/**
 * Download Reports Component
 * Simple unified PDF download button with i18n support
 */
"use client";

import { useState } from "react";
import { Download, FileText } from "lucide-react";
import { Button } from "@/components/ui/button";
import { useLanguage } from "@/contexts/LanguageContext";

interface AnalystInfo {
  key: string;
  label: string;
  reportKey: string;
  description: string;
}

interface DownloadReportsProps {
  ticker: string;
  analysisDate: string;
  taskId?: string | null;
  analysts: AnalystInfo[];
  reports: any;
  priceData?: any[];
  priceStats?: any;
  /** Compact mode - just the button, no card wrapper */
  compact?: boolean;
  /** Language for report generation */
  language?: string;
}

export function DownloadReports({
  ticker,
  analysisDate,
  taskId: _taskId,  // Kept for API compatibility, but direct mode is now preferred
  analysts,
  reports,
  priceData,
  priceStats,
  compact = false,
  language,
}: DownloadReportsProps) {
  const [isDownloading, setIsDownloading] = useState(false);
  const { t, locale } = useLanguage();

  // Helper to get nested value from reports object
  const getNestedValue = (obj: any, path: string) => {
    return path.split('.').reduce((current, key) => current?.[key], obj);
  };

  // Helper to detect report language based on trader's final decision keywords
  // This ensures PDF language matches the report content language, not UI language
  const detectReportLanguage = (data: any): 'zh-TW' | 'en' | null => {
    try {
      // Get trader's investment plan (final decision)
      const traderPlan = data?.trader_investment_plan;
      if (!traderPlan || typeof traderPlan !== 'string') {
        return null;
      }

      // Chinese decision keywords: 買入, 賣出, 持有
      const chineseKeywords = ['買入', '賣出', '持有'];
      // English decision keywords: buy, sell, hold (case insensitive)
      const englishKeywords = ['buy', 'sell', 'hold'];

      const lowerPlan = traderPlan.toLowerCase();

      // Check for Chinese keywords first
      for (const keyword of chineseKeywords) {
        if (traderPlan.includes(keyword)) {
          return 'zh-TW';
        }
      }

      // Check for English keywords
      for (const keyword of englishKeywords) {
        if (lowerPlan.includes(keyword)) {
          return 'en';
        }
      }

      // Fallback: check for any Chinese characters as secondary detection
      const chineseRegex = /[\u4e00-\u9fa5]/;
      if (chineseRegex.test(traderPlan)) {
        return 'zh-TW';
      }

      return 'en';
    } catch (e) {
      return null;
    }
  };

  // Get all available analyst keys (those with actual reports)
  const availableAnalystKeys = analysts
    .filter(analyst => {
      const reportContent = getNestedValue(reports, analyst.reportKey);
      return reportContent && reportContent.trim().length > 0;
    })
    .map(a => a.key);

  // Handle download - always download all available reports as combined PDF
  const handleDownload = async () => {
    if (availableAnalystKeys.length === 0) return;

    setIsDownloading(true);
    try {
      // Build request body with all available analysts
      // Always use direct mode when reports data is available (task may be cleaned up from Redis)
      // Detect report language based on trader's final decision keywords
      const contentLang = detectReportLanguage(reports);
      // Use detected language if available, otherwise fallback to prop or current locale
      // This ensures that if reports are in Chinese, the PDF headers will also be in Chinese
      // even if the UI is in English
      const finalLanguage = contentLang || language || locale;

      const requestBody: any = {
        ticker,
        analysis_date: analysisDate,
        analysts: availableAnalystKeys,  // Always include all available analysts
        language: finalLanguage,  // Pass language for PDF generation
        // Direct mode: send report data directly (more reliable than task-based)
        reports: reports,
        price_data: priceData,
        price_stats: priceStats,
      };
      
      const response = await fetch('/api/download/reports', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify(requestBody),
      });

      if (!response.ok) {
        const errorData = await response.json().catch(() => ({}));
        const errorMessage = errorData.detail || `${t.download.failed} (${response.status})`;
        throw new Error(errorMessage);
      }

      // Get the blob
      const blob = await response.blob();
      
      // Get filename from Content-Disposition header if available
      const contentDisposition = response.headers.get('Content-Disposition');
      let filename = `${ticker}_Combined_Report_${analysisDate}.pdf`;
      
      if (contentDisposition) {
        const filenameMatch = contentDisposition.match(/filename=(.+)/);
        if (filenameMatch) {
          filename = filenameMatch[1];
        }
      }

      // Create download link
      const url = window.URL.createObjectURL(blob);
      const link = document.createElement('a');
      link.href = url;
      link.download = filename;
      document.body.appendChild(link);
      link.click();
      
      // Cleanup
      document.body.removeChild(link);
      window.URL.revokeObjectURL(url);
    } catch (error: any) {
      console.error('Download error:', error);
      alert(error.message || t.download.failed);
    } finally {
      setIsDownloading(false);
    }
  };

  if (availableAnalystKeys.length === 0) {
    return null;
  }

  // Compact mode - just the button
  if (compact) {
    return (
      <Button
        onClick={handleDownload}
        disabled={isDownloading}
        variant="outline"
        className="gap-2 hover-lift"
      >
        {isDownloading ? (
          <>
            <Download className="h-4 w-4 animate-bounce" />
            {t.download.generating}
          </>
        ) : (
          <>
            <FileText className="h-4 w-4" />
            {t.common.download} PDF
          </>
        )}
      </Button>
    );
  }

  // Full mode - with description
  return (
    <div className="flex items-center justify-center p-4">
      <Button
        onClick={handleDownload}
        disabled={isDownloading}
        size="lg"
        className="gap-2 bg-gradient-to-r from-blue-500 to-purple-500 hover:from-blue-600 hover:to-purple-600"
      >
        {isDownloading ? (
          <>
            <Download className="h-5 w-5 animate-bounce" />
            {t.download.generating}
          </>
        ) : (
          <>
            <FileText className="h-5 w-5" />
            {t.download.fullReport}
          </>
        )}
      </Button>
    </div>
  );
}