/**
 * Posts Module - Config Parser
 * Parses ZEN_MODULE_ZEN_MODULE_POSTS_TYPES and ZEN_MODULE_POSTS_TYPE_* environment variables into a structured config.
 *
 * .env format:
 *   ZEN_MODULE_ZEN_MODULE_POSTS_TYPES=blogue|cve|emploi
 *   ZEN_MODULE_POSTS_TYPE_BLOGUE=title:title|slug:slug|category:category|date:date|resume:text|content:markdown|image:image
 *   ZEN_MODULE_POSTS_TYPE_CVE=title:title|slug:slug|cve_id:text|severity:text|description:markdown|date:date
 *
 * Supported field types: title, slug, text, markdown, date, datetime, color, category, image, relation
 *
 * Relation field format: name:relation:target_post_type
 *   e.g. keywords:relation:mots-cle
 */

const VALID_FIELD_TYPES = ['title', 'slug', 'text', 'markdown', 'date', 'datetime', 'color', 'category', 'image', 'relation'];

let _cachedConfig = null;

/**
 * Parse a single type's field string into an array of field definitions.
 * Format: "name:type" or "name:type:param" (param used for relation target)
 * e.g. "title:title|slug:slug|date:date|keywords:relation:mots-cle"
 * -> [{ name: 'title', type: 'title' }, ..., { name: 'keywords', type: 'relation', target: 'mots-cle' }]
 * @param {string} fieldString
 * @returns {Array<{name: string, type: string, target?: string}>}
 */
function parseFields(fieldString) {
  if (!fieldString) return [];

  return fieldString
    .split('|')
    .map(part => {
      const segments = part.trim().split(':');
      const name = segments[0];
      const type = segments[1];
      const param = segments[2] || null;
      if (!name) return null;
      const resolvedType = VALID_FIELD_TYPES.includes(type) ? type : 'text';
      const field = { name: name.trim(), type: resolvedType };
      if (resolvedType === 'relation' && param) {
        field.target = param.trim().toLowerCase();
      }
      return field;
    })
    .filter(Boolean);
}

/**
 * Parse all ZEN_MODULE_POSTS_TYPE_* env vars and build the config object.
 * @returns {Object} Parsed config
 */
function buildConfig() {
  const enabled = process.env.ZEN_MODULE_POSTS === 'true';

  if (!enabled) {
    return { enabled: false, types: {} };
  }

  const typesRaw = process.env.ZEN_MODULE_ZEN_MODULE_POSTS_TYPES || '';
  // Each entry can be "key" or "key:Label" — only lowercase the key part
  const typeKeys = typesRaw
    .split('|')
    .map(k => {
      const [key, ...rest] = k.trim().split(':');
      const label = rest.join(':'); // preserve colons in label if any
      return label ? `${key.toLowerCase()}:${label}` : key.toLowerCase();
    })
    .filter(Boolean);

  const types = {};

  for (const entry of typeKeys) {
    // Support "key:Label" format (label is optional)
    const [key, customLabel] = entry.split(':');
    const envKey = `ZEN_MODULE_POSTS_TYPE_${key.toUpperCase()}`;
    const fieldString = process.env[envKey] || '';
    const fields = parseFields(fieldString);

    const titleField = fields.find(f => f.type === 'title')?.name || null;
    const slugField = fields.find(f => f.type === 'slug')?.name || null;
    const hasCategory = fields.some(f => f.type === 'category');
    const hasRelations = fields.some(f => f.type === 'relation');
    const label = customLabel || (key.charAt(0).toUpperCase() + key.slice(1));

    types[key] = {
      key,
      label,
      fields,
      hasCategory,
      hasRelations,
      titleField,
      slugField,
    };
  }

  return { enabled: true, types };
}

/**
 * Get the parsed posts config (cached after first call).
 * @returns {{ enabled: boolean, types: Object }}
 */
export function getPostsConfig() {
  if (!_cachedConfig) {
    _cachedConfig = buildConfig();
  }
  return _cachedConfig;
}

/**
 * Get a single post type config by key.
 * @param {string} key - Type key (e.g. 'blogue')
 * @returns {Object|null}
 */
export function getPostType(key) {
  const config = getPostsConfig();
  return config.types[key] || null;
}

/**
 * Check if the posts module is enabled.
 * @returns {boolean}
 */
export function isPostsEnabled() {
  return process.env.ZEN_MODULE_POSTS === 'true';
}

/**
 * Reset cached config (useful for testing).
 */
export function resetConfig() {
  _cachedConfig = null;
}