/**
 * @license
 * SPDX-License-Identifier: Apache-2.0
*/
import React, { useState, ChangeEvent } from 'react';
import type { InitialInput } from '../lib/types';
import { getDocument, GlobalWorkerOptions } from 'pdfjs-dist';
import mammoth from 'mammoth';

// Set workerSrc for pdf.js. This is crucial for it to work.
GlobalWorkerOptions.workerSrc = 'pdfjs-dist/build/pdf.worker.min.js';

interface InitialInputFormProps {
  onSubmit: (formData: InitialInput) => void;
  onClear: () => void;
  disabled: boolean;
  isLoading: boolean;
}

const initialFormState: InitialInput = {
  fullName: '',
  jobTitle: '',
  careerGoal: '',
  jobDescription: '',
  uploadedResumeContent: '',
  yearsOfExperience: '2-4 Years',
  keySkills: '',
  previousRoles: '',
  education: '',
};

export default function InitialInputForm({ onSubmit, onClear, disabled, isLoading }: InitialInputFormProps) {
  const [formData, setFormData] = useState<InitialInput>(initialFormState);
  const [selectedFileName, setSelectedFileName] = useState<string>('');
  const [fileError, setFileError] = useState<string | null>(null);

  const handleChange = (e: React.ChangeEvent<HTMLInputElement | HTMLSelectElement | HTMLTextAreaElement>) => {
    const { name, value } = e.target;
    setFormData(prev => ({ ...prev, [name]: value }));
  };

  const handleFileChange = async (e: ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0];
    setFileError(null);
    setSelectedFileName('');
    setFormData(prev => ({ ...prev, uploadedResumeContent: '' }));

    if (file) {
      setSelectedFileName(file.name);
      try {
        let text = '';
        if (file.name.toLowerCase().endsWith('.txt')) {
          text = await file.text();
        } else if (file.name.toLowerCase().endsWith('.pdf')) {
          const arrayBuffer = await file.arrayBuffer();
          const pdf = await getDocument({ data: arrayBuffer }).promise;
          let pdfText = '';
          for (let i = 1; i <= pdf.numPages; i++) {
            const page = await pdf.getPage(i);
            const textContent = await page.getTextContent();
            pdfText += textContent.items.map((item: any) => item.str).join(' ') + '\n';
          }
          text = pdfText;
        } else if (file.name.toLowerCase().endsWith('.docx')) {
          const arrayBuffer = await file.arrayBuffer();
          const result = await mammoth.extractRawText({ arrayBuffer });
          text = result.value;
        } else {
          setFileError("Unsupported file type. Please use .txt, .pdf, or .docx.");
          return;
        }
        setFormData(prev => ({ ...prev, uploadedResumeContent: text }));
      } catch (error) {
        setFileError(`Error processing file: ${error instanceof Error ? error.message : "Unknown error"}.`);
      }
    }
  };

  const handleSubmit = (e: React.FormEvent) => {
    e.preventDefault();
    if (fileError) {
      alert(`Cannot submit: Please resolve the file error first. ${fileError}`);
      return;
    }
    onSubmit(formData);
  };

  const handleClear = () => {
    setFormData(initialFormState);
    setSelectedFileName('');
    setFileError(null);
    const fileInput = document.getElementById('resumeUpload') as HTMLInputElement;
    if (fileInput) fileInput.value = '';
    onClear();
  };

  return (
    <form onSubmit={handleSubmit} className="initial-input-form">
      <h2>Initial Setup</h2>
      
      {/* Form groups for all inputs */}
      <div className="form-group">
        <label htmlFor="fullName">Full Name</label>
        <input type="text" id="fullName" name="fullName" value={formData.fullName} onChange={handleChange} placeholder="e.g., Jane Doe" required disabled={disabled}/>
      </div>
      <div className="form-group">
        <label htmlFor="jobTitle">Current or Target Job Title</label>
        <input type="text" id="jobTitle" name="jobTitle" value={formData.jobTitle} onChange={handleChange} placeholder="e.g., Senior Software Engineer" required disabled={disabled}/>
      </div>
      <div className="form-group">
        <label htmlFor="jobDescription">Target Job Description (Crucial for Scoring)</label>
        <textarea id="jobDescription" name="jobDescription" value={formData.jobDescription} onChange={handleChange} placeholder="Paste the job description here..." rows={6} disabled={disabled}/>
      </div>
      <div className="form-group">
        <label htmlFor="resumeUpload">Upload Existing Resume (Optional)</label>
        <input type="file" id="resumeUpload" name="resumeUpload" accept=".txt,.pdf,.docx" onChange={handleFileChange} disabled={disabled}/>
        <small className="form-text text-muted">{selectedFileName ? `Selected: ${selectedFileName}` : "Upload for richer context."}</small>
        {fileError && <p role="alert" style={{color:'var(--color-error)',fontSize:'0.9em',marginTop:'0.5em'}}>{fileError}</p>}
      </div>
      <div className="form-group">
        <label htmlFor="keySkills">Key Skills (to supplement resume)</label>
        <textarea id="keySkills" name="keySkills" value={formData.keySkills} onChange={handleChange} placeholder="List skills not detailed in your resume..." rows={3} disabled={disabled}/>
      </div>
      {/* Additional fields like careerGoal, yearsOfExperience etc. can be added here if needed */}
      
      <div className="form-actions" style={{marginTop: '1.5rem', display: 'flex', gap: '1rem'}}>
        <button type="submit" className={`submit-button ${isLoading ? 'is-loading' : ''}`} disabled={disabled}>
          <span>{isLoading ? 'Generating...' : 'Generate Resume'}</span>
        </button>
        <button type="button" className="clear-button" onClick={handleClear} disabled={disabled}>
          Clear All
        </button>
      </div>
    </form>
  );
}