// =============================================================================
// NetForge Prisma Schema
// =============================================================================
//
// MULTI-TENANCY & RLS CONVENTION:
// All tenant-scoped models MUST include a `tenantId` field.
// This field is the foundation for Row-Level Security (RLS) policies.
// When adding new models (Subscriber, Invoice, Plan, Payment, etc.),
// always include: tenantId String + @@index([tenantId])
//
// Super-admin models that span tenants (e.g., audit logs, platform config)
// are the only exception to this rule.
// =============================================================================

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
}

// =============================================================================
// ENUMS
// =============================================================================

enum TenantStatus {
  ACTIVE
  PENDING_SUSPENSION
  SUSPENDED
}

enum Role {
  ADMIN
  OFFICE_STAFF
  COLLECTOR
  TECHNICIAN
  CLIENT
}

enum AccountType {
  ASSET
  LIABILITY
  EQUITY
  REVENUE
  EXPENSE
}

enum NormalBalance {
  DEBIT
  CREDIT
}

enum PeriodStatus {
  OPEN
  CLOSED
}

enum SubscriberStatus {
  ACTIVE
  SUSPENDED
  CANCELLED
}

enum BillingType {
  PREPAID
  POSTPAID
}

enum JournalEntryStatus {
  DRAFT
  PENDING_APPROVAL
  APPROVED
  POSTED
  REVERSED
}

enum JournalEntrySource {
  SYSTEM
  MANUAL
}

// =============================================================================
// MODELS
// =============================================================================

/// A Tenant represents a single ISP business using the NetForge platform.
/// All tenant-scoped data is isolated by tenantId (RLS-ready).
model Tenant {
  id        String       @id @default(uuid())
  name      String
  /// URL-friendly identifier, auto-generated from name (e.g., "my-isp" from "My ISP")
  slug      String       @unique
  ownerEmail String

  /// Physical address of the ISP business (optional)
  businessAddress String?
  /// Primary contact phone number (optional)
  contactPhone    String?

  status             TenantStatus @default(ACTIVE)
  /// Timestamp when suspension was triggered (starts grace period clock)
  suspendedAt        DateTime?
  /// When actual service interruption occurs (suspendedAt + 7 days grace period)
  gracePeriodEndsAt  DateTime?

  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt

  users User[]
}

/// An Account represents a node in the Chart of Accounts tree.
/// Account balances are NEVER stored — they are always derived from journal entry sums.
/// System accounts (isSystemAccount=true) are auto-created from ISP_CHART_OF_ACCOUNTS
/// and cannot be deleted by tenant admins.
model Account {
  id            String        @id @default(uuid())
  tenantId      String
  /// Account code (e.g., "1010" for Cash on Hand). Unique per tenant.
  code          String
  name          String
  accountType   AccountType
  normalBalance NormalBalance
  /// Optional parent account id for hierarchical COA (e.g., 1010 parent = 1000)
  parentId      String?
  parent        Account?      @relation("AccountSubAccounts", fields: [parentId], references: [id])
  children      Account[]     @relation("AccountSubAccounts")
  /// COA accounts seeded at tenant creation cannot be deleted by admins
  isSystemAccount Boolean     @default(true)
  createdAt     DateTime      @default(now())
  updatedAt     DateTime      @updatedAt

  journalEntryLines JournalEntryLine[]

  /// Account codes must be unique within a tenant
  @@unique([tenantId, code])
  /// RLS-ready index — always present on tenant-scoped models
  @@index([tenantId])
}

/// An AccountingPeriod represents one calendar month for a tenant.
/// Once CLOSED, no journal entries may be posted to that period.
/// Periods are created on-demand (first time an entry needs one).
model AccountingPeriod {
  id          String       @id @default(uuid())
  tenantId    String
  year        Int
  month       Int
  status      PeriodStatus @default(OPEN)
  /// Timestamp when the period was closed (null if OPEN)
  closedAt    DateTime?
  /// The admin user who closed this period
  closedById  String?
  closedBy    User?        @relation(fields: [closedById], references: [id])
  createdAt   DateTime     @default(now())
  updatedAt   DateTime     @updatedAt

  /// One period per month per tenant
  @@unique([tenantId, year, month])
  /// RLS-ready index — always present on tenant-scoped models
  @@index([tenantId])
}

/// TenantSettings holds per-tenant configuration for billing and auto-suspension.
/// One record per tenant, created on first access or at tenant provisioning.
model TenantSettings {
  id               String   @id @default(uuid())
  tenantId         String   @unique
  /// Days overdue before automatic subscriber suspension (default 30)
  autoSuspendDays  Int      @default(30)
  /// Days before billing date to generate prepaid invoices (default 7)
  prepaidLeadDays  Int      @default(7)
  createdAt        DateTime @default(now())
  updatedAt        DateTime @updatedAt

  /// RLS-ready index — always present on tenant-scoped models
  @@index([tenantId])
}

/// A ServicePlan defines the internet service offering (speed, price, billing type).
/// Plans are soft-deleted (isActive=false) to preserve subscriber history.
model ServicePlan {
  id           String      @id @default(uuid())
  tenantId     String
  name         String
  /// Human-readable speed description (e.g., "50 Mbps", "100/20 Mbps")
  speed        String
  /// Monthly charge for this plan (2 decimal places)
  monthlyPrice Decimal     @db.Decimal(10, 2)
  billingType  BillingType
  description  String?
  /// Soft-delete: inactive plans cannot be assigned to new subscribers
  isActive     Boolean     @default(true)
  createdAt    DateTime    @default(now())
  updatedAt    DateTime    @updatedAt

  subscribers  Subscriber[]

  /// Plan names must be unique within a tenant
  @@unique([tenantId, name])
  /// RLS-ready index — always present on tenant-scoped models
  @@index([tenantId])
}

/// A Subscriber is a customer of the ISP — the core billing entity.
/// All invoices, payments, and collections target subscribers.
model Subscriber {
  id            String           @id @default(uuid())
  tenantId      String
  /// Auto-generated sequential identifier per tenant (e.g., "SUB-0001")
  accountNumber String
  firstName     String
  lastName      String
  email         String?
  phone         String?
  address       String
  /// Zone for collector routing (Phase 3)
  zone          String?
  servicePlanId String
  servicePlan   ServicePlan      @relation(fields: [servicePlanId], references: [id])
  status        SubscriberStatus @default(ACTIVE)
  /// Day of month for invoice generation — derived from signup date, capped at 28
  billingDay    Int
  activatedAt   DateTime         @default(now())
  suspendedAt   DateTime?
  cancelledAt   DateTime?
  /// Per-subscriber auto-suspend override (null = use TenantSettings.autoSuspendDays)
  autoSuspendDays Int?
  notes         String?
  /// Overpayment credit balance — always updated atomically with journal entries.
  /// This is NOT a stored ledger balance; it tracks credits for the FIFO allocation
  /// system (02-05) and is always updated within the same transaction as the journal entry.
  creditBalance Decimal          @default(0) @db.Decimal(10, 2)
  createdAt     DateTime         @default(now())
  updatedAt     DateTime         @updatedAt

  /// Account numbers must be unique within a tenant
  @@unique([tenantId, accountNumber])
  /// RLS-ready index — always present on tenant-scoped models
  @@index([tenantId])
  @@index([tenantId, status])
  @@index([tenantId, servicePlanId])
}

/// A User belongs to a Tenant (or is a super-admin with no tenant).
/// Email uniqueness is enforced per-tenant, not globally.
/// Super-admins have isSuperAdmin=true and tenantId=null.
model User {
  id           String  @id @default(uuid())
  email        String
  passwordHash String
  firstName    String
  lastName     String

  /// Nullable for super-admins who are not scoped to a specific tenant
  tenantId String?
  tenant   Tenant? @relation(fields: [tenantId], references: [id], onDelete: Cascade)

  /// Multi-role support — a user can hold more than one role within a tenant
  roles Role[]

  isActive     Boolean @default(true)
  isSuperAdmin Boolean @default(false)

  /// Accounting periods this user has closed (as administrator)
  closedPeriods AccountingPeriod[]

  /// Journal entries this user created (maker)
  createdJournalEntries JournalEntry[] @relation("JournalEntryCreatedBy")
  /// Journal entries this user approved (checker)
  approvedJournalEntries JournalEntry[] @relation("JournalEntryApprovedBy")

  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt

  /// Email must be unique within a tenant (super-admins have tenantId=null)
  @@unique([email, tenantId])
  /// RLS-ready index — always present on tenant-scoped models
  @@index([tenantId])
}

/// A JournalEntry records a double-entry accounting transaction.
/// All financial events in the system flow through this model.
/// Entries are IMMUTABLE — no updates or deletes. Corrections use reversing entries.
model JournalEntry {
  id            String             @id @default(uuid())
  tenantId      String
  /// Auto-generated sequential identifier per tenant per year (e.g., "JE-2026-0001")
  entryNumber   String
  /// The accounting date (when the economic event occurred, not necessarily createdAt)
  date          DateTime
  description   String
  source        JournalEntrySource
  status        JournalEntryStatus @default(DRAFT)
  /// Optional reference to source record (e.g., "Invoice", "Payment")
  referenceType String?
  /// ID of the source record (e.g., the invoice UUID)
  referenceId   String?
  /// If this entry reverses another entry, this points to the original
  reversesEntryId    String?        @unique
  reversesEntry      JournalEntry?  @relation("JournalEntryReversal", fields: [reversesEntryId], references: [id])
  /// If this entry has been reversed, this points to the reversing entry (back-reference)
  reversedByEntry    JournalEntry?  @relation("JournalEntryReversal")
  /// The user who created the entry (maker)
  createdById   String
  createdBy     User               @relation("JournalEntryCreatedBy", fields: [createdById], references: [id])
  /// The user who approved the entry (checker — for MANUAL entries)
  approvedById  String?
  approvedBy    User?              @relation("JournalEntryApprovedBy", fields: [approvedById], references: [id])
  approvedAt    DateTime?
  createdAt     DateTime           @default(now())
  updatedAt     DateTime           @updatedAt

  lines         JournalEntryLine[]

  /// Entry numbers must be unique within a tenant
  @@unique([tenantId, entryNumber])
  /// RLS-ready index — always present on tenant-scoped models
  @@index([tenantId])
  @@index([tenantId, date])
  @@index([referenceType, referenceId])
}

/// A single line (debit or credit) within a JournalEntry.
/// Every entry must have at least 2 lines, and sum(debit) = sum(credit).
model JournalEntryLine {
  id             String       @id @default(uuid())
  tenantId       String
  journalEntryId String
  journalEntry   JournalEntry @relation(fields: [journalEntryId], references: [id])
  accountId      String
  account        Account      @relation(fields: [accountId], references: [id])
  /// Debit amount for this line (0 if this is a credit line)
  debit          Decimal      @default(0) @db.Decimal(15, 2)
  /// Credit amount for this line (0 if this is a debit line)
  credit         Decimal      @default(0) @db.Decimal(15, 2)
  /// Optional line-level memo
  description    String?
  createdAt      DateTime     @default(now())

  /// RLS-ready index — always present on tenant-scoped models
  @@index([tenantId])
  @@index([accountId])
  @@index([journalEntryId])
}