import * as plugins from './smartscaf.plugins';
import * as helpers from './smartscaf.helpers';

// interfaces
import { Smartfile } from '@pushrocks/smartfile';

export interface ScafTemplateContructorOptions {
  name?: string;
  description?: string;
  sourceDir?: string;
}

export class ScafTemplate {
  static async createTemplateFromDir() {

  }

  /**
   * the name of the template
   */
  name: string;

  /**
   * the descriptions of the template
   */
  description: string;

  /**
   * the location on disk of the template
   */
  dirPath: string;

  /**
   * the files of the template as array of Smartfiles
   */
  templateSmartfileArray: Smartfile[];
  requiredVariables: string[];
  defaultVariables: any;
  suppliedVariables: any = {};
  missingVariables: string[] = [];

  constructor(dirPathArg: string) {
    this.dirPath = plugins.path.resolve(dirPathArg);
  }

  /**
   * read a template from a directory
   */
  async readTemplateFromDir() {
    this.templateSmartfileArray = await plugins.smartfile.fs.fileTreeToObject(this.dirPath, '**/*');
    await this._resolveTemplateDependencies();
    await this._findVariablesInTemplate();
    await this._checkSuppliedVariables();
    await this._checkDefaultVariables();
  }

  /**
   * supply the variables to render the teplate with
   * @param variablesArg gets merged with this.suppliedVariables
   */
  async supplyVariables(variablesArg) {
    this.suppliedVariables = {
      ...this.suppliedVariables,
      ...variablesArg
    };
    this.missingVariables = await this._checkSuppliedVariables();
  }

  /**
   * Will ask for the missing variables by cli interaction
   */
  async askCliForMissingVariables() {
    this.missingVariables = await this._checkSuppliedVariables();
    let localSmartInteract = new plugins.smartinteract.SmartInteract();
    for (let missingVariable of this.missingVariables) {
      localSmartInteract.addQuestions([
        {
          name: missingVariable,
          type: 'input',
          default: (() => {
            if (this.defaultVariables && this.defaultVariables[missingVariable]) {
              return this.defaultVariables[missingVariable];
            } else {
              return 'undefined variable';
            }
          })(),
          message: `What is the value of ${missingVariable}?`
        }
      ]);
    }
    let answerBucket = await localSmartInteract.runQueue();
    await answerBucket.answerMap.forEach(async answer => {
      await helpers.deepAddToObject(this.suppliedVariables, answer.name, answer.value);
    });
  }

  /**
   * writes a file to disk
   * @param destinationDirArg
   */
  async writeToDisk(destinationDirArg) {
    const smartfileArrayToWrite: Smartfile[] = [];
    for (let smartfile of this.templateSmartfileArray) {
      // lets filter out template files
      if(smartfile.path === '.smartscaf.yml') {
        continue;
      }

      // render the template
      let template = await plugins.smarthbs.getTemplateForString(smartfile.contents.toString());
      let renderedTemplateString = template(this.suppliedVariables);

      // handle frontmatter
      const smartfmInstance = new plugins.smartfm.Smartfm({
        fmType: "yaml"
      });
      let parsedTemplate = smartfmInstance.parse(renderedTemplateString) as any;
      if (parsedTemplate.data.fileName) {
        smartfile.updateFileName(parsedTemplate.data.fileName);
      }

      smartfile.contents = Buffer.from(parsedTemplate.content);
      smartfileArrayToWrite.push(smartfile);
    }

    await plugins.smartfile.memory.smartfileArrayToFs(smartfileArrayToWrite, destinationDirArg);
  }

  /**
   * finds all variables in a Template in as string
   * e.g. myobject.someKey and myobject.someOtherKey
   */
  private async _findVariablesInTemplate() {
    let templateVariables: string[] = [];
    for (let templateSmartfile of this.templateSmartfileArray) {
      let localTemplateVariables = await plugins.smarthbs.findVarsInHbsString(
        templateSmartfile.contents.toString()
      );
      templateVariables = [...templateVariables, ...localTemplateVariables];
    }
    templateVariables = templateVariables.filter((value, index, self) => {
      return self.indexOf(value) === index;
    });
  }

  /**
   * checks if supplied Variables satisfy the template
   */
  private async _checkSuppliedVariables() {
    let missingVars: string[] = [];
    for (let templateSmartfile of this.templateSmartfileArray) {
      let localMissingVars = await plugins.smarthbs.checkVarsSatisfaction(
        templateSmartfile.contents.toString(),
        this.suppliedVariables
      );

      // combine with other missingVars
      missingVars = [...missingVars, ...localMissingVars];
    }

    // dedupe
    missingVars = missingVars.filter((value, index, self) => {
      return self.indexOf(value) === index;
    });
    return missingVars;
  }

  /**
   * checks the smartscaf.yml default values at the root of a template
   * allows 2 ways of notation in YAML:
   * >> myObject.myKey.someDeeperKey: someValue
   * >> myObject.yourKey.yourDeeperKey: yourValue
   * or
   * >> myObject:
   * >>   - someKey:
   * >>     - someDeeperKey: someValue
   * >>   - yourKey:
   * >>     - yourDeeperKey: yourValue
   */
  private async _checkDefaultVariables() {
    let smartscafSmartfile = this.templateSmartfileArray.find(smartfileArg => {
      return smartfileArg.parsedPath.base === '.smartscaf.yml';
    });

    if (smartscafSmartfile) {
      const smartscafObject = await plugins.smartyaml.yamlStringToObject(
        smartscafSmartfile.contents.toString()
      );
      const defaultObject = smartscafObject.defaults;
      this.defaultVariables = defaultObject;
    }

    // safeguard against non existent defaults
    if (!this.defaultVariables) {
      console.log('this template does not specify defaults')
      this.defaultVariables = {};
    }
  }

  /**
   * resolve template dependencies
   */
  private async _resolveTemplateDependencies() {
    const smartscafSmartfile = this.templateSmartfileArray.find(smartfileArg => {
      return smartfileArg.parsedPath.base === '.smartscaf.yml';
    });
    if(!smartscafSmartfile) {
      console.log('No further template dependencies defined!');
      return;
    }
    console.log('Found template dependencies! Resolving them now!');
    console.log('looking at templates to merge!');
    const smartscafYamlObject = await plugins.smartyaml.yamlStringToObject(smartscafSmartfile.contentBuffer.toString());
    if(!smartscafYamlObject) {
      console.log('Something seems strange about the supplied dependencies.yml file.');
      return;
    }
    for (const dependency of smartscafYamlObject.dependencies.merge) {
      console.log(`Now resolving ${dependency}`);
      const templatePathToMerge = plugins.path.join(this.dirPath, dependency);
      if(!plugins.smartfile.fs.isDirectory(templatePathToMerge)) {
        console.log(`dependency ${dependency} resolves to ${templatePathToMerge} which ist NOT a directory`);
        continue;
      };
      const templateSmartfileArray = await plugins.smartfile.fs.fileTreeToObject(templatePathToMerge, '**/*');
      this.templateSmartfileArray = this.templateSmartfileArray.concat(templateSmartfileArray);
    }
  }
}