import { AbilityBuilder, createMongoAbility, MongoQuery } from "@casl/ability";
import { Role } from "@prisma/client";
import type { AppAbility, AppActions, AppSubjects } from "./types";

/**
 * Permission matrix for each role.
 *
 * Builds and returns a CASL MongoAbility for a given role.
 * Uses createMongoAbility which includes built-in conditions matching,
 * supporting condition-based rules like { assignedToId: userId }.
 *
 * Rules are merged (additive union) for multi-role users via defineAbilityFor().
 *
 * Zone/ownership filtering (e.g., Collector assigned zones) is enforced
 * at the data layer — CASL handles the coarse-grained capability check here.
 *
 * Note on conditions: Subjects are currently string literals (no Prisma models yet).
 * Conditions are cast via `as MongoQuery` to bypass CASL's strict field inference.
 * Once Prisma models are defined (Phase 2+), subjects can be replaced with class types
 * for full type-safe condition checking.
 */
export function definePermissionsFor(
  role: Role,
  userId: string,
  tenantId: string
): AppAbility {
  const { can, cannot, build } = new AbilityBuilder<AppAbility>(
    createMongoAbility
  );

  // Helper to cast condition objects — required because subjects are string literals
  // (no Prisma model types yet). CASL infers MongoQuery<never> for string subjects,
  // so we cast through unknown. Conditions are enforced at runtime by CASL's MongoDB
  // query matcher. Type-safe conditions will be added when Prisma models are defined.
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  const cond = (obj: Record<string, unknown>) => obj as unknown as any;

  switch (role) {
    case Role.ADMIN: {
      // Full access within tenant
      can("manage", "all");
      break;
    }

    case Role.OFFICE_STAFF: {
      // Create and manage users, assign roles
      can("manage", "User");
      // Full subscriber management
      can("manage", "Subscriber");
      // Billing management
      can("manage", "Invoice");
      // Record payments
      can("manage", "Payment");
      // Zone management (assign subscribers and collectors to zones)
      can("manage", "Zone");
      // Ticketing
      can("manage", "Ticket");
      // Job order management
      can("manage", "JobOrder");
      // Technician profile management (read/update, not create — admin only for compensation config)
      can("read", "TechnicianProfile");
      can("update", "TechnicianProfile");
      // Inventory management
      can("manage", "Inventory");
      // Expense management (record, list, view)
      can("manage", "Expense");
      // Vendor management (CRUD)
      can("manage", "Vendor");
      // Collection and remittance management
      can("manage", "Collection");
      can("manage", "Remittance");
      // Job type rates (read-only for office staff — admin configures rates)
      can("read", "JobTypeRate");
      // View financial reports (read-only)
      can("read", "Report");
      // View accounting (read-only, cannot modify Chart of Accounts)
      can("read", "Account");
      // Explicitly block CoA modifications
      cannot("create", "Account");
      cannot("update", "Account");
      cannot("delete", "Account");
      break;
    }

    case Role.COLLECTOR: {
      // Can view all subscribers for context (zone filtering done at data layer)
      can("read", "Subscriber");
      // Can read zones they are assigned to (data layer enforces which zones)
      can("read", "Zone");
      // Can record payments (zone filtering done at data layer)
      can("create", "Payment");
      // View payment history
      can("read", "Payment");
      // Can create and view collections
      can("create", "Collection");
      can("read", "Collection");
      // Can create and view remittances
      can("create", "Remittance");
      can("read", "Remittance");
      // NOTE: No explicit cannot() needed — Collector simply has no rules for
      // Invoice, User management, or Reports. Absence of a rule = no access.
      break;
    }

    case Role.TECHNICIAN: {
      // Only their assigned jobs (conditions enforced at data layer too)
      can("read", "JobOrder", cond({ assignedToId: userId }));
      can("update", "JobOrder", cond({ assignedToId: userId }));
      // Limited subscriber access for contact info (data layer enforces scope)
      can("read", "Subscriber");
      // Only inventory checked out to them
      can("read", "Inventory", cond({ assignedToId: userId }));
      // NOTE: No cannot() needed — Technician simply has no billing/payment rules.
      // Absence of a rule = no access for Invoice, Payment, Report, User management.
      break;
    }

    case Role.CLIENT: {
      // Only their own invoices (scoped by conditions)
      can("read", "Invoice", cond({ subscriberId: userId }));
      // Only their own payments
      can("read", "Payment", cond({ subscriberId: userId }));
      // Only their own profile
      can("read", "Subscriber", cond({ id: userId }));
      // Submit support tickets
      can("create", "Ticket");
      // Only their own tickets
      can("read", "Ticket", cond({ submittedById: userId }));
      // NOTE: No cannot() needed — Client simply has no rules for User management or Reports.
      break;
    }

    default: {
      // No permissions by default — safe fallback
      break;
    }
  }

  return build();
}