"use client";

import { useState } from "react";
import { useUploadContext } from "../_context/upload-context";
import uploadApi from "@/shared/services/map-upload"; // Sesuaikan path ini
import * as XLSX from 'xlsx';
import { toast } from "sonner"; 

// Helper untuk load PDF.js via CDN (Bypassing Webpack)
const loadPdfJs = async () => {
  return new Promise<any>((resolve, reject) => {
    if ((window as any).pdfjsLib) {
      resolve((window as any).pdfjsLib);
      return;
    }

    const script = document.createElement("script");
    script.src = "https://cdnjs.cloudflare.com/ajax/libs/pdf.js/3.11.174/pdf.min.js";
    script.async = true;
    
    script.onload = () => {
      const pdfjsLib = (window as any).pdfjsLib;
      pdfjsLib.GlobalWorkerOptions.workerSrc = 
        "https://cdnjs.cloudflare.com/ajax/libs/pdf.js/3.11.174/pdf.worker.min.js";
      resolve(pdfjsLib);
    };

    script.onerror = (err) => reject(err);
    document.body.appendChild(script);
  });
};

export function useUploadLogic() {
  const { state, setState, goToStep } = useUploadContext();
  const [loading, setLoading] = useState(false);

  const handleFileSelect = async (file: File) => {
    setState((prev) => ({ 
      ...prev, 
      file, 
      sheetNames: [], 
      selectedSheet: null, 
      pdfPageCount: null,
      selectedPages: []
    }));
    
    const ext = file.name.split(".").pop()?.toLowerCase();

    // A. JIKA FILE EXCEL
    if (ext === "xlsx" || ext === "xls") {
       try {
         const data = await file.arrayBuffer();
         const workbook = XLSX.read(data, { type: 'array' });
         const sheetNames = workbook.SheetNames;
         setState((prev) => ({
           ...prev,
           sheetNames: sheetNames,
           selectedSheet: sheetNames.length === 1 ? sheetNames[0] : null
         }));
         if (sheetNames.length > 1) toast.info("Pilih sheet excel.");
       } catch (error) {
         console.error(error);
         toast.error("Gagal membaca file Excel.");
       }
    } 
    
    // B. JIKA FILE PDF -> LOAD VIA CDN RUNTIME
    else if (ext === "pdf") {
      try {
        const pdfjsLib = await loadPdfJs();
        const arrayBuffer = await file.arrayBuffer();
        const pdf = await pdfjsLib.getDocument({ data: arrayBuffer }).promise;
        
        setState((prev) => ({
           ...prev,
           pdfPageCount: pdf.numPages
        }));
        
        // Opsional: Beri info jika halaman banyak
        if (pdf.numPages > 1) {
            toast.info(`PDF terdeteksi memiliki ${pdf.numPages} halaman.`);
        }
      } catch (error) {
        console.error("Gagal baca PDF:", error);
        toast.error("Gagal membaca file PDF atau memuat library.");
      }
    }
  };

  const resetFile = () => {
      setState(prev => ({ 
        ...prev, 
        file: null, 
        fileDesc: "",
        sheetNames: [], 
        selectedSheet: null, 
        pdfPageCount: null,
        selectedPages: []
      }));
  };

  // 3. Logic Upload ke Backend
  const handleUploadProcess = async (selectedSheet?: string) => {
    if (!state.file) return;
    
    // Validasi Deskripsi
    if (!state.fileDesc) {
        toast.warning("Mohon isi deskripsi file terlebih dahulu.");
        return;
    }

    // Validasi Excel Sheet
    const isExcel = state.file.name.match(/\.(xlsx|xls)$/i);
    if (isExcel && state.sheetNames.length > 1 && !selectedSheet) {
        toast.warning("Mohon pilih sheet yang akan diproses.");
        return;
    }

    // 🔥 LOGIKA BARU: INTERCEPSI PDF MULTIPAGE
    const isPdf = state.file.name.match(/\.(pdf)$/i);
    if (isPdf && state.pdfPageCount && state.pdfPageCount > 1) {
        // Jangan upload dulu, arahkan ke Step 2 (PDF Viewer)
        goToStep("PDF_VIEWER");
        toast.info("File memiliki beberapa halaman. Silakan pilih halaman yang akan diproses.");
        return; // 🛑 BERHENTI DI SINI
    }

    // --- PROSES UPLOAD LANGSUNG (Untuk Excel, CSV, atau PDF 1 Halaman) ---
    setLoading(true);
    try {
      const res = await uploadApi.uploadFile(
        state.file, 
        state.selectedPages.length > 0 ? state.selectedPages : null, 
        selectedSheet || state.selectedSheet || null, 
        state.fileDesc
      );

      setState((prev) => ({ ...prev, result: res }));

      // Routing Logic setelah response backend (untuk kasus PDF 1 halaman atau file lain)
      if (res.file_type === ".pdf" && res.tables && res.tables.length > 1) {
         goToStep("TABLE_PICKER");
         toast.success("Beberapa tabel terdeteksi. Silakan pilih tabel.");
      } 
      else if (res.file_type === ".pdf" && (!res.tables || res.tables.length === 0)) {
         // Fallback jika PDF 1 halaman tapi tidak ada tabel
         goToStep("PDF_VIEWER");
         toast.info("Tabel tidak terdeteksi otomatis. Silakan pilih area manual.");
      } 
      else if (res.data) {
        goToStep("VALIDATE");
        toast.success("File berhasil diproses. Silakan validasi data.");
      } else {
        console.log(res);
        toast.warning(res.message)
      }

    } catch (err: any) {
      console.error(err);
      toast.error(err.message || "Gagal mengunggah file.");
    } finally {
      setLoading(false);
    }
  };

  // 4. Logic Upload ke Database
  const handleSaveToDatabase = async (payload: any) => {
    setLoading(true);
    try {
      // Panggil API
      const res = await uploadApi.saveToDatabase(payload);

      // Simpan hasil final ke context
      setState(prev => ({ ...prev, validatedData: res }));

      // Pindah ke halaman sukses
      goToStep("SUCCESS");
      
    } catch (err: any) {
      console.error(err);
      toast.error(err.message || "Gagal menyimpan data ke database.");
    } finally {
      setLoading(false);
    }
  };

  return {
    ...state,
    loading,
    handleFileSelect,
    handleUploadProcess,
    handleSaveToDatabase,
    resetFile,
    setState, 
    setFileDesc: (desc: string) => setState(prev => ({...prev, fileDesc: desc})),
    setSelectedSheet: (sheet: string) => setState(prev => ({...prev, selectedSheet: sheet})),
  };
}