Loan Management

model Loan {
  id            String      @id @default(cuid())
  loanNumber    String      @unique  // Auto-generated unique identifier
  
  // Borrower and Union
  unionMemberId String
  unionMember   UnionMember
  unionId       String
  union         Union
  
  // Loan Details
  loanTypeId        String?
  loanType          LoanType?
  principalAmount   Decimal   @db.Decimal(14, 2)
  currencyCode      String    @default("NGN")
  
  // Terms
  termCount         Int       // Duration count
  termUnit          TermUnit  // DAY, WEEK, or MONTH
  startDate         DateTime
  endDate           DateTime?
  
  // Fees
  processingFeeAmount    Decimal  @db.Decimal(14, 2)
  processingFeeCollected Boolean  @default(false)
  penaltyFeePerDayAmount Decimal  @db.Decimal(14, 2)
  
  // Status
  status            LoanStatus @default(DRAFT)
  
  // Assignment
  createdByUserId   String
  createdByUser     User
  assignedOfficerId String?
  assignedOfficer   User?
  
  // Dates
  disbursedAt DateTime?
  closedAt    DateTime?
  notes       String?
  
  // Relations
  scheduleItems RepaymentScheduleItem[]
  repayments    Repayment[]
  documents     LoanDocument[]
  
  createdAt DateTime  @default(now())
  updatedAt DateTime  @updatedAt
  deletedAt DateTime?
}

enum LoanStatus {
  DRAFT              // Just created, not submitted
  PENDING_APPROVAL   // Submitted, awaiting supervisor
  APPROVED           // Approved, ready for disbursement
  ACTIVE             // Disbursed and being repaid
  COMPLETED          // Fully repaid and closed
  DEFAULTED          // Borrower failed to repay
  WRITTEN_OFF        // Bad debt, removed from books
  CANCELED           // Canceled before disbursement
}

enum TermUnit {
  DAY    // Daily repayments (e.g., 30 days)
  WEEK   // Weekly repayments (e.g., 12 weeks)
  MONTH  // Monthly repayments (e.g., 6 months)
}

// POST /api/loans
const createLoan = async (data: {
  unionMemberId: string;
  unionId: string;
  loanTypeId?: string;
  principalAmount: number;
  termCount: number;
  termUnit: 'DAY' | 'WEEK' | 'MONTH';
  startDate: string;
  processingFeeAmount: number;
  penaltyFeePerDayAmount: number;
  notes?: string;
}) => {
  // Creates loan in DRAFT status
  // Generates repayment schedule
}

// Update loan status
POST /api/loans/:id/status
Body: {
  status: 'APPROVED' | 'REJECTED' | 'CANCELED',
  notes?: string
}

// POST /api/loans/:id/disburse
const disburseLoan = async (loanId: string, data: {
  disbursedAt?: Date;
}) => {
  // Updates status to ACTIVE
  // Records disbursement date
  // Activates repayment schedule
}

model RepaymentScheduleItem {
  id     String @id
  loanId String
  loan   Loan
  
  sequence     Int       // Payment number (1, 2, 3...)
  dueDate      DateTime  // When payment is due
  
  principalDue Decimal   @db.Decimal(14, 2)
  interestDue  Decimal   @default(0) @db.Decimal(14, 2)
  feeDue       Decimal   @default(0) @db.Decimal(14, 2)
  
  totalDue     Decimal   @db.Decimal(14, 2)
  paidAmount   Decimal   @default(0) @db.Decimal(14, 2)
  
  status   ScheduleStatus @default(PENDING)
  closedAt DateTime?
  
  allocations RepaymentAllocation[]
}

enum ScheduleStatus {
  PENDING  // Not yet paid
  PARTIAL  // Partially paid
  PAID     // Fully paid
  OVERDUE  // Past due date and unpaid
}

// POST /api/loans/:loanId/regenerate-schedule
// Admin only - regenerates payment schedule

// GET /api/loans/:id/summary
const getLoanSummary = async (loanId: string) => {
  // Returns comprehensive loan metrics
}

// Get all loans
GET /api/loans?page=1&limit=20&status=ACTIVE&unionId=xxx&unionMemberId=xxx

// Get loan by ID
GET /api/loans/:id

// Create loan
POST /api/loans
Body: { unionMemberId, unionId, principalAmount, termCount, termUnit, ... }

// Update loan
PUT /api/loans/:id
Body: { principalAmount?, termCount?, notes?, ... }

// Update status
POST /api/loans/:id/status
Body: { status: 'APPROVED' | 'REJECTED' | 'CANCELED', notes? }

// Disburse loan
POST /api/loans/:id/disburse
Body: { disbursedAt? }

// Assign loan
POST /api/loans/:id/assign
Body: { assignedOfficerId, reason? }

// Delete loan
DELETE /api/loans/:id

// Get loan schedule
GET /api/loans/:id/schedule

// Get loan summary
GET /api/loans/:id/summary

// Regenerate schedule (Admin)
POST /api/loans/:loanId/regenerate-schedule

// Generate missing schedules (Admin)
POST /api/loans/generate-missing-schedules