Template System

/**
 * Register a custom Handlebars helper
 * @param name - Helper name for use in templates
 * @param fn - Helper function
 */
setHelper(name: string, fn: HelperFunction): void;

/**
 * Get a registered helper function by name
 * @param name - Helper name
 * @returns Helper function
 */
getHelper(name: string): Function;

/**
 * Get list of all registered helper names
 * @returns Array of helper names
 */
getHelperList(): string[];

/**
 * @deprecated Use setHelper instead
 */
addHelper(name: string, fn: Function): void;

import { nodePlop } from "plop";

const plop = await nodePlop();

// Register a custom helper
plop.setHelper('upperCase', (text) => text.toUpperCase());

// Register a helper with options
plop.setHelper('repeat', (text, count) => {
  return new Array(count + 1).join(text);
});

// Use in templates
const template = '{{upperCase name}} - {{repeat "!" 3}}';
const result = plop.renderString(template, { name: 'hello' });
console.log(result); // "HELLO - !!!"

// List all helpers
const helpers = plop.getHelperList();
console.log(helpers);

// Case conversion helpers (all available by default)
const BUILT_IN_HELPERS = {
  // Basic case transformations
  camelCase: Function;      // myVariableName
  pascalCase: Function;     // MyVariableName  
  properCase: Function;     // Alias for pascalCase
  snakeCase: Function;      // my_variable_name
  kebabCase: Function;      // my-variable-name
  dashCase: Function;       // Alias for kebabCase
  kabobCase: Function;      // Alias for kebabCase
  constantCase: Function;   // MY_VARIABLE_NAME
  dotCase: Function;        // my.variable.name
  pathCase: Function;       // my/variable/name
  sentenceCase: Function;   // My variable name
  titleCase: Function;      // My Variable Name
  lowerCase: Function;      // my variable name
  upperCase: Function;      // MY VARIABLE NAME
  
  // Package helper
  pkg: Function;            // Access package.json properties
};

// Template using built-in helpers
const template = `
class {{pascalCase name}} {
  constructor() {
    this.{{camelCase name}} = '{{kebabCase name}}';
    this.version = '{{pkg "version"}}';
  }
}
`;

const result = plop.renderString(template, { name: 'my-component' });

/**
 * Register a Handlebars partial
 * @param name - Partial name for use in templates
 * @param str - Partial template string
 */
setPartial(name: string, str: string): void;

/**
 * Get a registered partial by name
 * @param name - Partial name
 * @returns Partial template string
 */
getPartial(name: string): string;

/**
 * Get list of all registered partial names
 * @returns Array of partial names
 */
getPartialList(): string[];

/**
 * @deprecated Use setPartial instead
 */
addPartial(name: string, str: string): void;

const plop = await nodePlop();

// Register partials
plop.setPartial('header', '// Generated by Plop on {{date}}');
plop.setPartial('footer', '// End of generated file');

// Register a partial with parameters
plop.setPartial('method', `
  {{#if async}}async {{/if}}{{name}}({{#each params}}{{name}}{{#unless @last}}, {{/unless}}{{/each}}) {
    {{body}}
  }
`);

// Use partials in templates
const template = `
{{> header}}

class {{pascalCase name}} {
  {{#each methods}}
  {{> method this}}
  {{/each}}
}

{{> footer}}
`;

const result = plop.renderString(template, {
  name: 'my-class',
  date: new Date().toISOString(),
  methods: [
    {
      name: 'getData',
      async: true,
      params: [{ name: 'id' }],
      body: 'return await api.get(id);'
    }
  ]
});

// Template source configuration
interface TemplateStrOrFile {
  template?: string;        // Inline template string
  templateFile?: string;    // Path to template file
}

// Used in action configurations
interface ActionWithTemplate extends ActionConfig, TemplateStrOrFile {
  // Action-specific properties
}

// Using inline template
{
  type: 'add',
  path: 'src/{{name}}.js',
  template: 'export const {{name}} = "{{value}}";'
}

// Using template file
{
  type: 'add',
  path: 'src/{{name}}.js',
  templateFile: 'templates/module.hbs'
}

// Template file: templates/module.hbs

import React from 'react';

export const {{pascalCase name}} = ({{#if props}}{ {{#each props}}{{name}}{{#unless @last}}, {{/unless}}{{/each}} }{{/if}}) => {
  return (
    <div className="{{kebabCase name}}">
      {{#if children}}
        {children}
      {{else}}
        <h1>{{titleCase name}}</h1>
      {{/if}}
    </div>
  );
};

/**
 * Transform function applied after template rendering
 * @param template - Rendered template string
 * @param data - Template data object
 * @param config - Action configuration
 * @returns Transformed template string
 */
type TransformFn<T> = (template: string, data: any, config: T) => string;

// Action with transform function
{
  type: 'add',
  path: 'src/{{name}}.js',
  templateFile: 'templates/component.hbs',
  transform: (template, data, config) => {
    // Add custom processing
    if (data.typescript) {
      template = template.replace(/\.js/g, '.ts');
    }
    
    // Add prettier formatting
    return prettier.format(template, { parser: 'babel' });
  }
}

// Advanced data processing in template
const template = `
{{#each items}}
  {{#if (eq type "component")}}
    {{> component-partial this}}
  {{else if (eq type "service")}}
    {{> service-partial this}}
  {{/if}}
{{/each}}
`;

interface TemplateData extends UserAnswers {
  // Built-in context available in all templates
  [key: string]: any;       // User-provided answers from prompts
}

{{!-- User answers from prompts --}}
Component: {{name}}
Type: {{type}}
Props: {{#each props}}{{name}}: {{type}}{{/each}}

{{!-- Built-in helpers --}}
File: {{kebabCase name}}.jsx
Class: {{pascalCase name}}
Constant: {{constantCase name}}_CONFIG

{{!-- Package.json access --}}
Version: {{pkg "version"}}
Author: {{pkg "author.name"}}

{{!-- Conditional rendering --}}
{{#if typescript}}
interface {{pascalCase name}}Props {
  {{#each props}}
  {{name}}: {{type}};
  {{/each}}
}
{{/if}}

{{!-- Loops and arrays --}}
{{#each methods}}
  {{#unless @first}}
  
  {{/unless}}
  {{name}}(): {{returnType}} {
    // TODO: Implement {{name}}
  }
{{/each}}

{{#if condition}}
  Render this when condition is true
{{else if otherCondition}}
  Render this when otherCondition is true
{{else}}
  Default content
{{/if}}

{{#unless disabled}}
  Render this when disabled is false
{{/unless}}

{{#each items}}
  Item {{@index}}: {{name}} ({{@first}} {{@last}})
{{/each}}

{{#each object}}
  {{@key}}: {{this}}
{{/each}}

{{pascalCase (replace name "-" "")}}
{{upperCase (substring description 0 50)}}
{{#each (sort items "name")}}
  {{camelCase name}}: {{value}}
{{/each}}