From d13f2956ac4022f6c0c0ef17d833cf749b4395eb Mon Sep 17 00:00:00 2001
From: turtlebasket <turtlebasket@gmail.com>
Date: Sun, 28 Aug 2022 20:28:25 +0000
Subject: [PATCH] basic auction bidding system

---
 x/cosmostest/keeper/msg_server_new_bid.go | 39 +++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/x/cosmostest/keeper/msg_server_new_bid.go b/x/cosmostest/keeper/msg_server_new_bid.go
index 80b4311..c5300df 100644
--- a/x/cosmostest/keeper/msg_server_new_bid.go
+++ b/x/cosmostest/keeper/msg_server_new_bid.go
@@ -2,16 +2,51 @@ package keeper
 
 import (
 	"context"
+	"fmt"
+	"math/big"
 
 	"cosmos-test/x/cosmostest/types"
+
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
 func (k msgServer) NewBid(goCtx context.Context, msg *types.MsgNewBid) (*types.MsgNewBidResponse, error) {
 	ctx := sdk.UnwrapSDKContext(goCtx)
 
-	// TODO: Handling the message
-	_ = ctx
+	auction, found := k.Keeper.GetAuction(ctx, msg.AuctionIndex)
+	if !found {
+		return nil, fmt.Errorf("didn't find auction of index %s", msg.AuctionIndex)
+	}
+
+	ok := false
+	amt := new(big.Int)
+	amt, ok = amt.SetString(msg.Amount, 10)
+	if !ok {
+		return nil, fmt.Errorf("failed to convert `%s` to a large integer", msg.Amount)
+	}
+	if amt.Sign() != 1 {
+		return nil, fmt.Errorf("bid amount must be greater than 0")
+	}
+
+	amtPrev := big.NewInt(0)
+	if len(auction.Bids) > 0 {
+		// shouldn't need to check validity, because we assume it's checked
+		// before approving & inserting the bid
+		latestBid := auction.Bids[len(auction.Bids)-1]
+		amtPrev, _ = amtPrev.SetString(latestBid.Amount, 10)
+	}
+
+	if amt.Cmp(amtPrev) < 1 {
+		return nil, fmt.Errorf("bid amount must be greater than largest bid")
+	}
+
+	bid := &types.Bid{
+		Amount: msg.Amount,
+		Owner:  msg.Creator,
+	}
+	auction.Bids = append(auction.Bids, bid)
+
+	k.Keeper.SetAuction(ctx, auction)
 
 	return &types.MsgNewBidResponse{}, nil
 }