import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import {
  cursorPage,
  PolicyPreviewSummary,
  PolicyRevision,
  type PolicyRevisionCreate,
  type PolicyRevisionUpdate,
  type PolicyStatus,
} from "@umt/contracts";
import { api } from "~/lib/api.ts";
import { getParsed, parseOrThrow } from "./library.ts";
import { fetchAllCursorPages } from "./parse.ts";

// 策略版本:草案 → 预览 → 授权发布 → 版本化 / 回滚(REQ §6.4)

export const policyKeys = {
  all: ["policies"] as const,
  list: (f: PolicyFilters) => ["policies", "list", f] as const,
};

export type PolicyFilters = { policyKey?: string; status?: PolicyStatus };

const Page = cursorPage(PolicyRevision);

export function usePolicyRevisions(filters: PolicyFilters = {}) {
  return useQuery({
    queryKey: policyKeys.list(filters),
    queryFn: ({ signal }) =>
      fetchAllCursorPages((cursor) => getParsed(Page, "/policy-revisions", { ...filters, limit: 200, cursor }, signal)),
  });
}

/** 预览结果(合同 PolicyPreviewSummary;存在 policy_revision.preview) */
export const PolicyPreview = PolicyPreviewSummary;
export type PolicyPreview = PolicyPreviewSummary;

const parse = (d: unknown) => parseOrThrow(PolicyRevision, d, "/policy-revisions");

function useAction<V>(fn: (v: V) => Promise<unknown>) {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: (v: V) => fn(v).then(parse),
    onSuccess: () => {
      void qc.invalidateQueries({ queryKey: policyKeys.all });
      void qc.invalidateQueries({ queryKey: ["subscriptions"] });
    },
  });
}

export const useCreatePolicy = () => useAction((body: PolicyRevisionCreate) => api.post("/policy-revisions", body));
export const useUpdatePolicy = () =>
  useAction(({ id, ...body }: PolicyRevisionUpdate & { id: string }) => api.patch(`/policy-revisions/${id}`, body));
export const usePreviewPolicy = () => useAction((id: string) => api.post(`/policy-revisions/${id}/preview`));
export const usePublishPolicy = () =>
  useAction((v: { id: string; expectedRevision: number }) =>
    api.post(`/policy-revisions/${v.id}/publish`, { expectedRevision: v.expectedRevision }),
  );
export const useRollbackPolicy = () => useAction((id: string) => api.post(`/policy-revisions/${id}/rollback`));