"use client";

import React from "react";
import { useQuery } from "@tanstack/react-query";
import { useTranslationStore } from "@/lib/store";
import { API_BASE } from "@/lib/config";
import type { StatsPeriod, TranslationStatsResponse } from "./types";

const TIMEOUT_MS = 15000;
export const REFETCH_INTERVAL_MS = 30000;

export const QUERY_KEY = (period: StatsPeriod) => ["admin", "stats", "translations", period];

async function fetchTranslationStats(
  adminToken: string | null | undefined,
  period: StatsPeriod
): Promise<TranslationStatsResponse> {
  if (!adminToken) {
    throw new Error("AUTH_REQUIRED");
  }

  const controller = new AbortController();
  const timeoutId = setTimeout(() => controller.abort(), TIMEOUT_MS);

  try {
    const response = await fetch(
      `${API_BASE}/api/v1/admin/stats/translations?period=${period}`,
      {
        headers: {
          Authorization: `Bearer ${adminToken}`,
        },
        signal: controller.signal,
      }
    );

    clearTimeout(timeoutId);

    if (!response.ok) {
      if (response.status === 401) {
        throw new Error("UNAUTHORIZED");
      }
      if (response.status === 404) {
        throw new Error("ENDPOINT_NOT_FOUND");
      }
      throw new Error(`HTTP_ERROR_${response.status}`);
    }

    return await response.json();
  } catch (err) {
    clearTimeout(timeoutId);
    throw err;
  }
}

function getMockData(period: StatsPeriod): TranslationStatsResponse {
  const baseCount = period === "today" ? 42 : period === "week" ? 287 : 1156;
  const lastPeriodCount = period === "today" ? 38 : period === "week" ? 254 : 1023;

  return {
    data: {
      period,
      total_translations: baseCount,
      total_translations_last_period: lastPeriodCount,
      error_rate: 2.3,
      error_count: Math.floor(baseCount * 0.023),
      success_count: Math.floor(baseCount * 0.977),
      top_users: [
        { user_id: "user_1", email: "sarah.chen@acme.com", translation_count: 15 },
        { user_id: "user_2", email: "marc.dubois@example.fr", translation_count: 12 },
        { user_id: "user_3", email: "anna.mueller@corp.de", translation_count: 8 },
        { user_id: "user_4", email: "john.smith@company.uk", translation_count: 6 },
        { user_id: "user_5", email: "lisa.wong@startup.io", translation_count: 5 },
        { user_id: "user_6", email: "pierre.leroux@mail.fr", translation_count: 4 },
        { user_id: "user_7", email: "emma.johnson@tech.us", translation_count: 3 },
        { user_id: "user_8", email: "klaus.weber@firm.de", translation_count: 2 },
        { user_id: "user_9", email: "sofia.garcia@empresa.es", translation_count: 2 },
        { user_id: "user_10", email: "yuki.tanaka@office.jp", translation_count: 1 },
      ],
      provider_breakdown: {
        google: { count: Math.floor(baseCount * 0.476), percentage: 47.6 },
        ollama: { count: Math.floor(baseCount * 0.119), percentage: 11.9 },
        openai: { count: Math.floor(baseCount * 0.048), percentage: 4.8 },
      },
      format_breakdown: {
        xlsx: { count: Math.floor(baseCount * 0.595), percentage: 59.5 },
        docx: { count: Math.floor(baseCount * 0.286), percentage: 28.6 },
        pptx: { count: Math.floor(baseCount * 0.119), percentage: 11.9 },
      },
    },
    meta: {
      generated_at: new Date().toISOString(),
    },
  };
}

export function useTranslationStats(period: StatsPeriod = "today") {
  const { settings } = useTranslationStore();

  const [isMockData, setIsMockData] = React.useState(false);

  const { data, isLoading, error, refetch } = useQuery({
    queryKey: QUERY_KEY(period),
    queryFn: async () => {
      try {
        const result = await fetchTranslationStats(settings.adminToken, period);
        setIsMockData(false);
        return result;
      } catch (err) {
        if ((err as Error).message === "ENDPOINT_NOT_FOUND") {
          setIsMockData(true);
          return getMockData(period);
        }
        throw err;
      }
    },
    enabled: !!settings.adminToken,
    refetchInterval: REFETCH_INTERVAL_MS,
    staleTime: 10000,
    retry: 1,
  });

  const getErrorMessage = (err: Error | null): string | null => {
    if (!err) return null;

    const errorMap: Record<string, string> = {
      AUTH_REQUIRED: "Veuillez vous connecter pour accéder aux statistiques",
      UNAUTHORIZED: "Session expirée. Veuillez vous reconnecter.",
      HTTP_ERROR_403: "Accès refusé. Droits administrateur requis.",
      HTTP_ERROR_500: "Erreur serveur. Veuillez réessayer plus tard.",
    };

    const code = err.message;
    if (errorMap[code]) {
      return errorMap[code];
    }

    if (err.name === "AbortError") {
      return "Le serveur met trop de temps à répondre.";
    }

    if (err.message.includes("fetch") || err.message.includes("network")) {
      return "Impossible de se connecter au serveur.";
    }

    return "Une erreur inattendue s'est produite.";
  };

  const errorMessage = error ? getErrorMessage(error as Error) : null;

  return {
    data: data?.data ?? null,
    isLoading,
    error: errorMessage,
    refetch,
    queryKey: QUERY_KEY(period),
    isMockData,
  };
}