import { z } from 'zod';

import type { ResolutionLevel } from './resolve';
import type { Grant, GrantSubjectType } from './types';

/**
 * Wire schemas and views for the grant-management API (`/ponds/:id/grants`,
 * issue #52). The structural rules beyond shape (pond_admin only at pond
 * scope, subject/scope id presence, personal-pond single admin) live in
 * {@link ./validate} and are applied by the service after parsing.
 */

export const GRANT_SUBJECT_TYPES = ['user', 'authenticated', 'public'] as const;
export const GRANT_ROLES = ['pond_admin', 'editor', 'reader'] as const;
export const GRANT_SCOPE_TYPES = ['pond', 'label', 'page'] as const;
export const GRANT_EFFECTS = ['allow', 'deny'] as const;

export const createGrantInputSchema = z.object({
  subjectType: z.enum(GRANT_SUBJECT_TYPES),
  /** Required for `user` subjects, absent otherwise (validate.ts checks). */
  subjectId: z.string().min(1).nullish(),
  role: z.enum(GRANT_ROLES),
  scopeType: z.enum(GRANT_SCOPE_TYPES),
  /** The label/page id for those scopes, absent at pond scope. */
  scopeId: z.string().min(1).nullish(),
  effect: z.enum(GRANT_EFFECTS),
});
export type CreateGrantInput = z.infer<typeof createGrantInputSchema>;

/** A stored grant as the API serves it. */
export interface GrantView extends Grant {
  id: string;
  pondId: string;
  createdBy: string;
  createdAt: string;
}

/**
 * A grant enriched with the display names the access-rules UI renders as
 * sentences (issue #55): the subject's display name and the scoped label/page
 * name. Names are resolved server-side so the client needs no id lookups.
 */
export interface AccessRuleView extends GrantView {
  /** The user subject's display name; `null` for `authenticated`/`public`. */
  subjectName: string | null;
  /** Label name or page title for label/page scope; `null` at pond scope. */
  scopeName: string | null;
}

/** Query for the effective-permissions inspector (issue #57). */
export const inspectSubjectSchema = z.object({
  subjectType: z.enum(GRANT_SUBJECT_TYPES),
  /** Required for `user`, absent for `authenticated`/`public`. */
  subjectId: z.string().min(1).optional(),
  /** Optional page to resolve against; omit for the pond-level base capability. */
  pageId: z.string().min(1).optional(),
});
export type InspectSubjectQuery = z.infer<typeof inspectSubjectSchema>;

/** A grant enriched with the names needed to render it as a sentence — the
 * shape the inspector highlights (no id: the decider is shown, not managed). */
export interface DecidingRule extends Grant {
  subjectName: string | null;
  scopeName: string | null;
}

/** One resolved capability (read or write) with the rule that decided it. */
export interface DecisionView {
  outcome: 'allow' | 'deny';
  /** Which specificity level settled it (permissions.md §Resolution). */
  decidedBy: ResolutionLevel;
  /** The deciding grant, enriched with names; `null` for site-admin/default. */
  decidingRule: DecidingRule | null;
}

/** The inspector's answer to "what can this subject do here?" (issue #57). */
export interface EffectivePermissionView {
  subject: { type: GrantSubjectType; id: string | null; name: string | null };
  page: { id: string; title: string } | null;
  read: DecisionView;
  write: DecisionView;
}

/** The parsed input as the resolver's grant shape (nullish → null). */
export function grantOfInput(input: CreateGrantInput): Grant {
  return {
    subjectType: input.subjectType,
    subjectId: input.subjectId ?? null,
    role: input.role,
    scopeType: input.scopeType,
    scopeId: input.scopeId ?? null,
    effect: input.effect,
  };
}