'use strict';

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

const QRCode = require('qrcode');

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

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

module.exports = class WireGuard {

  async getConfig() {
    if (!this.__configPromise) {
      this.__configPromise = Promise.resolve().then(async () => {
        let config;
        try {
          config = await fs.readFile(path.join(WG_PATH, 'wg0.json'), 'utf8');
          config = JSON.parse(config);
        } catch (err) {
          config = {
            server: {
              // TODO: Generate new config
              address: WG_DEFAULT_ADDRESS,
              dns: WG_DEFAULT_DNS,
            },
            clients: {},
          };
        }

        return config;
      });
    }

    return this.__configPromise;
  }

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

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

    for (const [clientId, client] of Object.entries(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(config, false, 2));
    await fs.writeFile(path.join(WG_PATH, 'wg0.conf'), result);
  }

  async getClients() {
    const config = await this.getConfig();
    const clients = Object.entries(config.clients).map(([clientId, client]) => ({
      id: clientId,
      name: client.name,
      enabled: client.enabled,
      publicKey: client.publicKey,
      createdAt: new Date(client.createdAt),
      updatedAt: new Date(client.updatedAt),
      allowedIPs: client.allowedIPs,

      persistentKeepalive: null,
      latestHandshakeAt: null,
      transferRx: null,
      transferTx: null,
    }));

    // Loop WireGuard status
    const clientsDump = await Util.exec('wg show wg0 dump');
    // const clientsDump = `iOQJS7OUUGPYATsX6nqlL+sOODoiWiN5IOE8Msfw/0o=	BkdntwYazhYZzEEHhcYayq6TGw9/YUDQ251s+5bTgC0=	51820	off
    // i8xWKqicnDkNL14I4B+I1zlB8od/booA1joIosWn7X4=	MzplKtOQ44/IaAKri2VKqCoIlg4XiVH7TCp5bcYRTQU=	172.17.0.1:60475	10.8.0.2/32	1621679257	7920	7440	off`;
    clientsDump
      .trim()
      .split('\n')
      .slice(1)
      .forEach(line => {
        const [
          publicKey,
          preSharedKey, // eslint-disable-line no-unused-vars
          endpoint,
          allowedIps, // eslint-disable-line no-unused-vars
          latestHandshakeAt,
          transferRx,
          transferTx,
          persistentKeepalive,
        ] = line.split('\t');

        const client = clients.find(client => client.publicKey === publicKey);
        if (!client) return;

        client.endpoint = endpoint === '(none)'
          ? null
          : endpoint;
        client.latestHandshakeAt = latestHandshakeAt === '0'
          ? null
          : new Date(Number(`${latestHandshakeAt}000`));
        client.transferRx = Number(transferRx);
        client.transferTx = Number(transferTx);
        client.persistentKeepalive = persistentKeepalive;
      });

    return clients;
  }

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

    return client;
  }

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

    return `
[Interface]
PrivateKey = ${client.privateKey}
Address = ${client.address}
DNS = ${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 }) {
    const config = await this.getConfig();

    if (config.clients[clientId]) {
      delete 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();
  }

};