/**
 * @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 {
  experimental,
  json,
  logging,
  normalize,
  schema,
  strings,
  tags,
  terminal,
  virtualFs,
} from '@angular-devkit/core';
import { NodeJsSyncHost } from '@angular-devkit/core/node';
import {
  DryRunEvent,
  Engine,
  SchematicEngine,
  UnsuccessfulWorkflowExecution,
  workflow,
} from '@angular-devkit/schematics';
import {
  FileSystemCollection,
  FileSystemCollectionDesc,
  FileSystemEngineHostBase,
  FileSystemSchematic,
  FileSystemSchematicDesc,
  NodeModulesEngineHost,
  NodeWorkflow,
  validateOptionsWithSchema,
} from '@angular-devkit/schematics/tools';
import * as inquirer from 'inquirer';
import * as systemPath from 'path';
import { take } from 'rxjs/operators';
import { WorkspaceLoader } from '../models/workspace-loader';
import {
  getPackageManager,
  getProjectByCwd,
  getSchematicDefaults,
  getWorkspace,
  getWorkspaceRaw,
} from '../utilities/config';
import { parseJsonSchemaToOptions } from '../utilities/json-schema';
import { BaseCommandOptions, Command } from './command';
import { Arguments, CommandContext, CommandDescription, Option } from './interface';
import { parseArguments, parseFreeFormArguments } from './parser';


export interface BaseSchematicSchema {
  debug?: boolean;
  dryRun?: boolean;
  force?: boolean;
  interactive?: boolean;
}

export interface RunSchematicOptions extends BaseSchematicSchema {
  collectionName: string;
  schematicName: string;

  schematicOptions?: string[];
  showNothingDone?: boolean;
}


export class UnknownCollectionError extends Error {
  constructor(collectionName: string) {
    super(`Invalid collection (${collectionName}).`);
  }
}

export abstract class SchematicCommand<
  T extends (BaseSchematicSchema & BaseCommandOptions),
> extends Command<T> {
  readonly allowPrivateSchematics: boolean = false;
  private _host = new NodeJsSyncHost();
  private _workspace: experimental.workspace.Workspace;
  private readonly _engine: Engine<FileSystemCollectionDesc, FileSystemSchematicDesc>;
  protected _workflow: workflow.BaseWorkflow;

  protected collectionName = '@schematics/angular';
  protected schematicName?: string;

  constructor(
    context: CommandContext,
    description: CommandDescription,
    logger: logging.Logger,
    private readonly _engineHost: FileSystemEngineHostBase = new NodeModulesEngineHost(),
  ) {
    super(context, description, logger);
    this._engine = new SchematicEngine(this._engineHost);
  }

  public async initialize(options: T & Arguments) {
    this._loadWorkspace();
    this.createWorkflow(options);

    if (this.schematicName) {
      // Set the options.
      const collection = this.getCollection(this.collectionName);
      const schematic = this.getSchematic(collection, this.schematicName, true);
      const options = await parseJsonSchemaToOptions(
        this._workflow.registry,
        schematic.description.schemaJson || {},
      );

      this.description.options.push(...options.filter(x => !x.hidden));
    }
  }

  public async printHelp(options: T & Arguments) {
    await super.printHelp(options);
    this.logger.info('');

    const subCommandOption = this.description.options.filter(x => x.subcommands)[0];

    if (!subCommandOption || !subCommandOption.subcommands) {
      return 0;
    }

    const schematicNames = Object.keys(subCommandOption.subcommands);

    if (schematicNames.length > 1) {
      this.logger.info('Available Schematics:');

      const namesPerCollection: { [c: string]: string[] } = {};
      schematicNames.forEach(name => {
        let [collectionName, schematicName] = name.split(/:/, 2);
        if (!schematicName) {
          schematicName = collectionName;
          collectionName = this.collectionName;
        }

        if (!namesPerCollection[collectionName]) {
          namesPerCollection[collectionName] = [];
        }

        namesPerCollection[collectionName].push(schematicName);
      });

      const defaultCollection = this.getDefaultSchematicCollection();
      Object.keys(namesPerCollection).forEach(collectionName => {
        const isDefault = defaultCollection == collectionName;
        this.logger.info(
          `  Collection "${collectionName}"${isDefault ? ' (default)' : ''}:`,
        );

        namesPerCollection[collectionName].forEach(schematicName => {
          this.logger.info(`    ${schematicName}`);
        });
      });
    } else if (schematicNames.length == 1) {
      this.logger.info('Help for schematic ' + schematicNames[0]);
      await this.printHelpSubcommand(subCommandOption.subcommands[schematicNames[0]]);
    }

    return 0;
  }

  async printHelpUsage() {
    const subCommandOption = this.description.options.filter(x => x.subcommands)[0];

    if (!subCommandOption || !subCommandOption.subcommands) {
      return;
    }

    const schematicNames = Object.keys(subCommandOption.subcommands);
    if (schematicNames.length == 1) {
      this.logger.info(this.description.description);

      const opts = this.description.options.filter(x => x.positional === undefined);
      const [collectionName, schematicName] = schematicNames[0].split(/:/)[0];

      // Display <collectionName:schematicName> if this is not the default collectionName,
      // otherwise just show the schematicName.
      const displayName = collectionName == this.getDefaultSchematicCollection()
        ? schematicName
        : schematicNames[0];

      const schematicOptions = subCommandOption.subcommands[schematicNames[0]].options;
      const schematicArgs = schematicOptions.filter(x => x.positional !== undefined);
      const argDisplay = schematicArgs.length > 0
        ? ' ' + schematicArgs.map(a => `<${strings.dasherize(a.name)}>`).join(' ')
        : '';

      this.logger.info(tags.oneLine`
        usage: ng ${this.description.name} ${displayName}${argDisplay}
        ${opts.length > 0 ? `[options]` : ``}
      `);
      this.logger.info('');
    } else {
      await super.printHelpUsage();
    }
  }

  protected getEngineHost() {
    return this._engineHost;
  }
  protected getEngine():
      Engine<FileSystemCollectionDesc, FileSystemSchematicDesc> {
    return this._engine;
  }

  protected getCollection(collectionName: string): FileSystemCollection {
    const engine = this.getEngine();
    const collection = engine.createCollection(collectionName);

    if (collection === null) {
      throw new UnknownCollectionError(collectionName);
    }

    return collection;
  }

  protected getSchematic(
    collection: FileSystemCollection,
    schematicName: string,
    allowPrivate?: boolean,
  ): FileSystemSchematic {
    return collection.createSchematic(schematicName, allowPrivate);
  }

  protected setPathOptions(options: Option[], workingDir: string) {
    if (workingDir === '') {
      return {};
    }

    return options
      .filter(o => o.format === 'path')
      .map(o => o.name)
      .reduce((acc, curr) => {
        acc[curr] = workingDir;

        return acc;
      }, {} as { [name: string]: string });
  }

  /*
   * Runtime hook to allow specifying customized workflow
   */
  protected createWorkflow(options: BaseSchematicSchema): workflow.BaseWorkflow {
    if (this._workflow) {
      return this._workflow;
    }

    const { force, dryRun } = options;
    const fsHost = new virtualFs.ScopedHost(new NodeJsSyncHost(), normalize(this.workspace.root));

    const workflow = new NodeWorkflow(
        fsHost,
        {
          force,
          dryRun,
          packageManager: getPackageManager(),
          root: normalize(this.workspace.root),
        },
    );

    this._engineHost.registerOptionsTransform(validateOptionsWithSchema(workflow.registry));

    workflow.registry.addPostTransform(schema.transforms.addUndefinedDefaults);

    workflow.registry.addSmartDefaultProvider('projectName', () => {
      if (this._workspace) {
        try {
          return this._workspace.getProjectByPath(normalize(process.cwd()))
            || this._workspace.getDefaultProjectName();
        } catch (e) {
          if (e instanceof experimental.workspace.AmbiguousProjectPathException) {
            this.logger.warn(tags.oneLine`
              Two or more projects are using identical roots.
              Unable to determine project using current working directory.
              Using default workspace project instead.
            `);

            return this._workspace.getDefaultProjectName();
          }
          throw e;
        }
      }

      return undefined;
    });

    if (options.interactive !== false && process.stdout.isTTY) {
      workflow.registry.usePromptProvider((definitions: Array<schema.PromptDefinition>) => {
        const questions: inquirer.Questions = definitions.map(definition => {
          const question: inquirer.Question = {
            name: definition.id,
            message: definition.message,
            default: definition.default,
          };

          const validator = definition.validator;
          if (validator) {
            question.validate = input => validator(input);
          }

          switch (definition.type) {
            case 'confirmation':
              question.type = 'confirm';
              break;
            case 'list':
              question.type = 'list';
              question.choices = definition.items && definition.items.map(item => {
                if (typeof item == 'string') {
                  return item;
                } else {
                  return {
                    name: item.label,
                    value: item.value,
                  };
                }
              });
              break;
            default:
              question.type = definition.type;
              break;
          }

          return question;
        });

        return inquirer.prompt(questions);
      });
    }

    return this._workflow = workflow;
  }

  protected getDefaultSchematicCollection(): string {
    let workspace = getWorkspace('local');

    if (workspace) {
      const project = getProjectByCwd(workspace);
      if (project && workspace.getProjectCli(project)) {
        const value = workspace.getProjectCli(project)['defaultCollection'];
        if (typeof value == 'string') {
          return value;
        }
      }
      if (workspace.getCli()) {
        const value = workspace.getCli()['defaultCollection'];
        if (typeof value == 'string') {
          return value;
        }
      }
    }

    workspace = getWorkspace('global');
    if (workspace && workspace.getCli()) {
      const value = workspace.getCli()['defaultCollection'];
      if (typeof value == 'string') {
        return value;
      }
    }

    return this.collectionName;
  }

  protected async runSchematic(options: RunSchematicOptions) {
    const { schematicOptions, debug, dryRun } = options;
    let { collectionName, schematicName } = options;

    let nothingDone = true;
    let loggingQueue: string[] = [];
    let error = false;

    const workflow = this._workflow;

    const workingDir = normalize(systemPath.relative(this.workspace.root, process.cwd()));

    // Get the option object from the schematic schema.
    const schematic = this.getSchematic(
      this.getCollection(collectionName),
      schematicName,
      this.allowPrivateSchematics,
    );
    // Update the schematic and collection name in case they're not the same as the ones we
    // received in our options, e.g. after alias resolution or extension.
    collectionName = schematic.collection.description.name;
    schematicName = schematic.description.name;

    // TODO: Remove warning check when 'targets' is default
    if (collectionName !== this.collectionName) {
      const [ast, configPath] = getWorkspaceRaw('local');
      if (ast) {
        const projectsKeyValue = ast.properties.find(p => p.key.value === 'projects');
        if (!projectsKeyValue || projectsKeyValue.value.kind !== 'object') {
          return;
        }

        const positions: json.Position[] = [];
        for (const projectKeyValue of projectsKeyValue.value.properties) {
          const projectNode = projectKeyValue.value;
          if (projectNode.kind !== 'object') {
            continue;
          }
          const targetsKeyValue = projectNode.properties.find(p => p.key.value === 'targets');
          if (targetsKeyValue) {
            positions.push(targetsKeyValue.start);
          }
        }

        if (positions.length > 0) {
          const warning = tags.oneLine`
            WARNING: This command may not execute successfully.
            The package/collection may not support the 'targets' field within '${configPath}'.
            This can be corrected by renaming the following 'targets' fields to 'architect':
          `;

          const locations = positions
            .map((p, i) => `${i + 1}) Line: ${p.line + 1}; Column: ${p.character + 1}`)
            .join('\n');

          this.logger.warn(warning + '\n' + locations + '\n');
        }
      }
    }

    // Set the options of format "path".
    let o: Option[] | null = null;
    let args: Arguments;

    if (!schematic.description.schemaJson) {
      args = await this.parseFreeFormArguments(schematicOptions || []);
    } else {
      o = await parseJsonSchemaToOptions(workflow.registry, schematic.description.schemaJson);
      args = await this.parseArguments(schematicOptions || [], o);
    }

    const pathOptions = o ? this.setPathOptions(o, workingDir) : {};
    let input = Object.assign(pathOptions, args);

    // Read the default values from the workspace.
    const projectName = input.project !== undefined ? '' + input.project : null;
    const defaults = getSchematicDefaults(collectionName, schematicName, projectName);
    input = Object.assign<{}, {}, typeof input>({}, defaults, input);

    workflow.reporter.subscribe((event: DryRunEvent) => {
      nothingDone = false;

      // Strip leading slash to prevent confusion.
      const eventPath = event.path.startsWith('/') ? event.path.substr(1) : event.path;

      switch (event.kind) {
        case 'error':
          error = true;
          const desc = event.description == 'alreadyExist' ? 'already exists' : 'does not exist.';
          this.logger.warn(`ERROR! ${eventPath} ${desc}.`);
          break;
        case 'update':
          loggingQueue.push(tags.oneLine`
            ${terminal.white('UPDATE')} ${eventPath} (${event.content.length} bytes)
          `);
          break;
        case 'create':
          loggingQueue.push(tags.oneLine`
            ${terminal.green('CREATE')} ${eventPath} (${event.content.length} bytes)
          `);
          break;
        case 'delete':
          loggingQueue.push(`${terminal.yellow('DELETE')} ${eventPath}`);
          break;
        case 'rename':
          loggingQueue.push(`${terminal.blue('RENAME')} ${eventPath} => ${event.to}`);
          break;
      }
    });

    workflow.lifeCycle.subscribe(event => {
      if (event.kind == 'end' || event.kind == 'post-tasks-start') {
        if (!error) {
          // Output the logging queue, no error happened.
          loggingQueue.forEach(log => this.logger.info(log));
        }

        loggingQueue = [];
        error = false;
      }
    });

    return new Promise<number | void>((resolve) => {
      workflow.execute({
        collection: collectionName,
        schematic: schematicName,
        options: input,
        debug: debug,
        logger: this.logger,
        allowPrivate: this.allowPrivateSchematics,
      })
      .subscribe({
        error: (err: Error) => {
          // In case the workflow was not successful, show an appropriate error message.
          if (err instanceof UnsuccessfulWorkflowExecution) {
            // "See above" because we already printed the error.
            this.logger.fatal('The Schematic workflow failed. See above.');
          } else if (debug) {
            this.logger.fatal(`An error occured:\n${err.message}\n${err.stack}`);
          } else {
            this.logger.fatal(err.message);
          }

          resolve(1);
        },
        complete: () => {
          const showNothingDone = !(options.showNothingDone === false);
          if (nothingDone && showNothingDone) {
            this.logger.info('Nothing to be done.');
          }
          if (dryRun) {
            this.logger.warn(`\nNOTE: The "dryRun" flag means no changes were made.`);
          }
          resolve();
        },
      });
    });
  }

  protected async parseFreeFormArguments(schematicOptions: string[]) {
    return parseFreeFormArguments(schematicOptions);
  }

  protected async parseArguments(
    schematicOptions: string[],
    options: Option[] | null,
  ): Promise<Arguments> {
    return parseArguments(schematicOptions, options);
  }

  private _loadWorkspace() {
    if (this._workspace) {
      return;
    }
    const workspaceLoader = new WorkspaceLoader(this._host);

    try {
      workspaceLoader.loadWorkspace(this.workspace.root).pipe(take(1))
        .subscribe(
          (workspace: experimental.workspace.Workspace) => this._workspace = workspace,
          (err: Error) => {
            if (!this.allowMissingWorkspace) {
              // Ignore missing workspace
              throw err;
            }
          },
        );
    } catch (err) {
      if (!this.allowMissingWorkspace) {
        // Ignore missing workspace
        throw err;
  }
    }
  }
}