kooltab-backoffice/apps/api/src/testing/fake-prisma.ts

/**
 * An in-memory stand-in for the Prisma client, for tests that follow a venue through several syncs. It supports the
 * queries the tab, stock and device services use: equality, `in`, `notIn`, `not`, `gt`, `gte`, `lte` and compound
 * unique keys, `orderBy` on one or more fields, `take` and `select`. Transactions run directly on the same data.
 */

import { randomUUID } from 'crypto';

type Row = Record<string, any>;

const COMPOUND_KEYS: Record<string, string[]> = {
  venueId_id: ['venueId', 'id'],
  venueId_productId: ['venueId', 'productId'],
};

function matches(row: Row, where: Row = {}): boolean {
  return Object.entries(where).every(([field, condition]) => {
    if (field in COMPOUND_KEYS) return COMPOUND_KEYS[field].every((key) => row[key] === condition[key]);
    const value = row[field];
    if (condition === null || typeof condition !== 'object' || condition instanceof Date) {
      return equal(value, condition);
    }
    return Object.entries(condition).every(([op, operand]: [string, any]) => {
      switch (op) {
        case 'in': return operand.some((o: unknown) => equal(value, o));
        case 'notIn': return !operand.some((o: unknown) => equal(value, o));
        case 'not': return !equal(value, operand);
        case 'gt': return value !== null && value > operand;
        case 'gte': return value !== null && value >= operand;
        case 'lte': return value !== null && value <= operand;
        default: throw new Error(`fake-prisma: unsupported operator ${op}`);
      }
    });
  });
}

function equal(a: unknown, b: unknown) {
  if (a instanceof Date && b instanceof Date) return a.getTime() === b.getTime();
  return (a ?? null) === (b ?? null);
}

/** A deep copy, so tests can't change stored rows by accident. structuredClone's Dates fail instanceof under Jest. */
function clone<T>(value: T): T {
  if (value instanceof Date) return new Date(value) as T;
  if (Array.isArray(value)) return value.map(clone) as T;
  if (value && typeof value === 'object') {
    return Object.fromEntries(Object.entries(value).map(([k, v]) => [k, clone(v)])) as T;
  }
  return value;
}

function pick(row: Row, select?: Row): Row {
  const copy = clone(row);
  if (!select) return copy;
  return Object.fromEntries(Object.keys(select).filter((key) => select[key]).map((key) => [key, copy[key]]));
}

function sort(rows: Row[], orderBy?: Row | Row[]) {
  const orders = orderBy ? (Array.isArray(orderBy) ? orderBy : [orderBy]) : [];
  return [...rows].sort((a, b) => {
    for (const order of orders) {
      const [field, direction] = Object.entries(order)[0];
      if (a[field] < b[field]) return direction === 'asc' ? -1 : 1;
      if (a[field] > b[field]) return direction === 'asc' ? 1 : -1;
    }
    return 0;
  });
}

class FakeTable {
  rows: Row[] = [];
  private sequence = 0;

  constructor(private defaults: () => Row = () => ({}), private sequenceField?: string) {}

  private insert(data: Row) {
    // Like @default(uuid()); harmless on tables keyed otherwise
    const row: Row = { id: randomUUID(), ...this.defaults(), ...clone(data) };
    if (this.sequenceField) row[this.sequenceField] = ++this.sequence;
    this.rows.push(row);
    return row;
  }

  async findMany(args: Row = {}) {
    const found = sort(this.rows.filter((row) => matches(row, args.where)), args.orderBy);
    return found.slice(0, args.take ?? found.length).map((row) => pick(row, args.select));
  }

  async findUnique(args: Row) {
    const row = this.rows.find((r) => matches(r, args.where));
    return row ? pick(row, args.select) : null;
  }

  async findFirst(args: Row = {}) {
    return (await this.findMany({ ...args, take: 1 }))[0] ?? null;
  }

  async create(args: Row) {
    return pick(this.insert(args.data), args.select);
  }

  async createMany(args: Row) {
    let count = 0;
    for (const data of args.data) {
      if (args.skipDuplicates && this.rows.some((row) => row.id !== undefined && row.id === data.id)) continue;
      this.insert(data);
      count++;
    }
    return { count };
  }

  async update(args: Row) {
    const row = this.rows.find((r) => matches(r, args.where));
    if (!row) throw new Error('fake-prisma: record to update not found');
    Object.assign(row, clone(args.data));
    return pick(row, args.select);
  }

  async updateMany(args: Row) {
    const found = this.rows.filter((row) => matches(row, args.where));
    for (const row of found) Object.assign(row, clone(args.data));
    return { count: found.length };
  }

  async upsert(args: Row) {
    const row = this.rows.find((r) => matches(r, args.where));
    if (row) {
      Object.assign(row, clone(args.update));
      return pick(row);
    }
    return pick(this.insert(args.create));
  }

  async deleteMany(args: Row = {}) {
    const before = this.rows.length;
    this.rows = this.rows.filter((row) => !matches(row, args.where));
    return { count: before - this.rows.length };
  }

  async aggregate(args: Row) {
    const found = this.rows.filter((row) => matches(row, args.where));
    const max = Object.fromEntries(Object.keys(args._max ?? {}).map((field) => [
      field,
      found.length === 0 ? null : Math.max(...found.map((row) => row[field])),
    ]));
    return { _max: max };
  }
}

export function createFakePrisma() {
  const now = () => new Date();
  const prisma = {
    venue: new FakeTable(() => ({ tabsSeededAt: null })),
    device: new FakeTable(),
    tab: new FakeTable(() => ({ updatedAt: now() })),
    product: new FakeTable(() => ({ stock: null, countedAt: null, lowStockThreshold: null })),
    tabEvent: new FakeTable(),
    settlement: new FakeTable(() => ({ createdAt: now() }), 'sequence'),
    stockAdjustment: new FakeTable(() => ({ status: 'pending', stockAfter: null, result: null, processedAt: null, createdAt: now() })),
    plannedTab: new FakeTable(() => ({ deliveredAt: null, email: null, position: 0 })),
    remoteCommand: new FakeTable(),
    auditLog: new FakeTable(),
    tabReminder: new FakeTable(),

    /** Only the venue lock of VenueLedger.open. */
    async $queryRaw(strings: TemplateStringsArray, venueId: string) {
      const venue = prisma.venue.rows.find((row) => row.id === venueId);
      return venue ? [{ tabsSeededAt: venue.tabsSeededAt }] : [];
    },

    async $transaction(fn: unknown) {
      if (typeof fn === 'function') return fn(prisma);
      return Promise.all(fn as Promise<unknown>[]);
    },
  };

  // Tab rows bump their update time like Prisma's @updatedAt
  const upsertTab = prisma.tab.upsert.bind(prisma.tab);
  prisma.tab.upsert = (args: Row) => upsertTab({
    ...args,
    create: { ...args.create, updatedAt: now() },
    update: { ...args.update, updatedAt: now() },
  });

  return prisma;
}

export type FakePrisma = ReturnType<typeof createFakePrisma>;