/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import {RuleFailure, Rules} from 'tslint';
import * as ts from 'typescript';

import {TslintUpdateRecorder} from '../missing-injectable/google3/tslint_update_recorder';
import {NgModuleCollector} from '../missing-injectable/module_collector';
import {MissingInjectableTransform} from '../missing-injectable/transform';


/**
 * TSLint rule that flags classes which are declared as providers in NgModules but
 * aren't decorated with any Angular decorator.
 */
export class Rule extends Rules.TypedRule {
  applyWithProgram(sourceFile: ts.SourceFile, program: ts.Program): RuleFailure[] {
    const ruleName = this.ruleName;
    const typeChecker = program.getTypeChecker();
    const sourceFiles = program.getSourceFiles().filter(
        s => !s.isDeclarationFile && !program.isSourceFileFromExternalLibrary(s));
    const moduleCollector = new NgModuleCollector(typeChecker);
    const failures: RuleFailure[] = [];

    // Analyze source files by detecting all NgModule definitions.
    sourceFiles.forEach(sourceFile => moduleCollector.visitNode(sourceFile));

    const {resolvedModules} = moduleCollector;
    const transformer = new MissingInjectableTransform(typeChecker, getUpdateRecorder);
    const updateRecorders = new Map<ts.SourceFile, TslintUpdateRecorder>();

    resolvedModules.forEach(module => {
      transformer.migrateModule(module).forEach(({message, node}) => {
        // Only report failures for the current source file that is visited.
        if (node.getSourceFile() === sourceFile) {
          failures.push(
              new RuleFailure(node.getSourceFile(), node.getStart(), 0, message, ruleName));
        }
      });
    });

    // Record the changes collected in the import manager and NgModule manager.
    transformer.recordChanges();

    if (updateRecorders.has(sourceFile)) {
      failures.push(...updateRecorders.get(sourceFile) !.failures);
    }

    return failures;

    /** Gets the update recorder for the specified source file. */
    function getUpdateRecorder(sourceFile: ts.SourceFile): TslintUpdateRecorder {
      if (updateRecorders.has(sourceFile)) {
        return updateRecorders.get(sourceFile) !;
      }
      const recorder = new TslintUpdateRecorder(ruleName, sourceFile);
      updateRecorders.set(sourceFile, recorder);
      return recorder;
    }
  }
}