import { useContext, useMemo, useState } from 'react';
import { useNavigate } from 'react-router-dom';
import { StoreContext } from '../../context/StoreContext';
import '../../styles/components/StoreTabs.css';

const DEFAULT_LOCATION_NAME = "Default Location";

function getStoreKey(store) {
  return String(store?.household_store_id ?? store?.store_id ?? store?.id ?? "");
}

function getStoreName(store) {
  return store?.name || store?.display_name || "Store";
}

function getLocationName(store) {
  if (!store) return "Location";
  const locationName = store.location_name || "";
  if (!locationName || locationName === DEFAULT_LOCATION_NAME) {
    return "Default";
  }
  return locationName;
}

function chooseStoreLocation(locations) {
  if (!locations || locations.length === 0) return null;
  return (
    locations.find((store) => store.location_name === "Default Location" || store.display_name === store.name) ||
    locations.find((store) => store.is_default) ||
    locations[0]
  );
}

function buildStoreOptions(stores) {
  const grouped = new Map();

  for (const store of stores) {
    const key = getStoreKey(store);
    if (!grouped.has(key)) {
      grouped.set(key, {
        key,
        name: getStoreName(store),
        locations: [],
      });
    }
    grouped.get(key).locations.push(store);
  }

  return Array.from(grouped.values()).map((group) => ({
    ...group,
    store: chooseStoreLocation(group.locations),
  }));
}

export default function StoreTabs() {
  const { stores, activeStore, setActiveStore, loading } = useContext(StoreContext);
  const navigate = useNavigate();
  const [activePicker, setActivePicker] = useState(null);
  const storeOptions = useMemo(() => buildStoreOptions(stores || []), [stores]);
  const activeStoreKey = getStoreKey(activeStore);
  const selectedStoreOption =
    storeOptions.find((option) => option.key === activeStoreKey) || storeOptions[0];
  const selectedLocations = selectedStoreOption?.locations || [];
  const selectedLocation =
    selectedLocations.find((location) => String(location.id) === String(activeStore?.id)) ||
    selectedStoreOption?.store;
  const canPickStore = storeOptions.length > 1 && !loading;
  const canPickLocation = selectedLocations.length > 1 && !loading;

  if (!stores || stores.length === 0 || storeOptions.length === 0) {
    return (
      <div className="store-tabs">
        <div className="store-tabs-empty">
          No stores available for this household
        </div>
      </div>
    );
  }

  const handleStoreTriggerClick = () => {
    if (!canPickStore) return;
    setActivePicker("store");
  };

  const handleLocationTriggerClick = () => {
    if (!canPickLocation) return;
    setActivePicker("location");
  };

  const handleStoreSelect = (store) => {
    setActiveStore(store);
    setActivePicker(null);
  };

  const handleLocationSelect = (location) => {
    setActiveStore(location);
    setActivePicker(null);
  };

  const handleManageMap = () => {
    const locationQuery = selectedLocation?.id ? `&locationId=${selectedLocation.id}` : "";
    navigate(`/manage?tab=stores${locationQuery}`);
  };

  return (
    <div className="store-tabs">
      <div className="store-tabs-container">
        <button
          type="button"
          className={`store-selector-trigger ${canPickStore ? "is-interactive" : ""}`}
          onClick={handleStoreTriggerClick}
          disabled={loading}
          aria-haspopup={canPickStore ? "dialog" : undefined}
          aria-expanded={canPickStore ? activePicker === "store" : undefined}
          aria-label={`Store: ${selectedStoreOption.name}`}
        >
          <span className="store-name">{selectedStoreOption.name}</span>
          {canPickStore ? <span className="store-selector-caret" aria-hidden="true" /> : null}
        </button>

        <button
          type="button"
          className={`store-selector-trigger location-selector-trigger ${canPickLocation ? "is-interactive" : ""}`}
          onClick={handleLocationTriggerClick}
          disabled={loading}
          aria-haspopup={canPickLocation ? "dialog" : undefined}
          aria-expanded={canPickLocation ? activePicker === "location" : undefined}
          aria-label={`Location: ${getLocationName(selectedLocation)}`}
        >
          <span className="store-name">{getLocationName(selectedLocation)}</span>
          {canPickLocation ? <span className="store-selector-caret" aria-hidden="true" /> : null}
        </button>

        <button
          type="button"
          className="store-map-button"
          onClick={handleManageMap}
          disabled={loading || !selectedLocation}
        >
          Manage Map
        </button>
      </div>

      {activePicker === "store" ? (
        <div className="store-selector-modal-overlay" onClick={() => setActivePicker(null)}>
          <div
            className="store-selector-modal"
            role="dialog"
            aria-modal="true"
            aria-label="Select store"
            onClick={(event) => event.stopPropagation()}
          >
            <h2>Stores</h2>
            <div className="store-selector-list">
              {storeOptions.map((option) => (
                <button
                  key={option.key}
                  type="button"
                  className={`store-selector-option ${option.key === selectedStoreOption.key ? "active" : ""}`}
                  onClick={() => handleStoreSelect(option.store)}
                >
                  {option.name}
                </button>
              ))}
            </div>
          </div>
        </div>
      ) : null}

      {activePicker === "location" ? (
        <div className="store-selector-modal-overlay" onClick={() => setActivePicker(null)}>
          <div
            className="store-selector-modal"
            role="dialog"
            aria-modal="true"
            aria-label="Select location"
            onClick={(event) => event.stopPropagation()}
          >
            <h2>Locations</h2>
            <div className="store-selector-list">
              {selectedLocations.map((location) => (
                <button
                  key={location.id}
                  type="button"
                  className={`store-selector-option ${String(location.id) === String(selectedLocation?.id) ? "active" : ""}`}
                  onClick={() => handleLocationSelect(location)}
                >
                  {getLocationName(location)}
                </button>
              ))}
            </div>
          </div>
        </div>
      ) : null}
    </div>
  );
}