import * as THREE from 'three'

export class ResourceTracker {
  constructor() {
    this.resources = new Set()
  }
  track(resource) {
    if (!resource) {
      return resource
    }

    // handle children and when material is an array of materials or
    // uniform is array of textures
    if (Array.isArray(resource)) {
      resource.forEach(resource => this.track(resource))
      return resource
    }

    if (resource.dispose || resource instanceof THREE.Object3D) {
      this.resources.add(resource)
    }
    if (resource instanceof THREE.Object3D) {
      this.track(resource.geometry)
      this.track(resource.material)
      this.track(resource.children)
    } else if (resource instanceof THREE.Material) {
      // We have to check if there are any textures on the material
      for (const value of Object.values(resource)) {
        if (value instanceof THREE.Texture) {
          this.track(value)
        }
      }
      // We also have to check if any uniforms reference textures or arrays of textures
      if (resource.uniforms) {
        for (const value of Object.values(resource.uniforms)) {
          if (value) {
            const uniformValue = value.value
            if (uniformValue instanceof THREE.Texture || Array.isArray(uniformValue)) {
              this.track(uniformValue)
            }
          }
        }
      }
    }
    return resource
  }
  untrack(resource) {
    this.resources.delete(resource)
  }
  dispose() {
    for (const resource of this.resources) {
      if (resource instanceof THREE.Object3D) {
        if (resource.parent) {
          resource.parent.remove(resource)
        }
      }
      if (resource.dispose) {
        resource.dispose()
      }
    }
    this.resources.clear()
  }
}
