/* @flow */

declare var __VERSION__: string;

import EventEmitter from 'events';

import {debugInOut} from '../debug-decorator';

type TrezorDeviceInfoDebug = {path: string, debug: boolean};

const T1HID_VENDOR = 0x534c;

const TREZOR_DESCS = [
  // TREZOR v1
  // won't get opened, but we can show error at least
  { vendorId: 0x534c, productId: 0x0001 },
  // TREZOR webusb Bootloader
  { vendorId: 0x1209, productId: 0x53c0 },
  // TREZOR webusb Firmware
  { vendorId: 0x1209, productId: 0x53c1 },
];

const CONFIGURATION_ID = 1;
const INTERFACE_ID = 0;
const ENDPOINT_ID = 1;
const DEBUG_INTERFACE_ID = 1;
const DEBUG_ENDPOINT_ID = 2;

export default class WebUsbPlugin {
  name: string = `WebUsbPlugin`;

  version: string = __VERSION__;
  debug: boolean = false;

  usb: USB;

  allowsWriteAndEnumerate: boolean = true;

  configurationId: number = CONFIGURATION_ID;
  normalInterfaceId: number = INTERFACE_ID;
  normalEndpointId: number = ENDPOINT_ID;
  debugInterfaceId: number = DEBUG_INTERFACE_ID;
  debugEndpointId: number = DEBUG_ENDPOINT_ID;

  unreadableHidDevice: boolean = false;

  unreadableHidDeviceChange: EventEmitter = new EventEmitter();

  @debugInOut
  async init(debug: ?boolean): Promise<void> {
    this.debug = !!debug;
    // $FlowIssue
    const usb = navigator.usb;
    if (usb == null) {
      throw new Error(`WebUSB is not available on this browser.`);
    } else {
      this.usb = usb;
    }
  }

  _deviceHasDebugLink(device: USBDevice): boolean {
    try {
      const iface = device.configurations[0].interfaces[DEBUG_INTERFACE_ID].alternates[0];
      return iface.interfaceClass === 255 && iface.endpoints[0].endpointNumber === DEBUG_ENDPOINT_ID;
    } catch (e) {
      return false;
    }
  }

  _deviceIsHid(device: USBDevice): boolean {
    return device.vendorId === T1HID_VENDOR;
  }

  async _listDevices(): Promise<Array<{path: string, device: USBDevice, debug: boolean}>> {
    let bootloaderId = 0;
    const devices = await this.usb.getDevices();
    const trezorDevices = devices.filter(dev => {
      const isTrezor = TREZOR_DESCS.some(desc =>
        dev.vendorId === desc.vendorId && dev.productId === desc.productId
      );
      return isTrezor;
    });
    const hidDevices = trezorDevices.filter(dev => this._deviceIsHid(dev));
    const nonHidDevices = trezorDevices.filter(dev => !this._deviceIsHid(dev));

    this._lastDevices = nonHidDevices.map(device => {
      // path is just serial number
      // more bootloaders => number them, hope for the best
      const serialNumber = device.serialNumber;
      let path = (serialNumber == null || serialNumber === ``) ? `bootloader` : serialNumber;
      if (path === `bootloader`) {
        bootloaderId++;
        path = path + bootloaderId;
      }
      const debug = this._deviceHasDebugLink(device);
      return {path, device, debug};
    });

    const oldUnreadableHidDevice = this.unreadableHidDevice;
    this.unreadableHidDevice = hidDevices.length > 0;

    if (oldUnreadableHidDevice !== this.unreadableHidDevice) {
      this.unreadableHidDeviceChange.emit(`change`);
    }

    return this._lastDevices;
  }

  _lastDevices: Array<{path: string, device: USBDevice, debug: boolean}> = [];

  async enumerate(): Promise<Array<TrezorDeviceInfoDebug>> {
    return (await this._listDevices()).map(info => ({path: info.path, debug: info.debug}));
  }

  async _findDevice(path: string): Promise<USBDevice> {
    const deviceO = (this._lastDevices).find(d => d.path === path);
    if (deviceO == null) {
      throw new Error(`Action was interrupted.`);
    }
    return deviceO.device;
  }

  async send(path: string, data: ArrayBuffer, debug: boolean): Promise<void> {
    const device: USBDevice = await this._findDevice(path);

    const newArray: Uint8Array = new Uint8Array(64);
    newArray[0] = 63;
    newArray.set(new Uint8Array(data), 1);

    if (!device.opened) {
      await this.connect(path, debug, false);
    }

    const endpoint = debug ? this.debugEndpointId : this.normalEndpointId;

    return device.transferOut(endpoint, newArray).then(() => {});
  }

  async receive(path: string, debug: boolean): Promise<ArrayBuffer> {
    const device: USBDevice = await this._findDevice(path);
    const endpoint = debug ? this.debugEndpointId : this.normalEndpointId;

    try {
      if (!device.opened) {
        await this.connect(path, debug, false);
      }

      const res = await device.transferIn(endpoint, 64);
      if (res.data.byteLength === 0) {
        return this.receive(path, debug);
      }
      return res.data.buffer.slice(1);
    } catch (e) {
      if (e.message === `Device unavailable.`) {
        throw new Error(`Action was interrupted.`);
      } else {
        throw e;
      }
    }
  }

  @debugInOut
  async connect(path: string, debug: boolean, first: boolean): Promise<void> {
    for (let i = 0; i < 5; i++) {
      if (i > 0) {
        await new Promise((resolve) => setTimeout(() => resolve(), i * 200));
      }
      try {
        return await this._connectIn(path, debug, first);
      } catch (e) {
        // ignore
        if (i === 4) {
          throw e;
        }
      }
    }
  }

  async _connectIn(path: string, debug: boolean, first: boolean): Promise<void> {
    const device: USBDevice = await this._findDevice(path);
    await device.open();

    if (first) {
      await device.selectConfiguration(this.configurationId);
      try {
        // reset fails on ChromeOS and windows
        await device.reset();
      } catch (error) {
        // do nothing
      }
    }

    const interfaceId = debug ? this.debugInterfaceId : this.normalInterfaceId;
    await device.claimInterface(interfaceId);
  }

  @debugInOut
  async disconnect(path: string, debug: boolean, last: boolean): Promise<void> {
    const device: USBDevice = await this._findDevice(path);

    const interfaceId = debug ? this.debugInterfaceId : this.normalInterfaceId;
    await device.releaseInterface(interfaceId);
    if (last) {
      await device.close();
    }
  }

  async requestDevice(): Promise<void> {
    // I am throwing away the resulting device, since it appears in enumeration anyway
    await this.usb.requestDevice({filters: TREZOR_DESCS});
  }

  requestNeeded: boolean = true;
}