feat: Airdrop Getters (#19)

* airdrop getters

* update GetClaimStatus test and add docs

* update test

* remove pointer receivers

* build airdrop from json string

* pure param getters

* strconv

* json example

airdrop/getter.gno

@@ -117,6 +117,20 @@ func GetClaimStatus(jsonStr string, claimID uint64) string {
 }
 
 // AirdropToJSON converts an Airdrop struct to a JSON string.
+//
+// Example:
+//
+// {
+// "config": {
+// "refundable_timestamp": "1234567890",
+// "refund_to": "g1234567890abcdefghijklmnop"
+// },
+// "address": "g1234567890abcdefghijklmnop",
+// "claimed_bitmap": { // ref: getter_test.gno/TestAirdropToJSONAndCreateAirdropFromJSON
+// "0": "101",
+// "1": "1101",
+// },
+// }
 func AirdropToJSON(a *Airdrop) string {
  node := json.ObjectNode("", nil)
 
@@ -166,7 +180,7 @@ func createAirdropFromJSON(jsonStr string) *Airdrop {
  configNode := node.MustKey("config")
 
  timestamp := configNode.MustKey("refundable_timestamp").MustString()
- refundableTimestamp, err := parseUint(timestamp, 10, 64)
+ refundableTimestamp, err := strconv.Atoi(timestamp)
  if err != nil {
  panic(err)
  }
@@ -180,20 +194,20 @@ func createAirdropFromJSON(jsonStr string) *Airdrop {
  claimedBitmap := make(map[uint64]uint64)
 
  claimedBitmapNode.ObjectEach(func(key string, value *json.Node) {
- index, err := parseUint(key, 10, 64)
+ index, err := strconv.Atoi(key)
  if err != nil {
  panic(err)
  }
  bitmap, err := parseUint(value.MustString(), 2, 64)
  if err != nil {
  panic(err)
  }
- claimedBitmap[index] = bitmap
+ claimedBitmap[uint64(index)] = bitmap
  })
 
  return &Airdrop{
  config: Config{
- RefundableTimestamp: refundableTimestamp,
+ RefundableTimestamp: uint64(refundableTimestamp),
  RefundTo: refundTo,
  },
  address: address,