added keeper reveal solution

Author: nashqueue

x/scavenge/keeper/msg_server_reveal_solution.go

@@ -1,17 +1,90 @@
+// x/scavenge/keeper/msg_server_reveal_solution.go
+
 package keeper
 
 import (
 	"context"
+	"crypto/sha256"
+	"encoding/hex"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	"github.com/tendermint/tendermint/crypto"
+
 	"scavenge/x/scavenge/types"
 )
 
 func (k msgServer) RevealSolution(goCtx context.Context, msg *types.MsgRevealSolution) (*types.MsgRevealSolutionResponse, error) {
 	ctx := sdk.UnwrapSDKContext(goCtx)
 
-	// TODO: Handling the message
-	_ = ctx
+	// concatenate a solution and a scavenger address and convert it to bytes
+	var solutionScavengerBytes = []byte(msg.Solution + msg.Creator)
+
+	// find the hash of solution and address
+	var solutionScavengerHash = sha256.Sum256(solutionScavengerBytes)
+
+	// convert the hash to a string
+	var solutionScavengerHashString = hex.EncodeToString(solutionScavengerHash[:])
+
+	// try getting a commit using the the hash of solution and address
+	_, isFound := k.GetCommit(ctx, solutionScavengerHashString)
+
+	// return an error if a commit doesn't exist
+	if !isFound {
+		return nil, sdkerrors.Wrap(sdkerrors.ErrInvalidRequest, "Commit with that hash doesn't exists")
+	}
+
+	// find a hash of the solution
+	var solutionHash = sha256.Sum256([]byte(msg.Solution))
+
+	// encode the solution hash to string
+	var solutionHashString = hex.EncodeToString(solutionHash[:])
+	var scavenge types.Scavenge
+
+	// get a scavenge from the stre using the solution hash
+	scavenge, isFound = k.GetScavenge(ctx, solutionHashString)
+
+	// return an error if the solution doesn't exist
+	if !isFound {
+		return nil, sdkerrors.Wrap(sdkerrors.ErrInvalidRequest, "Scavenge with that solution hash doesn't exists")
+	}
+
+	// check that the scavenger property contains a valid address
+	_, err := sdk.AccAddressFromBech32(scavenge.Scavenger)
+
+	// return an error if a scavenge has already been solved
+	if err == nil {
+		return nil, sdkerrors.Wrap(sdkerrors.ErrInvalidRequest, "Scavenge has already been solved")
+	}
+
+	// save the scavebger address to the scavenge
+	scavenge.Scavenger = msg.Creator
+
+	// save the correct solution to the scavenge
+	scavenge.Solution = msg.Solution
+
+	// get address of the module account
+	moduleAcct := sdk.AccAddress(crypto.AddressHash([]byte(types.ModuleName)))
+
+	// convert scavenger address from string to sdk.AccAddress
+	scavenger, err := sdk.AccAddressFromBech32(scavenge.Scavenger)
+	if err != nil {
+		panic(err)
+	}
+
+	// parse tokens from a string to sdk.Coins
+	reward, err := sdk.ParseCoinsNormalized(scavenge.Reward)
+	if err != nil {
+		panic(err)
+	}
+
+	// send tokens from a module account to the scavenger
+	sdkError := k.bankKeeper.SendCoins(ctx, moduleAcct, scavenger, reward)
+	if sdkError != nil {
+		return nil, sdkError
+	}
 
+	// save the udpated scavenge to the store
+	k.SetScavenge(ctx, scavenge)
 	return &types.MsgRevealSolutionResponse{}, nil
 }