import { defineStore } from 'pinia';
import { ref } from 'vue';
import { fetchWrapper } from '@KTXC/utils/helpers/fetch-wrapper';

export interface TenantState {
  id: string | null;
  domain: string | null;
  label: string | null;
}

export interface TenantData extends TenantState {
  settings?: Record<string, unknown>;
}

// Flush pending settings writes before the page unloads
if (typeof window !== 'undefined') {
  window.addEventListener('beforeunload', () => {
    useTenantStore().flushSettings();
  });
}

export const useTenantStore = defineStore('tenantStore', () => {
  // =========================================================================
  // State
  // =========================================================================

  const tenant = ref<TenantState | null>(null);
  const settings = ref<Record<string, unknown>>({});

  // Pending batch for debounced writes
  let _pendingSettings: Record<string, unknown> = {};
  let _debounceTimer: ReturnType<typeof setTimeout> | null = null;

  // =========================================================================
  // Getters
  // =========================================================================

  function getSetting(key: string): unknown {
    return settings.value[key] ?? null;
  }

  // =========================================================================
  // Settings actions
  // =========================================================================

  function setSetting(key: string, value: unknown): void {
    settings.value[key] = value;

    // Batch writes with a 500 ms debounce — same pattern as userService
    _pendingSettings[key] = value;

    if (_debounceTimer !== null) {
      clearTimeout(_debounceTimer);
    }

    _debounceTimer = setTimeout(() => {
      _flush();
    }, 500);
  }

  async function _flush(): Promise<void> {
    if (Object.keys(_pendingSettings).length === 0) return;

    const payload = { ..._pendingSettings };
    _pendingSettings = {};
    _debounceTimer = null;

    try {
      await fetchWrapper.patch('/tenant/settings', { data: payload });
    } catch (error) {
      console.error('Failed to save tenant settings:', error);
    }
  }

  /** Force-flush any pending settings writes (called on beforeunload). */
  async function flushSettings(): Promise<void> {
    if (_debounceTimer !== null) {
      clearTimeout(_debounceTimer);
      _debounceTimer = null;
    }
    await _flush();
  }

  // =========================================================================
  // Initialise from /init endpoint
  // =========================================================================

  function init(tenantData: Partial<TenantData> | null): void {
    tenant.value = tenantData
      ? {
          id: tenantData.id ?? null,
          domain: tenantData.domain ?? null,
          label: tenantData.label ?? null,
        }
      : null;

    settings.value = (tenantData?.settings as Record<string, unknown>) ?? {};
  }

  function reset(): void {
    tenant.value = null;
    settings.value = {};
    _pendingSettings = {};
    if (_debounceTimer !== null) {
      clearTimeout(_debounceTimer);
      _debounceTimer = null;
    }
  }

  return {
    // State
    tenant,
    settings,

    // Getters
    getSetting,

    // Actions
    setSetting,
    flushSettings,
    init,
    reset,
  };
});