const Host = require('./Host')
const ssh = require('ssh2')
const ExecutionResult = require('../logical/ExecutionResult')
const fs = require('fs').promises

class RemoteHost extends Host {
    _ssh = false

    async execute(command) {
        const conn = await this._get_ssh_connection()
        const result = new ExecutionResult()
        await new Promise((resolve, reject) => {
            conn.exec(command, (error, stream) => {
                if ( error ) reject(error)
                else {
                    stream.on('close', (code, signal) => {
                        result.exit(code)
                        resolve()
                    }).on('data', (data) => {
                        result.out(data)
                    }).stderr.on('data', (data) => {
                        result.error(data)
                    })
                }
            })
        })

        return result
    }

    async open_file_read_stream(file_path) {
        file_path = typeof file_path === 'string' ? file_path : file_path.path
        const sftp = await this._get_sftp_connection()
        return sftp.createReadStream(file_path)
    }

    async open_file_write_stream(file_path) {
        file_path = typeof file_path === 'string' ? file_path : file_path.path
        const sftp = await this._get_sftp_connection()
        return sftp.createWriteStream(file_path)
    }

    async _get_ssh_connection() {
        if ( this._ssh ) return this._ssh

        if ( this.config.ssh_params && this.config.ssh_params.key_file && !this.config.ssh_params.privateKey ) {
            this.config.ssh_params.privateKey = await fs.readFile(this.config.ssh_params.key_file)
        }

        return new Promise((resolve, reject) => {
            const client = new ssh.Client()
            client.on('ready', () => {
                this._ssh = client
                resolve(client)
            }).connect(this.config.ssh_params)
            client.on('error', reject)
        })
    }

    async _get_sftp_connection() {
        const ssh = await this._get_ssh_connection()
        return new Promise((resolve, reject) => {
            ssh.sftp((err, sftp) => {
                if ( err ) reject(err)
                else resolve(sftp)
            })
        })
    }

    async _cleanup() {
        if ( this._ssh ) {
            this._ssh.end()
        }
    }
}

module.exports = exports = RemoteHost