import { EventSubscription } from 'expo-modules-core';
import { DecoderConfig, DecoderContext, MediaCodecInfo } from './decoderConfig';
import NativeInstance from '../nativeInstance';
import DecoderConfigModule from './decoderConfigModule';

/**
 * Takes care of JS/Native communication for a `DecoderConfig`.
 */
export class DecoderConfigBridge extends NativeInstance<DecoderConfig> {
  /**
   * Whether this object's native instance has been created.
   */
  isInitialized = false;
  /**
   * Whether this object's native instance has been disposed.
   */
  isDestroyed = false;

  private onOverrideDecodersPrioritySubscription?: EventSubscription;

  initialize() {
    if (!this.isInitialized) {
      // Set up event listener for decoder priority override
      this.onOverrideDecodersPrioritySubscription =
        DecoderConfigModule.addListener(
          'onOverrideDecodersPriority',
          ({
            nativeId,
            context,
            preferredDecoders,
          }: {
            nativeId: string;
            context: DecoderContext;
            preferredDecoders: MediaCodecInfo[];
          }) => {
            if (nativeId !== this.nativeId) {
              return;
            }
            this.overrideDecodersPriority(context, preferredDecoders);
          }
        );

      // Create native configuration object.
      DecoderConfigModule.initializeWithConfig(
        this.nativeId,
        this.config || {}
      );
      this.isInitialized = true;
    }
  }

  /**
   * Destroys the native `DecoderConfig`
   */
  destroy() {
    if (!this.isDestroyed) {
      DecoderConfigModule.destroy(this.nativeId);
      this.onOverrideDecodersPrioritySubscription?.remove();
      this.onOverrideDecodersPrioritySubscription = undefined;
      this.isDestroyed = true;
    }
  }

  /**
   * Called by native code, when the decoder priority should be evaluated.
   */
  private overrideDecodersPriority(
    context: DecoderContext,
    preferredDecoders: MediaCodecInfo[]
  ): void {
    const orderedPriority =
      this.config?.decoderPriorityProvider?.overrideDecodersPriority(
        context,
        preferredDecoders
      ) ?? preferredDecoders;

    DecoderConfigModule.overrideDecoderPriorityProviderComplete(
      this.nativeId,
      orderedPriority
    );
  }
}