import { useResponsive } from "./use-responsive.svelte.js";
import { useForm } from "./use-form.svelte.js";
import { tick } from "svelte";

export function useMasterDetail(options = {}) {
  const { onSelect = null, formConfig = null, } = options;

  let selectedItem = $state(null);
  let mode = $state("view");
  let isLoadingDetail = $state(false);
  let formSnapshot = $state(null);
  let extraSnapshots = $state({});
  let extraRegistry = $state.raw([]);
  let showExitConfirm = $state(false);

  const formState = useForm(formConfig);

  const { isMobile } = useResponsive();

  const isFormMode = $derived(mode === "create" || mode === "edit");

  const showMaster = $derived(!isMobile || (mode === "view" && !selectedItem));

  const showDetail = $derived(!isMobile || selectedItem || isFormMode);

  const layout = $derived({
    masterWidth: isMobile ? "w-full" : isFormMode ? "w-[3%]" : "w-[35%]",
    detailWidth: isMobile ? "w-full" : isFormMode ? "w-[97%]" : "w-[65%]",
  });

  // const isDirty = $derived(
  //   JSON.stringify(formState.form) !== JSON.stringify(formSnapshot)
  // );

  // const isDirty = $derived(
  //   JSON.stringify(formState.form) !== JSON.stringify(formSnapshot) ||
  //   (extraRegistry.length > 0 && extraRegistry.some(({ key, get }) =>
  //     JSON.stringify(get()) !== JSON.stringify(extraSnapshots[key])
  //   ))
  // );

  const isDirty = $derived.by(() => {
    if (JSON.stringify(formState.form) !== JSON.stringify(formSnapshot)) {
        return true;
    }

    return extraRegistry.some((item) => {
        const current = item.get();
        const snapshot = extraSnapshots[item.key];
        return JSON.stringify(current) !== JSON.stringify(snapshot);
    });
  });

  async function select(item) {
    mode = "view";
    if (onSelect) {
      isLoadingDetail = true;
      try {
        const detailData = await onSelect(item);
        selectedItem = detailData;
      } catch (error) {
        console.error("Failed to fetch detail:", error);
        selectedItem = null;
      } finally {
        isLoadingDetail = false;
      }
    } else {
      selectedItem = item;
    }
  }

  async function enterCreate(initialData = null) {
    mode = "create";
    selectedItem = null;
    formState.reset();

    for (const item of extraRegistry) {
      item.reset?.();
    }

    if (initialData) {
      formState.setForm(initialData);
    }

    await tick();

    formSnapshot = $state.snapshot(formState.form);

    // extraSnapshots = extraRegistry.length > 0 ? Object.fromEntries(
    //   extraRegistry.map(({ key, get }) => [key, $state.snapshot(get())])
    // ) : {};
    extraSnapshots = extraRegistry.length > 0 
    ? Object.fromEntries(extraRegistry.map(item => [item.key, $state.snapshot(item.get())]))
    : {};
  }

  async function enterEdit(param) {
    if (!selectedItem) return;
    mode = "edit";

    const raw = param
    ? selectedItem[param]
    : selectedItem;

    if (!raw) return;

    const base = $state.snapshot(raw);

    const entity = formConfig.mapToForm
    ? formConfig.mapToForm(base)
    : base;

    formState.reset();
    formState.setForm(entity);

    Object.keys(formState.errors).forEach(key => {
        formState.errors[key] = null;
    });

    formSnapshot = $state.snapshot(formState.form);

    await tick();

    if (extraRegistry.length > 0) {
      extraSnapshots = Object.fromEntries(
        // extraRegistry.map(({ key, get }) => [key, $state.snapshot(get())])
        extraRegistry.map((item) => {
          const key = item.key;
          const get = item.get;

          return [key, $state.snapshot(get())];
        })
      );
    }
  }

  function exitForm(force = false) {
    if (!force && isDirty) {
      showExitConfirm = true;
      return;
    }

    // Direct exit
    mode = "view";
    selectedItem = null;
    formSnapshot = null;
  }

  function confirmExit() {
    mode = "view";
    selectedItem = null;
    formSnapshot = null;
    extraSnapshots = {};
  }

  function backToList() {
    selectedItem = null;
    mode = "view";
    formSnapshot = null;
    extraSnapshots = {}
  }

  function saveForm() {
    formSnapshot = { ...form };
  }

  function registerExtraState({ key, get, reset }) {
    const exists = extraRegistry.findIndex(e => e.key === key);
    if (exists !== -1) {
      extraRegistry[exists] = { key, get, reset };
    } else {
      extraRegistry = [...extraRegistry, { key, get, reset }]
    }
  }

  return {
    get selectedItem() {
      return selectedItem;
    },
    get mode() {
      return mode;
    },
    get isFormMode() {
      return isFormMode;
    },
    get isMobile() {
      return isMobile;
    },
    get showMaster() {
      return showMaster;
    },
    get showDetail() {
      return showDetail;
    },
    get layout() {
      return layout;
    },
    get formSnapshot() {
      return formSnapshot;
    },
    // get form() {
    //   return form;
    // },
    get isDirty() {
      return isDirty;
    },
    get isLoadingDetail() {
      return isLoadingDetail;
    },
    get formState() {
      return formState;
    },
    get showExitConfirm() { return showExitConfirm; },
    set showExitConfirm(value) { showExitConfirm = value; },

    select,
    enterCreate,
    enterEdit,
    exitForm,
    confirmExit,
    backToList,
    saveForm,
    registerExtraState,
  };
}