const _ = require('lodash');

const getType = (fn) => {
    const match = fn && fn.toString().match(/^\s*function (\w+)/);

    return match ? match[1] : '';
};

const simpleCheckRE = /^(String|Number|Boolean|Function|Symbol)$/;

const assetType = (value, type) => {
    const expectedType = getType(type);
    let valid;

    if (simpleCheckRE.test(expectedType)) {
        const t = typeof value;

        valid = t === expectedType.toLowerCase();

        // for primitive wrapper objects
        if (!valid && t === 'object') {
            valid = value instanceof type;
        }
    } else if (expectedType === 'Object') {
        valid = value.toString() === '[object Object]';
    } else if (expectedType === 'Array') {
        valid = Array.isArray(value);
    } else {
        valid = value instanceof type;
    }
    return valid;
};

const getParams = (params, apiInfo) => {
    let props = {};

    if (apiInfo.params) {
        _.each(apiInfo.params, (v, k) => {
            const paramItem = params[k];

            if (!paramItem) {
                if (v.require) {
                    throw Error(`${k} params is not undefined`);
                }
                return;
            }
            if (!assetType(paramItem, v.type)) {
                throw Error(`${k} params is not ${getType(v.type)}`);
            }
            props[k] = paramItem;
        });
    }
    return params;
};

module.exports = {
    getParams
};