'use client';

import { useState, useCallback, useRef } from 'react';
import { UploadedFile } from './tyeps';
import { SUPPORTED_EXTENSIONS } from './wordCount';
import { useMutation } from '@tanstack/react-query';
import { apiRequest } from '@/shared/request/apiRequest';
import { links } from '@/shared/request/links';
import { toast } from 'react-toastify';

// ── API response types ────────────────────────────────────────────────────────

interface WordCountApiResponse {
  word_count: number;
  total_price: number;
}

interface CreateSIOrderResponse {
  id: number;
  order_id: number;
}

interface SIPaymentResponse {
  payment_link: string;
}

// ── Return type ───────────────────────────────────────────────────────────────

interface UseFileUploadReturn {
  documentName: string;
  setDocumentName: (name: string) => void;
  uploadedFile: UploadedFile | null;
  isDragging: boolean;
  isProcessing: boolean;
  error: string | null;
  fileInputRef: React.RefObject<HTMLInputElement | null>;
  handleFileSelect: (file: File) => void;
  handleDrop: (e: React.DragEvent) => void;
  handleDragOver: (e: React.DragEvent) => void;
  handleDragLeave: () => void;
  handleRemoveFile: () => void;
  openFilePicker: () => void;
  handleSubmit: () => void;
  canSubmit: boolean;
}

// ── Hook ─────────────────────────────────────────────────────────────────────

export function useFileUpload(): UseFileUploadReturn {
  const [documentName, setDocumentName] = useState('');
  const [uploadedFile, setUploadedFile] = useState<UploadedFile | null>(null);
  const [isDragging, setIsDragging] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const fileInputRef = useRef<HTMLInputElement | null>(null);

  // ── Step 3: Payment ────────────────────────────────────────────────────────
  const siPayment = useMutation({
    mutationKey: ['si-payment'],
    mutationFn: (order_id: number) =>
      apiRequest<SIPaymentResponse>('POST', links.si_payment(order_id)),
    onSuccess: (res) => {
      window.open(res.data.payment_link, '_self');
    },
    onError: (err) => {
      toast.error(
        err instanceof Error ? err.message : "To'lovda xatolik yuz berdi",
      );
    },
  });

  // ── Step 2: Create SI order ────────────────────────────────────────────────
  const createSIOrder = useMutation({
    mutationKey: ['si-create'],
    mutationFn: (data: FormData) =>
      apiRequest<CreateSIOrderResponse>('POST', links.si_create, data),
    onSuccess: (res) => {
      siPayment.mutate(res.data.order_id);
    },
    onError: (err) => {
      toast.error(err instanceof Error ? err.message : 'Xatolik yuz berdi');
    },
  });

  // ── Step 1: Upload file & get word count + price ───────────────────────────
  const wordCountMutation = useMutation({
    mutationKey: ['si-word-count'],
    mutationFn: (data: FormData) =>
      apiRequest<WordCountApiResponse>('POST', links.wordCount, data),
    onSuccess: (res) => {
      setUploadedFile((prev) =>
        prev
          ? {
              ...prev,
              status: 'done',
              word_count: res.data.word_count ?? 0,
              total_price: res.data.total_price ?? 0,
            }
          : prev,
      );
    },
    onError: (err) => {
      const message = err instanceof Error ? err.message : 'Fayl yuklanmadi';
      setError(message);
      setUploadedFile((prev) => (prev ? { ...prev, status: 'error' } : prev));
    },
  });

  // ── File validation ────────────────────────────────────────────────────────

  const validateFile = (file: File): string | null => {
    const ext = '.' + file.name.split('.').pop()?.toLowerCase();
    if (!SUPPORTED_EXTENSIONS.includes(ext)) {
      return `Qo'llab-quvvatlanmaydigan fayl turi. Ruxsat etilgan: ${SUPPORTED_EXTENSIONS.join(', ')}`;
    }
    if (file.size > 50 * 1024 * 1024) {
      return 'Fayl hajmi 50 MB dan oshmasligi kerak';
    }
    return null;
  };

  // ── Step 1 trigger ─────────────────────────────────────────────────────────

  const handleFileSelect = useCallback(
    (file: File) => {
      setError(null);

      const validationError = validateFile(file);
      if (validationError) {
        setError(validationError);
        return;
      }

      // Optimistic: show file chip immediately while backend responds
      setUploadedFile({
        file,
        name: file.name,
        sizeKB: Math.round(file.size / 1024),
        word_count: 0,
        total_price: 0,
        status: 'uploading',
      });

      // Auto-fill document name if blank
      setDocumentName((prev) =>
        prev.trim() === '' ? file.name.replace(/\.[^/.]+$/, '') : prev,
      );

      const fd = new FormData();
      fd.append('file', file);
      wordCountMutation.mutate(fd);
    },
    [wordCountMutation],
  );

  // ── Step 2 trigger (Check button) ─────────────────────────────────────────

  const handleSubmit = useCallback(() => {
    if (!uploadedFile?.file || !documentName.trim()) return;
    const fd = new FormData();
    fd.append('title', documentName.trim());
    fd.append('file', uploadedFile.file);
    createSIOrder.mutate(fd);
  }, [uploadedFile, documentName, createSIOrder]);

  // ── Drag & drop ────────────────────────────────────────────────────────────

  const handleDrop = useCallback(
    (e: React.DragEvent) => {
      e.preventDefault();
      setIsDragging(false);
      const file = e.dataTransfer.files[0];
      if (file) handleFileSelect(file);
    },
    [handleFileSelect],
  );

  const handleDragOver = useCallback((e: React.DragEvent) => {
    e.preventDefault();
    setIsDragging(true);
  }, []);

  const handleDragLeave = useCallback(() => {
    setIsDragging(false);
  }, []);

  const handleRemoveFile = useCallback(() => {
    setUploadedFile(null);
    setError(null);
    if (fileInputRef.current) fileInputRef.current.value = '';
  }, []);

  const openFilePicker = useCallback(() => {
    fileInputRef.current?.click();
  }, []);

  // ── Derived state ──────────────────────────────────────────────────────────

  const isProcessing =
    wordCountMutation.isPending ||
    createSIOrder.isPending ||
    siPayment.isPending;

  const canSubmit =
    documentName.trim().length > 0 &&
    uploadedFile?.status === 'done' &&
    !isProcessing;

  return {
    documentName,
    setDocumentName,
    uploadedFile,
    isDragging,
    isProcessing,
    error,
    fileInputRef,
    handleFileSelect,
    handleDrop,
    handleDragOver,
    handleDragLeave,
    handleRemoveFile,
    openFilePicker,
    handleSubmit,
    canSubmit,
  };
}