### Notes on architectural changes

Motivation: By separating the code which manages conversation with other
Joinmarket participants from the code which manages this participant's Bitcoin
wallet actions, we get a considerable gain at a minor cost of an additional layer:
code dependencies for each part are much reduced, security requirements of the 
server/daemon layer are massively reduced (which can have several advantages such as
it being more acceptable to distribute this layer as a binary), and client code
can be written, implementing application-level logic (do join with coins X under condition X)
using other Bitcoin libraries, or wallets, without knowing anything about
Joinmarket's inter-participant protocol. An example is my work on the Joinmarket
electrum [plugin](https://github.com/AdamISZ/electrum-joinmarket-plugin).

It also
means that updates to the Bitcoin element of Joinmarket, such as P2SH and segwit, should
have extremely minimal to no impact on the backend code, since the latter just implements
communication of a set of formatted messages, and allows the client to decide on
their validity beyond simply syntax.

Joinmarket's own [messaging protocol](https://github.com/JoinMarket-Org/JoinMarket-Docs/blob/master/Joinmarket-messaging-protocol.md) is thus enforced *only* in the server/daemon.

The client and server currently communicate using twisted.protocol.amp, see
[AMP](https://amp-protocol.net/),
and the specification of the communication between the client and server is isolated to
[this](https://github.com/JoinMarket-Org/joinmarket-clientserver/blob/master/src/jmbase/commands.py) module.
Currently the messaging layer of Joinmarket is IRC-only (but easily extensible, see [here](https://github.com/JoinMarket-Org/joinmarket/issues/650).
The IRC layer is also implemented here using Twisted, reducing the complexity required with threading.

The "server" is just a daemon service that can be run as a separate process (see `scripts/joinmarketd.py`), or for convenience in the same process (the default for command line scripts).
