import { Injectable, Inject } from '@hapiness/core';

import { Etcd3, Namespace, Watcher, Lock, IPutResponse, Lease } from 'etcd3';
import { Observable } from 'rxjs';

import { ResponseFormat } from '../interfaces';
// import { Etcd3Manager } from '../managers';
import { Etcd3Ext } from '../etcd3.extension';

@Injectable()
export class Etcd3Service {

    /**
     *
     * @member {string} _basePath The base path from which all future key will be added
     *
     */
    private _basePath: string;

    /**
     *
     * @member {Namespace} _client The client having the base path to not concat manually all entry keys
     *
     */
    private _client: Namespace;


    constructor(@Inject(Etcd3Ext) private _manager) {
        let basePath = '/';

        if (this._manager.config.basePath) {
            basePath = this._manager.config.basePath;
            if (!this._manager.config.basePath.endsWith('/')) {
                basePath = `${basePath}/`;
            }
        }

        this._basePath = basePath;

        this._client = this._manager.client.namespace(this._basePath);
    }

    /**
     *
     * @returns {string} The value of the base path
     *
     */
    public get basePath(): string {
        return this._basePath;
    }

    /**
     *
     * Retrieve the client without basePath consideration
     *
     * @returns {Namespace} the client for the namespace
     *
     */
    public get client(): Namespace {
        return this._client;
    }

    /**
     *
     * Retrieve the client without basePath consideration
     *
     * @returns {Etcd3} the normal client (without namespace consideration)
     *
     */
    public etcd3Client(): Etcd3 {
        return this._manager.client;
    }


    /******************************************************************************************
     *
     *  KV operations
     *
     ******************************************************************************************/

    /**
     *
     * Get the value stored at path `key`.
     *
     * @param {string} key The key you want to retrieve the value
     * @param {ResponseFormat} format The format you want for the result (default is string)
     *
     * @returns {string | object | number | Buffer | null | Error} The value of the object stored
     *
     */
    public get(key: string, format: ResponseFormat = ResponseFormat.String):
        Observable<string | object | Buffer | null | Error> {
        const promise = this.client.get(key);
        switch (format) {
            case ResponseFormat.String:
                return Observable.fromPromise(promise.string());
            case ResponseFormat.Json:
                return Observable.fromPromise(promise.json());
            case ResponseFormat.Buffer:
                return Observable.fromPromise(promise.buffer());
            default:
        }

        return Observable.throw(new Error('Format not supported'));
    }

    /**
     *
     * Append the value `value` at path `key`.
     *
     * @param {string} key The key you want to retrieve the value
     * @param {string | Buffer | number} value The format you want for the result (default is string)
     *
     * @returns {IPutResponse} The result of the operation
     *
     */
    public put(key: string, value: string | number | Object | Buffer): Observable<IPutResponse> {
        if (!value) {
            return Observable.throw(new Error('"value" should not be null nor undefined'));
        }

        let _value: string | number | Buffer;

        if (typeof value === 'object') {
            try {
                const tmp = JSON.parse(JSON.stringify(value));
                if (tmp.type !== 'Buffer') {
                    _value = JSON.stringify(value);
                }
            } catch (err) {
                return Observable.throw(new Error('Unknown type of "value"'));
            }
        } else {
            _value = value;
        }

        return Observable.fromPromise(
            this.client.put(key).value(_value).exec()
        );
    }

    /******************************************************************************************
     *
     *  Watch operations
     *
     ******************************************************************************************/

    /**
     *
     * Create a watcher for a specific key.
     *
     * @param {string} key The key you want to watch
     *
     * @returns {Watcher} The watcher instance created
     *
     */
    public createWatcher(key: string): Observable<Watcher> {
        return Observable.fromPromise(
            this.client.watch().key(key).create()
        );
    }

    /******************************************************************************************
     *
     *  Lock operations
     *
     ******************************************************************************************/

    /**
     *
     * Create and acquire a lock for a key `key` specifying a ttl.
     * It will automatically contact etcd to keep the connection live.
     * When the connection is broken (end of process or lock released),
     * the TTL is the time after when the lock will be released.
     *
     * @param {string} key The key
     * @param {number} ttl The TTL value in seconds. Default value is 1
     *
     * @returns {Lock} The lock instance created
     *
     */
    public acquireLock(key: string, ttl: number = 1): Observable<Lock> {
        return Observable.fromPromise(
            this.client.lock(key).ttl(ttl || 1).acquire()
        );
    }

    /******************************************************************************************
     *
     * Lease Operations
     *
     ******************************************************************************************/

    /**
     *
     * Create a lease object with a ttl.
     * The lease is automatically keeping alive until it is close.
     *
     * @param {number} ttl The TTL value in seconds. Default value is 1
     *
     * @returns {Lease} The lease instance created
     *
     */
    public createLease(ttl: number = 1): Observable<Lease> {
        return Observable.of(this.client.lease(ttl || 1));
    }

    /**
     *
     * Create a lease object with a ttl and attach directly a key-value to it.
     * The lease is automatically keeping alive until it is close.
     *
     * NOTE: Once the lease is closed, the key-value will be destroyed by etcd.
     *
     * @param {string} key The key where to store the value
     * @param {string | Buffer | number} value The value that will be stored at `key` path
     * @param {number} ttl The TTL value in seconds. Default value is 1
     *
     * @returns {Lease} The lease instance created
     *
     */
    public createLeaseWithValue(key: string, value: string | Buffer, ttl: number = 1): Observable<Lease> {
        const lease = this.client.lease(ttl || 1);
        return Observable.fromPromise(
            lease.put(key).value(value).exec().then(_ => lease)
        );
    }
}