import * as fs from 'fs';
import * as nodePath from 'path';
import { FileConfigNodeFileResourceServiceOptions, IFileConfigNode } from './types';

import { getFsStats, merge } from '../lib';

const defaultOptions: FileConfigNodeFileResourceServiceOptions = {
    dirBaseName: 'resources',
};

export class FileConfigNodeFileResourceService {
    public get path(): string {
        if (!this._path) {
            // let configRootPath: string;
            const fileConfigNodeRootPathStats = getFsStats(this.fileConfigNode.path);
            if (fileConfigNodeRootPathStats) {
                const configRootPath = fileConfigNodeRootPathStats.isDirectory()
                    ? this.fileConfigNode.path
                    : nodePath.dirname(this.fileConfigNode.path);

                this._path = nodePath.join(configRootPath, this.options.dirBaseName);
            } else {
                // don't think this should be possible as would have already been hit by ConfigNode
                throw new Error(`FileConfigNodeFileResourceService Root Path Not Found`);
            }
        }
        return this._path;
    }
    public readonly options: FileConfigNodeFileResourceServiceOptions;
    private _path: string;

    constructor(
        private fileConfigNode: IFileConfigNode,
        options: FileConfigNodeFileResourceServiceOptions = defaultOptions
    ) {
        this.options = merge([defaultOptions, options]);
    }

    /**
     * Resolves first existing search paths matching passed path and subpath
     * @param path relative path from search path to find
     * @returns path
     */
    public resolvePath = (...path: string[]): string | null => {
        const subPathToFind = nodePath.join(...path);
        const fullPathToFind = nodePath.join(this.path, subPathToFind);
        if (fs.existsSync(fullPathToFind)) {
            return fullPathToFind;
        } else {
            const inheritedNodes = this.fileConfigNode.resolveInheritedNodes();
            for (const inheritedNode of inheritedNodes) {
                // tslint:disable-next-line: no-string-literal
                if (inheritedNode['fileResources']) {
                    const node = (inheritedNode as unknown) as IFileConfigNode;
                    const found = node.fileResources.resolvePath(...path);
                    if (found) {
                        return found;
                    }
                }
            }
        }
        return null;
    };
}