import { useState, useEffect, useCallback, useMemo } from "react";
import { useDebounce } from "../useDebounce";
import useLeaveTypeService from "./useLeaveTypeService";
import {
  type LeaveType,
  type LeaveTypeFilters,
  type CreateLeaveTypeData,
  type UpdateLeaveTypeData,
} from "../../services/leaveTypeService";

interface UseLeaveTypeState {
  leaveTypes: LeaveType[];
  total: number;
  currentPage: number;
  totalPages: number;
  itemsPerPage: number;
  searchTerm: string;
  statusFilter: "all" | "active" | "inactive";
  order: string;
  columnName: string | null;
  loading: boolean;
  error: string | null;
  viewMode: "flat" | "hierarchy";
}

interface UseLeaveTypeActions {
  setSearchTerm: (term: string) => void;
  setStatusFilter: (filter: "all" | "active" | "inactive") => void;
  setOrder: (order: string) => void;
  setColumnName: (columnName: string | null) => void;
  setCurrentPage: (page: number) => void;
  setItemsPerPage: (items: number) => void;
  setViewMode: (mode: "flat" | "hierarchy") => void;
  clearFilters: () => void;
  refreshData: () => Promise<void>;
  createLeaveType: (data: CreateLeaveTypeData) => Promise<boolean>;
  updateLeaveType: (data: UpdateLeaveTypeData) => Promise<boolean>;
  deleteLeaveType: (id: string) => Promise<boolean>;
  toggleLeaveTypeStatus: (id: string) => Promise<boolean>;
  getLeaveTypeById: (id: string) => Promise<LeaveType | null>;
}

const INITIAL_STATE: UseLeaveTypeState = {
  leaveTypes: [],
  total: 0,
  currentPage: 1,
  totalPages: 0,
  itemsPerPage: 100,
  searchTerm: "",
  statusFilter: "all",
  order: "",
  columnName: null,
  loading: false,
  error: null,
  viewMode: "hierarchy",
};

function useLeaveType() {
  const [state, setState] = useState<UseLeaveTypeState>(INITIAL_STATE);
  const service = useLeaveTypeService();

  // Debounce search term with 500ms delay
  const debouncedSearchTerm = useDebounce(state.searchTerm, 500);

  // Memoize filters to prevent unnecessary API calls
  const filters = useMemo<LeaveTypeFilters>(() => {
    let status: number | undefined = undefined;

    if (state.statusFilter === "active") status = 1;
    if (state.statusFilter === "inactive") status = 0;

    const result: LeaveTypeFilters = {
      search: debouncedSearchTerm,
      status, // pass 1 for active, 0 for inactive, undefined for all
      page: state.currentPage,
      limit: state.itemsPerPage,
      hierarchy: state.viewMode === "hierarchy",
    };

    if (state.order && state.columnName) {
      result.order = state.order as "ASC" | "DESC";
      result.column_name = state.columnName;
    }

    return result;
  }, [
    debouncedSearchTerm,
    state.statusFilter,
    state.currentPage,
    state.itemsPerPage,
    state.order,
    state.columnName,
    state.viewMode,
  ]);

  // Auto-fetch when filters change
  useEffect(() => {
    const fetchLeaveTypes = async () => {
      setState((prev) => ({ ...prev, loading: true, error: null }));

      const result = await service.getLeaveTypes(filters);

      if (result.success && result.data) {
        const total = result.data.data?.count ?? 0;
        const limit = filters.limit ?? 10;

        setState((prev) => ({
          ...prev,
          leaveTypes: result.data!.data?.data ?? [],
          total,
          totalPages: Math.ceil(total / limit),
          loading: false,
          error: null,
        }));
      } else {
        setState((prev) => ({
          ...prev,
          leaveTypes: [],
          total: 0,
          totalPages: 0,
          loading: false,
          error: result.message,
        }));
      }
    };

    fetchLeaveTypes();
  }, [filters]);

  // Action handlers
  const setSearchTerm = useCallback((term: string) => {
    setState((prev) => ({ ...prev, searchTerm: term, currentPage: 1 }));
  }, []);

  const setStatusFilter = useCallback(
    (filter: "all" | "active" | "inactive") => {
      setState((prev) => ({ ...prev, statusFilter: filter, currentPage: 1 }));
    },
    [],
  );

  const setOrder = useCallback((order: string) => {
    setState((prev) => ({ ...prev, order }));
  }, []);

  const setColumnName = useCallback((columnName: string | null) => {
    setState((prev) => ({ ...prev, columnName }));
  }, []);

  const setCurrentPage = useCallback((page: number) => {
    setState((prev) => ({ ...prev, currentPage: page }));
  }, []);

  const setItemsPerPage = useCallback((items: number) => {
    setState((prev) => ({ ...prev, itemsPerPage: items, currentPage: 1 }));
  }, []);

  const setViewMode = useCallback((mode: "flat" | "hierarchy") => {
    setState((prev) => ({ ...prev, viewMode: mode, currentPage: 1 }));
  }, []);

  // Clear only filter dropdowns; do not clear search
  const clearFilters = useCallback(() => {
    setState((prev) => ({
      ...prev,
      statusFilter: "all",
      order: "",
      columnName: null,
      currentPage: 1,
    }));
  }, []);

  const refreshData = useCallback(async () => {
    setState((prev) => ({ ...prev, loading: true, error: null }));

    const result = await service.getLeaveTypes(filters);

    if (result.success && result.data) {
      const total = result.data.data?.count ?? 0;
      const limit = filters.limit ?? 10;

      setState((prev) => ({
        ...prev,
        leaveTypes: result.data!.data?.data ?? [],
        total,
        totalPages: Math.ceil(total / limit),
        loading: false,
        error: null,
      }));
    } else {
      setState((prev) => ({
        ...prev,
        leaveTypes: [],
        total: 0,
        totalPages: 0,
        loading: false,
        error: result.message,
      }));
    }
  }, [service, filters]);

  // CRUD operations
  const createLeaveType = useCallback(
    async (data: CreateLeaveTypeData): Promise<boolean> => {
      const result = await service.createLeaveType(data);
      if (result.success) {
        await refreshData();
      }
      return result.success;
    },
    [service, refreshData],
  );

  const updateLeaveType = useCallback(
    async (data: UpdateLeaveTypeData): Promise<boolean> => {
      const result = await service.updateLeaveType(data);
      if (result.success) {
        await refreshData();
      }
      return result.success;
    },
    [service, refreshData],
  );

  const deleteLeaveType = useCallback(
    async (id: string): Promise<boolean> => {
      const result = await service.deleteLeaveType(id);
      if (result.success) {
        await refreshData();
      }
      return result.success;
    },
    [service, refreshData],
  );

  const toggleLeaveTypeStatus = useCallback(
    async (id: string): Promise<boolean> => {
      const result = await service.toggleLeaveTypeStatus(id);
      if (result.success) {
        await refreshData();
      }
      return result.success;
    },
    [service, refreshData],
  );

  const getLeaveTypeById = useCallback(
    async (id: string): Promise<LeaveType | null> => {
      const result = await service.getLeaveTypeById(id);
      return result.success && result.data ? result.data.data : null;
    },
    [service],
  );

  const actions: UseLeaveTypeActions = {
    setSearchTerm,
    setStatusFilter,
    setOrder,
    setColumnName,
    setCurrentPage,
    setItemsPerPage,
    setViewMode,
    clearFilters,
    refreshData,
    createLeaveType,
    updateLeaveType,
    deleteLeaveType,
    toggleLeaveTypeStatus,
    getLeaveTypeById,
  };

  return {
    ...state,
    loading: state.loading || service.loading,
    ...actions,
  };
}

export default useLeaveType;