import { NextResponse } from 'next/server';
import nodemailer from 'nodemailer';

// Email configuration
const emailConfig = {
  from_email: process.env.EMAIL_USER || "smukeshsn2000@gmail.com",
  from_email_password: process.env.EMAIL_PASS || "swoe hxko uzuc ichj",
  from_email_name: process.env.EMAIL_FROM_NAME || "Operify",
  to_email: process.env.EMAIL_TO || "smukesh1304@gmail.com",
  to_email_name: process.env.EMAIL_TO_NAME || "Mukesh",
};

// Form configurations
const configs = {
  contact: {
    subject: 'Contact Form Submission',
    fields: ['name', 'phone', 'service_interest', 'email', 'Organisation', 'message'],
    required: ['name', 'phone', 'service_interest', 'email', 'Organisation', 'message'],
    email_fields: ['email'],
    successMessage: 'Thank you for your submission. Our team will contact you soon!'
  },
  career: {
    subject: 'Career Application',
    fields: ['name', 'phone', 'email', 'Education_Qualification', 'experience', 'Specify_your_interest_in_Genomics', 'message'],
    required: ['name', 'phone', 'email', 'Education_Qualification', 'experience', 'Specify_your_interest_in_Genomics', 'message'],
    email_fields: ['email'],
    file_field: 'resume',
    successMessage: 'Thank you for your application. Our team will contact you soon!'
  },
  sample: {
    subject: 'SIF Form received for Project',
    fields: [
      'Principal_Investigator', 'Email', 'Company_Institution', 'Contact_Number', 'Address', 'City', 'State', 'Pin',
      'Secondary_Contact', 'Secondary_Email', 'Secondary_Company_Institution', 'Secondary_Contact_Number',
      'Project_Title', 'Number_of_Samples', 'Sample_Type', 'Sample_Type_Other', 'Sample_Source', 'Sample_Source_Other',
      'Pathogenicity', 'Sample_Remarks',
      'Service_Requested', 'Service_Requested_Other', 'Type_of_Library', 'Type_of_Library_Other',
      'Required_Library_Size', 'Required_Library_Size_Other', 'Index_Information', 'Kit_Information',
      'Sequencing_Platform', 'Sequencing_Platform_Other', 'Sequencing_Read_Length', 'Sequencing_Read_Length_Other',
      'Total_Data_Requirement', 'Service_Remarks',
      'Analysis_Requested', 'Analysis_Details', 'Reference_Genome_Available', 'Genome_Size', 'Special_Consideration'
    ],
    required: [
      'Principal_Investigator', 'Email', 'Company_Institution', 'Contact_Number', 'Address', 'City', 'State', 'Pin',
      'Project_Title', 'Number_of_Samples', 'Sample_Type', 'Sample_Source', 'Pathogenicity', 'Service_Requested',
      'Type_of_Library', 'Required_Library_Size', 'Sequencing_Platform', 'Sequencing_Read_Length',
      'Total_Data_Requirement', 'Analysis_Requested', 'Reference_Genome_Available', 'Special_Consideration'
    ],
    email_fields: ['Email', 'Secondary_Email'],
    successMessage: 'Thank you for your sample initiation form submission. Our team will contact you soon!'
  }
};

// Serial number tracker
let serialTracker = {};
function generateSerialNumber() {
  const today = new Date();
  const dateKey = today.toISOString().slice(0, 10); // "YYYY-MM-DD"
  if (!serialTracker[dateKey]) {
    serialTracker[dateKey] = 1;
  } else {
    serialTracker[dateKey] += 1;
  }
  const serialNum = String(serialTracker[dateKey]).padStart(2, '0');
  return {
    serialNum,
    formatted: `Operify Tech. ${today.getFullYear()}.${String(today.getMonth() + 1).padStart(2, '0')}.${String(today.getDate()).padStart(2, '0')}.${serialNum}`,
    dateString: dateKey
  };
}

// Utility functions
function isValidEmail(email) {
  const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
  return emailRegex.test(email);
}

function fieldName(key) {
  return key.replace(/[_-]/g, ' ').replace(/\b\w/g, l => l.toUpperCase());
}

export async function GET() {
  return NextResponse.json({ 
    message: 'Forms API is working',
    timestamp: new Date().toISOString()
  });
}

export async function POST(request) {
  try {
    const formData = await request.formData();
    const data = {};
    const files = {};
    
    for (const [key, value] of formData.entries()) {
      if (value instanceof File) {
        files[key] = value;
      } else {
        data[key] = value;
      }
    }

    const form_type = data.form_type;
    
    if (!form_type || !configs[form_type]) {
      return NextResponse.json({ 
        error: 'Invalid form type: ' + (form_type || 'missing') 
      }, { status: 400 });
    }

    const config = configs[form_type];
    const errors = [];

    for (const required_field of config.required) {
      if (!data[required_field] || String(data[required_field]).trim() === '') {
        errors.push(`The "${fieldName(required_field)}" field is required.`);
      } else if (config.email_fields.includes(required_field) && !isValidEmail(data[required_field])) {
        errors.push(`The "${fieldName(required_field)}" email is not valid.`);
      }
    }

    if (form_type === 'career') {
      const fileField = config.file_field;
      const uploadedFile = files[fileField];
      if (!uploadedFile || uploadedFile.size === 0) {
        errors.push('Please upload your resume.');
      } else {
        const allowedExtensions = ['pdf', 'doc', 'docx'];
        const fileExtension = uploadedFile.name.toLowerCase().split('.').pop();
        if (!allowedExtensions.includes(fileExtension)) {
          errors.push('Invalid file type. Please upload a PDF, DOC, or DOCX file.');
        }
        if (uploadedFile.size > 10 * 1024 * 1024) {
          errors.push('File is too large. Maximum size is 10MB.');
        }
      }
    }

    if (errors.length > 0) {
      return NextResponse.json({ error: errors.join(' ') }, { status: 400 });
    }

    let emailBody = `<h2>${config.subject}</h2><table style="border: 1px solid #b5b5b5; padding: 5px;">`;
    for (const [key, value] of Object.entries(data)) {
      if (config.fields.includes(key) && key !== 'form_type' && key !== 'sample_details') {
        emailBody += `<tr>
          <td style="border: 1px solid #b5b5b5; padding: 5px;"><strong>${fieldName(key)}</strong></td>
          <td style="border: 1px solid #b5b5b5; padding: 5px;">: ${String(value)}</td>
        </tr>`;
      }
    }

    if (form_type === 'career' && files.resume) {
      emailBody += `<tr>
        <td style="border: 1px solid #b5b5b5; padding: 5px;"><strong>Resume</strong></td>
        <td style="border: 1px solid #b5b5b5; padding: 5px;">: ${files.resume.name} (attached)</td>
      </tr>`;
    }

    if (form_type === 'sample' && data.sample_details) {
      try {
        const sampleDetails = JSON.parse(data.sample_details);
        if (sampleDetails.length > 0) {
          emailBody += `<tr>
            <td colspan="2" style="border: 1px solid #b5b5b5; padding: 10px; background-color: #e8f5f3; text-align: center;"><strong>SAMPLE DETAILS</strong></td>
          </tr>`;
          sampleDetails.forEach((sample, index) => {
            emailBody += `<tr>
              <td colspan="2" style="border: 1px solid #b5b5b5; padding: 8px; background-color: #f0f8f5; font-weight: bold;">Sample ${index + 1}</td>
            </tr>`;
            Object.entries(sample).forEach(([key, value]) => {
              if (value && String(value).trim() !== '') {
                emailBody += `<tr>
                  <td style="border: 1px solid #b5b5b5; padding: 5px; background-color: #f9f9f9;"><strong>${fieldName(key)}</strong></td>
                  <td style="border: 1px solid #b5b5b5; padding: 5px;">: ${String(value)}</td>
                </tr>`;
              }
            });
          });
        }
      } catch {
        emailBody += `<tr>
          <td colspan="2" style="border: 1px solid #b5b5b5; padding: 5px; color: red;">Error: Could not parse sample details</td>
        </tr>`;
      }
    }
    emailBody += '</table>';

    let replyToEmail = form_type === 'sample' ? data.Email : data.email;

    const transporter = nodemailer.createTransport({
      host: 'smtp.gmail.com',
      port: 587,
      secure: false,
      auth: {
        user: emailConfig.from_email,
        pass: emailConfig.from_email_password,
      },
    });

    // SERIAL NUMBER LOGIC
    let serialInfo;
    if (form_type === 'sample') {
      serialInfo = generateSerialNumber();
    }

    // Internal mail
    const mailOptions = {
      from: `${emailConfig.from_email_name} <${emailConfig.from_email}>`,
      to: `${emailConfig.to_email_name} <${emailConfig.to_email}>`,
      replyTo: replyToEmail || emailConfig.from_email,
      subject: form_type === 'sample'
        ? `${data.Company_Institution} | ${data.Principal_Investigator} | ${serialInfo.dateString} | ${serialInfo.formatted}`
        : config.subject,
      html: emailBody,
      text: emailBody.replace(/<[^>]*>/g, '')
    };

    if (form_type === 'career' && files.resume) {
      const fileBuffer = await files.resume.arrayBuffer();
      mailOptions.attachments = [{
        filename: files.resume.name,
        content: Buffer.from(fileBuffer),
      }];
    }

    await transporter.sendMail(mailOptions);

    // PI email for sample form
    if (form_type === 'sample') {
      const piMailOptions = {
        from: `${emailConfig.from_email_name} <${emailConfig.from_email}>`,
        to: `${data.Principal_Investigator} <${data.Email}>`,
        subject: `SIF Form received for Project with - ${serialInfo.formatted}`,
        html: emailBody,
        text: emailBody.replace(/<[^>]*>/g, '')
      };
      await transporter.sendMail(piMailOptions);
    }

    return NextResponse.json({ success: true, message: config.successMessage });

  } catch (error) {
    console.error('Email sending error:', error);
    return NextResponse.json({ error: 'Error sending email. Please try again later.' }, { status: 500 });
  }
}