'use strict';

const fs = require('fs').promises;
const path = require('path');

const QRCode = require('qrcode');

const ServerError = require('./ServerError');

const {
  WG_PATH,
  WG_HOST,
  WG_PORT,
  WG_DEFAULT_ADDRESS,
} = require('../config');

module.exports = class WireGuard {

  constructor() {
    Promise.resolve().then(async () => {
      try {
        const config = await fs.readFile(path.join(WG_PATH, 'wg0.json'), 'utf8');
        this.config = JSON.parse(config);
      } catch (err) {
        this.config = {
          // TODO: Generate new config
          server: {
            address: WG_DEFAULT_ADDRESS,
          },
          clients: {},
        };
        // TODO: Save JSON config
      }

      console.log('this.config', this.config);

      await this.saveConfig();
    }).catch(err => {
      // eslint-disable-next-line no-console
      console.error(err);

      // eslint-disable-next-line no-process-exit
      process.exit(1);
    });
  }

  async saveConfig() {
    let result = `
# Note: Do not edit this file directly.
# Your changes will be overwritten!

# Server
[Interface]
PrivateKey = ${this.config.server.privateKey}
Address = ${this.config.server.address}
ListenPort = ${this.config.server.port}
DNS = ${this.config.server.dns}`;

    for (const [clientId, client] of Object.entries(this.config.clients)) {
      if (!client.enabled) continue;

      result += `

# Client: ${client.name} (${clientId})
[Peer]
PublicKey = ${client.publicKey}
PresharedKey = ${client.preSharedKey}
AllowedIPs = ${client.allowedIPs}`;
    }

    await fs.writeFile(path.join(WG_PATH, 'wg0.json'), JSON.stringify(this.config, false, 2));
    await fs.writeFile(path.join(WG_PATH, 'wg0.conf'), result);
  }

  async getClients() {
    return Object.entries(this.config.clients).map(([clientId, client]) => ({
      id: clientId,
      name: client.name,
      enabled: client.enabled,
      publicKey: client.publicKey,
      createdAt: client.createdAt,
      updatedAt: client.updatedAt,
      allowedIPs: client.allowedIPs,

      // TODO:
      latestHandshake: new Date(),
      transferRx: 0,
      transferTx: 0,
    }));
    // const { stdout } = await Util.exec('sudo cat /etc/wireguard/configs/clients.txt');
    // return stdout
    //   .trim()
    //   .split('\n')
    //   .filter(line => {
    //     return line.length > 0;
    //   })
    //   .map(line => {
    //     const [ name, publicKey, createdAt ] = line.split(' ');
    //     return {
    //       name,
    //       publicKey,
    //       createdAt: new Date(Number(createdAt + '000')),
    //     };
    //   });
  }

  async getClient({ clientId }) {
    const client = this.config.clients[clientId];
    if (!client) {
      throw new ServerError(`Client Not Found: ${clientId}`, 404);
    }

    return client;
  }

  async getClientConfiguration({ clientId }) {
    const client = await this.getClient({ clientId });

    return `
[Interface]
PrivateKey = ${client.privateKey}
Address = ${client.address}
DNS = ${this.config.server.dns}

[Peer]
PublicKey = ${client.publicKey}
PresharedKey = ${client.preSharedKey}
AllowedIPs = ${client.allowedIPs}
Endpoint = ${WG_HOST}:${WG_PORT}`;
  }

  async getClientQRCodeSVG({ clientId }) {
    const config = await this.getClientConfiguration({ clientId });
    return QRCode.toString(config, {
      type: 'svg',
      width: 512,
    });
  }

  async createClient({ name }) {
    if (!name) {
      throw new Error('Missing: Name');
    }

    // try {
    //   await this.getClient({ name });
    //   throw new Error(`Duplicate Client: ${name}`);
    // } catch( err ) {
    //   if( err.message.startsWith('Duplicate Client') ) {
    //     throw err;
    //   }
    // }

    // // TODO: This is unsafe
    // await this.ssh.exec(`pivpn add -n ${name}`);

    // return this.getClient({ name });

    await this.saveConfig();
  }

  async deleteClient({ clientId }) {
    if (this.config.clients[clientId]) {
      delete this.config.clients[clientId];
      await this.saveConfig();
    }
  }

  async enableClient({ clientId }) {
    const client = await this.getClient({ clientId });
    client.enabled = true;

    await this.saveConfig();
  }

  async disableClient({ clientId }) {
    const client = await this.getClient({ clientId });
    client.enabled = false;

    await this.saveConfig();
  }

};