import type { HydrantEvent, HydrantRecordValue, UrlEntry } from './types';
import { sanitizeLastmod } from './xml';

export interface ExtractedAction {
  type: 'upsert' | 'delete';
  url: string;
  entry?: UrlEntry;
}

interface CollectionSpec {
  buildPath: (owner: string, rkey: string, record?: HydrantRecordValue) => string;
  changefreq: UrlEntry['changefreq'];
  priority: number;
}

export const COLLECTION_SPECS: Record<string, CollectionSpec> = {
  'sh.tangled.repo': {
    buildPath: (owner, rkey, record) => `${owner}/${(record?.name as string) || rkey}`,
    changefreq: 'daily',
    priority: 0.8,
  },
  'sh.tangled.actor.profile': {
    buildPath: (owner) => owner,
    changefreq: 'daily',
    priority: 0.8,
  },
  'sh.tangled.string': {
    buildPath: (owner, rkey) => `${owner}/strings/${rkey}`,
    changefreq: 'weekly',
    priority: 0.6,
  },
};

export function resolveIdentity(
  did: string,
  explicitHandle?: string,
  identityMap?: Map<string, string>,
): string {
  if (explicitHandle && explicitHandle.trim().length > 0) {
    if (identityMap) identityMap.set(did, explicitHandle);
    return explicitHandle;
  }
  return identityMap?.get(did) || did;
}

export function extractUrlAction(
  event: HydrantEvent,
  baseUrl: string,
  identityMap: Map<string, string>,
  now = new Date(),
): ExtractedAction | null {
  if (event.type === 'identity' && event.identity) {
    if (event.identity.handle) {
      identityMap.set(event.identity.did, event.identity.handle);
    }
    return null;
  }

  if (event.type !== 'record' || !event.record) {
    return null;
  }

  const { collection, rkey, action, did, handle, record } = event.record;
  const spec = COLLECTION_SPECS[collection];
  if (!spec) {
    return null;
  }

  const owner = resolveIdentity(did, handle, identityMap);
  const normalizedBase = baseUrl.replace(/\/+$/, '');
  const path = spec.buildPath(owner, rkey, record);
  const url = `${normalizedBase}/${path}`;

  if (action === 'delete') {
    return { type: 'delete', url };
  }

  const lastmod = sanitizeLastmod(record?.createdAt as string | undefined, now);
  return {
    type: 'upsert',
    url,
    entry: {
      loc: url,
      lastmod,
      changefreq: spec.changefreq,
      priority: spec.priority,
    },
  };
}