import { Buffer } from 'node:buffer'
import crypto from 'node:crypto'
import fs from 'node:fs'

import { HomebridgePluginUiServer } from '@homebridge/plugin-ui-utils'

interface CustomRequestResponse {
  status: string
  data?: any
}

export class PluginUiServer extends HomebridgePluginUiServer {
  constructor() {
    super()

    // OAuth PKCE flow handler
    this.onRequest('startOAuthFlow', async (payload): Promise<CustomRequestResponse> => {
      try {
        const { consumerKey, consumerSecret, code, codeVerifier } = payload || {}
        if (!consumerKey || !consumerSecret) {
          return { status: 'error', data: 'Missing consumerKey or consumerSecret' }
        }
        // If no code, generate PKCE and return authUrl for UI
        if (!code) {
          const generatedVerifier = crypto.randomBytes(32).toString('base64url')
          const challenge = crypto.createHash('sha256').update(generatedVerifier).digest('base64url')
          const redirectUri = 'urn:ietf:wg:oauth:2.0:oob'
          const authUrl = `https://api.honeywell.com/oauth2/authorize?response_type=code&client_id=${encodeURIComponent(consumerKey)}&redirect_uri=${encodeURIComponent(redirectUri)}&code_challenge=${encodeURIComponent(challenge)}&code_challenge_method=S256&appSelect=1`
          return { status: 'need_code', data: { authUrl, codeVerifier: generatedVerifier } }
        }
        // Exchange code for tokens
        if (!codeVerifier) {
          return { status: 'error', data: 'Missing PKCE code_verifier' }
        }
        const redirectUri = 'urn:ietf:wg:oauth:2.0:oob'
        const tokenRes = await fetch('https://api.honeywell.com/oauth2/token', {
          method: 'POST',
          headers: {
            'Authorization': `Basic ${Buffer.from(`${consumerKey}:${consumerSecret}`).toString('base64')}`,
            'Accept': 'application/json',
            'Content-Type': 'application/x-www-form-urlencoded',
          },
          body: `grant_type=authorization_code&code=${encodeURIComponent(code)}&redirect_uri=${encodeURIComponent(redirectUri)}&code_verifier=${encodeURIComponent(codeVerifier)}`,
        })
        const tokenData = await tokenRes.json()
        if (tokenData.refresh_token) {
          return { status: 'ok', data: { refreshToken: tokenData.refresh_token, accessToken: tokenData.access_token } }
        } else {
          return { status: 'error', data: tokenData }
        }
      } catch (err) {
        return { status: 'error', data: (err && typeof err === 'object' && 'message' in err) ? (err as any).message : String(err) }
      }
    })

    // Device discovery handler
    this.onRequest('discoverDevices', async (payload): Promise<CustomRequestResponse> => {
      try {
        const { accessToken } = payload || {}
        if (!accessToken) {
          return { status: 'error', data: 'No access token provided' }
        }
        const res = await fetch('https://api.honeywell.com/v2/devices', {
          headers: {
            Authorization: `Bearer ${accessToken}`,
            Accept: 'application/json',
          },
        })
        if (!res.ok) {
          return { status: 'error', data: await res.text() }
        }
        const data = await res.json()
        return { status: 'ok', data }
      } catch (err) {
        return { status: 'error', data: (err && typeof err === 'object' && 'message' in err) ? (err as any).message : String(err) }
      }
    })

    // Legacy: getCachedAccessories for older config-ui-x
    this.onRequest('/getCachedAccessories', async (): Promise<CustomRequestResponse> => {
      try {
        const plugin = '@homebridge-plugins/homebridge-firstalert'
        const devicesToReturn: any[] = []
        const accFile = `${this.homebridgeStoragePath}/accessories/cachedAccessories`
        if (fs.existsSync(accFile)) {
          const cachedAccessoriesData = await fs.promises.readFile(accFile, 'utf8')
          const cachedAccessories: any[] = JSON.parse(cachedAccessoriesData)
          cachedAccessories
            .filter((accessory: any) => accessory.plugin === plugin)
            .forEach((accessory: any) => devicesToReturn.push(accessory))
        }
        return { status: 'ok', data: devicesToReturn }
      } catch (err) {
        return { status: 'error', data: [] }
      }
    })

    this.ready()
  }
}

(() => new PluginUiServer())()