import { Injectable, OnModuleInit } from '@nestjs/common'
import { debug, Debugger } from 'debug'
import { chunk, isEmpty, isNil } from 'lodash'
import { nanoid } from 'nanoid'

import { Firebender } from '../firebender'

import { PushPayload } from './value-objects'

export const DEVICES_CHUNK_LIMIT = 800
export const FLUTTER_CLICK_ACTION = 'FLUTTER_NOTIFICATION_CLICK'

export type PushNotificationTemplate = { title: string; message: string; page: string }

@Injectable()
export class MessagingService implements OnModuleInit {
  private debug: Debugger = debug(`http:${this.constructor.name}`)
  private firebender: Firebender

  onModuleInit(): void {
    this.firebender = new Firebender()
  }

  async sendPushNotificationByTemplate(
    { title, message, page }: PushNotificationTemplate,
    deviceId: string,
  ): Promise<void> {
    const push: PushPayload = PushPayload.toInstance({
      notification: {
        title,
        body: message,
      },
      data: {
        click_action: FLUTTER_CLICK_ACTION,
        page,
      },
    })

    await this.sendPushNotification(deviceId, push)
  }

  async sendPushNotification(devices: string | Array<string>, payload: PushPayload): Promise<void> {
    if (isNil(devices) || isEmpty(devices) || isNil(payload)) return null

    if (Array.isArray(devices)) {
      const chunked = chunk(devices, DEVICES_CHUNK_LIMIT)

      for (const chunkDevices of chunked) {
        try {
          await this.push(payload, chunkDevices)
        } catch (err) {
          this.debug(`Error sending Push Notification '${payload?.notification?.title}': ${err.messages}`)
        }
      }

      return null
    }

    try {
      await this.push(payload, devices)
    } catch (err) {
      this.debug(`Error sending Push Notification '${payload?.notification?.title}': ${err.messages}`)
    }
  }

  private push = async (payload: PushPayload, devices: string | Array<string>): Promise<void> => {
    const id = nanoid()

    this.debug.extend('request')(JSON.stringify({ id, type: 'push', body: { ...payload, devices } }))

    const response = await this.firebender.firebaseAdmin.messaging().sendToDevice(devices, {
      ...JSON.parse(JSON.stringify(payload)),
    })

    this.debug.extend('response')(JSON.stringify({ id, response }))
  }
}