// Input/Components/AC_InputDevice.ts

import type { AC_DebugHUD } from '#root/Debug/Components/AC_DebugHUD.ts';
import type { AC_ToastSystem } from '#root/Toasts/Components/AC_ToastSystem.ts';
import { ActorComponent } from '#root/UE/ActorComponent.ts';
import { EHardwareDevicePrimaryType } from '#root/UE/EHardwareDevicePrimaryType.ts';
import type { Float } from '#root/UE/Float.ts';
import { InputDeviceSubsystem } from '#root/UE/InputDeviceSubsystem.ts';
import type { Integer } from '#root/UE/Integer.ts';
import { SystemLibrary } from '#root/UE/SystemLibrary.ts';
import { E_MessageType } from '#root/UI/Enums/E_MessageType.ts';

/**
 * Input Device Detection Component
 * Minimal wrapper around Unreal Engine's native InputDeviceSubsystem
 * Provides simple binary classification: Gamepad vs Everything Else
 */
export class AC_InputDevice extends ActorComponent {
  // ════════════════════════════════════════════════════════════════════════════════════════
  //                                    FUNCTIONS
  // ════════════════════════════════════════════════════════════════════════════════════════

  /**
   * Get current active input device type
   * @returns Current device type (cached from delegate events)
   * @category Device Queries
   * @pure true
   */
  public GetCurrentInputDevice(): EHardwareDevicePrimaryType {
    return this.CurrentDevice;
  }

  /**
   * Check if current device is keyboard/mouse
   * @returns True if keyboard is active
   * @category Device Queries
   * @pure true
   */
  public IsKeyboard(): boolean {
    return this.CurrentDevice === EHardwareDevicePrimaryType.KeyboardAndMouse;
  }

  /**
   * Check if current device is gamepad/controller
   * @returns True if gamepad is active
   * @category Device Queries
   * @pure true
   */
  public IsGamepad(): boolean {
    return this.CurrentDevice === EHardwareDevicePrimaryType.Gamepad;
  }

  /**
   * Initialize device detection system with delegate registration
   * @param ToastComponentRef - Toast system for debug notifications
   * @param DebugHUDComponentRef - Optional debug HUD for displaying device info
   * @category System Setup
   */
  public InitializeDeviceDetection(
    ToastComponentRef: AC_ToastSystem,
    DebugHUDComponentRef: AC_DebugHUD
  ): void {
    this.ToastComponent = ToastComponentRef;
    this.DebugHUDComponent = DebugHUDComponentRef;
    this.RegisterHardwareDeviceDelegate();
    this.DetectInitialDevice();
    this.IsInitialized = true;

    if (SystemLibrary.IsValid(this.DebugHUDComponent)) {
      this.DebugHUDComponent.AddDebugPage(
        this.DebugPageID,
        'Input Device Info',
        60
      );
    }

    if (SystemLibrary.IsValid(this.ToastComponent)) {
      this.ToastComponent.ShowToast(
        `Device Detection Initialized: ${this.CurrentDevice}`,
        E_MessageType.Success
      );
    }
  }

  /**
   * Register OnInputHardwareDeviceChanged delegate
   * Core of the event-driven approach
   * @category System Setup
   */
  private RegisterHardwareDeviceDelegate(): void {
    InputDeviceSubsystem.OnInputHardwareDeviceChanged.BindEvent(
      this.OnInputHardwareDeviceChanged.bind(this)
    );
  }

  /**
   * Detect initial device on system startup
   * Fallback for getting device before first hardware change event
   * @category System Setup
   */
  private DetectInitialDevice(): void {
    this.CurrentDevice =
      InputDeviceSubsystem.GetMostRecentlyUsedHardwareDevice().PrimaryDeviceType;
  }

  /**
   * Handle hardware device change events
   * Called automatically when input hardware changes
   * @param UserId - User ID (usually 0 for single-player)
   * @param DeviceId - Device name string
   * @category Event Handling
   */
  private OnInputHardwareDeviceChanged(
    UserId?: Integer,
    DeviceId?: Integer
  ): void {
    this.ProcessDeviceChange(
      InputDeviceSubsystem.GetInputDeviceHardwareIdentifier(DeviceId ?? 0)
        .PrimaryDeviceType
    );
  }

  /**
   * Process device change with debouncing
   * Prevents rapid switching and manages device state
   * @param NewDevice - Newly detected device type
   * @category Device Management
   */
  private ProcessDeviceChange(NewDevice: EHardwareDevicePrimaryType): void {
    if (NewDevice !== this.CurrentDevice && this.CanProcessDeviceChange()) {
      this.CurrentDevice = NewDevice;
      this.LastDeviceChangeTime = SystemLibrary.GetGameTimeInSeconds();

      if (SystemLibrary.IsValid(this.ToastComponent)) {
        this.ToastComponent.ShowToast(
          `Input switched to ${NewDevice}`,
          E_MessageType.Info
        );
      }
    }
  }

  /**
   * Check if device change can be processed (debouncing)
   * Prevents rapid device switching within cooldown period
   * @returns True if enough time has passed since last change
   * @category Debouncing
   * @pure true
   */
  private CanProcessDeviceChange(): boolean {
    const HasCooldownExpired = (): boolean =>
      SystemLibrary.GetGameTimeInSeconds() - this.LastDeviceChangeTime >=
      this.DeviceChangeCooldown;

    return HasCooldownExpired();
  }

  /**
   * Update debug HUD with current device info
   * @category Debug
   */
  public UpdateDebugPage(): void {
    if (SystemLibrary.IsValid(this.DebugHUDComponent)) {
      if (
        this.DebugHUDComponent.ShouldUpdatePage(
          this.DebugPageID,
          SystemLibrary.GetGameTimeInSeconds()
        )
      ) {
        this.DebugHUDComponent.UpdatePageContent(
          this.DebugPageID,
          `Hardware Device Identifier: ${this.GetCurrentInputDevice()}` +
            `Initialized: ${this.IsInitialized}` +
            `Last Change: ${this.LastDeviceChangeTime}`
        );
      }
    }
  }

  // ════════════════════════════════════════════════════════════════════════════════════════
  //                                    VARIABLES
  // ════════════════════════════════════════════════════════════════════════════════════════

  /**
   * Reference to toast system for debug notifications
   * @category Components
   */
  private ToastComponent: AC_ToastSystem | null = null;

  /**
   * Reference to debug HUD component for displaying camera info
   * Optional, used for debugging purposes
   * @category Components
   */
  public DebugHUDComponent: AC_DebugHUD | null = null;

  /**
   * Current active input device type
   * Updated by hardware device change events
   * @category Device State
   */
  private CurrentDevice: EHardwareDevicePrimaryType =
    EHardwareDevicePrimaryType.Unspecified;

  /**
   * System initialization status
   * @category System State
   */
  public IsInitialized: boolean = false;

  /**
   * Last device change timestamp for debouncing
   * @category Debouncing
   */
  public LastDeviceChangeTime: Float = 0;

  /**
   * Minimum time between device changes (prevents flickering)
   * Recommended: 300-500ms for most games
   * @category Debouncing
   * @instanceEditable true
   */
  private DeviceChangeCooldown: Float = 0.3;

  /**
   * Debug page identifier for organizing debug output
   * Used by debug HUD to categorize information
   * @category Debug
   * @instanceEditable true
   */
  public readonly DebugPageID: string = 'InputDeviceInfo';
}