variable needs to be created, then Get writes the value into it)
-This approach will be awkward if we ever need to write individual parameters (because they're stored all together). If this happens do as the sdk modules do - store parameters separately with custom get/set func for each.
-*/
-
-// CdpParams governance parameters for cdp module
-type CdpParams struct {
-	GlobalDebtLimit  sdk.Int
-	CollateralParams []CollateralParams
-	StableDenoms     []string
-}
-
-// CollateralParams governance parameters for each collateral type within the cdp module
-type CollateralParams struct {
-	Denom            string  // Coin name of collateral type
-	LiquidationRatio sdk.Dec // The ratio (Collateral (priced in stable coin) / Debt) under which a CDP will be liquidated
-	DebtLimit        sdk.Int // Maximum amount of debt allowed to be drawn from this collateral type
-	//DebtFloor        sdk.Int // used to prevent dust
-}
-
 // Parameter keys
 var (
 	// ParamStoreKeyAuctionParams Param store key for auction params
-	KeyGlobalDebtLimit  = []byte("GlobalDebtLimit")
+	KeyGlobalDebtLimit      = []byte("GlobalDebtLimit")
-	KeyCollateralParams = []byte("CollateralParams")
+	KeyCollateralParams     = []byte("CollateralParams")
-	KeyStableDenoms     = []byte("StableDenoms")
+	KeyDebtParams           = []byte("DebtParams")
+	DefaultGlobalDebt       = sdk.Coins{}
+	DefaultCircuitBreaker   = false
+	DefaultCollateralParams = CollateralParams{}
+	DefaultDebtParams       = DebtParams{}
 )
 
+// Params governance parameters for cdp module
+type Params struct {
+	CollateralParams CollateralParams `json:"collateral_params" yaml:"collateral_params"`
+	DebtParams       DebtParams       `json:"debt_params" yaml:"debt_params"`
+	GlobalDebtLimit  sdk.Coins        `json:"global_debt_limit" yaml:"global_debt_limit"`
+	CircuitBreaker   bool             `json:"circuit_breaker" yaml:"circuit_breaker"`
+}
+
+// String implements fmt.Stringer
+func (p Params) String() string {
+	return fmt.Sprintf(`Params:
+	Global Debt Limit: %s
+	Collateral Params: %s
+	Debt Params: %s
+	Circuit Breaker: %t`,
+		p.GlobalDebtLimit, p.CollateralParams, p.DebtParams, p.CircuitBreaker,
+	)
+}
+
+// NewParams returns a new params object
+func NewParams(debtLimit sdk.Coins, collateralParams CollateralParams, debtParams DebtParams, breaker bool) Params {
+	return Params{
+		GlobalDebtLimit:  debtLimit,
+		CollateralParams: collateralParams,
+		DebtParams:       debtParams,
+		CircuitBreaker:   breaker,
+	}
+}
+
+// DefaultParams returns default params for cdp module
+func DefaultParams() Params {
+	return NewParams(DefaultGlobalDebt, DefaultCollateralParams, DefaultDebtParams, DefaultCircuitBreaker)
+}
+
+// CollateralParam governance parameters for each collateral type within the cdp module
+type CollateralParam struct {
+	Denom            string    `json:"denom" yaml:"denom"`                         // Coin name of collateral type
+	LiquidationRatio sdk.Dec   `json:"liquidation_ratio" yaml:"liquidation_ratio"` // The ratio (Collateral (priced in stable coin) / Debt) under which a CDP will be liquidated
+	DebtLimit        sdk.Coins `json:"debt_limit" yaml:"debt_limit"`               // Maximum amount of debt allowed to be drawn from this collateral type
+	//DebtFloor        sdk.Int // used to prevent dust
+}
+
+// String implements fmt.Stringer
+func (cp CollateralParam) String() string {
+	return fmt.Sprintf(`Collateral:
+	Denom: %s
+	LiquidationRatio: %s
+	DebtLimit: %s`, cp.Denom, cp.LiquidationRatio, cp.DebtLimit)
+}
+
+// CollateralParams array of CollateralParam
+type CollateralParams []CollateralParam
+
+// String implements fmt.Stringer
+func (cps CollateralParams) String() string {
+	out := "Collateral Params\n"
+	for _, cp := range cps {
+		out += fmt.Sprintf("%s\n", cp)
+	}
+	return out
+}
+
+// DebtParam governance params for debt assets
+type DebtParam struct {
+	Denom          string    `json:"denom" yaml:"denom"`
+	ReferenceAsset string    `json:"reference_asset" yaml:"reference_asset"`
+	DebtLimit      sdk.Coins `json:"debt_limit" yaml:"debt_limit"`
+}
+
+func (dp DebtParam) String() string {
+	return fmt.Sprintf(`Debt:
+	Denom: %s
+	ReferenceAsset: %s
+	DebtLimit: %s`, dp.Denom, dp.ReferenceAsset, dp.DebtLimit)
+}
+
+// DebtParams array of DebtParam
+type DebtParams []DebtParam
+
+// String implements fmt.Stringer
+func (dps DebtParams) String() string {
+	out := "Debt Params\n"
+	for _, dp := range dps {
+		out += fmt.Sprintf("%s\n", dp)
+	}
+	return out
+}
+
 // ParamKeyTable Key declaration for parameters
-func ParamKeyTable() subspace.KeyTable {
+func ParamKeyTable() params.KeyTable {
-	return subspace.NewKeyTable().RegisterParamSet(&CdpParams{})
+	return params.NewKeyTable().RegisterParamSet(&Params{})
 }
 
 // ParamSetPairs implements the ParamSet interface and returns all the key/value pairs
 // pairs of auth module's parameters.
 // nolint
-func (p *CdpParams) ParamSetPairs() subspace.ParamSetPairs {
+func (p *Params) ParamSetPairs() params.ParamSetPairs {
-	return subspace.ParamSetPairs{
+	return params.ParamSetPairs{
 		{KeyGlobalDebtLimit, &p.GlobalDebtLimit},
 		{KeyCollateralParams, &p.CollateralParams},
-		{KeyStableDenoms, &p.StableDenoms},
+		{KeyDebtParams, &p.DebtParams},
 	}
 }
 
-// String implements fmt.Stringer
-func (p CdpParams) String() string {
-	out := fmt.Sprintf(`Params:
-	Global Debt Limit: %s
-	Collateral Params:`,
-		p.GlobalDebtLimit,
-	)
-	for _, cp := range p.CollateralParams {
-		out += fmt.Sprintf(`
-		%s
-			Liquidation Ratio: %s
-			Debt Limit:        %s`,
-			cp.Denom,
-			cp.LiquidationRatio,
-			cp.DebtLimit,
-		)
-	}
-	return out
-}
-
-// GetCollateralParams returns params for a specific collateral denom
-func (p CdpParams) GetCollateralParams(collateralDenom string) CollateralParams {
-	// search for matching denom, return
-	for _, cp := range p.CollateralParams {
-		if cp.Denom == collateralDenom {
-			return cp
-		}
-	}
-	// panic if not found, to be safe
-	panic("collateral params not found in module params")
-}
-
-// IsCollateralPresent returns true if the denom is among the collaterals in cdp module
-func (p CdpParams) IsCollateralPresent(collateralDenom string) bool {
-	// search for matching denom, return
-	for _, cp := range p.CollateralParams {
-		if cp.Denom == collateralDenom {
-			return true
-		}
-	}
-	return false
-}
-
 // Validate checks that the parameters have valid values.
-func (p CdpParams) Validate() error {
+func (p Params) Validate() error {
+	debtDenoms := make(map[string]int)
+	debtParamsDebtLimit := sdk.Coins{}
+	for _, dp := range p.DebtParams {
+		_, found := debtDenoms[dp.Denom]
+		if found {
+			return fmt.Errorf("duplicate debt denom: %s", dp.Denom)
+		}
+		debtDenoms[dp.Denom] = 1
+		if dp.DebtLimit.IsAnyNegative() {
+			return fmt.Errorf("debt limit for all debt tokens should be positive, is %s for %s", dp.DebtLimit, dp.Denom)
+		}
+		debtParamsDebtLimit = debtParamsDebtLimit.Add(dp.DebtLimit)
+	}
+	if debtParamsDebtLimit.IsAnyGT(p.GlobalDebtLimit) {
+		fmt.Errorf("debt limit exceeds global debt limit:\n\tglobal debt limit: %s\n\tdebt limits: %s",
+			p.GlobalDebtLimit, debtParamsDebtLimit)
+	}
+
 	collateralDupMap := make(map[string]int)
-	denomDupMap := make(map[string]int)
+	collateralParamsDebtLimit := sdk.Coins{}
-	for _, collateral := range p.CollateralParams {
+	for _, cp := range p.CollateralParams {
-		_, found := collateralDupMap[collateral.Denom]
+		_, found := collateralDupMap[cp.Denom]
 		if found {
-			return fmt.Errorf("duplicate denom: %s", collateral.Denom)
+			return fmt.Errorf("duplicate collateral denom: %s", cp.Denom)
 		}
-		collateralDupMap[collateral.Denom] = 1
+		collateralDupMap[cp.Denom] = 1
 
-		if collateral.DebtLimit.IsNegative() {
+		if cp.DebtLimit.IsAnyNegative() {
-			return fmt.Errorf("debt limit should be positive, is %s for %s", collateral.DebtLimit, collateral.Denom)
+			return fmt.Errorf("debt limit for all collaterals should be positive, is %s for %s", cp.DebtLimit, cp.Denom)
 		}
-
+		collateralParamsDebtLimit = collateralParamsDebtLimit.Add(cp.DebtLimit)
-		// TODO do we want to enforce overcollateralization at this level? -- probably not, as it's technically a governance thing (kevin)
 	}
-	if p.GlobalDebtLimit.IsNegative() {
+	if collateralParamsDebtLimit.IsAnyGT(p.GlobalDebtLimit) {
-		return fmt.Errorf("global debt limit should be positive, is %s", p.GlobalDebtLimit)
+		fmt.Errorf("collateral debt limit exceeds global debt limit:\n\tglobal debt limit: %s\n\tcollateral debt limits: %s",
+			p.GlobalDebtLimit, collateralParamsDebtLimit)
 	}
 
-	for _, denom := range p.StableDenoms {
+	if p.GlobalDebtLimit.IsAnyNegative() {
-		_, found := denomDupMap[denom]
+		return fmt.Errorf("global debt limit should be positive for all debt tokens, is %s", p.GlobalDebtLimit)
-		if found {
-			return fmt.Errorf("duplicate stable denom: %s", denom)
-		}
-		denomDupMap[denom] = 1
 	}
 	return nil
 }
-
-func DefaultParams() CdpParams {
-	return CdpParams{
-		GlobalDebtLimit:  sdk.NewInt(0),
-		CollateralParams: []CollateralParams{},
-		StableDenoms:     []string{"usdx"},
-	}
-}

x/cdp/types/types.go

@@ -3,6 +3,7 @@ package types
 import (
 	"fmt"
 	"strings"
+	"time"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
@@ -15,27 +16,41 @@ type CDP struct {
 	//ID             []byte                                    // removing IDs for now to make things simpler
 	Owner            sdk.AccAddress `json:"owner" yaml:"owner"`                         // Account that authorizes changes to the CDP
 	CollateralDenom  string         `json:"collateral_denom" yaml:"collateral_denom"`   // Type of collateral stored in this CDP
-	CollateralAmount sdk.Int        `json:"collateral_amount" yaml:"collateral_amount"` // Amount of collateral stored in this CDP
+	CollateralAmount sdk.Coins      `json:"collateral_amount" yaml:"collateral_amount"` // Amount of collateral stored in this CDP
-	Debt             sdk.Int        `json:"debt" yaml:"debt"`                           // Amount of stable coin drawn from this CDP
+	Debt             sdk.Coins      `json:"debt" yaml:"debt"`
+	AccumulatedFees  sdk.Coins      `json:"accumulated_fees" yaml:"accumulated_fees"`
+	FeesUpdated      time.Time      `json:"fees_updated" yaml:"fees_updated"` // Amount of stable coin drawn from this CDP
 }
 
+// IsUnderCollateralized checks if cdp is below the liquidation ratio
 func (cdp CDP) IsUnderCollateralized(price sdk.Dec, liquidationRatio sdk.Dec) bool {
-	collateralValue := sdk.NewDecFromInt(cdp.CollateralAmount).Mul(price)
+	collateralValue := sdk.NewDecFromInt(cdp.CollateralAmount.AmountOf(cdp.CollateralDenom)).Mul(price)
-	minCollateralValue := liquidationRatio.Mul(sdk.NewDecFromInt(cdp.Debt))
+	minCollateralValue := sdk.NewDec(0)
+	for _, c := range cdp.Debt {
+		minCollateralValue = minCollateralValue.Add(liquidationRatio.Mul(c.Amount.ToDec()))
+	}
 	return collateralValue.LT(minCollateralValue) // TODO LT or LTE?
 }
 
+// String implements fmt.stringer
 func (cdp CDP) String() string {
 	return strings.TrimSpace(fmt.Sprintf(`CDP:
   Owner:      %s
-  Collateral: %s
+	Collateral Type: %s
-  Debt:       %s`,
+	Collateral: %s
+	Debt: %s
+	Fees: %s
+	Fees Last Updated: %s`,
 		cdp.Owner,
-		sdk.NewCoin(cdp.CollateralDenom, cdp.CollateralAmount),
+		cdp.CollateralDenom,
-		sdk.NewCoin("usdx", cdp.Debt),
+		cdp.CollateralAmount,
+		cdp.Debt,
+		cdp.AccumulatedFees,
+		cdp.FeesUpdated,
 	))
 }
 
+// CDPs array of CDP
 type CDPs []CDP
 
 // String implements stringer
@@ -52,22 +67,23 @@ type ByCollateralRatio CDPs
 
 func (cdps ByCollateralRatio) Len() int      { return len(cdps) }
 func (cdps ByCollateralRatio) Swap(i, j int) { cdps[i], cdps[j] = cdps[j], cdps[i] }
-func (cdps ByCollateralRatio) Less(i, j int) bool {
+
-	// Sort by "collateral ratio" ie collateralAmount/Debt
+// func (cdps ByCollateralRatio) Less(i, j int) bool {
-	// The comparison is: collat_i/debt_i < collat_j/debt_j
+// 	// Sort by "collateral ratio" ie collateralAmount/Debt
-	// But to avoid division this can be rearranged to: collat_i*debt_j < collat_j*debt_i
+// 	// The comparison is: collat_i/debt_i < collat_j/debt_j
-	// Provided the values are positive, so check for positive values.
+// 	// But to avoid division this can be rearranged to: collat_i*debt_j < collat_j*debt_i
-	if cdps[i].CollateralAmount.IsNegative() ||
+// 	// Provided the values are positive, so check for positive values.
-		cdps[i].Debt.IsNegative() ||
+// 	if cdps[i].CollateralAmount.IsNegative() ||
-		cdps[j].CollateralAmount.IsNegative() ||
+// 		cdps[i].Debt.IsNegative() ||
-		cdps[j].Debt.IsNegative() {
+// 		cdps[j].CollateralAmount.IsNegative() ||
-		panic("negative collateral and debt not supported in CDPs")
+// 		cdps[j].Debt.IsNegative() {
-	}
+// 		panic("negative collateral and debt not supported in CDPs")
-	// TODO overflows could cause panics
+// 	}
-	left := cdps[i].CollateralAmount.Mul(cdps[j].Debt)
+// 	// TODO overflows could cause panics
-	right := cdps[j].CollateralAmount.Mul(cdps[i].Debt)
+// 	left := cdps[i].CollateralAmount.Mul(cdps[j].Debt)
-	return left.LT(right)
+// 	right := cdps[j].CollateralAmount.Mul(cdps[i].Debt)
-}
+// 	return left.LT(right)
+// }
 
 // CollateralState stores global information tied to a particular collateral type.
 type CollateralState struct {

x/pricefeed/types/params.go

@@ -5,7 +5,7 @@ import (
 	"strings"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
-	params "github.com/cosmos/cosmos-sdk/x/params/subspace"
+	"github.com/cosmos/cosmos-sdk/x/params"
 )
 
 var (