// No hyphens — would parse as subtraction in Groovy block syntax like `myRepo { ... }`.
const GROOVY_IDENTIFIER = /^[A-Za-z_][A-Za-z0-9_]*$/;
// Rejects dots and slashes so the value is also safe as a directory segment.
const GRADLE_PROJECT_NAME = /^[A-Za-z_][A-Za-z0-9_-]*$/;
const JAVA_PACKAGE = /^[A-Za-z_][A-Za-z0-9_]*(\.[A-Za-z_][A-Za-z0-9_]*)*$/;
const MAVEN_VERSION = /^[A-Za-z0-9._+-]+$/;
const ENV_VAR_NAME = /^[A-Za-z_][A-Za-z0-9_]*$/;

type GradleFieldKind =
  | 'groovyIdentifier'
  | 'gradleProjectName'
  | 'javaPackage'
  | 'mavenVersion'
  | 'envVarName';

const PATTERNS: Record<GradleFieldKind, { pattern: RegExp; shape: string }> = {
  groovyIdentifier: {
    pattern: GROOVY_IDENTIFIER,
    shape:
      'a Groovy identifier (letters, digits, and underscores, starting with a letter or underscore)',
  },
  gradleProjectName: {
    pattern: GRADLE_PROJECT_NAME,
    shape:
      'a Gradle project name (letters, digits, underscores, and hyphens, starting with a letter or underscore)',
  },
  javaPackage: {
    pattern: JAVA_PACKAGE,
    shape: 'a dot-separated Java package (e.g. com.example.app)',
  },
  mavenVersion: {
    pattern: MAVEN_VERSION,
    shape:
      'a Maven-compatible version (letters, digits, dots, hyphens, underscores, or plus signs)',
  },
  envVarName: {
    pattern: ENV_VAR_NAME,
    shape:
      'an environment variable name (letters, digits, and underscores, starting with a letter or underscore)',
  },
};

export const validateGradleField = (
  kind: GradleFieldKind,
  value: unknown,
  fieldName: string
): string => {
  const { pattern, shape } = PATTERNS[kind];
  if (typeof value !== 'string' || !pattern.test(value)) {
    throw new Error(
      `Invalid ${fieldName} ${JSON.stringify(value)}: must be ${shape}. Update your app config and re-run prebuild.`
    );
  }
  return value;
};

// Groovy double-quoted strings share JSON's escape grammar, except `$` (GString interpolation).
export const escapeGroovyDoubleQuotedString = (value: string): string => {
  return JSON.stringify(value).slice(1, -1).replace(/\$/g, '\\$');
};