import {
  apply,
  chain,
  url,
  mergeWith,
  template,
  move,
  noop,
  filter,
  Rule,
  Tree,
  SchematicContext,
} from '@angular-devkit/schematics';

import { Schema } from './schema';
import * as path from 'path';

import { names, toFileName } from '@nrwl/workspace';

import {
  addImportsToModule,
  addNgRxToPackageJson,
  addExportsToBarrel,
  RequestContext,
} from './rules';
import { formatFiles } from '@nrwl/workspace';

/**
 * Rule to generate the Nx 'ngrx' Collection
 * Note: see https://nx.dev/angular/guides/misc-ngrx for guide to generated files
 */
export default function generateNgrxCollection(_options: Schema): Rule {
  return (host: Tree, context: SchematicContext) => {
    const options = normalizeOptions(_options);

    if (!options.module) {
      throw new Error(`The required --module option must be passed`);
    } else if (!host.exists(options.module)) {
      throw new Error(`Path does not exist: ${options.module}`);
    }

    const requestContext: RequestContext = {
      featureName: options.name,
      moduleDir: path.dirname(options.module),
      options,
      host,
    };

    if (options.minimal) {
      options.onlyEmptyRoot = true;
    }

    if (options.skipImport) {
      options.onlyAddFiles = true;
    }

    const fileGeneration =
      !options.onlyEmptyRoot || (!options.root && options.minimal)
        ? [generateNgrxFilesFromTemplates(options)]
        : [];

    const moduleModification = !options.onlyAddFiles
      ? [
          addImportsToModule(requestContext),
          addExportsToBarrel(requestContext.options),
        ]
      : [];

    const packageJsonModification = !options.skipPackageJson
      ? [addNgRxToPackageJson()]
      : [];

    return chain([
      ...fileGeneration,
      ...moduleModification,
      ...packageJsonModification,
      formatFiles(options),
    ])(host, context);
  };
}

// ********************************************************
// Internal Function
// ********************************************************

/**
 * Generate 'feature' scaffolding: actions, reducer, effects, interfaces, selectors, facade
 */
function generateNgrxFilesFromTemplates(options: Schema) {
  const name = options.name;
  const moduleDir = path.dirname(options.module);
  const excludeFacade = (path) => path.match(/^((?!facade).)*$/);

  const templateSource = apply(
    url(options.syntax === 'creators' ? './creator-files' : './files'),
    [
      !options.facade ? filter(excludeFacade) : noop(),
      template({ ...options, tmpl: '', ...names(name) }),
      move(moduleDir),
    ]
  );

  return mergeWith(templateSource);
}

/**
 * Extract the parent 'directory' for the specified
 */
function normalizeOptions(options: Schema): Schema {
  return {
    ...options,
    directory: toFileName(options.directory),
  };
}