import { createContext, useCallback, useContext, useState } from "react";
import api from "@/utils/api.util";
import { toast } from "sonner";

const BASE = "/admin";
const UserGroupContext = createContext(null);

export function useUserGroups() {
  const ctx = useContext(UserGroupContext);
  if (!ctx) throw new Error("useUserGroups must be used within a UserGroupProvider");
  return ctx;
}

export function UserGroupProvider({ children }) {
  const [groups, setGroups] = useState([]);
  const [group, setGroup] = useState(null);
  const [members, setMembers] = useState([]);
  const [usersIn, setUsersIn] = useState([]);
  const [usersNotIn, setUsersNotIn] = useState([]);
  const [attributes, setAttributes] = useState([]);
  const [pagination, setPagination] = useState({ page: 1, limit: 10, total: 0, totalPages: 1 });
  const [loading, setLoading] = useState(false);

  const request = useCallback(async (fn) => {
    setLoading(true);
    try {
      return await fn();
    } catch (err) {
      const message = err?.response?.data?.message ?? "Something went wrong.";
      toast.error(message);
      return null;
    } finally {
      setLoading(false);
    }
  }, []);

  // ─── GET /api/admin/groups ─────────────────────────────────────────────────
  const fetchGroups = useCallback(
    ({ page = 1, limit = 10, filters = [], sort = [] } = {}) =>
      request(async () => {
        const res = await api.get(`${BASE}/groups`, {
          params: { page, limit, filters: JSON.stringify(filters), sort: JSON.stringify(sort) },
        });
        const { data, attributes: attrs, pagination: pg } = res.data?.data ?? {};
        setGroups(data ?? []);
        setAttributes(attrs ?? []);
        setPagination(pg ?? { page, limit, total: 0, totalPages: 1 });
        return res.data;
      }),
    [request]
  );

  // ─── GET /api/admin/groups/archived ───────────────────────────────────────
  const fetchArchivedGroups = useCallback(
    ({ page = 1, limit = 10, filters = [], sort = [] } = {}) =>
      request(async () => {
        const res = await api.get(`${BASE}/groups/archived`, {
          params: { page, limit, filters: JSON.stringify(filters), sort: JSON.stringify(sort) },
        });
        const { data, attributes: attrs, pagination: pg } = res.data?.data ?? {};
        setGroups(data ?? []);
        setAttributes(attrs ?? []);
        setPagination(pg ?? { page, limit, total: 0, totalPages: 1 });
        return res.data;
      }),
    [request]
  );

  // ─── GET /api/admin/groups/:gid ───────────────────────────────────────────
  const fetchGroup = useCallback(
    (gid, paginationParams = {}) =>
      request(async () => {
        const { page = 1, limit = 10, filters = [], sort = [] } = paginationParams;
        const res = await api.get(`${BASE}/groups/${gid}`, {
          params: { page, limit, filters: JSON.stringify(filters), sort: JSON.stringify(sort) },
        });
        const { group: g, members: m } = res.data?.data ?? {};
        setGroup(g ?? null);
        setMembers(m?.data ?? []);
        setPagination(m?.pagination ?? { page, limit, total: 0, totalPages: 1 });
        return res.data;
      }),
    [request]
  );

  // ─── GET /api/admin/groups/:gid/users ─────────────────────────────────────
  const fetchUsersInGroup = useCallback(
    (gid) =>
      request(async () => {
        const res = await api.get(`${BASE}/groups/${gid}/users`);
        setUsersIn(res.data?.data ?? []);
        return res.data;
      }),
    [request]
  );

  // ─── GET /api/admin/groups/:gid/users/add ─────────────────────────────────
  const fetchUsersNotInGroup = useCallback(
    (gid) =>
      request(async () => {
        const res = await api.get(`${BASE}/groups/${gid}/users/add`);
        setUsersNotIn(res.data?.data ?? []);
        return res.data;
      }),
    [request]
  );

  // ─── GET /api/admin/groups/field-values ───────────────────────────────────
  const fetchGroupFieldValues = useCallback(
    (field) =>
      request(async () => {
        const res = await api.get(`${BASE}/groups/field-values`, { params: { field } });
        return res.data;
      }),
    [request]
  );

  // ─── POST /api/admin/groups ────────────────────────────────────────────────
  const createGroup = useCallback(
    ({ name, description, group_code }) =>
      request(async () => {
        const res = await api.post(`${BASE}/groups`, { name, description, group_code });
        setGroups((prev) => [res.data?.data, ...prev]);
        toast.success("Group created successfully.");
        return res.data;
      }),
    [request]
  );

  // ─── PUT /api/admin/groups/:gid ───────────────────────────────────────────
  const updateGroup = useCallback(
    (gid, { name, description, group_code }) =>
      request(async () => {
        const res = await api.put(`${BASE}/groups/${gid}`, { name, description, group_code });
        setGroups((prev) =>
          prev.map((g) => (g.group_id === gid ? { ...g, ...res.data?.data } : g))
        );
        setGroup((prev) => (prev?.group_id === gid ? { ...prev, ...res.data?.data } : prev));
        toast.success("Group updated successfully.");
        return res.data;
      }),
    [request]
  );

  // ─── PATCH /api/admin/groups/:gid/deactivate ──────────────────────────────
  const deactivateGroup = useCallback(
    (gid) =>
      request(async () => {
        const res = await api.patch(`${BASE}/groups/${gid}/deactivate`);
        setGroups((prev) =>
          prev.map((g) => (g.group_id === gid ? { ...g, is_active: false } : g))
        );
        toast.success("Group deactivated.");
        return res.data;
      }),
    [request]
  );

  // ─── DELETE /api/admin/groups/bulk ────────────────────────────────────────
  const deactivateGroups = useCallback(
    ({ ids }) =>
      request(async () => {
        const res = await api.delete(`${BASE}/groups/bulk`, { data: { ids } });
        const { deactivated_ids } = res.data?.data ?? {};
        if (deactivated_ids?.length) {
          setGroups((prev) =>
            prev.map((g) =>
              deactivated_ids.includes(g.group_id) ? { ...g, is_active: false } : g
            )
          );
          toast.success(`${deactivated_ids.length} group(s) deactivated.`);
        }
        return res.data;
      }),
    [request]
  );

  // ─── PATCH /api/admin/groups/:gid/restore ─────────────────────────────────
  const restoreGroup = useCallback(
    (gid) =>
      request(async () => {
        const res = await api.patch(`${BASE}/groups/${gid}/restore`);
        setGroups((prev) =>
          prev.map((g) => (g.group_id === gid ? { ...g, is_active: true } : g))
        );
        toast.success("Group restored.");
        return res.data;
      }),
    [request]
  );

  // ─── POST /api/admin/groups/bulk/restore ──────────────────────────────────
  const restoreGroups = useCallback(
    ({ ids }) =>
      request(async () => {
        const res = await api.post(`${BASE}/groups/bulk/restore`, { ids });
        const { restored_ids } = res.data?.data ?? {};
        if (restored_ids?.length) {
          setGroups((prev) =>
            prev.map((g) =>
              restored_ids.includes(g.group_id) ? { ...g, is_active: true } : g
            )
          );
          toast.success(`${restored_ids.length} group(s) restored.`);
        }
        return res.data;
      }),
    [request]
  );

  // ─── DELETE /api/admin/groups/:gid/permanent ──────────────────────────────
  const permanentlyDeleteGroup = useCallback(
    (gid) =>
      request(async () => {
        const res = await api.delete(`${BASE}/groups/${gid}/permanent`);
        setGroups((prev) => prev.filter((g) => g.group_id !== gid));
        toast.success("Group permanently deleted.");
        return res.data;
      }),
    [request]
  );

  // ─── DELETE /api/admin/groups/bulk/permanent ──────────────────────────────
  const permanentlyDeleteGroups = useCallback(
    ({ ids }) =>
      request(async () => {
        const res = await api.delete(`${BASE}/groups/bulk/permanent`, { data: { ids } });
        const { deleted_ids } = res.data?.data ?? {};
        if (deleted_ids?.length) {
          setGroups((prev) => prev.filter((g) => !deleted_ids.includes(g.group_id)));
          toast.success(`${deleted_ids.length} group(s) permanently deleted.`);
        }
        return res.data;
      }),
    [request]
  );

  // ─── POST /api/admin/groups/:gid/users ────────────────────────────────────
  const addUsersToGroup = useCallback(
    (gid, user_ids) =>
      request(async () => {
        const res = await api.post(`${BASE}/groups/${gid}/users`, { user_ids });
        setUsersNotIn((prev) => prev.filter((u) => !user_ids.includes(u.user_id)));
        toast.success("Users added to group.");
        return res.data;
      }),
    [request]
  );

  // ─── DELETE /api/admin/groups/:gid/users ──────────────────────────────────
  const removeUsersFromGroup = useCallback(
    (gid, user_ids) =>
      request(async () => {
        const res = await api.delete(`${BASE}/groups/${gid}/users`, { data: { user_ids } });
        setMembers((prev) => prev.filter((u) => !user_ids.includes(u.user_id)));
        setUsersIn((prev) => prev.filter((u) => !user_ids.includes(u.user_id)));
        toast.success("Users removed from group.");
        return res.data;
      }),
    [request]
  );

  return (
    <UserGroupContext.Provider value={{
      groups, group, members, usersIn, usersNotIn, attributes, pagination, loading,
      setPagination,
      fetchGroups, fetchArchivedGroups, fetchGroup,
      fetchUsersInGroup, fetchUsersNotInGroup, fetchGroupFieldValues,
      createGroup, updateGroup,
      deactivateGroup, deactivateGroups,
      restoreGroup, restoreGroups,
      permanentlyDeleteGroup, permanentlyDeleteGroups,
      addUsersToGroup, removeUsersFromGroup,
    }}>
      {children}
    </UserGroupContext.Provider>
  );
}