Audio player state model

Player.re

type progress =
  | Stopped
  | Playing
  | Rewinding
  | FastForwarding
  | Paused;
type playerState = {
  status: progress,
  activeTrackIndex: option(int),
};
type playerEvent =
  | PlayTrack(option(int))
  | TogglePlaying
  | Stop
  | FastForward
  | Rewind
  | DoNothing;
...  
let (playerState, playerSend) =
    React.useReducer(
      (state, event) =>
        switch (state.status, event) {
        | (_, PlayTrack(None)) => {
            activeTrackIndex: Some(0),
            status: Playing,
          }
        | (_, PlayTrack(i)) => {activeTrackIndex: i, status: Playing}
        | (Stopped | Paused | Rewinding | FastForwarding, TogglePlaying) => {
            ...state,
            status: Playing,
          }
        | (Playing, TogglePlaying) => {...state, status: Paused}
        | (Paused | Playing | Rewinding | FastForwarding, Rewind) => {
            ...state,
            status: Rewinding,
          }
        | (Paused | Playing | Rewinding | FastForwarding, FastForward) => {
            ...state,
            status: FastForwarding,
          }
        | (_, Stop) => {activeTrackIndex: None, status: Stopped}
        | (Stopped, FastForward | Rewind)
        | (_, DoNothing) => state
        },
      {activeTrackIndex: None, status: Stopped},
    );

Feel free to code review this if you feel so inclined 😅