wip

By doing something like
```
fn input_output_loop(input_output: Subject(List(String))) -> Nil {
  let output = process.receive_forever(input_output)

  echo output

  input_output_loop(input_output)
}
```

src/input/key.gleam

@@ -1,5 +1,7 @@
 import gleam/erlang/atom
+import gleam/erlang/process.{type Subject}
 import gleam/list
+import gleam/string
 
 import input/internal as internal_input
 
@@ -22,7 +24,7 @@ pub const esc = "\u{001B}"
 pub const csi = "["
 
 // input introducer
-const input_introducer = "$"
+pub const input_introducer = "::"
 
 pub fn from_list(l: List(String)) -> Key {
   case l {
@@ -35,9 +37,12 @@ pub fn from_list(l: List(String)) -> Key {
 
     [ci] | [ci, _] if ci == input_introducer -> Continue(l)
     [ii, cmd, tail] if ii == input_introducer -> {
-      case tail == "\r" {
+      case tail {
-        True -> Input(cmd)
+        // Return
-        False -> Continue([ii, cmd <> tail])
+        "\r" -> Input(cmd)
+        // Backspace
+        "\u{007F}" -> Continue([ii, string.drop_end(cmd, 1)])
+        _ -> Continue([ii, cmd <> tail])
       }
     }
 
@@ -55,14 +60,24 @@ pub fn start_raw_shell() {
   internal_input.shell_start_interactive(#(no_shell, raw))
 }
 
-pub fn read_input_until_key(l: List(String)) -> Key {
+pub fn read_input_until_key(
+  l: List(String),
+  input_sink: Subject(List(String)),
+) -> Key {
   case
     internal_input.read_input()
     |> list.wrap
     |> list.append(l, _)
     |> from_list
   {
-    Continue(l) -> read_input_until_key(l)
+    Continue(l) -> {
-    k -> k
+      echo "key:read_input_until_key continue: " <> string.inspect(l)
+      process.send(input_sink, l)
+      read_input_until_key(l, input_sink)
+    }
+    k -> {
+      echo "key:read_input_until_key k: " <> string.inspect(k)
+      k
+    }
   }
 }

src/mpv/control.gleam

@@ -20,7 +20,6 @@ pub type ControlError {
 }
 
 pub fn from_key(key: Key) -> Result(Control, Nil) {
-  echo key
   case key {
     key.Char(char) -> char_control(char)
     _ -> Error(Nil)
@@ -30,8 +29,8 @@ pub fn from_key(key: Key) -> Result(Control, Nil) {
 fn char_control(char: String) -> Result(Control, Nil) {
   case char {
     " " -> Ok(TogglePlayPause)
-    "q" -> Ok(Exit)
     "/" -> Ok(Search)
+    "q" -> Ok(Exit)
     _ -> Error(Nil)
   }
 }

src/mpv/mpv.gleam

@@ -4,24 +4,40 @@ import gleam/otp/actor
 import gleam/result
 import gleam/string
 
-import input/key
+import input/key.{type Key}
 import mpv/control.{type Control}
 import tcp/reason
 import tcp/tcp.{type Socket}
+import ui/ui.{type Event}
 
-type State(socket, exit) {
+type State(socket, inject_input, ui, exit) {
-  State(socket: Socket, exit: Subject(Nil))
+  State(
+    socket: Socket,
+    inject_input: Subject(Key),
+    ui: Subject(Event),
+    exit: Subject(Nil),
+  )
 }
 
-pub fn new(exit: Subject(Nil)) -> Result(Nil, String) {
+pub fn new(
+  ui: Subject(Event),
+  input_sink: Subject(List(String)),
+  exit: Subject(Nil),
+) -> Result(Nil, String) {
   // TODO start up mvp here, currently hi-jacking `naviterm`s socket
   let socket_path = "/tmp/naviterm_mpv"
 
   case tcp.connect(socket_path) {
     Error(r) -> Error("Could not connect to mpv: " <> reason.to_string(r))
     Ok(socket) -> {
+      // `inject_input` is created by name to allow the process that
+      // owns `read_input` to be able to register it, while the agent
+      // also have a reference to it to be able to inject input
+      let inject_input_name = process.new_name("inject_input")
+      let inject_input = process.named_subject(inject_input_name)
+
       case
-        actor.new(State(socket, exit))
+        actor.new(State(socket, inject_input, ui, exit))
         |> actor.on_message(handle_message)
         |> actor.start
       {
@@ -30,12 +46,14 @@ pub fn new(exit: Subject(Nil)) -> Result(Nil, String) {
         Ok(actor.Started(data:, ..)) -> {
           echo "waiting for input"
           key.start_raw_shell()
-          let input = process.new_subject()
-          process.self()
-          process.receive
 
-          process.spawn(fn() { input_handler(input, data) })
+          process.spawn(fn() {
-          process.spawn(fn() { read_input(data) })
+            let assert Ok(_) =
+              process.register(process.self(), inject_input_name)
+
+            read_input(data, inject_input, input_sink)
+          })
+
           Ok(Nil)
         }
       }
@@ -44,11 +62,16 @@ pub fn new(exit: Subject(Nil)) -> Result(Nil, String) {
 }
 
 fn handle_message(
-  state: State(socket, exit),
+  state: State(socket, inject, ui, exit),
   control: Control,
-) -> actor.Next(State(socket, exit), Control) {
+) -> actor.Next(State(socket, inject, ui, exit), Control) {
   case control {
-    control.Search -> todo
+    control.Search -> {
+      echo "mpv search"
+      process.send(state.inject_input, key.Continue([key.input_introducer]))
+      process.send(state.ui, ui.Search)
+      actor.continue(state)
+    }
     control.TogglePlayPause -> {
       echo "toggling play/pause"
 
@@ -71,32 +94,25 @@ fn handle_message(
   }
 }
 
-// TODO create new input_handler_loop that recieves on a subject and 
+/// `read_input` operates by reading from input until a `Key` can be created.
-// TODO read_input reads until a key is found, and then sends it to
+/// It is possible to create a `Key` without the users input by sending
-
+/// messages to `inject_input` which will initialize the "input to key" sequence.
-// TODO a function that can recieve on a subject, and it can receive two types of messages:
+/// This is useful to ultimately create a `Control` without the user having to
-// 1. a Control message from read_input
+/// input all of the character(s) needed.
-// 2. an injected controlMessage with pre-defined buffer
+fn read_input(
-// it then forwards the message to the actor subject
+  subject: Subject(Control),
-
+  inject_input: Subject(Key),
-fn read_input(input_handler: Subject(Control)) -> Nil {
+  input_sink: Subject(List(String)),
-  case
-    key.read_input_until_key([])
-    |> control.from_key
-  {
-    Error(_) -> Nil
-    Ok(control) -> process.send(input_handler, control)
-  }
-
-  read_input(input_handler)
-}
-
-fn input_handler(
-  input: Subject(Control),
-  actor_subject: Subject(Control),
 ) -> Nil {
-  case process.receive(input, 1000) {
+  let buffer = case process.receive(inject_input, 1) {
-    Error(_) -> Nil
+    Ok(key.Continue(buffer)) -> buffer
-    Ok(control) -> process.send(actor_subject, control)
+    Ok(_) | Error(_) -> []
   }
+
+  let _ =
+    key.read_input_until_key(buffer, input_sink)
+    |> control.from_key
+    |> result.map(process.send(subject, _))
+
+  read_input(subject, inject_input, input_sink)
 }

src/musicplayer.gleam

@@ -1,8 +1,30 @@
 import gleam/erlang/process
+
 import mpv/mpv
+import ui/ui
 
 pub fn main() -> Nil {
+  // 1. user starts search
+  // ui should show "input: "
+  // user presses enter
+  // ui should show "input was: x"
+
+  // 1. listen for control.Search
+  // 2. start listening to tap_input and print io.print "input: "
+  // 3. simultaniously listen for control.Input
+  // 4. print "input was: x"
+
+  // ui need: tap_input
+  // input need: ui subject to send control events from
+
+  // new input process should return `Key`
+  // this key should be sent both to ui and mpv, and they will decide if they can act on it.
+  // its probably ok if both act on it, e.g. "TogglePlayPause" could stop mpv music and display |> or || in ui
+
   let exit = process.new_subject()
-  let assert Ok(_) = mpv.new(exit)
+
+  let assert Ok(#(ui, input_sink)) = ui.new()
+  let assert Ok(_) = mpv.new(ui, input_sink, exit)
+
   process.receive_forever(exit)
 }

src/ui/ui.gleam

@@ -0,0 +1,62 @@
+import gleam/erlang/process.{type Name, type Subject}
+import gleam/otp/actor
+import gleam/string
+
+pub type Event {
+  Search
+  Input(List(String))
+}
+
+// TODO in input, split input into events and control?
+
+pub fn new() -> Result(#(Subject(Event), Subject(List(String))), String) {
+  let input_sink_name: Name(List(String)) = process.new_name("input_sink")
+  let input_sink = process.named_subject(input_sink_name)
+
+  // let input_sink = process.new_subject()
+
+  case
+    actor.new(Nil)
+    |> actor.on_message(handle_message)
+    |> actor.start
+  {
+    Error(start_error) ->
+      Error("Could not start ui actor: " <> string.inspect(start_error))
+    Ok(actor.Started(data: ui, ..)) -> {
+      echo "ui started"
+
+      // let assert Ok(_) = process.register(process.self(), input_sink_name)
+      process.spawn(fn() {
+        let assert Ok(_) = process.register(process.self(), input_sink_name)
+        drain_input_sink(ui, input_sink)
+      })
+
+      Ok(#(ui, input_sink))
+    }
+  }
+}
+
+fn handle_message(state: Nil, event: Event) -> actor.Next(Nil, Event) {
+  case event {
+    Search -> {
+      echo "ui:search"
+      actor.continue(state)
+    }
+    Input(content) -> {
+      echo "ui:input: " <> string.inspect(content)
+      actor.continue(state)
+    }
+  }
+}
+
+fn drain_input_sink(
+  subject: Subject(Event),
+  input_sink: Subject(List(String)),
+) -> Nil {
+  echo "ui:drain_input_sink"
+  let content = process.receive_forever(input_sink)
+
+  process.send(subject, Input(content))
+
+  drain_input_sink(subject, input_sink)
+}

test/input/input_test.gleam

@@ -1,7 +1,7 @@
 import gleam/list
 import gleeunit
 
-import input/key.{type Key, Char, csi, esc}
+import input/key.{type Key, Char, csi, esc, input_introducer as ii}
 
 pub fn main() -> Nil {
   gleeunit.main()
@@ -27,10 +27,11 @@ pub fn key_from_list_test() {
   ]
 
   let input_tests = [
-    TestCase(["$"], key.Continue(["$"])),
+    TestCase([ii], key.Continue([ii])),
-    TestCase(["$", "a"], key.Continue(["$", "a"])),
+    TestCase([ii, "a"], key.Continue([ii, "a"])),
-    TestCase(["$", "a", "b"], key.Continue(["$", "ab"])),
+    TestCase([ii, "a", "b"], key.Continue([ii, "ab"])),
-    TestCase(["$", "ab", "\r"], key.Input("ab")),
+    TestCase([ii, "ab", "\u{007F}"], key.Continue([ii, "a"])),
+    TestCase([ii, "ab", "\r"], key.Input("ab")),
   ]
 
   let test_cases = [base_tests, char_tests, escape_tests, input_tests]