/**
 * Copyright (c) Microsoft Corporation.
 *
 * 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 * as fs from 'fs';
import * as mime from 'mime';
import * as path from 'path';
import * as util from 'util';
import { TimeoutError } from '../errors';
import * as types from '../types';
import { helper, assert } from '../helper';
import { SerializedError, AXNode, SerializedValue } from './channels';

export function serializeError(e: any): SerializedError {
  if (helper.isError(e))
    return { error: { message: e.message, stack: e.stack, name: e.name } };
  return { value: serializeValue(e, value => ({ fallThrough: value }), new Set()) };
}

export function parseError(error: SerializedError): Error {
  if (!error.error) {
    if (error.value === undefined)
      throw new Error('Serialized error must have either an error or a value');
    return parseSerializedValue(error.value, undefined);
  }
  if (error.error.name === 'TimeoutError') {
    const e = new TimeoutError(error.error.message);
    e.stack = error.error.stack || '';
    return e;
  }
  const e = new Error(error.error.message);
  e.stack = error.error.stack || '';
  return e;
}

export async function normalizeFilePayloads(files: string | types.FilePayload | string[] | types.FilePayload[]): Promise<types.FilePayload[]> {
  let ff: string[] | types.FilePayload[];
  if (!Array.isArray(files))
    ff = [ files ] as string[] | types.FilePayload[];
  else
    ff = files;
  const filePayloads: types.FilePayload[] = [];
  for (const item of ff) {
    if (typeof item === 'string') {
      const file: types.FilePayload = {
        name: path.basename(item),
        mimeType: mime.getType(item) || 'application/octet-stream',
        buffer: await util.promisify(fs.readFile)(item)
      };
      filePayloads.push(file);
    } else {
      filePayloads.push(item);
    }
  }
  return filePayloads;
}

export async function normalizeFulfillParameters(params: types.FulfillResponse & { path?: string }): Promise<types.NormalizedFulfillResponse> {
  let body = '';
  let isBase64 = false;
  let length = 0;
  if (params.path) {
    const buffer = await util.promisify(fs.readFile)(params.path);
    body = buffer.toString('base64');
    isBase64 = true;
    length = buffer.length;
  } else if (helper.isString(params.body)) {
    body = params.body;
    isBase64 = false;
    length = Buffer.byteLength(body);
  } else if (params.body) {
    body = params.body.toString('base64');
    isBase64 = true;
    length = params.body.length;
  }
  const headers: types.Headers = {};
  for (const header of Object.keys(params.headers || {}))
    headers[header.toLowerCase()] = String(params.headers![header]);
  if (params.contentType)
    headers['content-type'] = String(params.contentType);
  else if (params.path)
    headers['content-type'] = mime.getType(params.path) || 'application/octet-stream';
  if (length && !('content-length' in headers))
    headers['content-length'] = String(length);

  return {
    status: params.status || 200,
    headers: headersObjectToArray(headers),
    body,
    isBase64
  };
}

export function normalizeContinueOverrides(overrides: types.ContinueOverrides): types.NormalizedContinueOverrides {
  return {
    method: overrides.method,
    headers: overrides.headers ? headersObjectToArray(overrides.headers) : undefined,
    postData: helper.isString(overrides.postData) ? Buffer.from(overrides.postData, 'utf8') : overrides.postData,
  };
}

export function headersObjectToArray(headers: types.Headers): types.HeadersArray {
  const result: types.HeadersArray = [];
  for (const name in headers) {
    if (!Object.is(headers[name], undefined)) {
      const value = headers[name];
      assert(helper.isString(value), `Expected value of header "${name}" to be String, but "${typeof value}" is found.`);
      result.push({ name, value });
    }
  }
  return result;
}

export function headersArrayToObject(headers: types.HeadersArray): types.Headers {
  const result: types.Headers = {};
  for (const { name, value } of headers)
    result[name] = value;
  return result;
}

export function envObjectToArray(env: types.Env): types.EnvArray {
  const result: types.EnvArray = [];
  for (const name in env) {
    if (!Object.is(env[name], undefined))
      result.push({ name, value: String(env[name]) });
  }
  return result;
}

export function envArrayToObject(env: types.EnvArray): types.Env {
  const result: types.Env = {};
  for (const { name, value } of env)
    result[name] = value;
  return result;
}

export function axNodeToProtocol(axNode: types.SerializedAXNode): AXNode {
  const result: AXNode = {
    ...axNode,
    valueNumber: typeof axNode.value === 'number' ? axNode.value : undefined,
    valueString: typeof axNode.value === 'string' ? axNode.value : undefined,
    checked: axNode.checked === true ? 'checked' : axNode.checked === false ? 'unchecked' : axNode.checked,
    pressed: axNode.pressed === true ? 'pressed' : axNode.pressed === false ? 'released' : axNode.pressed,
    children: axNode.children ? axNode.children.map(axNodeToProtocol) : undefined,
  };
  delete (result as any).value;
  return result;
}

export function axNodeFromProtocol(axNode: AXNode): types.SerializedAXNode {
  const result: types.SerializedAXNode = {
    ...axNode,
    value: axNode.valueNumber !== undefined ? axNode.valueNumber : axNode.valueString,
    checked: axNode.checked === 'checked' ? true : axNode.checked === 'unchecked' ? false : axNode.checked,
    pressed: axNode.pressed === 'pressed' ? true : axNode.pressed === 'released' ? false : axNode.pressed,
    children: axNode.children ? axNode.children.map(axNodeFromProtocol) : undefined,
  };
  delete (result as any).valueNumber;
  delete (result as any).valueString;
  return result;
}

export function parseSerializedValue(value: SerializedValue, handles: any[] | undefined): any {
  if (value.n !== undefined)
    return value.n;
  if (value.s !== undefined)
    return value.s;
  if (value.b !== undefined)
    return value.b;
  if (value.v !== undefined) {
    if (value.v === 'undefined')
      return undefined;
    if (value.v === 'null')
      return null;
    if (value.v === 'NaN')
      return NaN;
    if (value.v === 'Infinity')
      return Infinity;
    if (value.v === '-Infinity')
      return -Infinity;
    if (value.v === '-0')
      return -0;
  }
  if (value.d !== undefined)
    return new Date(value.d);
  if (value.r !== undefined)
    return new RegExp(value.r.p, value.r.f);
  if (value.a !== undefined)
    return value.a.map((a: any) => parseSerializedValue(a, handles));
  if (value.o !== undefined) {
    const result: any = {};
    for (const { k, v } of value.o)
      result[k] = parseSerializedValue(v, handles);
    return result;
  }
  if (value.h !== undefined) {
    if (handles === undefined)
      throw new Error('Unexpected handle');
    return handles[value.h];
  }
  throw new Error('Unexpected value');
}

export type HandleOrValue = { h: number } | { fallThrough: any };
export function serializeValue(value: any, handleSerializer: (value: any) => HandleOrValue, visited: Set<any>): SerializedValue {
  const handle = handleSerializer(value);
  if ('fallThrough' in handle)
    value = handle.fallThrough;
  else
    return handle;

  if (visited.has(value))
    throw new Error('Argument is a circular structure');
  if (typeof value === 'symbol')
    return { v: 'undefined' };
  if (Object.is(value, undefined))
    return { v: 'undefined' };
  if (Object.is(value, null))
    return { v: 'null' };
  if (Object.is(value, NaN))
    return { v: 'NaN' };
  if (Object.is(value, Infinity))
    return { v: 'Infinity' };
  if (Object.is(value, -Infinity))
    return { v: '-Infinity' };
  if (Object.is(value, -0))
    return { v: '-0' };
  if (typeof value === 'boolean')
    return { b: value };
  if (typeof value === 'number')
    return { n: value };
  if (typeof value === 'string')
    return { s: value };
  if (isError(value)) {
    const error = value;
    if ('captureStackTrace' in global.Error) {
      // v8
      return { s: error.stack || '' };
    }
    return { s: `${error.name}: ${error.message}\n${error.stack}` };
  }
  if (isDate(value))
    return { d: value.toJSON() };
  if (isRegExp(value))
    return { r: { p: value.source, f: value.flags } };
  if (Array.isArray(value)) {
    const a = [];
    visited.add(value);
    for (let i = 0; i < value.length; ++i)
      a.push(serializeValue(value[i], handleSerializer, visited));
    visited.delete(value);
    return { a };
  }
  if (typeof value === 'object') {
    const o: { k: string, v: SerializedValue }[] = [];
    visited.add(value);
    for (const name of Object.keys(value))
      o.push({ k: name, v: serializeValue(value[name], handleSerializer, visited) });
    visited.delete(value);
    return { o };
  }
  throw new Error('Unexpected value');
}

function isRegExp(obj: any): obj is RegExp {
  return obj instanceof RegExp || Object.prototype.toString.call(obj) === '[object RegExp]';
}

function isDate(obj: any): obj is Date {
  return obj instanceof Date || Object.prototype.toString.call(obj) === '[object Date]';
}

function isError(obj: any): obj is Error {
  return obj instanceof Error || (obj && obj.__proto__ && obj.__proto__.name === 'Error');
}