// (C) 2007-2019 GoodData Corporation
import { Application, Request, Response } from "express";
import { isEqual } from "lodash";
import * as HttpStatusCodes from "http-status-codes";

export interface IMockResponseConfig {
    params?: { [key: string]: any };
    query?: { [key: string]: any };
    headers?: { [key: string]: any };
    body?: { [key: string]: any };
    response: any;
}

function isRequestHeadersMatching(headers: any, config: IMockResponseConfig) {
    if (!config.headers) {
        return true;
    }
    if (!headers) {
        return false;
    }
    return Object.keys(config.headers).every(key => config.headers[key] === headers[key]);
}

export function isMockRequestMatching(req: Request, config: IMockResponseConfig) {
    const keysMatch = ["params", "query", "body"].every(key => isEqual(req[key] || {}, config[key] || {}));
    const headersMatch = isRequestHeadersMatching(req.headers, config);
    return keysMatch && headersMatch;
}

export function getMatchingResponse(req: Request, mocks: IMockResponseConfig[] = []) {
    return mocks.find(mock => isMockRequestMatching(req, mock));
}

type HttpMethod = "get" | "post";

export function mock(
    app: Application,
    method: HttpMethod,
    uri: string,
    mockConfigs: IMockResponseConfig[],
    defaultMockConfig: IMockResponseConfig = null,
) {
    app[method](uri, (req: Request, res: Response) => {
        const mockedResponseConfig = getMatchingResponse(req, mockConfigs) || defaultMockConfig;
        if (mockedResponseConfig) {
            res.status(HttpStatusCodes.OK).json(mockedResponseConfig.response);
            return;
        }

        res.status(HttpStatusCodes.BAD_REQUEST).send("Can't find mock for this request");
    });
}