Previously the receive_tabs widget was allowed to be much smaller
than its inner main widget (e.g. truncating visible QR code).
A bit hackish to overwrite/monkeypatch sizeHint,
but I've tried a few approaches and this seems to work best.
Disable rebalance/swap suggestions attached to requests/invoices if there is an ongoing task.
Note: This assumes that all tasks are lightning payments, which is true for the moment.
These methods return a list of channels that can be rebalanced,
in order to receive or send a given amount.
Also add 'channels' parameter to submarine swaps.
Previously, swaps were not considering which channel to use.
When we do not have liquidity to pay an invoice:
- add 'rebalance' option in order to pay an invoice
- use the suggested channel in the 'swap' option
When we do not have the liquidity to receive an invoice:
- add 'Rebalance' and 'Swap' buttons to the receive tab
I believe lightning requests created before https://github.com/spesmilo/electrum/pull/7730
can have an amount of None - ones created after have amount 0 instead.
We could do a wallet db upgrade potentially.
Regardless, the type hint is `get_amount_sat(self) -> Union[int, str, None]`,
so None should be handled. (well, arguably "!" should be handled too...)
```
E | gui.qt.exception_window.Exception_Hook | exception caught by crash reporter
Traceback (most recent call last):
File "...\electrum\electrum\gui\qt\request_list.py", line 101, in item_changed
self.parent.show_receive_request(req)
File "...\electrum\electrum\gui\qt\main_window.py", line 1279, in show_receive_request
URI = req.get_bip21_URI(lightning=bip21_lightning)
File "...\electrum\electrum\invoices.py", line 164, in get_bip21_URI
amount = int(self.get_amount_sat())
TypeError: int() argument must be a string, a bytes-like object or a real number, not 'NoneType'
```
```
E | gui.qt.exception_window.Exception_Hook | exception caught by crash reporter
Traceback (most recent call last):
File "...\electrum\electrum\gui\qt\request_list.py", line 101, in item_changed
self.parent.show_receive_request(req)
File "...\electrum\electrum\gui\qt\main_window.py", line 1281, in show_receive_request
can_receive_lightning = self.wallet.lnworker and req.get_amount_sat() <= self.wallet.lnworker.num_sats_can_receive()
TypeError: '<=' not supported between instances of 'NoneType' and 'decimal.Decimal'
```
follow-up https://github.com/spesmilo/electrum/pull/7818
- note it matters whether a sender pays us end-to-end-trampoline or just via legacy
- consider: Alice has 0.1 BTC recv cap in chan1 and 1 BTC recv cap in chan2, both with border-node T1
- if sender is paying e2e trampoline, it can realistically pay even ~1.1 BTC, as T1 can resplit the HTLCs
- if sender is paying legacy, it will have a hard time trying to pay more than 1 BTC, in practice
- although note if T1 has implemented non-strict-forwarding (see BOLT-04), achieving 1 BTC is easy,
as T1 can redirect HTLCs (but cannot split them, in this case)
- to make num_sats_can_receive realistic, it assumes the legacy case
- To calc num_sats_can_receive, we sort our channels in decreasing order of receive-capacities, iterate over them
and calculate a running sum - we stop adding channels when the next chan's recv cap is small compared to
the running total.
- When putting routing hints in an invoice, we do the same, with the added condition that we keep adding channels
if their recv cap is larger than the invoice amount.
- consider: Alice has 0.1 BTC recv cap in chan1 with Bob, and 1 BTC recv cap in chan2 with Carol
- if Alice wants to recv 100 sats, it is useful to add hints for both channels into the invoice, for redundancy
- if Alice wants to recv 0.9 BTC, it is questionable whether adding the smaller chan is useful - the code here won't add it
- increase MPP_RECEIVE_CUTOFF from 5 to 20 percent
- filter channels by node_id, not channel_id
- make num_sats_can_receive consistent with routing hints
return the max value allowed for legacy payments.
(that is, do not assume we can do MPP involving two trampolines)
This reverts fb6047ec46
Reason: num_sats_can_send may be used to decide the amount
we put in a new channel.
