"use client";

import React, { useState, useRef, useEffect } from 'react';
import { UploadCloud, X, Check, Loader2 } from 'lucide-react';
import { Button } from '@/components/ui/button';
import { useSession } from 'next-auth/react';
import { toast } from '@/components/ui/use-toast';

interface FileUploadProps {
  type: 'logo' | 'attachment';
  missionId?: string; // Make missionId optional
  onUploadComplete?: (data: any) => void;
  onFileSelect?: (file: File) => void; // New callback for when file is selected but not uploaded yet
  maxSize?: number; // in bytes, default 5MB
  acceptedFileTypes?: string;
  isNewMission?: boolean; // Flag to indicate if this is a new mission being created
}

export function FileUpload({
  type,
  missionId,
  onUploadComplete,
  onFileSelect,
  maxSize = 5 * 1024 * 1024, // 5MB
  acceptedFileTypes = type === 'logo' ? 'image/*' : '.pdf,.doc,.docx,.xls,.xlsx,.jpg,.jpeg,.png',
  isNewMission = false
}: FileUploadProps) {
  // Log props on init
  console.log('FileUpload component initialized with props:', { 
    type, 
    missionId, 
    hasMissionId: !!missionId,
    maxSize, 
    acceptedFileTypes 
  });
  
  const { data: session } = useSession();
  const [isDragging, setIsDragging] = useState(false);
  const [isUploading, setIsUploading] = useState(false);
  const [progress, setProgress] = useState(0);
  const [file, setFile] = useState<File | null>(null);
  const [error, setError] = useState<string | null>(null);
  const fileInputRef = useRef<HTMLInputElement>(null);
  const isMounted = useRef(true);
  
  // Cleanup on unmount
  useEffect(() => {
    return () => {
      isMounted.current = false;
    };
  }, []);
  
  // Log when session changes
  useEffect(() => {
    console.log('Session state in FileUpload:', { 
      isSessionLoaded: !!session,
      hasUser: !!session?.user,
      userId: session?.user?.id
    });
  }, [session]);
  
  // Log when missionId changes
  useEffect(() => {
    console.log('MissionId in FileUpload component:', missionId);
  }, [missionId]);
  
  // Handle drag events
  const handleDragOver = (e: React.DragEvent) => {
    e.preventDefault();
    e.stopPropagation();
    setIsDragging(true);
  };
  
  const handleDragLeave = (e: React.DragEvent) => {
    e.preventDefault();
    e.stopPropagation();
    setIsDragging(false);
  };
  
  const validateFile = (file: File): boolean => {
    // Check file size
    if (file.size > maxSize) {
      setError(`File size exceeds the limit of ${maxSize / (1024 * 1024)}MB`);
      return false;
    }
    
    // Check file type for logo
    if (type === 'logo' && !file.type.startsWith('image/')) {
      setError('Only image files are allowed for logo');
      return false;
    }
    
    // For attachments, check file extension
    if (type === 'attachment') {
      const ext = file.name.split('.').pop()?.toLowerCase();
      const allowedExt = ['pdf', 'doc', 'docx', 'xls', 'xlsx', 'jpg', 'jpeg', 'png'];
      if (ext && !allowedExt.includes(ext)) {
        setError(`File type .${ext} is not allowed. Allowed types: ${allowedExt.join(', ')}`);
        return false;
      }
    }
    
    setError(null);
    return true;
  };
  
  const handleFileDrop = (e: React.DragEvent) => {
    e.preventDefault();
    e.stopPropagation();
    setIsDragging(false);
    
    if (e.dataTransfer.files && e.dataTransfer.files.length > 0) {
      const droppedFile = e.dataTransfer.files[0];
      if (validateFile(droppedFile)) {
        setFile(droppedFile);
        // If this is a new mission, call onFileSelect instead of waiting for upload
        if (isNewMission && onFileSelect) {
          onFileSelect(droppedFile);
        }
      }
    }
  };
  
  const handleFileChange = (e: React.ChangeEvent<HTMLInputElement>) => {
    if (e.target.files && e.target.files.length > 0) {
      const selectedFile = e.target.files[0];
      if (validateFile(selectedFile)) {
        setFile(selectedFile);
        // If this is a new mission, call onFileSelect instead of waiting for upload
        if (isNewMission && onFileSelect) {
          onFileSelect(selectedFile);
        }
      }
    }
  };
  
  const handleUpload = async () => {
    if (!file) {
      console.error('Upload failed: No file selected');
      toast({
        title: 'Upload failed',
        description: 'No file selected. Please select a file first.',
        variant: 'destructive',
      });
      return;
    }
    
    if (!session?.user?.id) {
      console.error('Upload failed: No user session');
      toast({
        title: 'Authentication required',
        description: 'You need to be logged in to upload files. Please log in and try again.',
        variant: 'destructive',
      });
      return;
    }
    
    // For new missions, just notify through the callback and don't try to upload
    if (isNewMission) {
      if (onFileSelect) {
        onFileSelect(file);
      }
      toast({
        title: 'File selected',
        description: 'The file will be uploaded when you save the mission.',
        variant: 'default',
      });
      return;
    }
    
    // For existing missions, we need a missionId
    if (!missionId) {
      console.error('Upload failed: Missing mission ID');
      toast({
        title: 'Upload failed',
        description: 'Missing mission ID. Please refresh the page and try again.',
        variant: 'destructive',
      });
      return;
    }
    
    console.log('Starting upload process...', {
      fileName: file.name,
      fileSize: file.size,
      fileType: file.type,
      missionId,
      userId: session.user.id,
      uploadType: type
    });
    
    setIsUploading(true);
    setProgress(0);
    
    try {
      // Create form data
      const formData = new FormData();
      formData.append('file', file);
      formData.append('missionId', missionId);
      formData.append('type', type);
      
      console.log('FormData prepared, sending to API...');
      
      // Upload the file
      const response = await fetch('/api/missions/upload', {
        method: 'POST',
        body: formData
      });
      
      console.log('API response received:', { 
        status: response.status, 
        statusText: response.statusText, 
        ok: response.ok 
      });
      
      if (!response.ok) {
        const errorData = await response.json();
        console.error('API returned error:', errorData);
        throw new Error(errorData.error || 'Upload failed');
      }
      
      const result = await response.json();
      console.log('Upload successful, result:', result);
      
      // Only update state if the component is still mounted
      if (isMounted.current) {
        setProgress(100);
        
        // Reset file after successful upload
        setTimeout(() => {
          if (isMounted.current) {
            setFile(null);
            setIsUploading(false);
            setProgress(0);
            
            // Call the callback if provided
            if (onUploadComplete) {
              onUploadComplete(result);
            }
          }
          
          toast({
            title: 'File uploaded successfully',
            description: type === 'logo' ? 'Logo has been updated' : `${file.name} has been added to attachments`,
            variant: 'default',
          });
        }, 1000);
      }
    } catch (error) {
      console.error('Upload error details:', error);
      
      // Only update state if the component is still mounted
      if (isMounted.current) {
        setIsUploading(false);
      }
      
      toast({
        title: 'Upload failed',
        description: error instanceof Error ? error.message : 'An error occurred during upload',
        variant: 'destructive',
      });
    }
  };
  
  const handleCancel = () => {
    setFile(null);
    setError(null);
  };
  
  return (
    <div className="w-full">
      {!file ? (
        <div
          className={`border-2 border-dashed rounded-md p-6 text-center transition-colors ${
            isDragging ? 'border-blue-500 bg-blue-50' : 'border-gray-300 bg-gray-50'
          }`}
          onDragOver={handleDragOver}
          onDragLeave={handleDragLeave}
          onDrop={handleFileDrop}
        >
          <div className="flex flex-col items-center justify-center">
            <UploadCloud className="h-10 w-10 text-gray-400 mb-2" />
            <p className="text-sm mb-2 font-medium text-gray-700">
              {type === 'logo' ? 'Upload logo image' : 'Upload attachment'}
            </p>
            <p className="text-xs text-gray-500 mb-4">
              Drag and drop or click to browse
            </p>
            <Button
              variant="outline"
              size="sm"
              className="bg-white text-gray-700 border-gray-300 hover:bg-gray-50"
              onClick={() => fileInputRef.current?.click()}
            >
              Browse Files
            </Button>
            <input
              type="file"
              ref={fileInputRef}
              className="hidden"
              onChange={handleFileChange}
              accept={acceptedFileTypes}
            />
            {error && (
              <p className="text-xs text-red-500 mt-2">{error}</p>
            )}
          </div>
        </div>
      ) : (
        <div className="border rounded-md p-4 bg-white">
          <div className="flex items-center justify-between">
            <div className="flex items-center space-x-3">
              <div className="flex-shrink-0 h-10 w-10 bg-gray-100 rounded-md flex items-center justify-center">
                {type === 'logo' ? (
                  <img
                    src={URL.createObjectURL(file)}
                    alt="Preview"
                    className="h-full w-full object-cover rounded-md"
                  />
                ) : (
                  <div className="text-xs font-bold bg-blue-100 text-blue-600 h-full w-full rounded-md flex items-center justify-center">
                    {file.name.split('.').pop()?.toUpperCase()}
                  </div>
                )}
              </div>
              <div className="min-w-0 flex-1">
                <p className="text-sm font-medium text-gray-900 truncate">
                  {file.name}
                </p>
                <p className="text-xs text-gray-500">
                  {(file.size / 1024).toFixed(2)} KB
                </p>
              </div>
            </div>
            
            <div className="flex items-center space-x-2">
              {isUploading ? (
                <div className="flex items-center">
                  <Loader2 className="animate-spin h-4 w-4 mr-1 text-blue-500" />
                  <span className="text-xs text-gray-500">{progress}%</span>
                </div>
              ) : (
                <>
                  <Button
                    variant="ghost"
                    size="sm"
                    className="text-red-500 hover:text-red-700 hover:bg-red-50"
                    onClick={handleCancel}
                  >
                    <X className="h-4 w-4" />
                  </Button>
                  
                  {!isNewMission && (
                    <Button
                      variant="default"
                      size="sm"
                      className="bg-blue-600 hover:bg-blue-700 text-white"
                      onClick={handleUpload}
                    >
                      <Check className="h-4 w-4 mr-1" />
                      Upload
                    </Button>
                  )}
                </>
              )}
            </div>
          </div>
          
          {isUploading && (
            <div className="w-full bg-gray-200 rounded-full h-1.5 mt-3">
              <div
                className="bg-blue-600 h-1.5 rounded-full"
                style={{ width: `${progress}%` }}
              ></div>
            </div>
          )}
        </div>
      )}
    </div>
  );
}