/**
 * Copyright 2022 The MediaPipe Authors. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import {CalculatorGraphConfig} from '../../../../framework/calculator_pb';
import {CalculatorOptions} from '../../../../framework/calculator_options_pb';
import {EmbeddingResult} from '../../../../tasks/cc/components/containers/proto/embeddings_pb';
import {TextEmbedderGraphOptions as TextEmbedderGraphOptionsProto} from '../../../../tasks/cc/text/text_embedder/proto/text_embedder_graph_options_pb';
import {convertBaseOptionsToProto} from '../../../../tasks/web/components/processors/base_options';
import {convertEmbedderOptionsToProto} from '../../../../tasks/web/components/processors/embedder_options';
import {convertFromEmbeddingResultProto} from '../../../../tasks/web/components/processors/embedder_result';
import {TaskRunner} from '../../../../tasks/web/core/task_runner';
import {WasmLoaderOptions} from '../../../../tasks/web/core/wasm_loader_options';
import {createMediaPipeLib, FileLocator} from '../../../../web/graph_runner/wasm_mediapipe_lib';
// Placeholder for internal dependency on trusted resource url

import {TextEmbedderOptions} from './text_embedder_options';
import {TextEmbedderResult} from './text_embedder_result';

export * from './text_embedder_options';
export * from './text_embedder_result';

// The OSS JS API does not support the builder pattern.
// tslint:disable:jspb-use-builder-pattern

const INPUT_STREAM = 'text_in';
const EMBEDDINGS_STREAM = 'embeddings_out';
const TEXT_EMBEDDER_CALCULATOR =
    'mediapipe.tasks.text.text_embedder.TextEmbedderGraph';

/**
 * Performs embedding extraction on text.
 */
export class TextEmbedder extends TaskRunner {
  private embeddingResult: TextEmbedderResult = {embeddings: []};
  private readonly options = new TextEmbedderGraphOptionsProto();

  /**
   * Initializes the Wasm runtime and creates a new text embedder from the
   * provided options.
   * @param wasmLoaderOptions A configuration object that provides the location
   *     of the Wasm binary and its loader.
   * @param textEmbedderOptions The options for the text embedder. Note that
   *     either a path to the TFLite model or the model itself needs to be
   *     provided (via `baseOptions`).
   */
  static async createFromOptions(
      wasmLoaderOptions: WasmLoaderOptions,
      textEmbedderOptions: TextEmbedderOptions): Promise<TextEmbedder> {
    // Create a file locator based on the loader options
    const fileLocator: FileLocator = {
      locateFile() {
        // The only file we load is the Wasm binary
        return wasmLoaderOptions.wasmBinaryPath.toString();
      }
    };

    const embedder = await createMediaPipeLib(
        TextEmbedder, wasmLoaderOptions.wasmLoaderPath,
        /* assetLoaderScript= */ undefined,
        /* glCanvas= */ undefined, fileLocator);
    await embedder.setOptions(textEmbedderOptions);
    return embedder;
  }

  /**
   * Initializes the Wasm runtime and creates a new text embedder based on the
   * provided model asset buffer.
   * @param wasmLoaderOptions A configuration object that provides the location
   *     of the Wasm binary and its loader.
   * @param modelAssetBuffer A binary representation of the TFLite model.
   */
  static createFromModelBuffer(
      wasmLoaderOptions: WasmLoaderOptions,
      modelAssetBuffer: Uint8Array): Promise<TextEmbedder> {
    return TextEmbedder.createFromOptions(
        wasmLoaderOptions, {baseOptions: {modelAssetBuffer}});
  }

  /**
   * Initializes the Wasm runtime and creates a new text embedder based on the
   * path to the model asset.
   * @param wasmLoaderOptions A configuration object that provides the location
   *     of the Wasm binary and its loader.
   * @param modelAssetPath The path to the TFLite model.
   */
  static async createFromModelPath(
      wasmLoaderOptions: WasmLoaderOptions,
      modelAssetPath: string): Promise<TextEmbedder> {
    const response = await fetch(modelAssetPath.toString());
    const graphData = await response.arrayBuffer();
    return TextEmbedder.createFromModelBuffer(
        wasmLoaderOptions, new Uint8Array(graphData));
  }

  /**
   * Sets new options for the text embedder.
   *
   * Calling `setOptions()` with a subset of options only affects those options.
   * You can reset an option back to its default value by explicitly setting it
   * to `undefined`.
   *
   * @param options The options for the text embedder.
   */
  async setOptions(options: TextEmbedderOptions): Promise<void> {
    if (options.baseOptions) {
      const baseOptionsProto = await convertBaseOptionsToProto(
          options.baseOptions, this.options.getBaseOptions());
      this.options.setBaseOptions(baseOptionsProto);
    }

    this.options.setEmbedderOptions(convertEmbedderOptionsToProto(
        options, this.options.getEmbedderOptions()));

    this.refreshGraph();
  }


  /**
   * Performs embeding extraction on the provided text and waits synchronously
   * for the response.
   *
   * @param text The text to process.
   * @return The embedding resuls of the text
   */
  embed(text: string): TextEmbedderResult {
    // Get text embeddings by running our MediaPipe graph.
    this.addStringToStream(
        text, INPUT_STREAM, /* timestamp= */ performance.now());
    this.finishProcessing();
    return this.embeddingResult;
  }

  /** Updates the MediaPipe graph configuration. */
  private refreshGraph(): void {
    const graphConfig = new CalculatorGraphConfig();
    graphConfig.addInputStream(INPUT_STREAM);
    graphConfig.addOutputStream(EMBEDDINGS_STREAM);

    const calculatorOptions = new CalculatorOptions();
    calculatorOptions.setExtension(
        TextEmbedderGraphOptionsProto.ext, this.options);

    const embedderNode = new CalculatorGraphConfig.Node();
    embedderNode.setCalculator(TEXT_EMBEDDER_CALCULATOR);
    embedderNode.addInputStream('TEXT:' + INPUT_STREAM);
    embedderNode.addOutputStream('EMBEDDINGS:' + EMBEDDINGS_STREAM);
    embedderNode.setOptions(calculatorOptions);

    graphConfig.addNode(embedderNode);

    this.attachProtoListener(EMBEDDINGS_STREAM, binaryProto => {
      const embeddingResult = EmbeddingResult.deserializeBinary(binaryProto);
      this.embeddingResult = convertFromEmbeddingResultProto(embeddingResult);
    });

    const binaryGraph = graphConfig.serializeBinary();
    this.setGraph(new Uint8Array(binaryGraph), /* isBinary= */ true);
  }
}