const { Injectable } = require('flitter-di')
const moment = require('moment')

class UniversalPath extends Injectable {
    static get services() {
        return [...super.services, 'hosts']
    }

    static PATH_TYPE_FILE = Symbol('file')
    static PATH_TYPE_DIRECTORY = Symbol('directory')
    static PATH_TYPE_UNKNOWN = Symbol('unknown')
    _directory_classify_command = 'test -d'
    _file_classify_command = 'test -f'
    _datetime_format = 'Y-MM-DD_HH-mm-ss-SSSS'

    static fromString(path_string) {
        const parts = path_string.split('::')
        const hostname = parts.length > 1 ? parts[0] : 'localhost'
        const path = parts.length > 1 ? parts[1] : parts[0]
        const host = this.prototype.hosts.get(hostname)
        return new this(host, path)
    }

    constructor(host, host_path, type) {
        super()
        this._host = host
        this._path = host_path
        this._type = type ? type : this.constructor.PATH_TYPE_UNKNOWN
    }

    get host() {
        return this._host
    }

    get path() {
        return this._path
    }

    get type() {
        return this._type
    }

    async resolve() {
        return this._host.resolve_path(this._path)
    }

    is_directory() {
        return this.type === this.constructor.PATH_TYPE_DIRECTORY
    }

    is_file() {
        return this.type === this.constructor.PATH_TYPE_FILE
    }

    is_valid() {
        return this.is_file() || this.is_directory()
    }

    async classify() {
        const dir_result = await this._host.execute(`${this._directory_classify_command} ${this._path}`)
        if ( dir_result.exit_code === 0 ) {
            this._type = this.constructor.PATH_TYPE_DIRECTORY
            return
        }

        const file_result = await this._host.execute(`${this._file_classify_command} ${this._path}`)
        if ( file_result.exit_code === 0 ) {
            this._type = this.constructor.PATH_TYPE_FILE
            return
        }

        this._type = this.constructor.PATH_TYPE_UNKNOWN
    }

    async open_read_stream() {
        await this.classify()
        if ( this._type === this.constructor.PATH_TYPE_FILE ) {
            return this._host.open_file_read_stream(this._path)
        } else {
            throw new Error('Maestro does not support generation of read streams for this type of path: '+this._type.description)
        }
    }

    async open_write_stream() {
        await this.classify()
        if (
            [this.constructor.PATH_TYPE_FILE, this.constructor.PATH_TYPE_UNKNOWN].includes(this._type)
        ) {
            return this._host.open_file_write_stream(this._path)
        } else {
            throw new Error('Maestro does not support generation of write streams for this type of path: '+this._type.description)
        }
    }

    async copy_from(other_path) {
        const read = await other_path.open_read_stream()
        const write = await this.open_write_stream()
        await read.pipe(write)
    }

    async copy_to(other_path) {
        const read = await this.open_read_stream()
        const write = await other_path.open_write_stream()
        await read.pipe(write)
    }

    async unlink() {
        await this.host.delete_path(this._path)
    }

    async move_from(other_path) {
        await this.copy_from(other_path)
        await other_path.unlink()
    }

    async move_to(other_path) {
        await this.copy_to(other_path)
        await this.unlink()
    }

    async touch(directory = false) {
        await this.classify()
        if ( !directory ) {
            const base_dir = this._path.split('/').slice(0, -1).join('/')
            await this._host.run(`mkdir -p ${base_dir}`)
            await this._host.run(`touch ${this._path}`)
        } else {
            await this._host.run(`mkdir -p ${this._path}`)
        }
    }

    async echo(text) {
        await this.classify()
        if ( this.is_directory() ) {
            throw new Error('Cannot echo to a directory.')
        }

        if ( !this.is_valid() ) {
            await this.touch()
        }

        const ws = await this.open_write_stream()
        ws.write(text)
        return new Promise(resolve => {
            ws.on('finish', () => resolve())
            ws.end()
        })
    }

    async hash() {
        const line = await this._host.run_line_result(`sha256sum ${this._path}`)
        return line.split(' ')[0]
    }

    async backup() {
        const now = moment().format(this._datetime_format)
        const backup_path = `${this}.maestro-backup-${now}`
        const backup_target = this.constructor.fromString(backup_path)
        await this.copy_to(backup_target)
    }

    toString() {
        return `${this._host.name}::${this._path}`
    }
}

module.exports = exports = UniversalPath