;; Simple wallet smart contract

_ unpack_state() inline_ref {
  var ds = begin_parse(get_data());
  var res = (ds~load_uint(32), ds~load_uint(8), ds~load_uint(8), ds~load_uint(64), ds~load_dict(), ds~load_dict());
  ds.end_parse();
  return res;
}

_ pack_state(cell pending_queries, cell owner_infos, int last_cleaned, int k, int n, int wallet_id) inline_ref {
  return begin_cell()
    .store_uint(wallet_id, 32)
    .store_uint(n, 8)
    .store_uint(k, 8)
    .store_uint(last_cleaned, 64)
    .store_dict(owner_infos)
    .store_dict(pending_queries)
  .end_cell();
}

_ pack_owner_info(int public_key, int flood) inline_ref {
  return begin_cell()
    .store_uint(public_key, 256)
    .store_uint(flood, 8);
}

_ unpack_owner_info(slice cs) inline_ref {
  return (cs~load_uint(256), cs~load_uint(8));
}

(int, int) check_signatures(cell public_keys, cell signatures, int hash, int cnt_bits) inline_ref {
  int cnt = 0;
  
  do {
    slice cs = signatures.begin_parse();
    slice signature = cs~load_bits(512);

    int i = cs~load_uint(8);
    signatures = cs~load_dict();

    (slice public_key, var found?) = public_keys.udict_get?(8, i);
    throw_unless(37, found?);
    throw_unless(38, check_signature(hash, signature, public_key.preload_uint(256)));

    int mask = (1 << i);
    int old_cnt_bits = cnt_bits;
    cnt_bits |= mask;
    int should_check = cnt_bits != old_cnt_bits;
    cnt -= should_check;
  } until (cell_null?(signatures));

  return (cnt, cnt_bits);
}

() recv_internal(slice in_msg) impure {
  ;; do nothing for internal messages
}

(int, int, int, slice) unpack_query_data(slice in_msg, int n, slice query, var found?, int root_i) inline_ref {
  if (found?) {
    throw_unless(35, query~load_int(1));
    (int creator_i, int cnt, int cnt_bits, slice msg) = (query~load_uint(8), query~load_uint(8), query~load_uint(n), query);
    throw_unless(36, slice_hash(msg) == slice_hash(in_msg));
    return (creator_i, cnt, cnt_bits, msg);
  }
  return (root_i, 0, 0, in_msg);
}

(cell, ()) dec_flood(cell owner_infos, int creator_i) {
  (slice owner_info, var found?) = owner_infos.udict_get?(8, creator_i);
  (int public_key, int flood) = unpack_owner_info(owner_info);
  owner_infos~udict_set_builder(8, creator_i, pack_owner_info(public_key, flood - 1));
  return (owner_infos, ());
}

() try_init() impure inline_ref {
  ;; first query without signatures is always accepted
  (int wallet_id, int n, int k, int last_cleaned, cell owner_infos, cell pending_queries) = unpack_state();
  throw_if(37, last_cleaned);
  accept_message();
  set_data(pack_state(pending_queries, owner_infos, 1, k, n, wallet_id));
}

(cell, cell) update_pending_queries(cell pending_queries, cell owner_infos, slice msg, int query_id, int creator_i, int cnt, int cnt_bits, int n, int k) impure inline_ref {
  if (cnt >= k) {
    accept_message();
    while (msg.slice_refs()) {
      var mode = msg~load_uint(8);
      send_raw_message(msg~load_ref(), mode);
    }
    pending_queries~udict_set_builder(64, query_id, begin_cell().store_int(0, 1));
    owner_infos~dec_flood(creator_i);
  } else {
    pending_queries~udict_set_builder(64, query_id, begin_cell()
      .store_uint(1, 1)
      .store_uint(creator_i, 8)
      .store_uint(cnt, 8)
      .store_uint(cnt_bits, n)
      .store_slice(msg));
  }
  return (pending_queries, owner_infos);
}

(int, int) calc_boc_size(int cells, int bits, slice root) {
  cells += 1;
  bits += root.slice_bits();

  while (root.slice_refs()) {
    (cells, bits) = calc_boc_size(cells, bits, root~load_ref().begin_parse());
  }

  return (cells, bits);
}

() recv_external(slice in_msg) impure {
  ;; empty message triggers init
  if (slice_empty?(in_msg)) {
    return try_init();
  }

  ;; Check root signature
  slice root_signature = in_msg~load_bits(512);
  int root_hash = slice_hash(in_msg);
  int root_i = in_msg~load_uint(8);

  (int wallet_id, int n, int k, int last_cleaned, cell owner_infos, cell pending_queries) = unpack_state();
  last_cleaned -= last_cleaned == 0;

  (slice owner_info, var found?) = owner_infos.udict_get?(8, root_i);
  throw_unless(31, found?);
  (int public_key, int flood) = unpack_owner_info(owner_info);
  throw_unless(32, check_signature(root_hash, root_signature, public_key));

  cell signatures = in_msg~load_dict();

  var hash = slice_hash(in_msg);
  int query_wallet_id = in_msg~load_uint(32);
  throw_unless(42, query_wallet_id == wallet_id);

  int query_id = in_msg~load_uint(64);

  (int cnt, int bits) = calc_boc_size(0, 0, in_msg);
  throw_if(40, (cnt > 8) | (bits > 2048));

  (slice query, var found?) = pending_queries.udict_get?(64, query_id);

  ifnot (found?) {
    flood += 1;
    throw_if(39, flood > 10);
  }

  var bound = (now() << 32);
  throw_if(33, query_id < bound);

  (int creator_i, int cnt, int cnt_bits, slice msg) = unpack_query_data(in_msg, n, query, found?, root_i);
  int mask = 1 << root_i;
  throw_if(34, cnt_bits & mask);
  cnt_bits |= mask;
  cnt += 1;

  throw_if(41, ~ found? & (cnt < k) & (bound + ((60 * 60) << 32) > query_id));

  set_gas_limit(100000);

  ifnot (found?) {
    owner_infos~udict_set_builder(8, root_i, pack_owner_info(public_key, flood));
  }

  (pending_queries, owner_infos) = update_pending_queries(pending_queries, owner_infos, msg, query_id, creator_i, cnt, cnt_bits, n, k);
  set_data(pack_state(pending_queries, owner_infos, last_cleaned, k, n, wallet_id));

  commit();
  
  int need_save = 0;
  ifnot (cell_null?(signatures) | (cnt >= k)) {
    (int new_cnt, cnt_bits) = check_signatures(owner_infos, signatures, hash, cnt_bits);
    cnt += new_cnt;
    (pending_queries, owner_infos) = update_pending_queries(pending_queries, owner_infos, msg, query_id, creator_i, cnt, cnt_bits, n, k);
    need_save = -1;
  }

  accept_message();
  bound -= (64 << 32);   ;; clean up records expired more than 64 seconds ago
  int old_last_cleaned = last_cleaned;
  do {
    var (pending_queries', i, query, f) = pending_queries.udict_delete_get_min(64);
    f~touch();
    if (f) {
      f = (i < bound);
    }
    if (f) {
      if (query~load_int(1)) {
        owner_infos~dec_flood(query~load_uint(8));
      }
      pending_queries = pending_queries';
      last_cleaned = i;
      need_save = -1;
    }
  } until (~ f);

  if (need_save) {
    set_data(pack_state(pending_queries, owner_infos, last_cleaned, k, n, wallet_id));
  }
}

;; Get methods
;; returns -1 for processed queries, 0 for unprocessed, 1 for unknown (forgotten)
(int, int) get_query_state(int query_id) method_id {
  (_, int n, _, int last_cleaned, _, cell pending_queries) = unpack_state();
  (slice cs, var found) = pending_queries.udict_get?(64, query_id);
  if (found) {
    if (cs~load_int(1)) {
      cs~load_uint(8 + 8);
      return (0, cs~load_uint(n));
    } else {
      return (-1, 0);
    }
  }  else {
    return (-(query_id <= last_cleaned), 0);
  }
}

int processed?(int query_id) method_id {
  (int x, _) = get_query_state(query_id);
  return x;
}

cell create_init_state(int wallet_id, int n, int k, cell owners_info) method_id {
  return pack_state(new_dict(), owners_info, 0, k, n, wallet_id);
}

cell merge_list(cell a, cell b) {
  if (cell_null?(a)) {
    return b;
  }
  if (cell_null?(b)) {
    return a;
  }
  slice as = a.begin_parse();
  if (as.slice_refs() != 0) {
    cell tail = merge_list(as~load_ref(), b);
    return begin_cell().store_slice(as).store_ref(tail).end_cell();
  }
  
  as~skip_last_bits(1);
  ;; as~skip_bits(1);
  return begin_cell().store_slice(as).store_dict(b).end_cell();
  
}

cell get_public_keys() method_id {
  (_, _, _, _, cell public_keys, _) = unpack_state();
  return public_keys;
}

(int, int) check_query_signatures(cell query) method_id {
  slice cs = query.begin_parse();
  slice root_signature = cs~load_bits(512);
  int root_hash = slice_hash(cs);
  int root_i = cs~load_uint(8);

  cell public_keys = get_public_keys();
  (slice public_key, var found?) = public_keys.udict_get?(8, root_i);
  throw_unless(31, found?);
  throw_unless(32, check_signature(root_hash, root_signature, public_key.preload_uint(256)));

  int mask = 1 << root_i;

  cell signatures = cs~load_dict();
  if (cell_null?(signatures)) {
    return (1, mask);
  }
  (int cnt, mask) = check_signatures(public_keys, signatures, slice_hash(cs), mask);
  return (cnt + 1, mask);
}

cell messages_by_mask(int mask) method_id {
  (_, int n, _, _, _, cell pending_queries) = unpack_state();
  int i = -1;
  cell a = new_dict();
  do {
    (i, var cs, var f) = pending_queries.udict_get_next?(64, i);
    if (f) {
      if (cs~load_int(1)) {
        int cnt_bits = cs.skip_bits(8 + 8).preload_uint(n);
        if (cnt_bits & mask) {
          a~udict_set_builder(64, i, begin_cell().store_slice(cs));
        }
      }
    }
  } until (~ f);
  return a;
}

cell get_messages_unsigned_by_id(int id) method_id {
  return messages_by_mask(1 << id);
}

cell get_messages_unsigned() method_id {
  return messages_by_mask(~ 0);
}

(int, int) get_n_k() method_id {
  (_, int n, int k, _, _, _) = unpack_state();
  return (n, k);
}

cell merge_inner_queries(cell a, cell b) method_id {
  slice ca = a.begin_parse();
  slice cb = b.begin_parse();
  cell list_a = ca~load_dict();
  cell list_b = cb~load_dict();
  throw_unless(31, slice_hash(ca) == slice_hash(cb));
  return begin_cell()
    .store_dict(merge_list(list_a, list_b))
    .store_slice(ca)
  .end_cell();
}