defmodule Love.View do
@moduledoc """
Extend LiveViews.
Add `use Love.View` to a `Phoenix.LiveView`. This adds:
- `@behaviour Love.Events` for the optional `c:Love.Events.handle_message/4` callback
- `import Love.View` to make macros and functions locally available
- Hooks into `mount` and `handle_info`
"""
alias Love.Internal
alias Phoenix.LiveView
##################################################
# __using__/1
##################################################
defmacro __using__(_opts) do
Internal.init_module_attributes(__CALLER__, [:prop, :react, :state, :defaults])
quote do
@behaviour Love.Events
@before_compile Love.View
use Love.React
import Love.View
on_mount({Love.View, __MODULE__})
end
end
##################################################
# __before_compile__/1
##################################################
defmacro __before_compile__(env) do
# Evaluate quoted opts and turn them into more useful structures
Internal.before_compile_eval_metas(env, [:state])
# Add the :triggers fields, so we know what to reevaluate when a field changes
Internal.before_compile_put_meta_triggers(env.module, [:state])
# Delay these function definitions until as late as possible, so we can ensure the attributes
# are fully set up (i.e. wait for __on_definition__/6 to evaluate first!)
[
Internal.before_compile_define_meta_fns(env, [:prop, :state]),
Internal.define_defaults(env.module)
]
end
##################################################
# PUBLIC API
##################################################
@doc """
Defines a state assign.
State is internal to the view and is modified via `put_state/2`.
## Options
- `:default` - optional; if specified, the state will be assigned the default value during mount.
The expression for the default value is wrapped in a function and its evaluation is deferred until runtime
at the moment the view is mounted. If not specified, you should `put_state/2` during view
initialization to set an initial value.
## Example
# State with no initial value
state :changeset
# State with an initial value, evaluated during mount
state :now, default: DateTime.utc_now()
"""
@doc group: :fields
@spec state(key :: atom, opts :: keyword) :: nil
defmacro state(key, opts \\ []) when is_atom(key) do
Internal.define_state(__CALLER__, key, opts)
end
@doc """
Updates state assigns.
When called outside of a reactive function, any reactive functions that depend on the changed
state will be immediately evaluated, so call this function as infrequently as possible. In
other words, try to batch state changes and limit `put_state/2` calls to once per function.
Within a reactive function, any additionally-triggered reactive functions will
be deferred until after the current reactive function completely executes.
Returns the socket with the new state and after any reactive callbacks have run.
## Example
state :first_name
put_state(socket, first_name: "Marvin")
"""
@spec put_state(LiveView.Socket.t(), map | keyword) :: LiveView.Socket.t()
def put_state(socket, changes) do
Internal.put_state(socket, changes)
end
@doc false
def on_mount(module, _params, _session, socket) do
socket =
socket
|> Internal.put_private(:module, module)
|> Internal.put_private(:assigns_validated?, false)
{:cont,
socket
|> LiveView.assign(Internal.initial_state(socket))
|> LiveView.attach_hook(:love_view_info, :handle_info, &handle_info_hook/2)}
end
defp handle_info_hook(%Love.Events.Message{} = message, socket) do
{:halt,
Internal.live_view_module(socket).handle_message(
message.name,
message.source,
message.payload,
socket
)}
end
defp handle_info_hook(_message, socket), do: {:cont, socket}
end