using { /Fortnite.com/Characters }
using { /Fortnite.com/Animation/PlayAnimation }
using { /Fortnite.com/Devices }
using { /Verse.org/Assets }
using { /Verse.org/Simulation }
using { /UnrealEngine.com/Temporary/Diagnostics }

# PLAY AN ANIMATION ON A PLAYER'S CHARACTER — directly, from Verse.
#
# Before the /Fortnite.com/Animation/PlayAnimation module, playing an animation
# on the *player's own character* meant hacks: spawning a hidden NPC, swapping
# meshes, or driving an Animated Mesh device standing in for the player. Now the
# path is a straight line:
#
#   1. agent  -> fort_character          Presser.GetFortCharacter[]
#   2. character -> play_animation_controller
#                                        Character.GetPlayAnimationController[]
#   3. controller.Play(sequence, ...)  -> play_animation_instance
#
# The instance is a remote control for that one playback: Stop it, read its
# GetState, or subscribe to its CompletedEvent / InterruptedEvent.
#
# This device wires two buttons: one plays an editor-chosen animation sequence
# on whoever pressed it, the other stops the most recent playback.
play_emote_on_press_device := class(creative_device):

    # The animation to play. You CANNOT build an animation_sequence in Verse
    # (its constructor is epic_internal) -- it's an editor-imported asset. So the
    # slot is an OPTION: pick the asset in the device's Details panel in UEFN,
    # and we unwrap it at use with `EmoteAnim?`.
    @editable
    EmoteAnim : ?animation_sequence = false

    # Press to play the animation on the presser's character.
    @editable
    PlayButton : button_device = button_device{}

    # Press to stop the most recent playback.
    @editable
    StopButton : button_device = button_device{}

    # Remember the latest instance so the Stop button can cancel it.
    var CurrentAnim : ?play_animation_instance = false

    OnBegin<override>()<suspends> : void =
        PlayButton.InteractedWithEvent.Subscribe(OnPlayPressed)
        StopButton.InteractedWithEvent.Subscribe(OnStopPressed)

    # GetFortCharacter and GetPlayAnimationController both <decide>, so they go
    # in an `if` together with the option unwrap -- all three must succeed.
    OnPlayPressed(Presser : agent) : void =
        if:
            Anim := EmoteAnim?
            Character := Presser.GetFortCharacter[]
            Controller := Character.GetPlayAnimationController[]
        then:
            # Play() returns the instance IMMEDIATELY -- it does not suspend.
            # The optional ?params let you re-time and blend the clip.
            Instance := Controller.Play(
                Anim,
                ?PlayRate := 1.0,      # 1.0 = authored speed
                ?BlendInTime := 0.2,   # ease in over 0.2s
                ?BlendOutTime := 0.2)  # ease out over 0.2s
            set CurrentAnim = option{Instance}
            Print("Playing animation on the presser's character")

    # Stop() halts the playback (it blends out and fires InterruptedEvent).
    OnStopPressed(Presser : agent) : void =
        if (Instance := CurrentAnim?):
            Instance.Stop()
            Print("Stopped the animation")