added keeper commit solution

Author: nashqueue

x/scavenge/keeper/msg_server_commit_solution.go

@@ -1,17 +1,35 @@
+// x/scavenge/keeper/msg_server_commit_solution.go
+
 package keeper
 
 import (
 	"context"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+
 	"scavenge/x/scavenge/types"
 )
 
 func (k msgServer) CommitSolution(goCtx context.Context, msg *types.MsgCommitSolution) (*types.MsgCommitSolutionResponse, error) {
 	ctx := sdk.UnwrapSDKContext(goCtx)
 
-	// TODO: Handling the message
-	_ = ctx
+	// create a new commit from the information in the MsgCommitSolution message
+	var commit = types.Commit{
+		Index:                 msg.SolutionScavengerHash,
+		SolutionHash:          msg.SolutionHash,
+		SolutionScavengerHash: msg.SolutionScavengerHash,
+	}
+
+	// try getting a commit from the store using the solution+scavenger hash as the key
+	_, isFound := k.GetCommit(ctx, commit.SolutionScavengerHash)
+
+	// return an error if a commit already exists in the store
+	if isFound {
+		return nil, sdkerrors.Wrap(sdkerrors.ErrInvalidRequest, "Commit with that hash already exists")
+	}
 
+	// write commit to the store
+	k.SetCommit(ctx, commit)
 	return &types.MsgCommitSolutionResponse{}, nil
 }