import nodeFetch, { RequestInit } from 'node-fetch';

import { BoxApiError, BoxSdkError } from '../box/errors';
import {
  ByteStream,
  FormData,
  generateByteStreamFromBuffer,
  isBrowser,
  readByteStream,
  calculateMD5Hash,
  multipartStreamToBuffer,
  multipartBufferToStream,
} from '../internal/utils';
import { sdkVersion } from './version';
import { NetworkClient } from './networkClient.generated';
import {
  SerializedData,
  jsonToSerializedData,
  sdIsMap,
  sdToJson,
  sdToUrlParams,
} from '../serialization/json';
import { Interceptor } from './interceptors.generated';
import { FetchOptions } from './fetchOptions.generated';
import { FetchResponse } from './fetchResponse.generated';
import { RetryStrategy } from './retries.generated.js';
import { BoxRetryStrategy } from './retries.generated.js';
import { DataSanitizer } from '../internal/logging.generated.js';

export const userAgentHeader = `Box JavaScript generated SDK v${sdkVersion} (${
  isBrowser() ? navigator.userAgent : `Node ${process.version}`
})`;

export const xBoxUaHeader = constructBoxUAHeader();
export const shouldIncludeBoxUaHeader = (options: FetchOptions) => {
  return !(
    isBrowser() &&
    (options.responseFormat === 'binary' ||
      options.responseFormat === 'no_content')
  );
};

export interface MultipartItem {
  readonly partName: string;
  readonly data?: SerializedData;
  readonly fileStream?: ByteStream;
  readonly fileName?: string;
  readonly contentType?: string;
}

type FetchOptionsExtended = FetchOptions & {
  attemptNumber?: number;
  numberOfRetriesOnException?: number;
};

async function createRequestInit(options: FetchOptions): Promise<RequestInit> {
  const {
    method = 'GET',
    headers = {},
    contentType: contentTypeInput = 'application/json',
    data,
    fileStream,
  } = options;

  const { contentHeaders = {}, body } = await (async (): Promise<{
    contentHeaders: { [key: string]: string };
    body: ByteStream | string | Buffer;
  }> => {
    const contentHeaders: { [key: string]: string } = {};
    if (options.multipartData) {
      const FormDataClass = isBrowser() ? window.FormData : FormData;
      const formData: any = new FormDataClass();
      for (const item of options.multipartData) {
        if (item.fileStream) {
          const buffer = await readByteStream(item.fileStream);
          const blob = isBrowser()
            ? new Blob([new Uint8Array(buffer)])
            : buffer;
          contentHeaders['content-md5'] = await calculateMD5Hash(buffer);
          formData.append(item.partName, blob, {
            filename: item.fileName ?? 'file',
            contentType: item.contentType ?? 'application/octet-stream',
          });
        } else if (item.data) {
          formData.append(item.partName, sdToJson(item.data));
        } else {
          throw new BoxSdkError({
            message: 'Multipart item must have either body or fileStream',
          });
        }
      }
      return {
        contentHeaders: {
          ...(!isBrowser() && {
            'Content-Type': `multipart/form-data; boundary=${formData.getBoundary()}`,
          }),
          ...contentHeaders,
        },
        body: formData,
      };
    }

    contentHeaders['Content-Type'] = contentTypeInput;
    switch (contentTypeInput) {
      case 'application/json':
      case 'application/json-patch+json':
        return { contentHeaders, body: sdToJson(data) };

      case 'application/x-www-form-urlencoded':
        return { contentHeaders, body: sdToUrlParams(data) };

      case 'application/octet-stream':
        if (!fileStream) {
          throw new BoxSdkError({
            message:
              'fileStream required for application/octet-stream content type',
          });
        }
        return {
          contentHeaders,
          body: isBrowser()
            ? await readByteStream(fileStream)
            : (fileStream as any),
        };

      default:
        throw new BoxSdkError({
          message: `Unsupported content type : ${contentTypeInput}`,
        });
    }
  })();

  return {
    method,
    headers: {
      // Only set content type if it is not a GET request
      ...(method != 'GET' && contentHeaders),
      ...headers,
      ...(options.auth && {
        Authorization: await options.auth.retrieveAuthorizationHeader(
          options.networkSession,
        ),
      }),
      ...(shouldIncludeBoxUaHeader(options) && {
        'User-Agent': userAgentHeader,
        'X-Box-UA': xBoxUaHeader,
      }),
      // Additional headers will override the default headers
      ...options.networkSession?.additionalHeaders,
    },
    body: body as any,
    signal: options.cancellationToken as RequestInit['signal'],
    agent: options.networkSession?.agent,
    ...(fileStream && isBrowser() && { duplex: 'half' }),
  };
}

export class BoxNetworkClient implements NetworkClient {
  constructor(
    fields?: Omit<BoxNetworkClient, 'fetch'> &
      Partial<Pick<BoxNetworkClient, 'fetch'>>,
  ) {
    Object.assign(this, fields);
  }
  async fetch(options: FetchOptionsExtended): Promise<FetchResponse> {
    const attemptNumber = options.attemptNumber ?? 1;
    let numberOfRetriesOnException = options.numberOfRetriesOnException ?? 0;
    const interceptors: readonly Interceptor[] =
      options.networkSession?.interceptors ?? [];
    const retryStrategy: RetryStrategy =
      options.networkSession?.retryStrategy ?? new BoxRetryStrategy({});
    const dataSanitizer: DataSanitizer =
      options.networkSession?.dataSanitizer ?? new DataSanitizer({});
    const fetchOptions: typeof options = interceptors.length
      ? interceptors.reduce(
          (modifiedOptions: FetchOptions, interceptor: Interceptor) =>
            interceptor.beforeRequest(modifiedOptions),
          options,
        )
      : options;
    const fileStreamBuffer = fetchOptions.fileStream
      ? await readByteStream(fetchOptions.fileStream)
      : void 0;
    const multipartBuffer = fetchOptions.multipartData
      ? await multipartStreamToBuffer(fetchOptions.multipartData)
      : void 0;

    let isExceptionCase: boolean = false;
    let fetchResponse: FetchResponse;
    let responseBytesBuffer;
    const { params = {} } = fetchOptions;

    const requestInit = await createRequestInit({
      ...fetchOptions,
      fileStream: fileStreamBuffer
        ? generateByteStreamFromBuffer(fileStreamBuffer)
        : void 0,
      multipartData: multipartBuffer
        ? multipartBufferToStream(multipartBuffer)
        : void 0,
    });

    try {
      const response = await nodeFetch(
        ''.concat(
          fetchOptions.url,
          Object.keys(params).length === 0 || fetchOptions.url.endsWith('?')
            ? ''
            : '?',
          new URLSearchParams(params).toString(),
        ),
        { ...requestInit, redirect: isBrowser() ? 'follow' : 'manual' },
      );

      const contentType = response.headers.get('content-type') ?? '';
      const ignoreResponseBody = fetchOptions.followRedirects === false;

      let data: SerializedData | undefined;
      let content: ByteStream = generateByteStreamFromBuffer(
        new Uint8Array().buffer,
      );

      if (!ignoreResponseBody) {
        if (options.responseFormat === 'binary') {
          content = response.body as unknown as ByteStream;
          responseBytesBuffer = new Uint8Array();
        } else if (options.responseFormat === 'json') {
          responseBytesBuffer = await response.arrayBuffer();
          const text = new TextDecoder().decode(responseBytesBuffer);
          if (contentType.includes('application/json')) {
            data = jsonToSerializedData(text);
          }
          content = generateByteStreamFromBuffer(responseBytesBuffer);
        }
      }

      fetchResponse = {
        url: response.url,
        status: response.status,
        data,
        content,
        headers: Object.fromEntries(Array.from(response.headers.entries())),
      };
      if (interceptors.length) {
        fetchResponse = interceptors.reduce(
          (modifiedResponse: FetchResponse, interceptor: Interceptor) =>
            interceptor.afterRequest(modifiedResponse),
          fetchResponse,
        );
      }
    } catch (error) {
      isExceptionCase = true;
      numberOfRetriesOnException++;
      fetchResponse = {
        status: 0,
        headers: {},
      };
    }
    const attemptForRetry = isExceptionCase
      ? numberOfRetriesOnException
      : attemptNumber;

    const shouldRetry = await retryStrategy.shouldRetry(
      fetchOptions,
      fetchResponse,
      attemptForRetry,
    );

    if (shouldRetry) {
      const retryTimeout = retryStrategy.retryAfter(
        fetchOptions,
        fetchResponse,
        attemptForRetry,
      );
      await new Promise((resolve) => setTimeout(resolve, retryTimeout));
      return this.fetch({
        ...options,
        attemptNumber: attemptNumber + 1,
        numberOfRetriesOnException: numberOfRetriesOnException,
        fileStream: fileStreamBuffer
          ? generateByteStreamFromBuffer(fileStreamBuffer)
          : void 0,
        multipartData: multipartBuffer
          ? multipartBufferToStream(multipartBuffer)
          : void 0,
      });
    }

    if (
      fetchResponse.status >= 300 &&
      fetchResponse.status < 400 &&
      fetchOptions.followRedirects !== false
    ) {
      if (!fetchResponse.headers['location']) {
        throw new BoxSdkError({
          message: `Unable to follow redirect for ${fetchOptions.url}`,
        });
      }
      const sameOrigin =
        new URL(fetchResponse.headers['location']).origin ===
        new URL(fetchOptions.url).origin;
      return this.fetch({
        ...options,
        params: undefined,
        auth: sameOrigin ? fetchOptions.auth : undefined,
        url: fetchResponse.headers['location'],
      });
    }

    if (fetchResponse.status >= 200 && fetchResponse.status < 400) {
      return fetchResponse;
    }

    const [code, contextInfo, requestId, helpUrl, message] = sdIsMap(
      fetchResponse.data,
    )
      ? [
          sdToJson(fetchResponse.data['code']),
          sdIsMap(fetchResponse.data['context_info'])
            ? fetchResponse.data['context_info']
            : undefined,
          sdToJson(fetchResponse.data['request_id']),
          sdToJson(fetchResponse.data['help_url']),
          sdToJson(fetchResponse.data['message']),
        ]
      : [];

    throw new BoxApiError({
      message: `${fetchResponse.status} ${message}; Request ID: ${requestId}`,
      timestamp: `${Date.now()}`,
      requestInfo: {
        method: requestInit.method!,
        url: fetchOptions.url,
        queryParams: params,
        headers: (requestInit.headers as { [key: string]: string }) ?? {},
        body:
          typeof requestInit.body === 'string' ? requestInit.body : undefined,
      },
      responseInfo: {
        statusCode: fetchResponse.status,
        headers: fetchResponse.headers,
        body: fetchResponse.data,
        rawBody: new TextDecoder().decode(responseBytesBuffer),
        code: code,
        contextInfo: contextInfo,
        requestId: requestId,
        helpUrl: helpUrl,
      },
      dataSanitizer: dataSanitizer,
    });
  }
}

function constructBoxUAHeader() {
  const analyticsIdentifiers = {
    agent: `box-javascript-generated-sdk/${sdkVersion}`,
    env: isBrowser()
      ? navigator.userAgent
      : `Node/${process.version.replace('v', '')}`,
  } as Record<string, string>;

  return Object.keys(analyticsIdentifiers)
    .map((k) => `${k}=${analyticsIdentifiers[k]}`)
    .join('; ');
}

// Retry intervals are between 50% and 150% of the exponentially increasing base amount
const RETRY_RANDOMIZATION_FACTOR = 0.5;

/**
 * Calculate the exponential backoff time with randomized jitter
 * @param {int} numRetries Which retry number this one will be
 * @param {int} baseInterval The base retry interval set in config
 * @returns {int} The number of milliseconds after which to retry
 */
export function getRetryTimeout(numRetries: number, baseInterval: number) {
  var minRandomization = 1 - RETRY_RANDOMIZATION_FACTOR;
  var maxRandomization = 1 + RETRY_RANDOMIZATION_FACTOR;
  var randomization =
    Math.random() * (maxRandomization - minRandomization) + minRandomization;
  var exponential = Math.pow(2, numRetries - 1);
  return Math.ceil(exponential * baseInterval * randomization);
}