/**
 * @license
 * Copyright 2024 Google LLC
 *
 * 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 { CachedContent, RequestOptions } from "../../types";
import { CachedContentUrl, getHeaders, makeServerRequest } from "./request";
import {
  CachedContentCreateParams,
  CachedContentUpdateParams,
  ListCacheResponse,
  ListParams,
  _CachedContentUpdateRequestFields,
} from "../../types/server";
import { RpcTask } from "./constants";
import {
  GoogleGenerativeAIError,
  GoogleGenerativeAIRequestInputError,
} from "../errors";
import { formatSystemInstruction } from "../requests/request-helpers";

/**
 * Class for managing GoogleAI content caches.
 * @public
 */
export class GoogleAICacheManager {
  constructor(
    public apiKey: string,
    private _requestOptions?: RequestOptions,
  ) {}

  /**
   * Upload a new content cache
   */
  async create(
    createOptions: CachedContentCreateParams,
  ): Promise<CachedContent> {
    const newCachedContent: CachedContent = { ...createOptions };
    if (createOptions.ttlSeconds) {
      if (createOptions.expireTime) {
        throw new GoogleGenerativeAIRequestInputError(
          "You cannot specify both `ttlSeconds` and `expireTime` when creating" +
            " a content cache. You must choose one.",
        );
      }
      if (createOptions.systemInstruction) {
        newCachedContent.systemInstruction = formatSystemInstruction(
          createOptions.systemInstruction,
        );
      }
      newCachedContent.ttl = createOptions.ttlSeconds.toString() + "s";
      delete (newCachedContent as CachedContentCreateParams).ttlSeconds;
    }
    if (!newCachedContent.model) {
      throw new GoogleGenerativeAIRequestInputError(
        "Cached content must contain a `model` field.",
      );
    }
    if (!newCachedContent.model.includes("/")) {
      // If path is not included, assume it's a non-tuned model.
      newCachedContent.model = `models/${newCachedContent.model}`;
    }
    const url = new CachedContentUrl(
      RpcTask.CREATE,
      this.apiKey,
      this._requestOptions,
    );

    const headers = getHeaders(url);

    const response = await makeServerRequest(
      url,
      headers,
      JSON.stringify(newCachedContent),
    );
    return response.json();
  }

  /**
   * List all uploaded content caches
   */
  async list(listParams?: ListParams): Promise<ListCacheResponse> {
    const url = new CachedContentUrl(
      RpcTask.LIST,
      this.apiKey,
      this._requestOptions,
    );
    if (listParams?.pageSize) {
      url.appendParam("pageSize", listParams.pageSize.toString());
    }
    if (listParams?.pageToken) {
      url.appendParam("pageToken", listParams.pageToken);
    }
    const headers = getHeaders(url);
    const response = await makeServerRequest(url, headers);
    return response.json();
  }

  /**
   * Get a content cache
   */
  async get(name: string): Promise<CachedContent> {
    const url = new CachedContentUrl(
      RpcTask.GET,
      this.apiKey,
      this._requestOptions,
    );
    url.appendPath(parseCacheName(name));
    const headers = getHeaders(url);
    const response = await makeServerRequest(url, headers);
    return response.json();
  }

  /**
   * Update an existing content cache
   */
  async update(
    name: string,
    updateParams: CachedContentUpdateParams,
  ): Promise<CachedContent> {
    const url = new CachedContentUrl(
      RpcTask.UPDATE,
      this.apiKey,
      this._requestOptions,
    );
    url.appendPath(parseCacheName(name));
    const headers = getHeaders(url);
    const formattedCachedContent: _CachedContentUpdateRequestFields = {
      ...updateParams.cachedContent,
    };
    if (updateParams.cachedContent.ttlSeconds) {
      formattedCachedContent.ttl =
        updateParams.cachedContent.ttlSeconds.toString() + "s";
      delete (formattedCachedContent as CachedContentCreateParams).ttlSeconds;
    }
    if (updateParams.updateMask) {
      url.appendParam(
        "update_mask",
        updateParams.updateMask.map((prop) => camelToSnake(prop)).join(","),
      );
    }
    const response = await makeServerRequest(
      url,
      headers,
      JSON.stringify(formattedCachedContent),
    );
    return response.json();
  }

  /**
   * Delete content cache with given name
   */
  async delete(name: string): Promise<void> {
    const url = new CachedContentUrl(
      RpcTask.DELETE,
      this.apiKey,
      this._requestOptions,
    );
    url.appendPath(parseCacheName(name));
    const headers = getHeaders(url);
    await makeServerRequest(url, headers);
  }
}

/**
 * If cache name is prepended with "cachedContents/", remove prefix
 */
function parseCacheName(name: string): string {
  if (name.startsWith("cachedContents/")) {
    return name.split("cachedContents/")[1];
  }
  if (!name) {
    throw new GoogleGenerativeAIError(
      `Invalid name ${name}. ` +
        `Must be in the format "cachedContents/name" or "name"`,
    );
  }
  return name;
}
function camelToSnake(str: string): string {
  return str.replace(/[A-Z]/g, (letter) => `_${letter.toLowerCase()}`);
}