package keeper

import (
	"context"
	"errors"
	"fmt"
	"math/big"
	"reflect"

	"colinear/x/colinearcore/memdb"
	"colinear/x/colinearcore/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)

	lockedUsers, ok := k.Keeper.GetLockedUsers(ctx)
	if !ok {
		return nil, errors.New("unable to read locked providers (uninitialized)")
	}
	if lockedAmtStr, ok := lockedUsers.Users[msg.Creator]; !ok {
		return nil, fmt.Errorf("provider has not locked CLR tokens (min: %d uCLR)", k.GetParams(ctx).ProviderMinLockedUClr)
	} else {
		lockedAmt := new(big.Int)
		lockedAmt.SetString(lockedAmtStr, 10)
		required := big.NewInt(int64(k.GetParams(ctx).ProviderMinLockedUClr))
		if lockedAmt.Cmp(required) == -1 {
			return nil, fmt.Errorf("provider has not locked enough CLR tokens (min: %d uCLR, locked: %s)", k.GetParams(ctx).ProviderMinLockedUClr, lockedAmt.String())
		}
	}

	auction, found := k.Keeper.GetAuction(ctx, msg.AuctionIndex)
	if !found {
		return nil, fmt.Errorf("didn't find auction of index %s", msg.AuctionIndex)
	}

	auctionExpired, err := k.Keeper.AuctionIsExpired(ctx, msg.AuctionIndex)
	if err != nil {
		return nil, fmt.Errorf("error while checking auction %s expiry status: %s", msg.AuctionIndex, err)
	}
	if auctionExpired {
		return nil, fmt.Errorf("auction %s is expired", msg.AuctionIndex)
	}

	if verProvs, err := memdb.AuctionDB.GetVerifiedProviders(msg.AuctionIndex); err == nil {
		if len(verProvs) == 0 {
			goto bidderVerified
		} else {
			for _, provider := range verProvs {
				if msg.Creator == provider {
					goto bidderVerified
				}
			}
			return nil, fmt.Errorf("bid sender is not verified by the creator of auction %s", auction.Index)
		}
	}

bidderVerified:

	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")
	}

	ceiling := new(big.Int)
	ceiling.SetString(auction.Ceiling, 10)
	if amt.Cmp(ceiling) == 1 {
		return nil, fmt.Errorf("bid amount cannot be greater than auction price ceiling (%s)", auction.Ceiling)
	}

	lowestBid, err := memdb.AuctionDB.GetLowestBid(msg.AuctionIndex)
	// we manually handle KeyNotFound in GetHighestBid, so should return (nil, nil) if not found
	if err != nil {
		return nil, fmt.Errorf("failed to get lowest bid: %s", reflect.TypeOf(err))
	}

	if lowestBid != nil {
		amtPrev := new(big.Int)
		amtPrev, ok = amtPrev.SetString(lowestBid.Amount, 10)
		if !ok { // this should have been checked before, but whatever
			return nil, fmt.Errorf("failed to convert max bid (%s) to a large integer", msg.Amount)
		}

		if amt.Cmp(amtPrev) != -1 {
			return nil, fmt.Errorf("bid amount must be less than current lowest bid (%s)", amtPrev)
		}
	}

	// check that user has locked minimum required CLR

	bid := &types.Bid{
		Amount: msg.Amount,
		Owner:  msg.Creator,
	}

	if err := memdb.AuctionDB.AddBid(msg.AuctionIndex, bid); err != nil {
		return nil, fmt.Errorf("failed to add bid: %s", err)
	}

	// emit bid event

	ctx.EventManager().EmitEvent(
		sdk.NewEvent(types.BidCreatedEventType,
			sdk.NewAttribute(types.BidCreatedEventCreator, msg.Creator),
			sdk.NewAttribute(types.BidCreatedAuctionIndex, msg.AuctionIndex),
			sdk.NewAttribute(types.BidCreatedAmount, msg.Amount),
		),
	)

	return &types.MsgNewBidResponse{}, nil
}