import React, { useState, useRef } from 'react';
import { Button } from './ui/button';
import { Input } from './ui/input';
import { Label } from './ui/label';
import { Textarea } from './ui/textarea';
import { Dialog, DialogContent, DialogTitle } from './ui/dialog';
import type { User as UserType } from '../App';
import { toast } from 'sonner';
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from './ui/select';
import { ChevronLeft, ChevronRight } from 'lucide-react';

interface OnboardingProps {
  user: UserType;
  onComplete: (user: UserType) => void;
  onSkip: () => void;
}

const TOTAL_STEPS = 5;

export function Onboarding({ user, onComplete, onSkip }: OnboardingProps) {
  const [currentStep, setCurrentStep] = useState(1);
  const [name, setName] = useState(user.name);
  const [email, setEmail] = useState(user.email);
  const [studentId, setStudentId] = useState('');
  const [department, setDepartment] = useState('');
  const [year, setYear] = useState('');
  const [major, setMajor] = useState('');
  const [bio, setBio] = useState('');
  const [photoPreview, setPhotoPreview] = useState<string | null>(null);
  const fileInputRef = useRef<HTMLInputElement>(null);

  const handlePhotoSelect = (e: React.ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0];
    if (file) {
      // Validate file type
      if (!file.type.startsWith('image/')) {
        toast.error('Please select an image file');
        return;
      }
      // Validate file size (2MB)
      if (file.size > 2 * 1024 * 1024) {
        toast.error('File size must be less than 2MB');
        return;
      }
      // Create preview
      const reader = new FileReader();
      reader.onload = (e) => {
        setPhotoPreview(e.target?.result as string);
      };
      reader.readAsDataURL(file);
    }
  };

  const handleChangePhotoClick = () => {
    fileInputRef.current?.click();
  };

  const handleNext = () => {
    if (currentStep < TOTAL_STEPS) {
      setCurrentStep(currentStep + 1);
    } else {
      handleComplete();
    }
  };

  const handlePrevious = () => {
    if (currentStep > 1) {
      setCurrentStep(currentStep - 1);
    }
  };

  const handleSkip = () => {
    // Skip all remaining steps and complete onboarding
    onSkip();
  };

  const handleComplete = () => {
    if (name.trim() && email.trim()) {
      onComplete({ name: name.trim(), email: email.trim() });
      toast.success('Profile setup completed!');
    } else {
      toast.error('Please fill in all required fields');
    }
  };

  const renderStepContent = () => {
    switch (currentStep) {
      case 1:
        return (
          <div className="space-y-4">
            <h3 className="text-lg font-medium">Basic Information</h3>
            <p className="text-sm text-muted-foreground">
              Let's start with your basic information
            </p>
            <div className="space-y-4">
              <div className="space-y-2">
                <Label htmlFor="onboarding-name">Full Name *</Label>
                <Input
                  id="onboarding-name"
                  value={name}
                  onChange={(e) => setName(e.target.value)}
                  placeholder="Enter your full name"
                />
              </div>
              <div className="space-y-2">
                <Label htmlFor="onboarding-email">Email *</Label>
                <Input
                  id="onboarding-email"
                  type="email"
                  value={email}
                  onChange={(e) => setEmail(e.target.value)}
                  placeholder="Enter your email"
                />
              </div>
            </div>
          </div>
        );
      case 2:
        return (
          <div className="space-y-4">
            <h3 className="text-lg font-medium">Academic Background</h3>
            <p className="text-sm text-muted-foreground">
              Tell us about your academic information
            </p>
            <div className="space-y-4">
              <div className="space-y-2">
                <Label htmlFor="onboarding-student-id">Student ID</Label>
                <Input
                  id="onboarding-student-id"
                  value={studentId}
                  onChange={(e) => setStudentId(e.target.value)}
                  placeholder="Enter your student ID"
                />
              </div>
              <div className="space-y-2">
                <Label htmlFor="onboarding-department">Department</Label>
                <Input
                  id="onboarding-department"
                  value={department}
                  onChange={(e) => setDepartment(e.target.value)}
                  placeholder="Enter your department"
                />
              </div>
              <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
                <div className="space-y-2">
                  <Label htmlFor="onboarding-year">Year Level</Label>
                  <Select value={year} onValueChange={setYear}>
                    <SelectTrigger id="onboarding-year">
                      <SelectValue placeholder="Select year level" />
                    </SelectTrigger>
                    <SelectContent>
                      <SelectItem value="1st Year">1st Year</SelectItem>
                      <SelectItem value="2nd Year">2nd Year</SelectItem>
                      <SelectItem value="3rd Year">3rd Year</SelectItem>
                      <SelectItem value="4th Year">4th Year</SelectItem>
                      <SelectItem value="Graduate">Graduate</SelectItem>
                    </SelectContent>
                  </Select>
                </div>
                <div className="space-y-2">
                  <Label htmlFor="onboarding-major">Major</Label>
                  <Input
                    id="onboarding-major"
                    value={major}
                    onChange={(e) => setMajor(e.target.value)}
                    placeholder="Enter your major"
                  />
                </div>
              </div>
            </div>
          </div>
        );
      case 3:
        return (
          <div className="space-y-4">
            <h3 className="text-lg font-medium">About You</h3>
            <p className="text-sm text-muted-foreground">
              Share a brief introduction about yourself
            </p>
            <div className="space-y-2">
              <Label htmlFor="onboarding-bio">Bio</Label>
              <Textarea
                id="onboarding-bio"
                value={bio}
                onChange={(e) => setBio(e.target.value)}
                placeholder="Tell us about yourself..."
                className="min-h-[120px] resize-none"
              />
              <p className="text-xs text-muted-foreground">
                Brief description for your profile. Max 200 characters.
              </p>
            </div>
          </div>
        );
      case 4:
        return (
          <div className="space-y-4">
            <h3 className="text-lg font-medium">Learning Preferences</h3>
            <p className="text-sm text-muted-foreground">
              Help us personalize your learning experience
            </p>
            <div className="space-y-4">
              <div className="space-y-2">
                <Label htmlFor="onboarding-learning-style">Preferred Learning Style</Label>
                <Select defaultValue="visual">
                  <SelectTrigger id="onboarding-learning-style">
                    <SelectValue />
                  </SelectTrigger>
                  <SelectContent>
                    <SelectItem value="visual">Visual</SelectItem>
                    <SelectItem value="auditory">Auditory</SelectItem>
                    <SelectItem value="reading">Reading/Writing</SelectItem>
                    <SelectItem value="kinesthetic">Kinesthetic</SelectItem>
                  </SelectContent>
                </Select>
              </div>
              <div className="space-y-2">
                <Label htmlFor="onboarding-pace">Learning Pace</Label>
                <Select defaultValue="moderate">
                  <SelectTrigger id="onboarding-pace">
                    <SelectValue />
                  </SelectTrigger>
                  <SelectContent>
                    <SelectItem value="slow">Slow & Steady</SelectItem>
                    <SelectItem value="moderate">Moderate</SelectItem>
                    <SelectItem value="fast">Fast-paced</SelectItem>
                  </SelectContent>
                </Select>
              </div>
            </div>
          </div>
        );
      case 5:
        return (
          <div className="space-y-4">
            <h3 className="text-lg font-medium">Profile Picture</h3>
            <p className="text-sm text-muted-foreground">
              Upload a photo to personalize your profile (optional)
            </p>
            <div className="flex items-center gap-4">
              <div className="w-24 h-24 rounded-full bg-gradient-to-br from-red-500 to-orange-500 flex items-center justify-center text-white text-3xl overflow-hidden">
                {photoPreview ? (
                  <img src={photoPreview} alt="Profile" className="w-full h-full object-cover" />
                ) : (
                  name.charAt(0).toUpperCase()
                )}
              </div>
              <div>
                <input
                  ref={fileInputRef}
                  type="file"
                  accept="image/jpeg,image/png,image/gif,image/webp"
                  onChange={handlePhotoSelect}
                  className="hidden"
                />
                <Button 
                  variant="outline" 
                  size="sm"
                  onClick={handleChangePhotoClick}
                >
                  Change Photo
                </Button>
                <p className="text-xs text-muted-foreground mt-1">
                  JPG, PNG or GIF. Max size 2MB
                </p>
              </div>
            </div>
          </div>
        );
      default:
        return null;
    }
  };

  return (
    <Dialog open onOpenChange={(open) => { if (!open) onSkip(); }}>
      <DialogContent 
        className="sm:max-w-lg p-0 gap-0 max-h-[90vh] overflow-hidden"
        style={{ zIndex: 1001 }}
        overlayClassName="!inset-0 !z-[99]"
        overlayStyle={{ 
          top: 0, 
          left: 0, 
          right: 0, 
          bottom: 0, 
          zIndex: 99,
          position: 'fixed'
        }}
      >
        <div className="flex flex-col max-h-[90vh]">
          {/* Header */}
          <div className="border-b border-border p-4 flex items-center justify-between flex-shrink-0">
            <div className="flex-1">
              <DialogTitle className="text-xl font-medium">Welcome! Let's set up your profile</DialogTitle>
              <p className="text-sm text-muted-foreground mt-1">
                Step {currentStep} of {TOTAL_STEPS}
              </p>
            </div>
            {/* Progress indicator */}
            <div className="flex gap-1">
              {Array.from({ length: TOTAL_STEPS }).map((_, index) => (
                <div
                  key={index}
                  className={`h-2 w-2 rounded-full transition-colors ${
                    index + 1 <= currentStep
                      ? 'bg-primary'
                      : 'bg-muted'
                  }`}
                />
              ))}
            </div>
          </div>

          {/* Content */}
          <div className="p-6 overflow-y-auto flex-1">
            {renderStepContent()}
          </div>

          {/* Footer */}
          <div className="border-t border-border p-4 flex justify-between gap-2 flex-shrink-0">
            <div className="flex gap-2">
              {currentStep > 1 && (
                <Button variant="outline" onClick={handlePrevious}>
                  <ChevronLeft className="h-4 w-4 mr-1" />
                  Previous
                </Button>
              )}
            </div>
            <div className="flex gap-2">
              <Button variant="outline" onClick={handleSkip}>
                Skip all
              </Button>
              <Button onClick={handleNext}>
                {currentStep === TOTAL_STEPS ? 'Complete' : 'Next Step'}
                {currentStep < TOTAL_STEPS && <ChevronRight className="h-4 w-4 ml-1" />}
              </Button>
            </div>
          </div>
        </div>
      </DialogContent>
    </Dialog>
  );
}