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

import {names, toClassName, toFileName, toPropertyName} from "../name-utils";
import * as path from 'path';
import * as ts from 'typescript';
import {addImportToModule, addProviderToModule, insert} from '../utility/ast-utils';
import {insertImport} from '@schematics/angular/utility/route-utils';

function addImportsToModule(name: string, options: any): Rule {
  return (host: Tree) => {
    if (options.skipImport) {
      return host;
    }

    if (!host.exists(options.module)) {
      throw new Error('Specified module does not exist');
    }

    const modulePath = options.module;

    const sourceText = host.read(modulePath) !.toString('utf-8');
    const source = ts.createSourceFile(modulePath, sourceText, ts.ScriptTarget.Latest, true);

    if (options.emptyRoot) {
      const reducer = `StoreModule.forRoot({})`;
      insert(host, modulePath, [
        insertImport(source, modulePath, 'StoreModule', '@ngrx/store'),
        ...addImportToModule(source, modulePath, reducer)
      ]);
      return host;

    } else {
      const reducerPath = `./+state/${toFileName(name)}.reducer`;
      const effectsPath = `./+state/${toFileName(name)}.effects`;
      const initPath = `./+state/${toFileName(name)}.init`;

      const reducerName = `${toPropertyName(name)}Reducer`;
      const effectsName = `${toClassName(name)}Effects`;
      const initName = `${toPropertyName(name)}InitialState`;

      const effects = options.root ? `EffectsModule.forRoot([${effectsName}])` : `EffectsModule.forFeature([${effectsName}])`;
      const reducer = options.root ? `StoreModule.forRoot(${reducerName}, {initialState: ${initName}})` : `StoreModule.forFeature('${toPropertyName(name)}', ${reducerName}, {initialState: ${initName}})`;

      insert(host, modulePath, [
        insertImport(source, modulePath, 'StoreModule', '@ngrx/store'),
        insertImport(source, modulePath, 'EffectsModule', '@ngrx/effects'),
        insertImport(source, modulePath, reducerName, reducerPath),
        insertImport(source, modulePath, initName, initPath),
        insertImport(source, modulePath, effectsName, effectsPath),
        ...addImportToModule(source, modulePath, reducer),
        ...addImportToModule(source, modulePath, effects),
        ...addProviderToModule(source, modulePath, effectsName)
      ]);
      return host;
    }
  };
}

export default function (options: any): Rule {
  const name = path.basename(options.module, ".module.ts");
  const moduleDir = path.dirname(options.module);

  if (options.emptyRoot) {
    return chain([
      addImportsToModule(name, options)
    ]);
  } else {
    const templateSource = apply(url('./files'), [
      template({...options, tmpl: '', ...names(name)}),
      move(moduleDir)
    ]);
    return chain([
      branchAndMerge(chain([
        mergeWith(templateSource)
      ])),
      addImportsToModule(name, options)
    ]);
  }
}