frontend/hooks/use-reading-tracker.ts

import { useCallback } from "react";

interface ReadingTrackerData {
  chapterPage: { [chapterId: number]: number };
}

export const useReadingTracker = () => {
  const setCurrentChapterPage = useCallback(
    (id: number, pageNumber: number) => {
      const jsonString = localStorage.getItem("readingTrackerData");

      let readingTrackerData: ReadingTrackerData;
      try {
        readingTrackerData = jsonString
          ? JSON.parse(jsonString)
          : { chapterPage: {} };
      } catch (error) {
        console.error("Error parsing reading tracker data:", error);
        readingTrackerData = { chapterPage: {} };
      }

      const updatedData = {
        ...readingTrackerData,
        chapterPage: {
          ...readingTrackerData.chapterPage,
          [id]: pageNumber,
        },
      };

      localStorage.setItem("readingTrackerData", JSON.stringify(updatedData));
    },
    [],
  );

  const getCurrentChapterPage = useCallback(
    (id: number): number | undefined => {
      const jsonString = localStorage.getItem("readingTrackerData");
      if (!jsonString) return undefined;

      try {
        const readingTrackerData: ReadingTrackerData = JSON.parse(jsonString);
        return readingTrackerData.chapterPage[id];
      } catch (error) {
        console.error("Error parsing reading tracker data:", error);
        return undefined;
      }
    },
    [],
  );

  return { setCurrentChapterPage, getCurrentChapterPage };
};