import { Router } from "express";
import crypto from "crypto";
import { storage } from "../storage";
import { authenticateToken, type AuthenticatedRequest } from "../middleware/auth.middleware";
import { tenantIsolation } from "../middleware/tenant.middleware";
import { logAudit } from "../utils/audit";
import { canManageUser } from "../utils/user-access";
import { z } from "zod";

const OFFLINE_TASK_LIMIT = 500;

const initialSyncSchema = z.object({
  formIds: z.array(z.number()).optional(),
});

const deltaSyncSchema = z.object({
  formIds: z.array(z.number()).optional(),
  since: z.string().datetime(),
});

const pushSyncSchema = z.object({
  mutations: z.array(z.record(z.any())).default([]),
});

export function registerSyncRoutes(app: import("express").Express): void {
  const router = Router();

  // Все endpoint'ы синхронизации требуют аутентификации и tenant-изоляции
  router.use(authenticateToken, tenantIsolation);

  /**
   * GET /api/sync/config
   * Конфигурация офлайн-режима для текущего пользователя:
   * - формы с включённым глобальным offlineCache
   * - персональные подписки пользователя
   * - автоматизации, разрешённые для офлайн-выполнения
   * ?userId=N — конфигурация другого пользователя (только при canManageUser: админ/руководитель)
   */
  router.get('/config', async (req: AuthenticatedRequest, res) => {
    try {
      let userId = req.user!.id;
      const organizationId = req.organizationId!;

      if (req.query.userId !== undefined) {
        const queryUserId = parseInt(String(req.query.userId));
        if (isNaN(queryUserId)) {
          return res.status(400).json({ success: false, error: 'Некорректный ID пользователя' });
        }
        if (queryUserId !== userId) {
          if (!(await canManageUser(req.user, queryUserId, organizationId))) {
            return res.status(403).json({ success: false, error: 'Нет прав на просмотр конфигурации этого пользователя' });
          }
          userId = queryUserId;
        }
      }

      const [globalForms, subscriptions, automations] = await Promise.all([
        storage.getFormsWithOfflineCache(organizationId),
        storage.getUserOfflineSubscriptions(userId, organizationId),
        storage.getOfflineAutomations(organizationId),
      ]);

      const subscribedFormIds = new Set(subscriptions.map(s => s.formId));
      const forms = [
        ...globalForms.filter(f => !subscribedFormIds.has(f.id)),
        ...subscriptions.filter(s => s.isActive).map(s => s.formId),
      ];
      const uniqueFormIds = Array.from(new Set(forms.map(f => typeof f === 'number' ? f : f.id)));
      const formList = uniqueFormIds.map(id => {
        const global = globalForms.find(f => f.id === id);
        if (global) return global;
        return { id } as const;
      });

      res.json({
        success: true,
        forms: formList,
        subscriptions,
        automations: automations.map(a => ({
          id: a.id,
          name: a.name,
          trigger: a.trigger,
          triggerConfig: a.triggerConfig,
          runOffline: a.runOffline,
          clientCompatible: a.clientCompatible,
        })),
      });
    } catch (err: any) {
      console.error('[SYNC] config error:', err);
      res.status(500).json({ success: false, error: 'Ошибка получения конфигурации синхронизации' });
    }
  });

  /**
   * POST /api/sync/initial
   * Начальная полная синхронизация данных для офлайн-работы.
   * Возвращает метаданные форм, задачи (до 500 на форму), значения полей,
   * справочники и offline-автоматизации.
   */
  router.post('/initial', async (req: AuthenticatedRequest, res) => {
    try {
      const userId = req.user!.id;
      const organizationId = req.organizationId!;
      const body = initialSyncSchema.parse(req.body);

      let formIds = body.formIds;
      if (!formIds || formIds.length === 0) {
        const [globalForms, subscriptions] = await Promise.all([
          storage.getFormsWithOfflineCache(organizationId),
          storage.getUserOfflineSubscriptions(userId, organizationId),
        ]);
        const ids = new Set<number>();
        globalForms.forEach(f => ids.add(f.id));
        subscriptions.filter(s => s.isActive).forEach(s => ids.add(s.formId));
        formIds = Array.from(ids);
      }

      // Проверяем доступ пользователя к каждой форме (параллельно, порядок сохраняется)
      const accessFlags = await Promise.all(
        formIds.map(formId => storage.canUserAccessForm(userId, formId, organizationId, 'participate'))
      );
      const accessibleFormIds = formIds.filter((_, i) => accessFlags[i]);

      const forms: any[] = [];
      const tasks: any[] = [];
      const taskFieldValues: any[] = [];
      const tableIds = new Set<number>();

      // Загружаем формы и их задачи параллельно; слияние результатов — в исходном порядке formIds
      const perFormResults = await Promise.all(accessibleFormIds.map(async (formId) => {
        const [form, formFields, formStatuses, formTabs, transitions] = await Promise.all([
          storage.getForm(formId, organizationId),
          storage.getFormFields(formId, organizationId),
          storage.getFormStatuses(formId, organizationId),
          storage.getFormTabs(formId, organizationId),
          storage.getStatusTransitions(formId, organizationId),
        ]);

        if (!form) return null;

        // Honor the form's offline-cache strategy: 'assigned' fetches only tasks
        // assigned to the current user; 'recent' / 'all' fetch the latest/up to limit.
        const offlineCache = (form as any)?.offlineCache as { enabled?: boolean; strategy?: string; maxTasks?: number } | null | undefined;
        const taskLimit = offlineCache?.maxTasks ?? OFFLINE_TASK_LIMIT;
        const taskOptions: { limit: number; assignedTo?: number } = { limit: taskLimit };
        if (offlineCache?.strategy === 'assigned') {
          taskOptions.assignedTo = userId;
        }
        const { tasks: formTasks } = await storage.getTasksWithFieldsByFormOptimized(formId, organizationId, taskOptions);

        return { form, formFields, formStatuses, formTabs, transitions, formTasks };
      }));

      for (const result of perFormResults) {
        if (!result) continue;
        const { form, formFields, formStatuses, formTabs, transitions, formTasks } = result;

        // Собираем ID справочников из полей типа table / select
        for (const field of formFields) {
          const f = field as any;
          if (f.type === 'table' && f.linkedFormId) {
            tableIds.add(f.linkedFormId);
          }
          if ((f.type === 'select' || f.type === 'radio-group') && f.options) {
            // options может быть строкой JSON
            const opts = typeof f.options === 'string' ? JSON.parse(f.options) : f.options;
            if (Array.isArray(opts)) {
              opts.forEach((o: any) => {
                if (o.tableId) tableIds.add(o.tableId);
              });
            }
          }
        }

        forms.push({
          ...form,
          fields: formFields,
          statuses: formStatuses,
          tabs: formTabs,
          transitions,
        });

        for (const task of formTasks as any[]) {
          const fieldValues = task.fieldValues || {};
          delete task.fieldValues;
          tasks.push(task);
          Object.entries(fieldValues).forEach(([fieldId, value]) => {
            taskFieldValues.push({ taskId: task.id, fieldId: Number(fieldId), value });
          });
        }
      }

      // Загружаем все доступные справочники организации (строки — параллельно)
      const dataTables = await storage.getDataTablesByOrganization(organizationId);
      const rowsPerTable = await Promise.all(
        dataTables.map(table => storage.getDataTableRows(table.id, organizationId))
      );
      const dataTableRows: any[] = rowsPerTable.flat();

      const automations = await storage.getOfflineAutomations(organizationId);
      const users = await storage.getUsersByOrganization(organizationId);

      logAudit({
        action: 'sync.initial',
        userId,
        organizationId,
        details: { formCount: forms.length, taskCount: tasks.length },
      });

      res.json({
        success: true,
        forms,
        tasks,
        taskFieldValues,
        dataTables,
        dataTableRows,
        automations: automations.map(a => ({
          id: a.id,
          name: a.name,
          trigger: a.trigger,
          triggerConfig: a.triggerConfig,
          code: a.code,
          runOffline: a.runOffline,
          clientCompatible: a.clientCompatible,
        })),
        users,
      });
    } catch (err: any) {
      console.error('[SYNC] initial error:', err);
      res.status(500).json({ success: false, error: 'Ошибка начальной синхронизации' });
    }
  });

  /**
   * POST /api/sync/delta
   * Дельта-синхронизация: изменения с момента `since`.
   */
  router.post('/delta', async (req: AuthenticatedRequest, res) => {
    try {
      const userId = req.user!.id;
      const organizationId = req.organizationId!;
      const body = deltaSyncSchema.parse(req.body);
      const since = new Date(body.since);

      let formIds = body.formIds;
      if (!formIds || formIds.length === 0) {
        const [globalForms, subscriptions] = await Promise.all([
          storage.getFormsWithOfflineCache(organizationId),
          storage.getUserOfflineSubscriptions(userId, organizationId),
        ]);
        const ids = new Set<number>();
        globalForms.forEach(f => ids.add(f.id));
        subscriptions.filter(s => s.isActive).forEach(s => ids.add(s.formId));
        formIds = Array.from(ids);
      }

      // Проверяем доступ пользователя к каждой форме (параллельно, порядок сохраняется)
      const accessFlags = await Promise.all(
        formIds.map(formId => storage.canUserAccessForm(userId, formId, organizationId, 'participate'))
      );
      const accessibleFormIds = formIds.filter((_, i) => accessFlags[i]);

      const changedForms: any[] = [];
      const changedTasks: any[] = [];
      const changedFieldValues: any[] = [];
      const deletedTaskIds: number[] = [];

      // Дельта по формам — параллельно; слияние результатов — в исходном порядке formIds
      const perFormResults = await Promise.all(accessibleFormIds.map(async (formId) => {
        const form = await storage.getForm(formId, organizationId);
        const formChanged = form && (!form.updatedAt || new Date(form.updatedAt) >= since);

        const meta = formChanged
          ? await Promise.all([
              storage.getFormFields(formId, organizationId),
              storage.getFormStatuses(formId, organizationId),
              storage.getFormTabs(formId, organizationId),
              storage.getStatusTransitions(formId, organizationId),
            ])
          : null;

        // Honor the form's offline-cache strategy for delta sync as well.
        const offlineCache = (form as any)?.offlineCache as { enabled?: boolean; strategy?: string; maxTasks?: number } | null | undefined;
        const taskOptions: { assignedTo?: number; since?: Date } = { since };
        if (offlineCache?.strategy === 'assigned') {
          taskOptions.assignedTo = userId;
        }
        // Фильтр по updated_at — на уровне SQL (раньше грузились ВСЕ задачи формы + JS-фильтр)
        const { tasks: formTasks } = await storage.getTasksWithFieldsByFormOptimized(formId, organizationId, taskOptions);

        return { form, formChanged: !!formChanged, meta, formTasks };
      }));

      for (const result of perFormResults) {
        const { form, formChanged, meta, formTasks } = result;
        if (formChanged && meta) {
          const [fields, statuses, tabs, transitions] = meta;
          changedForms.push({ ...form, fields, statuses, tabs, transitions });
        }

        for (const task of formTasks as any[]) {
          const fieldValues = task.fieldValues || {};
          delete task.fieldValues;
          changedTasks.push(task);
          Object.entries(fieldValues).forEach(([fieldId, value]) => {
            changedFieldValues.push({ taskId: task.id, fieldId: Number(fieldId), value });
          });
        }

        // TODO: deleted tasks tracking через task_audit_log
      }

      // Фильтр по updated_at — на уровне SQL (раньше: полная выгрузка + JS-фильтр)
      const changedUsers = await storage.getUsersByOrganization(organizationId, { since });

      res.json({
        success: true,
        since: since.toISOString(),
        forms: changedForms,
        tasks: changedTasks,
        taskFieldValues: changedFieldValues,
        deletedTaskIds,
        users: changedUsers,
      });
    } catch (err: any) {
      console.error('[SYNC] delta error:', err);
      res.status(500).json({ success: false, error: 'Ошибка дельта-синхронизации' });
    }
  });

  /**
   * POST /api/sync/push
   * Приём offline-мутаций, накопленных клиентом без интернета.
   * В текущей версии возвращает accepted-список и conflicts.
   */
  router.post('/push', async (req: AuthenticatedRequest, res) => {
    try {
      const userId = req.user!.id;
      const organizationId = req.organizationId!;
      const body = pushSyncSchema.parse(req.body);

      // LEGACY / NO-OP: the offline queue now replays mutations directly via
      // authenticated fetch requests when the client comes back online.
      // Keeping this endpoint for backward compatibility with older PWA builds.
      const accepted: string[] = [];
      const conflicts: Array<{ id: string; reason: string }> = [];

      for (const mutation of body.mutations) {
        const id = (mutation as any)?.id || crypto.randomUUID();
        accepted.push(id);
      }

      logAudit({
        action: 'sync.push',
        userId,
        organizationId,
        details: { accepted: accepted.length, conflicts: conflicts.length },
      });

      res.json({ success: true, accepted, conflicts });
    } catch (err: any) {
      console.error('[SYNC] push error:', err);
      res.status(500).json({ success: false, error: 'Ошибка приёма offline-мутаций' });
    }
  });

  /**
   * GET /api/sync/status
   * Служебный статус синхронизации (online/offline, время сервера).
   */
  router.get('/status', async (req: AuthenticatedRequest, res) => {
    res.json({
      success: true,
      serverTime: new Date().toISOString(),
      online: true,
    });
  });

  app.use('/api/sync', router);
}