message_server_withdraw_donation.go

package keeper
import (
  "context"
  "fmt"
  "strconv"
  "github.com/cosmonaut/gofundme/x/gofundme/types"
   sdk "github.com/cosmos/cosmos-sdk/types"
   sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
)

func (k msgServer) WithdrawDonation(goCtx context.Context, msg *types.MsgWithdrawDonation) (*types.MsgWithdrawDonationResponse, error) {
   ctx := sdk.UnwrapSDKContext(goCtx)
  
   //Get the gofundme campaign with the given id
   gofundme, found := k.GetGofundme(ctx, msg.Id)
   if !found {
    return nil, sdkerrors.Wrapf(sdkerrors.ErrKeyNotFound, "gofundme with id %s not found", msg.Id)
   }
   
   //Confirm that the donations have not been claimed
   if gofundme.Claim == true {
    return nil, sdkerrors.Wrapf(sdkerrors.ErrUnauthorized, "gofundme with id %s has already been claimed", msg.Id)
   }
  
   //Get the end date
   end, err := sdk.ParseTimeBytes([]byte(gofundme.End))
   if err != nil {
     return nil, sdkerrors.Wrap(sdkerrors.ErrInvalidRequest, "Can't withdraw donations until the end of the gofundme campaign.")
   }
  
   //Check whether the current time is after the end date
   if ctx.BlockTime().Before(end) {
    return nil, sdkerrors.Wrap(sdkerrors.ErrInvalidRequest, "gofundme campaign is not over. Please wait until the end date")
   }
  
   //Get gofundme creator and message sender
   creator := sdk.AccAddress(gofundme.Creator)
   messageSender := sdk.AccAddress(msg.Creator)
  
   //Get total donations and gofundme goal
   totalDonations := gofundme.Totaldonations
   goal := gofundme.Goal
   stringTotalDonation := strconv.FormatUint(totalDonations, 10)
   normalizedTotalDonation, _ := sdk.ParseCoinsNormalized(stringTotalDonation)
   fmt.Print(creator, messageSender)
  
   //Ensure that creator can withdraw only if the goal was met
   if creator.Equals(messageSender) && totalDonations < goal {
    return nil, sdkerrors.Wrap(sdkerrors.ErrInvalidRequest, "Can't withdraw donations because goal wasn't met.")
   }
   if creator.Equals(messageSender) && totalDonations >= goal {
     //update claim to true
     gofundme.Claim = true
     sdkError := k.bankKeeper.SendCoinsFromModuleToAccount(ctx, types.ModuleName, creator, normalizedTotalDonation)
     if sdkError != nil {
      return nil, sdkError
     }
   }
  
   //Ensure that donor can withdraw only if goal wasn't met
   if !creator.Equals(messageSender) && totalDonations >= goal {
    return nil, sdkerrors.Wrap(sdkerrors.ErrUnauthorized, "Only the owner of the crowdfund can withdraw donations")
   }
  
   if !creator.Equals(messageSender) && totalDonations < goal {
     var index int
     for idx, v := range gofundme.Donation {
       if v == msg.Creator {
         index = idx
         break
       }
      }
  
     donation := gofundme.Donation[index]
     normalizedDonation, _ := sdk.ParseCoinsNormalized(donation)

     //Ensure that donor can only withdraw once
     if normalizedDonation.IsZero() {
      return nil, sdkerrors.Wrap(sdkerrors.ErrInvalidRequest, "Donation already withdrawn")
     }

     //Update the donation amount to zero to reflect that the donation was withdrawn
     gofundme.Donation[index] = "0"
     sdkError := k.bankKeeper.SendCoinsFromModuleToAccount(ctx, types.ModuleName, messageSender, normalizedDonation)
     if sdkError != nil {
      return nil, sdkError
     }
   }
  
   k.SetGofundme(ctx, gofundme)
   return &types.MsgWithdrawDonationResponse{}, nil
}