/**
 * Policies API client — ABAC entity policies (attribute-based access
 * control) management (UI-Backlog module 10/16).
 *
 * Backend: /api/v1/policies
 * - GET  /{entity_type}   → list policies for one entity type
 * - POST /                → create policy (201)
 * - PUT  /{policy_id}     → update policy
 * - DELETE /{policy_id}   → delete policy (204)
 * Permissions: policies:read (list) / policies:write (create, update, delete).
 *
 * Conditions format (JSONB):
 * { operator: 'AND' | 'OR', rules: [{ field, op, value }] }
 * Supported ops: eq, neq, in, not_in, gt, gte, lt, lte, contains,
 * starts_with, is_null, is_not_null.
 */

import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
import { apiGet, apiPost, apiPut, apiDelete } from '@/api/client';

export type PrincipalType = 'user' | 'group' | 'role';
export type PolicyEffect = 'allow' | 'deny';
export type ConditionOperator = 'AND' | 'OR';

export interface PolicyRule {
  field: string;
  op: string;
  value: unknown;
}

export interface PolicyConditions {
  operator: ConditionOperator;
  rules: PolicyRule[];
}

export interface Policy {
  id: string;
  name: string;
  entity_type: string;
  principal_type: PrincipalType;
  principal_id: string;
  effect: PolicyEffect;
  conditions: PolicyConditions | null;
  priority: number;
  tenant_id: string;
  enabled: boolean;
  created_at: string | null;
  updated_at: string | null;
}

export interface PolicyListResponse {
  items: Policy[];
  total: number;
}

export interface PolicyCreatePayload {
  name: string;
  entity_type: string;
  principal_type: PrincipalType;
  principal_id: string;
  effect?: PolicyEffect;
  conditions?: PolicyConditions | null;
  priority?: number;
}

export interface PolicyUpdatePayload {
  name?: string;
  entity_type?: string;
  principal_type?: PrincipalType;
  principal_id?: string;
  effect?: PolicyEffect;
  conditions?: PolicyConditions | null;
  priority?: number;
  enabled?: boolean;
}

/** Entity types with ABAC field whitelists (backend ABAC_ALLOWED_FIELDS). */
export const POLICY_ENTITY_TYPES = [
  'contact',
  'file',
  'task',
  'calendar_event',
  'mailbox',
  'address',
  'contact_folder',
  'workflow',
] as const;

export const POLICY_OPS = [
  'eq', 'neq', 'in', 'not_in', 'gt', 'gte', 'lt', 'lte',
  'contains', 'starts_with', 'is_null', 'is_not_null',
] as const;

/**
 * Mirrored from backend policy_service.ABAC_ALLOWED_FIELDS — the fields
 * each entity type may reference in policy conditions. The backend skips
 * non-whitelisted fields; showing them here prevents invalid input.
 * Keep in sync with app/services/policy_service.py.
 */
export const ABAC_ALLOWED_FIELDS: Record<string, string[]> = {
  contact: ['status', 'type', 'country', 'tags', 'created_at', 'updated_at', 'owner_id', 'name', 'displayname', 'firstname', 'surname', 'email_1', 'email_2', 'code'],
  file: ['status', 'size', 'mime_type', 'created_at'],
  task: ['status', 'priority', 'due_date', 'created_at'],
  calendar_event: ['status', 'start_time', 'end_time', 'created_at'],
  mailbox: ['status', 'created_at'],
  address: ['country', 'city', 'created_at', 'updated_at'],
  contact_folder: ['name', 'created_at'],
  workflow: ['status', 'created_at'],
};

/** Ops where the rule value is ignored (null checks). */
export const NULL_OPS = ['is_null', 'is_not_null'] as const;

// ─── Query hooks ─────────────────────────────────────────────

export function usePolicies(entityType: string, enabled = true) {
  return useQuery<PolicyListResponse>({
    queryKey: ['policies', entityType],
    queryFn: () => apiGet<PolicyListResponse>(`/policies/${entityType}`),
    enabled: enabled && !!entityType,
  });
}

// ─── Mutation hooks ──────────────────────────────────────────

export function useCreatePolicy() {
  const qc = useQueryClient();
  return useMutation<Policy, Error, PolicyCreatePayload>({
    mutationFn: (data) => apiPost<Policy>('/policies', data),
    onSuccess: (policy) => {
      qc.invalidateQueries({ queryKey: ['policies', policy.entity_type] });
    },
  });
}

export function useUpdatePolicy() {
  const qc = useQueryClient();
  return useMutation<Policy, Error, { id: string; data: PolicyUpdatePayload }>({
    mutationFn: ({ id, data }) => apiPut<Policy>(`/policies/${id}`, data),
    onSuccess: (policy) => {
      qc.invalidateQueries({ queryKey: ['policies', policy.entity_type] });
    },
  });
}

export function useDeletePolicy() {
  const qc = useQueryClient();
  return useMutation<void, Error, { id: string; entityType: string }>({
    mutationFn: ({ id }) => apiDelete(`/policies/${id}`),
    onSuccess: (_, vars) => {
      qc.invalidateQueries({ queryKey: ['policies', vars.entityType] });
    },
  });
}