"use client";

import { useCallback, useEffect, useReducer, useState } from "react";
import { getStoredToken } from "@/src/lib/auth";
import { roleService } from "@/src/services/role.service";
import { parseApiError } from "@/src/lib/apiError";
import { Notification } from "../types/notif";
import { Permission, Role, RoleFormData } from "../types/role";

// ── Table state / reducer ─────────────────────────────────────────────────────

interface TableState {
  roles: Role[];
  loading: boolean;
  total: number;
  pages: number;
  error: string | null;
}

type TableAction =
  | { type: "LOAD_START" }
  | { type: "LOAD_OK"; roles: Role[]; total: number; pages: number }
  | { type: "LOAD_ERR"; error: string }
  | { type: "ADD"; role: Role }
  | { type: "UPDATE"; role: Role }
  | { type: "DELETE"; id: string }
  | { type: "CLEAR_ERR" };

function tableReducer(s: TableState, a: TableAction): TableState {
  switch (a.type) {
    case "LOAD_START":
      return { ...s, loading: true, error: null };
    case "LOAD_OK":
      return {
        ...s,
        loading: false,
        roles: a.roles,
        total: a.total,
        pages: a.pages,
      };
    case "LOAD_ERR":
      return { ...s, loading: false, error: a.error };
    case "ADD":
      return { ...s, roles: [a.role, ...s.roles] };
    case "UPDATE":
      return {
        ...s,
        roles: s.roles.map((r) => (r.id === a.role.id ? a.role : r)),
      };
    case "DELETE":
      return { ...s, roles: s.roles.filter((r) => r.id !== a.id) };
    case "CLEAR_ERR":
      return { ...s, error: null };
    default:
      return s;
  }
}

const initialState: TableState = {
  roles: [],
  loading: true,
  total: 0,
  pages: 1,
  error: null,
};

// ── Main hook ─────────────────────────────────────────────────────────────────

export function useRoles() {
  const [state, dispatch] = useReducer(tableReducer, initialState);
  const [search, setSearch] = useState("");
  const [page, setPage] = useState(1);
  const [permissions, setPermissions] = useState<Permission[]>([]);
  const [notification, setNotification] = useState<Notification | null>(
    null,
  );

  const notify = useCallback((n: Notification) => {
    setNotification(n);
    setTimeout(() => setNotification(null), 4000);
  }, []);

  // ── Fetch roles ─────────────────────────────────────────────────────────────
  const loadRoles = useCallback(async (p: number, q: string) => {
    dispatch({ type: "LOAD_START" });
    try {
      const token = getStoredToken();
      const res = await roleService.getAll(p, q, token);
      const payload =
        (
          res as unknown as {
            data: {
              data: Role[];
              meta?: { total: number; pages: number };
              pagination?: { total: number; pages: number };
            };
          }
        ).data ?? res;
      dispatch({
        type: "LOAD_OK",
        roles: payload.data ?? [],
        total: payload.meta?.total ?? payload.pagination?.total ?? 0,
        pages: payload.meta?.pages ?? payload.pagination?.pages ?? 1,
      });
    } catch {
      dispatch({
        type: "LOAD_ERR",
        error: "تعذّر تحميل بيانات الأدوار. يرجى المحاولة مجدداً.",
      });
    }
  }, []);

  // ── Load permissions on mount ────────────────────────────────────────────────
  useEffect(() => {
    const token = getStoredToken();
    roleService
      .getPermissions(token)
      .then((res) => {
        const raw = (
          res as unknown as { data: { premissions: { data: Permission[] } } }
        ).data;
        setPermissions(raw?.premissions?.data ?? []);
      })
      .catch(() => {});
  }, []);

  // ── Reload when page / search changes ────────────────────────────────────────
  useEffect(() => {
    loadRoles(page, search);
  }, [page, search, loadRoles]);

  // ── CRUD actions ─────────────────────────────────────────────────────────────

  const createRole = useCallback(
    async (data: RoleFormData): Promise<boolean> => {
      try {
        const token = getStoredToken();
        const res = await roleService.create(data, token);
        const role = (res as unknown as { data: Role }).data;

        // Endpoint 2 (PATCH /role/{id}/permissions/bulk): attach selected
        // permissions right after creation, since POST /role only accepts
        // name/description.
        if (data.permissionIds.length) {
          await roleService.bulkAssignPermissions(role.id, data.permissionIds, token);
        }

        await loadRoles(page, search);
        notify({
          type: "success",
          message: "تم إنشاء الدور وتعيين الصلاحيات بنجاح.",
        });
        return true;
      } catch (err) {
        notify({
          type: "error",
          message: parseApiError(err, "تعذّر إنشاء الدور."),
        });
        return false;
      }
    },
    [page, search, loadRoles, notify],
  );

  const updateRole = useCallback(
    async (
      id: string,
      data: RoleFormData,
      _currentPermIds: string[],
    ): Promise<boolean> => {
      try {
        const token = getStoredToken();
        // Update basic fields
        await roleService.update(id, data, token);

        // Endpoint 2: replace the full permission set in one call rather
        // than diffing add/remove client-side — the bulk endpoint already
        // performs the replacement atomically on the backend.
        await roleService.bulkAssignPermissions(id, data.permissionIds, token);

        await loadRoles(page, search);
        notify({
          type: "success",
          message: "تم تحديث الدور بنجاح.",
        });
        return true;
      } catch (err) {
        notify({
          type: "error",
          message: parseApiError(err, "تعذّر تحديث الدور."),
        });
        return false;
      }
    },
    [page, search, loadRoles, notify],
  );

  const deleteRole = useCallback(
    async (id: string): Promise<boolean> => {
      try {
        const token = getStoredToken();
        await roleService.delete(id, token);
        dispatch({ type: "DELETE", id });
        notify({ type: "success", message: "تم حذف الدور بنجاح." });
        return true;
      } catch (err) {
        notify({
          type: "error",
          message: parseApiError(err, "تعذّر حذف الدور."),
        });
        return false;
      }
    },
    [notify],
  );

  // ── Endpoint 1: assign a single permission (used from the detail modal) ─────
  const assignPermission = useCallback(
    async (roleId: string, permissionId: string): Promise<boolean> => {
      try {
        const token = getStoredToken();
        await roleService.assignPermission(roleId, permissionId, token);
        notify({ type: "success", message: "تم إضافة الصلاحية للدور بنجاح." });
        return true;
      } catch (err) {
        notify({
          type: "error",
          message: parseApiError(err, "تعذّر إضافة الصلاحية."),
        });
        return false;
      }
    },
    [notify],
  );

  // ── Endpoint 3: remove a single permission (used from the detail modal) ─────
  const removePermission = useCallback(
    async (roleId: string, permissionId: string): Promise<boolean> => {
      try {
        const token = getStoredToken();
        await roleService.removePermission(roleId, permissionId, token);
        notify({ type: "success", message: "تم إزالة الصلاحية من الدور بنجاح." });
        return true;
      } catch (err) {
        notify({
          type: "error",
          message: parseApiError(err, "تعذّر إزالة الصلاحية."),
        });
        return false;
      }
    },
    [notify],
  );

  const handleSearch = useCallback((q: string) => {
    setSearch(q);
    setPage(1);
  }, []);

  return {
    ...state,
    permissions,
    page,
    search,
    setPage,
    handleSearch,
    clearError: () => dispatch({ type: "CLEAR_ERR" }),
    createRole,
    updateRole,
    deleteRole,
    assignPermission,
    removePermission,
    notification,
  };
}