import policyFile from '../../includes/settings-policy.json';
import { INITIAL_SETTINGS } from '../stores/main/constants';
import type { Settings } from '../stores/main/models';

/**
 * Which table settings this plugin applies. The policy is the SAME file PHP
 * enforces on save (includes/settings-policy.json via
 * includes/settings-policy.php), so what renders and what can be saved never
 * drift apart.
 *
 * Settings that belong to vTables Pro stay in the database untouched (the
 * server keeps their stored values on every save); here they are replaced
 * with their defaults for rendering, so a table made with Pro — or with
 * vTables 0.2.x, where some of them were still free — shows with the free
 * options until Pro is active again.
 */

type SectionPolicy = boolean | Record<string, boolean>;

const SECTIONS = (policyFile as { sections: Record<string, SectionPolicy> })
  .sections;

type AnyRecord = Record<string, unknown>;

function isRecord(value: unknown): value is AnyRecord {
  return typeof value === 'object' && value !== null && !Array.isArray(value);
}

function clone<T>(value: T): T {
  return value === undefined ? value : JSON.parse(JSON.stringify(value));
}

/** Whether a settings path (section, optional key) is applied by this plugin. */
export function isSettingAllowed(section: string, key?: string): boolean {
  const policy = SECTIONS[section];

  if (policy === undefined) return true;
  if (typeof policy === 'boolean') return policy;
  if (key !== undefined && key in policy && key !== '*') return policy[key];

  return policy['*'] ?? true;
}

/**
 * Returns a copy of `settings` where every locked path holds its default
 * (from INITIAL_SETTINGS) — or is dropped when there is no default.
 */
export function applySettingsPolicy<T extends Settings>(settings: T): T {
  const result = clone(settings) as unknown as AnyRecord;
  const defaults = INITIAL_SETTINGS as unknown as AnyRecord;

  for (const section of Object.keys(result)) {
    const policy = SECTIONS[section];
    if (policy === undefined || policy === true) continue;

    if (policy === false) {
      if (section in defaults) {
        result[section] = clone(defaults[section]);
      } else {
        delete result[section];
      }
      continue;
    }

    const current = result[section];
    if (!isRecord(current)) continue;

    const sectionDefaults = isRecord(defaults[section])
      ? (defaults[section] as AnyRecord)
      : {};

    for (const key of Object.keys(current)) {
      if (isSettingAllowed(section, key)) continue;

      if (key in sectionDefaults) {
        current[key] = clone(sectionDefaults[key]);
      } else {
        delete current[key];
      }
    }
  }

  return result as unknown as T;
}