import { useReducer, useEffect, useRef, useCallback } from "react";
import type { HighlightsData } from "../shared/types";
import { getHighlights } from "../services/reportService";
import { useReportsPeriod } from "./useReportsPeriod";

interface State {
  data: HighlightsData | null;
  windowDays: 30 | 60 | 90;
  isLoading: boolean;
  error: string | null;
}

type Action =
  | { type: "SET_LOADING"; payload: boolean }
  | { type: "SET_DATA"; payload: HighlightsData }
  | { type: "SET_ERROR"; payload: string }
  | { type: "SET_WINDOW_DAYS"; payload: 30 | 60 | 90 };

const initialState: State = {
  data: null,
  windowDays: 30,
  isLoading: false,
  error: null,
};

function reducer(state: State, action: Action): State {
  switch (action.type) {
    case "SET_LOADING":
      return { ...state, isLoading: action.payload };
    case "SET_DATA":
      return { ...state, data: action.payload, isLoading: false, error: null };
    case "SET_ERROR":
      return { ...state, error: action.payload, isLoading: false };
    case "SET_WINDOW_DAYS":
      return { ...state, windowDays: action.payload };
    default:
      return state;
  }
}

export function useHighlights() {
  const { from, to } = useReportsPeriod();
  const [state, dispatch] = useReducer(reducer, initialState);
  const fetchIdRef = useRef(0);

  const fetch = useCallback(async (windowDays: 30 | 60 | 90, referenceDate: string) => {
    const id = ++fetchIdRef.current;
    dispatch({ type: "SET_LOADING", payload: true });
    try {
      const data = await getHighlights(windowDays, referenceDate);
      if (id !== fetchIdRef.current) return;
      dispatch({ type: "SET_DATA", payload: data });
    } catch (e) {
      if (id !== fetchIdRef.current) return;
      dispatch({ type: "SET_ERROR", payload: e instanceof Error ? e.message : String(e) });
    }
  }, []);

  useEffect(() => {
    fetch(state.windowDays, to);
  }, [fetch, state.windowDays, to]);

  const setWindowDays = useCallback((d: 30 | 60 | 90) => {
    dispatch({ type: "SET_WINDOW_DAYS", payload: d });
  }, []);

  return { ...state, setWindowDays, from, to };
}