import { Document, Packer, Paragraph, TextRun, HeadingLevel, AlignmentType } from 'docx';
import { GeneratedQuestion } from '@/types/quiz';

export async function exportQuestionsToDocx(
  questions: GeneratedQuestion[], 
  filename: string = 'quiz-questions.docx',
  includeAnswers: boolean = true
) {
  // Create document
  const doc = new Document({
    sections: [{
      properties: {},
      children: [
        // Title
        new Paragraph({
          text: 'Quiz Questions',
          heading: HeadingLevel.HEADING_1,
          alignment: AlignmentType.CENTER,
          spacing: {
            after: 400,
          }
        }),
        
        // Date created
        new Paragraph({
          text: `Generated: ${new Date().toLocaleDateString()}`,
          alignment: AlignmentType.CENTER,
          spacing: {
            after: 200
          }
        }),
        
        // Total questions
        new Paragraph({
          text: `Total Questions: ${questions.length}`,
          alignment: AlignmentType.CENTER,
          spacing: {
            after: 300
          }
        }),
        
        // Questions
        ...questions.map((question, index) => 
          renderQuestion(question, index + 1, includeAnswers)
        ).flat()
      ]
    }]
  });

  // Generate and download the document
  const blob = await Packer.toBlob(doc);
  const url = URL.createObjectURL(blob);
  const link = document.createElement('a');
  link.href = url;
  link.download = filename;
  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
  URL.revokeObjectURL(url);
}

function renderQuestion(question: GeneratedQuestion, questionNumber: number, includeAnswers: boolean = true): Paragraph[] {
  const elements: Paragraph[] = [];
  
  // Question number and type
  elements.push(
    new Paragraph({
      children: [
        new TextRun({
          text: `Question ${questionNumber}`,
          bold: true,
          size: 24
        }),
        new TextRun({
          text: ` (${question.type})`,
          size: 20,
          color: '666666'
        })
      ],
      spacing: {
        before: 300,
        after: 150
      }
    })
  );
  
  // Question stem
  elements.push(
    new Paragraph({
      children: [
        new TextRun({
          text: question.stem,
          size: 22
        })
      ],
      spacing: {
        after: 200
      }
    })
  );
  
  // Points
  elements.push(
    new Paragraph({
      children: [
        new TextRun({
          text: `Points: ${question.points}`,
          size: 18,
          italics: true,
          color: '666666'
        })
      ],
      spacing: {
        after: 150
      }
    })
  );
  
  // Question content
  elements.push(...renderQuestionContent(question, includeAnswers));
  
  // Separator
  elements.push(
    new Paragraph({
      children: [
        new TextRun({
          text: '─'.repeat(50),
          color: 'CCCCCC'
        })
      ],
      spacing: {
        before: 200,
        after: 200
      }
    })
  );
  
  return elements;
}

function renderQuestionContent(question: GeneratedQuestion, includeAnswers: boolean = true): Paragraph[] {
  const elements: Paragraph[] = [];
  
  // Handle the actual content structure for multiple choice questions
  if (question.content && typeof question.content === 'object') {
    // Handle multiple choice questions with the actual structure
    if ('Options' in question.content && question.content.Options) {
      // Options is an object with keys A, B, C, D
      const options = question.content.Options as { A: string; B: string; C: string; D: string; };
      const correctAnswer = (question.content as { Answer?: string }).Answer;
      
      Object.entries(options).forEach(([key, value]) => {
        const isCorrect = key === correctAnswer;
        
        elements.push(
          new Paragraph({
            children: [
              new TextRun({
                text: `${key}. ${value}`,
                size: 20,
                color: includeAnswers && isCorrect ? '008000' : '000000',
                bold: includeAnswers && isCorrect
              })
            ],
            spacing: {
              after: 100
            }
          })
        );
      });
      
      // Add answer key if including answers
      if (includeAnswers && correctAnswer) {
        elements.push(
          new Paragraph({
            children: [
              new TextRun({
                text: `Answer: ${correctAnswer}`,
                bold: true,
                size: 20,
                color: '008000'
              })
            ],
            spacing: {
              before: 200,
              after: 200
            }
          })
        );
      }
    }
  }
  
  return elements;
}

export async function exportQuestionsToJson(questions: GeneratedQuestion[], filename: string = 'quiz-questions.json') {
  const data = {
    metadata: {
      exportDate: new Date().toISOString(),
      totalQuestions: questions.length,
      totalPoints: questions.reduce((sum, q) => sum + q.points, 0)
    },
    questions: questions.map(q => ({
      id: q.id,
      type: q.type,
      stem: q.stem,
      content: q.content,
      points: q.points,
      createdAt: q.createdAt
    }))
  };
  
  const blob = new Blob([JSON.stringify(data, null, 2)], { type: 'application/json' });
  const url = URL.createObjectURL(blob);
  const link = document.createElement('a');
  link.href = url;
  link.download = filename;
  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
  URL.revokeObjectURL(url);
}

export async function exportQuestionsToMarkdown(
  questions: GeneratedQuestion[], 
  filename: string = 'quiz-questions.md',
  includeAnswers: boolean = true
) {
  let markdown = '# Quiz Questions\n\n';
  markdown += `Generated: ${new Date().toLocaleDateString()}\n\n`;
  markdown += `Total Questions: ${questions.length}\n\n`;
  markdown += '---\n\n';
  
  questions.forEach((question, index) => {
    markdown += `## Question ${index + 1} (${question.type})\n\n`;
    markdown += `**Points:** ${question.points}\n\n`;
    markdown += `${question.stem}\n\n`;
    
    if (question.content && typeof question.content === 'object') {
      if ('Options' in question.content && question.content.Options) {
        const options = question.content.Options as { A: string; B: string; C: string; D: string; };
        const correctAnswer = (question.content as { Answer?: string }).Answer;
        
        Object.entries(options).forEach(([key, value]) => {
          const isCorrect = includeAnswers && key === correctAnswer;
          markdown += `${key}. ${value}${isCorrect ? ' ✓' : ''}\n`;
        });
        
        if (includeAnswers && correctAnswer) {
          markdown += `\n**Answer:** ${correctAnswer}\n`;
        }
      }
    }
    
    markdown += '\n---\n\n';
  });
  
  const blob = new Blob([markdown], { type: 'text/markdown' });
  const url = URL.createObjectURL(blob);
  const link = document.createElement('a');
  link.href = url;
  link.download = filename;
  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
  URL.revokeObjectURL(url);
}

export async function exportQuestionsToCsv(questions: GeneratedQuestion[], filename: string = 'quiz-questions.csv') {
  // CSV header
  let csv = 'Question Number,Type,Points,Question,Option A,Option B,Option C,Option D,Correct Answer\n';
  
  questions.forEach((question, index) => {
    const row = [];
    row.push(index + 1);
    row.push(question.type);
    row.push(question.points);
    row.push(`"${question.stem.replace(/"/g, '""')}"`);
    
    if (question.content && typeof question.content === 'object' && 'Options' in question.content) {
      const options = question.content.Options as { A: string; B: string; C: string; D: string; };
      const correctAnswer = (question.content as { Answer?: string }).Answer;
      
      row.push(`"${options.A.replace(/"/g, '""')}"`);
      row.push(`"${options.B.replace(/"/g, '""')}"`);
      row.push(`"${options.C.replace(/"/g, '""')}"`);
      row.push(`"${options.D.replace(/"/g, '""')}"`);
      row.push(correctAnswer || '');
    } else {
      // Add empty cells for non-multiple choice questions
      row.push('', '', '', '', '');
    }
    
    csv += row.join(',') + '\n';
  });
  
  const blob = new Blob([csv], { type: 'text/csv' });
  const url = URL.createObjectURL(blob);
  const link = document.createElement('a');
  link.href = url;
  link.download = filename;
  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
  URL.revokeObjectURL(url);
}