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)
}
```

gleam.toml

@@ -17,6 +17,7 @@ gleam_stdlib = ">= 0.44.0 and < 2.0.0"
 gleam_otp = ">= 1.2.0 and < 2.0.0"
 gleam_erlang = ">= 1.3.0 and < 2.0.0"
 simplifile = ">= 2.3.1 and < 3.0.0"
+gleam_json = ">= 3.1.0 and < 4.0.0"
 
 [dev-dependencies]
 gleeunit = ">= 1.0.0 and < 2.0.0"

manifest.toml

@@ -4,6 +4,7 @@
 packages = [
   { name = "filepath", version = "1.1.2", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "filepath", source = "hex", outer_checksum = "B06A9AF0BF10E51401D64B98E4B627F1D2E48C154967DA7AF4D0914780A6D40A" },
   { name = "gleam_erlang", version = "1.3.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_erlang", source = "hex", outer_checksum = "1124AD3AA21143E5AF0FC5CF3D9529F6DB8CA03E43A55711B60B6B7B3874375C" },
+  { name = "gleam_json", version = "3.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_json", source = "hex", outer_checksum = "44FDAA8847BE8FC48CA7A1C089706BD54BADCC4C45B237A992EDDF9F2CDB2836" },
   { name = "gleam_otp", version = "1.2.0", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_stdlib"], otp_app = "gleam_otp", source = "hex", outer_checksum = "BA6A294E295E428EC1562DC1C11EA7530DCB981E8359134BEABC8493B7B2258E" },
   { name = "gleam_stdlib", version = "0.65.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "7C69C71D8C493AE11A5184828A77110EB05A7786EBF8B25B36A72F879C3EE107" },
   { name = "gleeunit", version = "1.9.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "DA9553CE58B67924B3C631F96FE3370C49EB6D6DC6B384EC4862CC4AAA718F3C" },
@@ -12,6 +13,7 @@ packages = [
 
 [requirements]
 gleam_erlang = { version = ">= 1.3.0 and < 2.0.0" }
+gleam_json = { version = ">= 3.1.0 and < 4.0.0" }
 gleam_otp = { version = ">= 1.2.0 and < 2.0.0" }
 gleam_stdlib = { version = ">= 0.44.0 and < 2.0.0" }
 gleeunit = { version = ">= 1.0.0 and < 2.0.0" }

src/input/internal.gleam

@@ -10,6 +10,6 @@ pub type NotUsed
 @external(erlang, "shell", "start_interactive")
 pub fn shell_start_interactive(options: #(atom.Atom, atom.Atom)) -> NotUsed
 
-// https://www.erlang.org/doc/apps/stdlib/io.html#get_line/1
+// https://www.erlang.org/doc/apps/stdlib/io.html#get_chars/2
 @external(erlang, "io", "get_chars")
 fn io_get_chars(prompt: String, count: Int) -> String

src/input/key.gleam

@@ -0,0 +1,83 @@
+import gleam/erlang/atom
+import gleam/erlang/process.{type Subject}
+import gleam/list
+import gleam/string
+
+import input/internal as internal_input
+
+pub type Key {
+  Char(String)
+
+  Input(String)
+  Left
+  Right
+  Up
+  Down
+
+  Continue(buffer: List(String))
+  Unknown
+}
+
+pub const esc = "\u{001B}"
+
+// control sequence introducer
+pub const csi = "["
+
+// input introducer
+pub const input_introducer = "::"
+
+pub fn from_list(l: List(String)) -> Key {
+  case l {
+    [e, c, "D"] if e == esc && c == csi -> Left
+    [e, c, "C"] if e == esc && c == csi -> Right
+    [e, c, "A"] if e == esc && c == csi -> Up
+    [e, c, "B"] if e == esc && c == csi -> Down
+
+    [e, c] if e == esc && c == csi -> Continue(l)
+
+    [ci] | [ci, _] if ci == input_introducer -> Continue(l)
+    [ii, cmd, tail] if ii == input_introducer -> {
+      case tail {
+        // Return
+        "\r" -> Input(cmd)
+        // Backspace
+        "\u{007F}" -> Continue([ii, string.drop_end(cmd, 1)])
+        _ -> Continue([ii, cmd <> tail])
+      }
+    }
+
+    [e] if e == esc -> Continue(l)
+    [char] -> Char(char)
+
+    [] -> Continue([])
+    _ -> Unknown
+  }
+}
+
+pub fn start_raw_shell() {
+  let no_shell = atom.create("noshell")
+  let raw = atom.create("raw")
+  internal_input.shell_start_interactive(#(no_shell, raw))
+}
+
+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) -> {
+      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

@@ -0,0 +1,77 @@
+import gleam/json
+import gleam/result
+import gleam/string
+
+import input/key.{type Key}
+import mpv/internal/control as internal_control
+import tcp/reason.{type Reason}
+import tcp/tcp.{type Socket}
+
+pub type Control {
+  TogglePlayPause
+
+  Search
+
+  Exit
+}
+
+pub type ControlError {
+  ControlError(details: String)
+}
+
+pub fn from_key(key: Key) -> Result(Control, Nil) {
+  case key {
+    key.Char(char) -> char_control(char)
+    _ -> Error(Nil)
+  }
+}
+
+fn char_control(char: String) -> Result(Control, Nil) {
+  case char {
+    " " -> Ok(TogglePlayPause)
+    "/" -> Ok(Search)
+    "q" -> Ok(Exit)
+    _ -> Error(Nil)
+  }
+}
+
+pub fn toggle_play_pause(socket: Socket) -> Result(Nil, ControlError) {
+  let command =
+    json.object([#("command", json.array(["cycle", "pause"], of: json.string))])
+
+  case send_command(socket, command) {
+    Error(r) -> Error(ControlError(reason.to_string(r)))
+    Ok(_) -> Ok(Nil)
+  }
+}
+
+// https://mpv.io/manual/master/#command-interface-playback-time
+pub type PlaybackTime {
+  PlaybackTime(data: Float)
+}
+
+pub fn get_playback_time(socket: Socket) -> Result(PlaybackTime, ControlError) {
+  let command =
+    json.object([
+      #(
+        "command",
+        json.array(["get_property_string", "playback-time"], of: json.string),
+      ),
+    ])
+
+  case send_command(socket, command) {
+    Error(r) -> Error(ControlError(reason.to_string(r)))
+    Ok(json_string) ->
+      case internal_control.parse_playback_time(json_string) {
+        Error(e) -> Error(ControlError(string.inspect(e)))
+        Ok(data) -> Ok(PlaybackTime(data))
+      }
+  }
+}
+
+fn send_command(socket: Socket, command: json.Json) -> Result(String, Reason) {
+  result.try(tcp.send(socket, json.to_string(command) <> "\n"), fn(_) {
+    let timeout_ms = 10_000
+    tcp.receive(socket, timeout_ms)
+  })
+}

src/mpv/internal/control.gleam

@@ -0,0 +1,25 @@
+import gleam/dynamic/decode
+import gleam/float
+import gleam/json
+import gleam/string
+
+pub fn parse_playback_time(
+  json_string: String,
+) -> Result(Float, json.DecodeError) {
+  let decoder = {
+    let float_dececoder = fn(data_string) {
+      case float.parse(data_string) {
+        Error(_) -> decode.failure(0.0, "data")
+        Ok(float_value) -> decode.success(float_value)
+      }
+    }
+    use data <- decode.field(
+      "data",
+      decode.then(decode.string, float_dececoder),
+    )
+
+    decode.success(data)
+  }
+
+  json.parse(from: string.trim(json_string), using: decoder)
+}

src/mpv/key.gleam

@@ -1,54 +0,0 @@
-import gleam/erlang/atom
-import gleam/list
-
-import mpv/internal/key as internal_key
-
-pub type Key {
-  Char(String)
-
-  Left
-  Right
-  Up
-  Down
-
-  Continue
-  Unknown
-}
-
-pub const esc = "\u{001B}"
-
-// control sequence introducer
-pub const csi = "["
-
-pub fn from_list(l: List(String)) -> Key {
-  case l {
-    [e, c, "D"] if e == esc && c == csi -> Left
-    [e, c, "C"] if e == esc && c == csi -> Right
-    [e, c, "A"] if e == esc && c == csi -> Up
-    [e, c, "B"] if e == esc && c == csi -> Down
-
-    [e, c] if e == esc && c == csi -> Continue
-
-    [e] if e == esc -> Continue
-    [char] -> Char(char)
-
-    [] -> Continue
-    _ -> Unknown
-  }
-}
-
-pub fn start_raw_shell() {
-  let no_shell = atom.create("noshell")
-  let raw = atom.create("raw")
-  internal_key.shell_start_interactive(#(no_shell, raw))
-}
-
-// TODO map key to something like Control, to not leak `Continue` etc.
-pub fn read_input_until_key(l: List(String)) -> Key {
-  let l = internal_key.read_input() |> list.wrap |> list.append(l, _)
-
-  case from_list(l) {
-    Continue -> read_input_until_key(l)
-    k -> k
-  }
-}

src/mpv/mpv.gleam

@@ -1,28 +1,43 @@
 import gleam/erlang/process.{type Subject}
+import gleam/float
 import gleam/otp/actor
+import gleam/result
 import gleam/string
 
-import mpv/key.{type Key, Char}
+import input/key.{type Key}
-import tcp/reason.{type Reason}
+import mpv/control.{type Control}
+import tcp/reason
 import tcp/tcp.{type Socket}
+import ui/ui.{type Event}
 
-pub type Message {
+type State(socket, inject_input, ui, exit) {
-  KeyPress(Key)
+  State(
+    socket: Socket,
+    inject_input: Subject(Key),
+    ui: Subject(Event),
+    exit: Subject(Nil),
+  )
 }
 
-type State(socket, exit) {
+pub fn new(
-  State(socket: Socket, exit: Subject(Nil))
+  ui: Subject(Event),
-}
+  input_sink: Subject(List(String)),
-
+  exit: Subject(Nil),
-pub fn new(exit: Subject(Nil)) -> Result(Nil, String) {
+) -> 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
       {
@@ -31,7 +46,14 @@ pub fn new(exit: Subject(Nil)) -> Result(Nil, String) {
         Ok(actor.Started(data:, ..)) -> {
           echo "waiting for input"
           key.start_raw_shell()
-          process.spawn(fn() { read_input(data) })
+
+          process.spawn(fn() {
+            let assert Ok(_) =
+              process.register(process.self(), inject_input_name)
+
+            read_input(data, inject_input, input_sink)
+          })
+
           Ok(Nil)
         }
       }
@@ -39,28 +61,58 @@ pub fn new(exit: Subject(Nil)) -> Result(Nil, String) {
   }
 }
 
-pub fn toggle_play_pause(socket: Socket) -> Result(Nil, Reason) {
-  tcp.send(socket, "{\"command\":[\"cycle\",\"pause\"]}\n")
-}
-
 fn handle_message(
-  state: State(socket, exit),
+  state: State(socket, inject, ui, exit),
-  message: Message,
+  control: Control,
-) -> actor.Next(State(socket, exit), Message) {
+) -> actor.Next(State(socket, inject, ui, exit), Control) {
-  case message {
+  case control {
-    KeyPress(Char("q")) -> {
+    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"
+
+      let _ =
+        result.map_error(control.toggle_play_pause(state.socket), fn(err) {
+          echo "Could not toggle play/pause: " <> err.details
+        })
+
+      let _ =
+        result.map(control.get_playback_time(state.socket), fn(playback) {
+          echo "playback: " <> float.to_string(playback.data)
+        })
+
+      actor.continue(state)
+    }
+    control.Exit -> {
       process.send(state.exit, Nil)
       actor.stop()
     }
-    KeyPress(key) -> {
-      echo "key: " <> string.inspect(key)
-      actor.continue(state)
-    }
   }
 }
 
-fn read_input(subject: Subject(Message)) -> Nil {
+/// `read_input` operates by reading from input until a `Key` can be created.
-  key.read_input_until_key([]) |> KeyPress |> process.send(subject, _)
+/// 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.
-  read_input(subject)
+/// This is useful to ultimately create a `Control` without the user having to
+/// input all of the character(s) needed.
+fn read_input(
+  subject: Subject(Control),
+  inject_input: Subject(Key),
+  input_sink: Subject(List(String)),
+) -> Nil {
+  let buffer = case process.receive(inject_input, 1) {
+    Ok(key.Continue(buffer)) -> buffer
+    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

@@ -0,0 +1,42 @@
+import gleam/list
+import gleeunit
+
+import input/key.{type Key, Char, csi, esc, input_introducer as ii}
+
+pub fn main() -> Nil {
+  gleeunit.main()
+}
+
+type TestCase {
+  TestCase(input: List(String), expected: Key)
+}
+
+pub fn key_from_list_test() {
+  let base_tests = [TestCase([], key.Continue([]))]
+
+  let char_tests = [TestCase(["c"], Char("c"))]
+
+  let escape_tests = [
+    TestCase([esc, csi], key.Continue([esc, csi])),
+    TestCase([esc], key.Continue([esc])),
+
+    TestCase([esc, csi, "D"], key.Left),
+    TestCase([esc, csi, "C"], key.Right),
+    TestCase([esc, csi, "A"], key.Up),
+    TestCase([esc, csi, "B"], key.Down),
+  ]
+
+  let input_tests = [
+    TestCase([ii], key.Continue([ii])),
+    TestCase([ii, "a"], key.Continue([ii, "a"])),
+    TestCase([ii, "a", "b"], key.Continue([ii, "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]
+
+  list.each(list.flatten(test_cases), fn(tc) {
+    assert tc.expected == key.from_list(tc.input)
+  })
+}

test/mpv/control_test.gleam

@@ -0,0 +1,33 @@
+import gleam/list
+import gleeunit
+
+import input/key.{type Key, Char}
+import mpv/control.{type Control}
+import mpv/internal/control as control_internal
+
+pub fn main() -> Nil {
+  gleeunit.main()
+}
+
+type TestCase {
+  TestCase(key: Key, expected: Result(Control, Nil))
+}
+
+pub fn control_from_key_test() {
+  let test_cases = [
+    TestCase(Char(" "), Ok(control.TogglePlayPause)),
+    TestCase(Char("q"), Ok(control.Exit)),
+  ]
+
+  list.each(test_cases, fn(tc) {
+    assert tc.expected == control.from_key(tc.key)
+  })
+}
+
+pub fn parse_playback_time_test() {
+  let json_string =
+    "{\"data\":\"123.456789\",\"request_id\":0,\"error\":\"success\"}\n"
+
+  let assert Ok(data) = control_internal.parse_playback_time(json_string)
+  assert data == 123.456789
+}

test/mpv/key_test.gleam

@@ -1,29 +0,0 @@
-import gleam/list
-import gleeunit
-
-import mpv/key.{type Key, Char, csi, esc}
-
-pub fn main() -> Nil {
-  gleeunit.main()
-}
-
-type TestCase {
-  TestCase(input: List(String), expected: Key)
-}
-
-pub fn key_from_list_test() {
-  let test_cases = [
-    TestCase(["c"], Char("c")),
-    TestCase([esc, csi, "D"], key.Left),
-    TestCase([esc, csi, "C"], key.Right),
-    TestCase([esc, csi, "A"], key.Up),
-    TestCase([esc, csi, "B"], key.Down),
-    TestCase([esc, csi], key.Continue),
-    TestCase([esc], key.Continue),
-    TestCase([], key.Continue),
-  ]
-
-  list.each(test_cases, fn(tc) {
-    assert tc.expected == key.from_list(tc.input)
-  })
-}