import { assert } from '@0xproject/assert';
import { schemas } from '@0xproject/json-schemas';
import 'isomorphic-fetch';
import * as _ from 'lodash';
import * as queryString from 'query-string';

import { schemas as clientSchemas } from './schemas/schemas';
import {
    Client,
    FeesRequest,
    FeesResponse,
    HttpRequestOptions,
    HttpRequestType,
    OrderbookRequest,
    OrderbookResponse,
    OrdersRequest,
    SignedOrder,
    TokenPairsItem,
    TokenPairsRequest,
} from './types';
import { relayerResponseJsonParsers } from './utils/relayer_response_json_parsers';

/**
 * This class includes all the functionality related to interacting with a set of HTTP endpoints
 * that implement the standard relayer API v0
 */
export class HttpClient implements Client {
    private _apiEndpointUrl: string;
    /**
     * Instantiates a new HttpClient instance
     * @param   url    The relayer API base HTTP url you would like to interact with
     * @return  An instance of HttpClient
     */
    constructor(url: string) {
        assert.isHttpUrl('url', url);
        this._apiEndpointUrl = url;
    }
    /**
     * Retrieve token pair info from the API
     * @param   request     A TokenPairsRequest instance describing specific token information
     *                      to retrieve
     * @return  The resulting TokenPairsItems that match the request
     */
    public async getTokenPairsAsync(request?: TokenPairsRequest): Promise<TokenPairsItem[]> {
        if (!_.isUndefined(request)) {
            assert.doesConformToSchema('request', request, clientSchemas.relayerTokenPairsRequestSchema);
        }
        const requestOpts = {
            params: request,
        };
        const result = await this._requestAsync(
            '/token_pairs',
            HttpRequestType.Get,
            relayerResponseJsonParsers.parseTokenPairsJson,
            requestOpts,
        );
        return result;
    }
    /**
     * Retrieve orders from the API
     * @param   request     An OrdersRequest instance describing specific orders to retrieve
     * @return  The resulting SignedOrders that match the request
     */
    public async getOrdersAsync(request?: OrdersRequest): Promise<SignedOrder[]> {
        if (!_.isUndefined(request)) {
            assert.doesConformToSchema('request', request, clientSchemas.relayerOrdersRequestSchema);
        }
        const requestOpts = {
            params: request,
        };
        const result = await this._requestAsync(
            `/orders`,
            HttpRequestType.Get,
            relayerResponseJsonParsers.parseOrdersJson,
            requestOpts,
        );
        return result;
    }
    /**
     * Retrieve a specific order from the API
     * @param   orderHash     An orderHash generated from the desired order
     * @return  The SignedOrder that matches the supplied orderHash
     */
    public async getOrderAsync(orderHash: string): Promise<SignedOrder> {
        assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
        const result = await this._requestAsync(
            `/order/${orderHash}`,
            HttpRequestType.Get,
            relayerResponseJsonParsers.parseOrderJson,
        );
        return result;
    }
    /**
     * Retrieve an orderbook from the API
     * @param   request     An OrderbookRequest instance describing the specific orderbook to retrieve
     * @return  The resulting OrderbookResponse that matches the request
     */
    public async getOrderbookAsync(request: OrderbookRequest): Promise<OrderbookResponse> {
        assert.doesConformToSchema('request', request, clientSchemas.relayerOrderBookRequestSchema);
        const requestOpts = {
            params: request,
        };
        const result = await this._requestAsync(
            '/orderbook',
            HttpRequestType.Get,
            relayerResponseJsonParsers.parseOrderbookResponseJson,
            requestOpts,
        );
        return result;
    }
    /**
     * Retrieve fee information from the API
     * @param   request     A FeesRequest instance describing the specific fees to retrieve
     * @return  The resulting FeesResponse that matches the request
     */
    public async getFeesAsync(request: FeesRequest): Promise<FeesResponse> {
        assert.doesConformToSchema('request', request, schemas.relayerApiFeesPayloadSchema);
        const requestOpts = {
            payload: request,
        };
        const result = await this._requestAsync(
            '/fees',
            HttpRequestType.Post,
            relayerResponseJsonParsers.parseFeesResponseJson,
            requestOpts,
        );
        return result;
    }
    /**
     * Submit a signed order to the API
     * @param   signedOrder     A SignedOrder instance to submit
     */
    public async submitOrderAsync(signedOrder: SignedOrder): Promise<void> {
        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
        const requestOpts = {
            payload: signedOrder,
        };
        await this._requestAsync(
            '/order',
            HttpRequestType.Post,
            _.noop,
            requestOpts,
        );
    }
    private async _requestAsync<T>(path: string, requestType: HttpRequestType,
                                   jsonParser: (json: any) => T,
                                   requestOptions?: HttpRequestOptions): Promise<T> {
        const params = _.get(requestOptions, 'params');
        const payload = _.get(requestOptions, 'payload');
        let query = '';
        if (!_.isUndefined(params) && !_.isEmpty(params)) {
            const stringifiedParams = queryString.stringify(params);
            query = `?${stringifiedParams}`;
        }
        const url = `${this._apiEndpointUrl}/v0${path}${query}`;
        const headers = new Headers({
            'content-type': 'application/json',
        });

        const response = await fetch(url, {
            method: requestType,
            body: JSON.stringify(payload),
            headers,
        });
        if (!response.ok) {
            throw Error(response.statusText);
        }
        const json = await response.json();
        return jsonParser(json);
    }
}