import { newId, logger } from '@rareindex/shared';
import { costs } from '@rareindex/database';
import { db } from './db.ts';

/**
 * Cost ledger (§169). Unit prices are approximations configurable by env:
 *  FIRECRAWL_USD_PER_CREDIT (default 0.00083 ≈ $83 / 100k credits plan)
 *  SCRAPFLY_USD_PER_CREDIT  (default 0.00030 ≈ $30 / 100k credits plan)
 *  AI prices are passed by the caller (per provider/model).
 */
export const UNIT_USD = {
  firecrawl: Number(process.env.FIRECRAWL_USD_PER_CREDIT ?? 0.00083),
  scrapfly: Number(process.env.SCRAPFLY_USD_PER_CREDIT ?? 0.0003),
};

export interface CostEntry {
  kind: 'firecrawl' | 'scrapfly' | 'ai' | 'storage' | 'http';
  provider?: string;
  connectorId?: string;
  categorySlug?: string;
  endpoint?: string;
  userId?: string;
  units?: number;
  credits?: number;
  usdEst?: number;
  metadata?: Record<string, unknown>;
}

const buffer: CostEntry[] = [];
let flushing: Promise<void> | null = null;

export function recordCost(entry: CostEntry): void {
  buffer.push(entry);
  if (buffer.length >= 200) void flushCosts();
}

export async function flushCosts(): Promise<void> {
  if (flushing) return flushing;
  if (buffer.length === 0) return;
  const batch = buffer.splice(0, buffer.length);
  flushing = (async () => {
    try {
      await db()
        .insert(costs)
        .values(
          batch.map((e) => ({
            id: newId('event'),
            occurredAt: new Date(),
            kind: e.kind,
            provider: e.provider ?? null,
            connectorId: e.connectorId ?? null,
            categorySlug: e.categorySlug ?? null,
            endpoint: e.endpoint ?? null,
            userId: e.userId ?? null,
            units: e.units ?? 1,
            credits: e.credits ?? 0,
            usdEst: e.usdEst ?? (e.kind === 'firecrawl' ? (e.credits ?? 0) * UNIT_USD.firecrawl : e.kind === 'scrapfly' ? (e.credits ?? 0) * UNIT_USD.scrapfly : 0),
            metadata: e.metadata ?? {},
          })),
        );
    } catch (err) {
      logger.error({ err }, 'cost flush failed');
    } finally {
      flushing = null;
    }
  })();
  return flushing;
}