template-saas/apps/backend/src/modules/ai/entities/ai-usage.entity.ts

import {
  Entity,
  PrimaryGeneratedColumn,
  Column,
  CreateDateColumn,
} from 'typeorm';
import { AIProvider } from './ai-config.entity';

export enum AIModelType {
  CHAT = 'chat',
  COMPLETION = 'completion',
  EMBEDDING = 'embedding',
  IMAGE = 'image',
}

export enum UsageStatus {
  PENDING = 'pending',
  COMPLETED = 'completed',
  FAILED = 'failed',
  CANCELLED = 'cancelled',
}

@Entity({ name: 'usage', schema: 'ai' })
export class AIUsage {
  @PrimaryGeneratedColumn('uuid')
  id: string;

  @Column({ type: 'uuid' })
  tenant_id: string;

  @Column({ type: 'uuid' })
  user_id: string;

  @Column({ type: 'enum', enum: AIProvider })
  provider: AIProvider;

  @Column({ type: 'varchar', length: 100 })
  model: string;

  @Column({ type: 'enum', enum: AIModelType, default: AIModelType.CHAT })
  model_type: AIModelType;

  @Column({ type: 'enum', enum: UsageStatus, default: UsageStatus.PENDING })
  status: UsageStatus;

  @Column({ type: 'int', default: 0 })
  input_tokens: number;

  @Column({ type: 'int', default: 0 })
  output_tokens: number;

  // total_tokens is computed in DB, but we can add it for convenience
  get total_tokens(): number {
    return this.input_tokens + this.output_tokens;
  }

  @Column({ type: 'numeric', precision: 12, scale: 6, default: 0 })
  cost_input: number;

  @Column({ type: 'numeric', precision: 12, scale: 6, default: 0 })
  cost_output: number;

  get cost_total(): number {
    return Number(this.cost_input) + Number(this.cost_output);
  }

  @Column({ type: 'int', nullable: true })
  latency_ms: number;

  @Column({ type: 'timestamptz', default: () => 'NOW()' })
  started_at: Date;

  @Column({ type: 'timestamptz', nullable: true })
  completed_at: Date;

  @Column({ type: 'varchar', length: 100, nullable: true })
  request_id: string;

  @Column({ type: 'varchar', length: 50, nullable: true })
  endpoint: string;

  @Column({ type: 'text', nullable: true })
  error_message: string;

  @Column({ type: 'jsonb', default: {} })
  metadata: Record<string, any>;

  @CreateDateColumn({ type: 'timestamptz' })
  created_at: Date;
}