import * as vscode from 'vscode';
import * as path from 'path';
import * as os from 'os';
import * as fs from 'fs';
const {
  generateKeyPairSync,
  createHash
} = require('node:crypto');
const sshpk = require('sshpk');

export default class User {
    private context:vscode.ExtensionContext;
    private username:string|undefined;
    private userToken:string|undefined;
    private usernameKey:string = 'devstarUsername'
    private userTokenKey:string = 'devstarUserToken'

    constructor(context: vscode.ExtensionContext) {
        this.context = context;
        this.username = this.context.globalState.get(this.usernameKey);
        this.userToken = this.context.globalState.get(this.userTokenKey);
    }

    private isLogged() {
        var existUsername = false;
        var existUserToken = false;
        if(this.username != undefined && this.username != '') {
            existUsername = true;
        }
        if(this.userToken != undefined && this.userToken != '') {
            existUserToken = true;
        }

        if (existUsername && existUserToken) {
            return true;
        } else {
            return false;
        }
    }

    public getUsernameFromLocal(): string|undefined {
        return this.username;
    }

    public getUserTokenFromLocal(): string|undefined{
        return this.userToken;
    }

    public setUsernameToLocal(username:string) {
        this.context.globalState.update(this.usernameKey, username);
        this.username = username;
    }

    public setUserTokenToLocal(userToken:string) {
        this.context.globalState.update(this.userTokenKey, userToken)
        this.userToken = userToken
    }

    public getUserPrivateKeyPath() : string{
        if (!this.isLogged) {
            return '';
        }

        return path.join(os.homedir(), '.ssh', `id_rsa_${this.username}`)
    }

    public getUserPublicKeyPath() :string{
        if (!this.isLogged) {
            return '';
        }

        return path.join(os.homedir(), '.ssh', `id_rsa_${this.username}.pub`)
    }

    public existUserPublicKey() :boolean{
        const userPublicKeyPath = this.getUserPublicKeyPath();
        return fs.existsSync(userPublicKeyPath)
    }

    public existUserPrivateKey() :boolean{
        const userPrivateKeyPath = this.getUserPrivateKeyPath();
        return fs.existsSync(userPrivateKeyPath)
    }

    public getUserPublicKey(): string {
        const userPublicKeyPath = this.getUserPublicKeyPath();
        const userPublicKey = fs.readFileSync(userPublicKeyPath, 'utf-8');
        // remove `\r` `\n`
        const trimmedDefaultPublicKey = userPublicKey.replace(/[\r\n]/g, "");
        return trimmedDefaultPublicKey;
    }

    public getUserPrivateKey(): string {
        const userPrivateKey = this.getUserPrivateKeyPath();
        return fs.readFileSync(userPrivateKey, 'utf-8');
    }

    public async createUserSSHKey() {
        if (this.existUserPublicKey() && this.existUserPrivateKey()) {
            // if both public and private key exists, stop
            return;
        }

        const {
          publicKey,
          privateKey,
        } = await generateKeyPairSync('rsa', {
          modulusLength: 4096,
          publicKeyEncoding: {
            type: 'spki',
            format: 'pem',
          },
          privateKeyEncoding: {
            type: 'pkcs8',
            format: 'pem',
          },
        });
        const publicKeyFingerprint = sshpk.parseKey(publicKey, 'pem').toString('ssh');
        const publicKeyStr = publicKeyFingerprint; // public key is public key fingerprint
        const privateKeyStr = privateKey;

        try {
          await fs.writeFileSync(this.getUserPublicKeyPath(), publicKeyStr);
          await fs.writeFileSync(this.getUserPrivateKeyPath(), privateKeyStr);
          // limit the permission of private key to prevent that the private key not works
          await fs.chmodSync(this.getUserPrivateKeyPath(), 0o600)
        } catch(error) {
          console.error("Failed to write public/private key into the default ssh public/key file: ", error);
        }
    }
}