import { ClientParams, MapperFn, UrlFn} from '../models';
import { hasProp, isString, toQuery } from '../utils';

export class UrlBuilder {

	private paramMatcher = /(:\b\D\w*)/g;
	private options: any = {};
	private clientParams: ClientParams;
	private mappers: { [key: string]: MapperFn } = {};

	static create(url: string | UrlFn, query: { [key: string]: any } = null) {
		return new UrlBuilder(url, query);
	}

	constructor(private url: string | UrlFn, private query: { [key: string]: any }) {
	}

	addOptions(options: any, defaultParamName: string = null) {
		if (isString(options) && !!defaultParamName) {
			this.options[defaultParamName] = options;
		} else {
			this.options = { ...this.options, ...options };
		}
		return this;
	}

	setParams(clientParams: ClientParams) {
		this.clientParams = clientParams;
		return this;
	}

	addMappers(mappers: { [key: string]: MapperFn }) {
		if (mappers) {
			Object.keys(mappers).forEach(key => {
				this.mappers[key] = mappers[key];
			});
		}
		return this;
	}

	toUrl(): string {
		let namedParams = {};
		let urlTemplate = typeof this.url === 'function' ? this.url(this.options, this.clientParams) : this.url;

		let paramNames = urlTemplate.match(this.paramMatcher);
		if (paramNames) {
			paramNames.forEach(paramName => {
				let key = paramName.substring(1);
				let value: any = null;
				if (hasProp(this.options, key)
					&& this.options[key] !== null) {
					value = this.options[key];
				} else if (hasProp(this.clientParams, key)
					&& this.clientParams[key] !== null) {
					value = this.clientParams[key];
				}

				let mapperValue: any = null;
				if (this.mappers[paramName]) {
					mapperValue = this.mappers[paramName](value, this.options, this.clientParams);
				}

				namedParams[paramName] = mapperValue !== null ? mapperValue : value;
			});
		}

		let query = {};
		if (this.query) {
			query = { ...this.query };
			Object.keys(this.query).forEach(paramName => {
				let value = query[paramName];
				if (hasProp(this.options, paramName)
					&& this.options[paramName] !== null) {
					value = this.options[paramName];
				} else if (hasProp(this.clientParams, paramName)
					&& this.clientParams[paramName] !== null) {
					value = this.clientParams[paramName];
				}

				query[paramName] = this.mappers[paramName] ?
					this.mappers[paramName](value, this.options, this.clientParams) : value;
			});
		}

		let url = Object.keys(namedParams)
			.reduce((url, key) => url.replace(key, namedParams[key]), urlTemplate);
		let queryString = toQuery(query);

		return `${url}${queryString}`;
	}

}