SkyMoney/api/tests/irregular-income-simple.test.ts

import { describe, it, expect, beforeEach } from 'vitest';
import { allocateBudget, applyIrregularIncome, previewAllocation } from '../src/allocator.ts';
import { prisma, U, resetUser, ensureUser, cid, pid } from './helpers.ts';

describe('Irregular Income Allocation', () => {
  const userId = U;

  beforeEach(async () => {
    await resetUser(userId);
    await ensureUser(userId);
  });

  async function createFixedPlan(totalCents: number, name: string, priority: number, dueInDays: number) {
    const id = pid();
    const now = new Date();
    await prisma.fixedPlan.create({
      data: {
        id,
        userId,
        name,
        totalCents: BigInt(totalCents),
        priority,
        dueOn: new Date(Date.now() + dueInDays * 24 * 60 * 60 * 1000),
        cycleStart: now, // Required field
      },
    });
    return id;
  }

  async function createVariableCategory(name: string, percent: number, priority: number, isSavings = false) {
    const id = cid();
    await prisma.variableCategory.create({
      data: {
        id,
        userId,
        name,
        percent,
        priority,
        isSavings,
      },
    });
    return id;
  }

  async function createIncomeEvent(amountCents: number, daysAgo = 0) {
    const id = `income_${Date.now()}_${Math.random()}`;
    await prisma.incomeEvent.create({
      data: {
        id,
        userId,
        amountCents: BigInt(amountCents),
        postedAt: new Date(Date.now() - daysAgo * 24 * 60 * 60 * 1000),
      },
    });
    return id;
  }

  describe('Basic Allocation Logic', () => {
    it('should allocate percentage of new income to fixed expenses', async () => {
      // Setup: Create fixed plans and variable categories
      const rentId = await createFixedPlan(50000, 'Rent', 1, 10); // $500, due in 10 days (reduced so both can get funding)
      const carId = await createFixedPlan(40000, 'Car Payment', 2, 5); // $400, due in 5 days

      await createVariableCategory('Groceries', 50, 1);
      await createVariableCategory('Entertainment', 30, 2);
      await createVariableCategory('Savings', 20, 3, true);

      // Add some available budget
      await createIncomeEvent(50000, 1); // $500 from 1 day ago

      // Test: Allocate $2,000 with 30% to fixed expenses
      const result = await allocateBudget(prisma, userId, 200000, 30);

      expect(result.totalBudgetCents).toBe(200000); // $2,000 new income
      
      // Fixed expenses should get 30% of new income = $600
      const totalFixedAllocated = result.fixedAllocations.reduce((sum, a) => sum + a.amountCents, 0);
      expect(totalFixedAllocated).toBe(60000); // $600

      // Car payment (5 days, crisis for irregular) should get some allocation
      const carAllocation = result.fixedAllocations.find(a => a.fixedPlanId === carId);
      expect(carAllocation).toBeDefined();
      expect(carAllocation!.amountCents).toBeGreaterThan(0);

      // Variables should get available budget + remaining new income
      const totalVariableAllocated = result.variableAllocations.reduce((sum, a) => sum + a.amountCents, 0);
      expect(totalVariableAllocated).toBeGreaterThan(0);
      

    });

    it('should treat plans due within 14 days as crisis', async () => {
      // Setup: Create fixed plan due in 12 days
      const urgentBillId = await createFixedPlan(80000, 'Urgent Bill', 1, 12); // $800, due in 12 days

      const result = await allocateBudget(prisma, userId, 100000, 50); // $1,000 with 50% to fixed

      expect(result.crisis.active).toBe(true);
      expect(result.crisis.plans).toHaveLength(1);
      expect(result.crisis.plans[0].id).toBe(urgentBillId);
      expect(result.crisis.plans[0].daysUntilDue).toBe(12);
    });

    it('should work with different fixed expense percentages', async () => {
      await createFixedPlan(100000, 'Rent', 1, 30); // $1,000
      await createVariableCategory('Everything', 100, 1);

      // Test 10% to fixed expenses
      const result10 = await allocateBudget(prisma, userId, 200000, 10);
      const fixed10 = result10.fixedAllocations.reduce((sum, a) => sum + a.amountCents, 0);
      
      // Test 50% to fixed expenses  
      const result50 = await allocateBudget(prisma, userId, 200000, 50);
      const fixed50 = result50.fixedAllocations.reduce((sum, a) => sum + a.amountCents, 0);

      expect(fixed50).toBeGreaterThan(fixed10);
      console.log('10% allocation to fixed:', fixed10);
      console.log('50% allocation to fixed:', fixed50);
    });
  });

  describe('Comparison with Regular Income', () => {
    it('should show meaningful differences from regular income allocation', async () => {
      // Setup same scenario for both
      await createFixedPlan(120000, 'Rent', 1, 10); // $1,200, due in 10 days
      await createFixedPlan(40000, 'Car Payment', 2, 5); // $400, due in 5 days

      await createVariableCategory('Groceries', 60, 1);
      await createVariableCategory('Savings', 40, 2, true);

      // Add available budget
      await createIncomeEvent(75000, 1); // $750 available

      // Set user to biweekly frequency for regular income test
      await prisma.user.update({
        where: { id: userId },
        data: { incomeFrequency: 'biweekly' }
      });

      // Test regular income allocation
      const regularResult = await previewAllocation(prisma, userId, 200000); // $2,000

      // Test irregular income allocation
      const irregularResult = await allocateBudget(prisma, userId, 200000, 30); // $2,000 with 30% fixed

      // Compare results
      const regularFixedTotal = regularResult.fixedAllocations.reduce((sum, a) => sum + a.amountCents, 0);
      const irregularFixedTotal = irregularResult.fixedAllocations.reduce((sum, a) => sum + a.amountCents, 0);

      // The strategies should be different
      expect(regularFixedTotal).not.toBe(irregularFixedTotal);
      
      console.log('Regular Income Fixed Allocation:', regularFixedTotal);
      console.log('Irregular Income Fixed Allocation:', irregularFixedTotal);
      console.log('Irregular should be capped at 30% = $600:', irregularFixedTotal <= 60000);
    });
  });

  describe('Edge Cases', () => {
    it('should handle 0% fixed expense allocation', async () => {
      await createFixedPlan(100000, 'Rent', 1, 30);
      await createVariableCategory('Everything', 100, 1);

      const result = await allocateBudget(prisma, userId, 200000, 0); // 0% to fixed

      const fixedTotal = result.fixedAllocations.reduce((sum, a) => sum + a.amountCents, 0);
      expect(fixedTotal).toBe(0);
    });

    it('should handle no fixed expenses', async () => {
      await createVariableCategory('Everything', 100, 1);

      const result = await allocateBudget(prisma, userId, 200000, 30);

      expect(result.fixedAllocations).toHaveLength(0);
      const variableTotal = result.variableAllocations.reduce((sum, a) => sum + a.amountCents, 0);
      expect(variableTotal).toBe(200000); // All income to variables
    });
  });
});