eslint-rules/packages/eslint-define-config/scripts/rule-file.ts

import { Logger, colors as cliColors } from '@poppinss/cliui';
import { pascalCase, kebabCase } from 'change-case';
import type { Rule } from 'eslint';
import type { JSONSchema4 } from 'json-schema';
import { execSync } from 'node:child_process';
import { existsSync, mkdirSync, writeFileSync } from 'node:fs';
import { dirname, resolve } from 'node:path';
import { format } from 'prettier';
import { generateTypeFromSchema } from './json-schema-to-ts';
import { buildJSDoc, prettierConfig, type Plugin } from './utils';

const logger = new Logger();
const colors = cliColors.ansi();

/**
 * Build the rule description to append to the JSDoc.
 */
function buildDescription(description = ''): string {
  description = description.charAt(0).toUpperCase() + description.slice(1);
  if (description.length > 0 && !description.endsWith('.')) {
    description += '.';
  }

  return description.replace('*/', '');
}

export async function RuleFile(
  plugin: Plugin,
  pluginDirectory: string,
  ruleName: string,
  rule: Rule.RuleModule,
) {
  let content = '';

  const rulePath = resolve(pluginDirectory, `${ruleName}.d.ts`);
  const ruleNamePascalCase = pascalCase(ruleName);
  const schema: JSONSchema4 | JSONSchema4[] | undefined = rule.meta?.schema;
  const isSchemaArray = Array.isArray(schema);

  const mainSchema = isSchemaArray ? schema[0] : schema;
  const sideSchema = isSchemaArray && schema.length > 1 ? schema[1] : undefined;
  const thirdSchema = isSchemaArray && schema.length > 2 ? schema[2] : undefined;

  /**
   * Generate a JSDoc with the rule description and `@see` url.
   */
  function generateTypeJsDoc(): string {
    const { meta } = rule;
    const seeDocLink: string = meta?.docs?.url
      ? `@see [${ruleName}](${meta.docs.url})`
      : '';

    return buildJSDoc([
      buildDescription(rule.meta?.docs?.description),
      ' ',
      rule.meta?.deprecated ? '@deprecated' : '',
      rule.meta?.deprecated ? ' ' : '',
      seeDocLink,
    ]);
  }

  /**
   * Generate a type from a JSON schema and append it to the file content.
   */
  async function appendJsonSchemaType(
    schema: JSONSchema4,
    comment: string,
  ): Promise<void> {
    const type = await generateTypeFromSchema(schema, ruleNamePascalCase + comment);
    const jsdoc = buildJSDoc([`${comment}.`]);
    content += `\n${jsdoc}`;
    content += `\n${type}\n`;
  }

  /**
   * Scoped rule name ESLint config uses.
   */
  function prefixedRuleName(): string {
    const { prefix, name } = plugin;
    const rulePrefix = (prefix ?? kebabCase(name)) + '/';
    return name === 'ESLint' ? ruleName : `${rulePrefix}${ruleName}`;
  }

  /**
   * Append the `import type { RuleConfig } from '../rule-config'` at the top of the file.
   */
  const nestedDepth = ruleName.split('/').length;
  content += `import type { RuleConfig } from '${'../'.repeat(nestedDepth)}rule-config'\n\n`;

  /**
   * Generate and append types for the rule schemas.
   */
  if (thirdSchema) {
    await appendJsonSchemaType(thirdSchema, 'Setting');
  }
  if (sideSchema) {
    await appendJsonSchemaType(sideSchema, 'Config');
  }
  if (mainSchema) {
    await appendJsonSchemaType(mainSchema, 'Option');
  }

  if (mainSchema) {
    /**
     * Append the rule type options to the file content.
     */
    let type: string = '';
    if (!isSchemaArray) {
      type = `${ruleNamePascalCase}Option`;
    } else if (thirdSchema) {
      type = `[${ruleNamePascalCase}Option?, ${ruleNamePascalCase}Config?, ${ruleNamePascalCase}Setting?]`;
    } else if (sideSchema) {
      type = `[${ruleNamePascalCase}Option?, ${ruleNamePascalCase}Config?]`;
    } else if (mainSchema) {
      type = `[${ruleNamePascalCase}Option?]`;
    }

    content += buildJSDoc(['Options.']) + '\n';
    content += `export type ${ruleNamePascalCase}Options = ${type}\n\n`;
  }

  /**
   * Append the rule config type to the file content.
   */
  content += generateTypeJsDoc() + '\n';
  content += `export type ${ruleNamePascalCase}RuleConfig = RuleConfig<${mainSchema ? `${ruleNamePascalCase}Options` : '[]'}>;\n\n`;

  /**
   * Append the final rule interface to the file content.
   */
  content += generateTypeJsDoc() + '\n';
  content += `export interface ${ruleNamePascalCase}Rule {`;
  content += `${generateTypeJsDoc()}\n`;
  content += `'${prefixedRuleName()}': ${ruleNamePascalCase}RuleConfig;`;
  content += '}';

  content = await format(content, prettierConfig);

  /**
   * Create the directory of the rule file if it doesn't exist.
   */
  const subPath = dirname(rulePath);
  if (!existsSync(subPath)) {
    mkdirSync(subPath, { recursive: true });
  }

  writeFileSync(rulePath, content);

  /**
   * Apply a patch to the generated content if a diff file exists for it.
   *
   * Must be called after `generate()`.
   */
  const pathParts = rulePath.split('/');
  const diffFile = resolve(
    __dirname,
    './diffs/rules',
    pathParts.at(-2) ?? '',
    `${pathParts.at(-1) ?? ''}.diff`,
  );

  if (existsSync(diffFile)) {
    logger.logUpdate(colors.yellow(`  🧹 Adjusting ${prefixedRuleName()}`));
    logger.logUpdatePersist();

    execSync(`git apply ${diffFile}`);
  }
}