/**
 * AI usage ledger.
 *
 * Every server-side AI provider call records one row here so admins can
 * audit spend per port, per feature, per user. Per-port budgets (stored
 * in `system_settings` under `ai.budget`) read this table to enforce
 * soft warnings and hard caps.
 *
 * Token-denominated rather than dollar-denominated so the cap survives
 * model price changes - and it's the unit both OpenAI and Anthropic
 * SDKs return in `response.usage`.
 */

import { pgTable, text, timestamp, integer, index } from 'drizzle-orm/pg-core';

import { ports } from './ports';
import { user } from './users';

export const aiUsageLedger = pgTable(
  'ai_usage_ledger',
  {
    id: text('id')
      .primaryKey()
      .$defaultFn(() => crypto.randomUUID()),
    portId: text('port_id')
      .notNull()
      .references(() => ports.id, { onDelete: 'cascade' }),
    /** Optional - system-initiated calls (e.g. scheduled summarizers) won't have a user. */
    userId: text('user_id').references(() => user.id, { onDelete: 'set null' }),
    /** Stable feature key: 'ocr', 'summary', 'embedding', 'reply_draft', etc. */
    feature: text('feature').notNull(),
    /** 'openai' | 'claude' | 'tesseract' (free, recorded for parity). */
    provider: text('provider').notNull(),
    model: text('model').notNull(),
    inputTokens: integer('input_tokens').notNull().default(0),
    outputTokens: integer('output_tokens').notNull().default(0),
    /** input + output. Indexed and used for budget rollup queries. */
    totalTokens: integer('total_tokens').notNull().default(0),
    /** Provider-side request id for cross-referencing with provider logs. */
    requestId: text('request_id'),
    createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
  },
  (table) => [
    index('idx_ai_usage_port_created').on(table.portId, table.createdAt),
    index('idx_ai_usage_port_feature_created').on(table.portId, table.feature, table.createdAt),
  ],
);

export type AiUsageRow = typeof aiUsageLedger.$inferSelect;
export type NewAiUsageRow = typeof aiUsageLedger.$inferInsert;
