const { SESClient, SendEmailCommand } = require("@aws-sdk/client-ses");
const fs = require("fs").promises;
const path = require("path");
const { getAWSConfig } = require("../config/aws");
const { User } = require("../models");

class EmailService {
  constructor() {
    this.sesClient = null;
    this.initialized = false;
    this.templates = new Map();
  }

  async initialize() {
    if (this.initialized) return;

    try {
      // Use centralized AWS configuration with credential profiles
      const awsConfig = getAWSConfig();
      this.sesClient = new SESClient(awsConfig);

      await this.loadEmailTemplates();
      this.initialized = true;
      console.log("SES Email Service initialized successfully");
    } catch (error) {
      console.error("Failed to initialize SES Email Service:", error);
      throw error;
    }
  }

  async loadEmailTemplates() {
    const templatesDir = path.join(__dirname, "..", "templates", "emails");

    try {
      const templateFiles = [
        "conditionCheckReminder.html",
        "rentalConfirmation.html",
        "emailVerification.html",
        "passwordReset.html",
        "passwordChanged.html",
        "lateReturnCS.html",
        "damageReportCS.html",
        "lostItemCS.html",
      ];

      for (const templateFile of templateFiles) {
        try {
          const templatePath = path.join(templatesDir, templateFile);
          const templateContent = await fs.readFile(templatePath, "utf-8");
          const templateName = path.basename(templateFile, ".html");
          this.templates.set(templateName, templateContent);
        } catch (error) {
          console.warn(`Template ${templateFile} not found, will use fallback`);
        }
      }

      console.log(`Loaded ${this.templates.size} email templates`);
    } catch (error) {
      console.warn("Templates directory not found, using fallback templates");
    }
  }

  /**
   * Convert HTML to plain text for email fallback
   * Strips HTML tags and formats content for plain text email clients
   */
  htmlToPlainText(html) {
    return html
      // Remove style and script tags and their content
      .replace(/<style[^>]*>[\s\S]*?<\/style>/gi, '')
      .replace(/<script[^>]*>[\s\S]*?<\/script>/gi, '')
      // Convert common HTML elements to text equivalents
      .replace(/<br\s*\/?>/gi, '\n')
      .replace(/<\/p>/gi, '\n\n')
      .replace(/<\/div>/gi, '\n')
      .replace(/<\/li>/gi, '\n')
      .replace(/<\/h[1-6]>/gi, '\n\n')
      .replace(/<li>/gi, '• ')
      // Remove remaining HTML tags
      .replace(/<[^>]+>/g, '')
      // Decode HTML entities
      .replace(/&nbsp;/g, ' ')
      .replace(/&amp;/g, '&')
      .replace(/&lt;/g, '<')
      .replace(/&gt;/g, '>')
      .replace(/&quot;/g, '"')
      .replace(/&#39;/g, "'")
      // Remove emojis and special characters that don't render well in plain text
      .replace(/[\u{1F600}-\u{1F64F}]/gu, '') // Emoticons
      .replace(/[\u{1F300}-\u{1F5FF}]/gu, '') // Misc Symbols and Pictographs
      .replace(/[\u{1F680}-\u{1F6FF}]/gu, '') // Transport and Map
      .replace(/[\u{2600}-\u{26FF}]/gu, '') // Misc symbols
      .replace(/[\u{2700}-\u{27BF}]/gu, '') // Dingbats
      .replace(/[\u{FE00}-\u{FE0F}]/gu, '') // Variation Selectors
      .replace(/[\u{1F900}-\u{1F9FF}]/gu, '') // Supplemental Symbols and Pictographs
      .replace(/[\u{1FA70}-\u{1FAFF}]/gu, '') // Symbols and Pictographs Extended-A
      // Clean up excessive whitespace
      .replace(/\n\s*\n\s*\n/g, '\n\n')
      .trim();
  }

  async sendEmail(to, subject, htmlContent, textContent = null) {
    if (!this.initialized) {
      await this.initialize();
    }

    if (!process.env.EMAIL_ENABLED || process.env.EMAIL_ENABLED !== "true") {
      console.log("Email sending disabled in environment");
      return { success: true, messageId: "disabled" };
    }

    // Auto-generate plain text from HTML if not provided
    if (!textContent) {
      textContent = this.htmlToPlainText(htmlContent);
    }

    // Use friendly sender name format for better recognition
    const fromName = process.env.SES_FROM_NAME || "RentAll";
    const fromEmail = process.env.SES_FROM_EMAIL;
    const source = `${fromName} <${fromEmail}>`;

    const params = {
      Source: source,
      Destination: {
        ToAddresses: Array.isArray(to) ? to : [to],
      },
      Message: {
        Subject: {
          Data: subject,
          Charset: "UTF-8",
        },
        Body: {
          Html: {
            Data: htmlContent,
            Charset: "UTF-8",
          },
          Text: {
            Data: textContent,
            Charset: "UTF-8",
          },
        },
      },
    };

    if (process.env.SES_REPLY_TO_EMAIL) {
      params.ReplyToAddresses = [process.env.SES_REPLY_TO_EMAIL];
    }

    try {
      const command = new SendEmailCommand(params);
      const result = await this.sesClient.send(command);

      console.log(
        `Email sent successfully to ${to}, MessageId: ${result.MessageId}`
      );
      return { success: true, messageId: result.MessageId };
    } catch (error) {
      console.error("Failed to send email:", error);
      return { success: false, error: error.message };
    }
  }

  renderTemplate(templateName, variables = {}) {
    let template = this.templates.get(templateName);

    if (!template) {
      template = this.getFallbackTemplate(templateName);
    }

    let rendered = template;

    Object.keys(variables).forEach((key) => {
      const regex = new RegExp(`{{${key}}}`, "g");
      rendered = rendered.replace(regex, variables[key] || "");
    });

    return rendered;
  }

  getFallbackTemplate(templateName) {
    const baseTemplate = `
      <!DOCTYPE html>
      <html>
      <head>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>{{title}}</title>
        <style>
          body { font-family: Arial, sans-serif; margin: 0; padding: 20px; background-color: #f5f5f5; }
          .container { max-width: 600px; margin: 0 auto; background-color: white; padding: 30px; border-radius: 8px; box-shadow: 0 2px 4px rgba(0,0,0,0.1); }
          .header { text-align: center; border-bottom: 2px solid #e9ecef; padding-bottom: 20px; margin-bottom: 30px; }
          .logo { font-size: 24px; font-weight: bold; color: #333; }
          .content { line-height: 1.6; color: #555; }
          .button { display: inline-block; background-color: #007bff; color: white; padding: 12px 24px; text-decoration: none; border-radius: 4px; margin: 20px 0; }
          .footer { margin-top: 30px; padding-top: 20px; border-top: 1px solid #e9ecef; text-align: center; font-size: 12px; color: #6c757d; }
        </style>
      </head>
      <body>
        <div class="container">
          <div class="header">
            <div class="logo">RentAll</div>
          </div>
          <div class="content">
            {{content}}
          </div>
          <div class="footer">
            <p>This email was sent from RentAll. If you have any questions, please contact support.</p>
          </div>
        </div>
      </body>
      </html>
    `;

    const templates = {
      conditionCheckReminder: baseTemplate.replace(
        "{{content}}",
        `
        <h2>{{title}}</h2>
        <p>{{message}}</p>
        <p><strong>Rental Item:</strong> {{itemName}}</p>
        <p><strong>Deadline:</strong> {{deadline}}</p>
        <p>Please complete this condition check as soon as possible to ensure proper documentation.</p>
      `
      ),

      rentalConfirmation: baseTemplate.replace(
        "{{content}}",
        `
        <p>Hi {{recipientName}},</p>
        <h2>{{title}}</h2>
        <p>{{message}}</p>
        <p><strong>Item:</strong> {{itemName}}</p>
        <p><strong>Rental Period:</strong> {{startDate}} to {{endDate}}</p>
        <p>Thank you for using RentAll!</p>
      `
      ),

      emailVerification: baseTemplate.replace(
        "{{content}}",
        `
        <p>Hi {{recipientName}},</p>
        <h2>Verify Your Email Address</h2>
        <p>Thank you for registering with RentAll! Please verify your email address by clicking the button below.</p>
        <p><a href="{{verificationUrl}}" class="button">Verify Email Address</a></p>
        <p>If the button doesn't work, copy and paste this link into your browser: {{verificationUrl}}</p>
        <p><strong>This link will expire in 24 hours.</strong></p>
      `
      ),

      passwordReset: baseTemplate.replace(
        "{{content}}",
        `
        <p>Hi {{recipientName}},</p>
        <h2>Reset Your Password</h2>
        <p>We received a request to reset the password for your RentAll account. Click the button below to choose a new password.</p>
        <p><a href="{{resetUrl}}" class="button">Reset Password</a></p>
        <p>If the button doesn't work, copy and paste this link into your browser: {{resetUrl}}</p>
        <p><strong>This link will expire in 1 hour.</strong></p>
        <p>If you didn't request this, you can safely ignore this email.</p>
      `
      ),

      passwordChanged: baseTemplate.replace(
        "{{content}}",
        `
        <p>Hi {{recipientName}},</p>
        <h2>Your Password Has Been Changed</h2>
        <p>This is a confirmation that the password for your RentAll account ({{email}}) has been successfully changed.</p>
        <p><strong>Changed on:</strong> {{timestamp}}</p>
        <p>For your security, all existing sessions have been logged out.</p>
        <p><strong>Didn't change your password?</strong> If you did not make this change, please contact our support team immediately.</p>
      `
      ),
    };

    return (
      templates[templateName] ||
      baseTemplate.replace(
        "{{content}}",
        `
      <h2>{{title}}</h2>
      <p>{{message}}</p>
    `
      )
    );
  }

  async sendConditionCheckReminder(userEmail, notification, rental) {
    const variables = {
      title: notification.title,
      message: notification.message,
      itemName: rental?.item?.name || "Unknown Item",
      deadline: notification.metadata?.deadline
        ? new Date(notification.metadata.deadline).toLocaleDateString()
        : "Not specified",
    };

    const htmlContent = this.renderTemplate(
      "conditionCheckReminder",
      variables
    );

    return await this.sendEmail(
      userEmail,
      `RentAll: ${notification.title}`,
      htmlContent
    );
  }

  async sendRentalConfirmation(userEmail, notification, rental, recipientName = null) {
    const itemName = rental?.item?.name || "Unknown Item";

    const variables = {
      recipientName: recipientName || "there",
      title: notification.title,
      message: notification.message,
      itemName: itemName,
      startDate: rental?.startDateTime
        ? new Date(rental.startDateTime).toLocaleDateString()
        : "Not specified",
      endDate: rental?.endDateTime
        ? new Date(rental.endDateTime).toLocaleDateString()
        : "Not specified",
    };

    const htmlContent = this.renderTemplate("rentalConfirmation", variables);

    // Use clear, transactional subject line with item name
    const subject = `Rental Confirmation - ${itemName}`;

    return await this.sendEmail(
      userEmail,
      subject,
      htmlContent
    );
  }

  async sendVerificationEmail(user, verificationToken) {
    const frontendUrl = process.env.FRONTEND_URL || "http://localhost:3000";
    const verificationUrl = `${frontendUrl}/verify-email?token=${verificationToken}`;

    const variables = {
      recipientName: user.firstName || "there",
      verificationUrl: verificationUrl,
    };

    const htmlContent = this.renderTemplate("emailVerification", variables);

    return await this.sendEmail(
      user.email,
      "Verify Your Email - RentAll",
      htmlContent
    );
  }

  async sendPasswordResetEmail(user, resetToken) {
    const frontendUrl = process.env.FRONTEND_URL || "http://localhost:3000";
    const resetUrl = `${frontendUrl}/reset-password?token=${resetToken}`;

    const variables = {
      recipientName: user.firstName || "there",
      resetUrl: resetUrl,
    };

    const htmlContent = this.renderTemplate("passwordReset", variables);

    return await this.sendEmail(
      user.email,
      "Reset Your Password - RentAll",
      htmlContent
    );
  }

  async sendPasswordChangedEmail(user) {
    const timestamp = new Date().toLocaleString("en-US", {
      dateStyle: "long",
      timeStyle: "short",
    });

    const variables = {
      recipientName: user.firstName || "there",
      email: user.email,
      timestamp: timestamp,
    };

    const htmlContent = this.renderTemplate("passwordChanged", variables);

    return await this.sendEmail(
      user.email,
      "Password Changed Successfully - RentAll",
      htmlContent
    );
  }

  async sendTemplateEmail(toEmail, subject, templateName, variables = {}) {
    const htmlContent = this.renderTemplate(templateName, variables);
    return await this.sendEmail(toEmail, subject, htmlContent);
  }

  async sendLateReturnToCustomerService(rental, lateCalculation) {
    try {
      // Get owner and renter details
      const owner = await User.findByPk(rental.ownerId);
      const renter = await User.findByPk(rental.renterId);

      if (!owner || !renter) {
        console.error("Owner or renter not found for late return notification");
        return;
      }

      // Format dates
      const scheduledEnd = new Date(rental.endDateTime).toLocaleString();
      const actualReturn = new Date(
        rental.actualReturnDateTime
      ).toLocaleString();

      // Send email to customer service
      await this.sendTemplateEmail(
        process.env.CUSTOMER_SUPPORT_EMAIL,
        "Late Return Detected - Action Required",
        "lateReturnCS",
        {
          rentalId: rental.id,
          itemName: rental.item.name,
          ownerName: owner.name,
          ownerEmail: owner.email,
          renterName: renter.name,
          renterEmail: renter.email,
          scheduledEnd,
          actualReturn,
          hoursLate: lateCalculation.lateHours.toFixed(1),
          lateFee: lateCalculation.lateFee.toFixed(2),
        }
      );

      console.log(
        `Late return notification sent to customer service for rental ${rental.id}`
      );
    } catch (error) {
      console.error(
        "Failed to send late return notification to customer service:",
        error
      );
    }
  }

  async sendDamageReportToCustomerService(
    rental,
    damageAssessment,
    lateCalculation = null
  ) {
    try {
      // Get owner and renter details
      const owner = await User.findByPk(rental.ownerId);
      const renter = await User.findByPk(rental.renterId);

      if (!owner || !renter) {
        console.error(
          "Owner or renter not found for damage report notification"
        );
        return;
      }

      // Calculate total fees
      const damageFee = damageAssessment.feeCalculation.amount;
      const lateFee = lateCalculation?.lateFee || 0;
      const totalFees = damageFee + lateFee;

      // Determine fee type description
      let feeTypeDescription = "";
      if (damageAssessment.feeCalculation.type === "repair") {
        feeTypeDescription = "Repair Cost";
      } else if (damageAssessment.feeCalculation.type === "replacement") {
        feeTypeDescription = "Replacement Cost";
      } else {
        feeTypeDescription = "Damage Assessment Fee";
      }

      // Send email to customer service
      await this.sendTemplateEmail(
        process.env.CUSTOMER_SUPPORT_EMAIL,
        "Damage Report Filed - Action Required",
        "damageReportCS",
        {
          rentalId: rental.id,
          itemName: rental.item.name,
          ownerName: `${owner.firstName} ${owner.lastName}`,
          ownerEmail: owner.email,
          renterName: `${renter.firstName} ${renter.lastName}`,
          renterEmail: renter.email,
          damageDescription: damageAssessment.description,
          canBeFixed: damageAssessment.canBeFixed ? "Yes" : "No",
          repairCost: damageAssessment.repairCost
            ? damageAssessment.repairCost.toFixed(2)
            : "N/A",
          needsReplacement: damageAssessment.needsReplacement ? "Yes" : "No",
          replacementCost: damageAssessment.replacementCost
            ? damageAssessment.replacementCost.toFixed(2)
            : "N/A",
          feeTypeDescription,
          damageFee: damageFee.toFixed(2),
          lateFee: lateFee.toFixed(2),
          totalFees: totalFees.toFixed(2),
          hasProofOfOwnership:
            damageAssessment.proofOfOwnership &&
            damageAssessment.proofOfOwnership.length > 0
              ? "Yes"
              : "No",
        }
      );

      console.log(
        `Damage report notification sent to customer service for rental ${rental.id}`
      );
    } catch (error) {
      console.error(
        "Failed to send damage report notification to customer service:",
        error
      );
    }
  }

  async sendLostItemToCustomerService(rental) {
    try {
      // Get owner and renter details
      const owner = await User.findByPk(rental.ownerId);
      const renter = await User.findByPk(rental.renterId);

      if (!owner || !renter) {
        console.error("Owner or renter not found for lost item notification");
        return;
      }

      // Format dates
      const reportedAt = new Date(rental.itemLostReportedAt).toLocaleString();
      const scheduledReturnDate = new Date(rental.endDateTime).toLocaleString();

      // Send email to customer service
      await this.sendTemplateEmail(
        process.env.CUSTOMER_SUPPORT_EMAIL,
        "Lost Item Claim Filed - Action Required",
        "lostItemCS",
        {
          rentalId: rental.id,
          itemName: rental.item.name,
          ownerName: `${owner.firstName} ${owner.lastName}`,
          ownerEmail: owner.email,
          renterName: `${renter.firstName} ${renter.lastName}`,
          renterEmail: renter.email,
          reportedAt,
          scheduledReturnDate,
          replacementCost: parseFloat(rental.item.replacementCost).toFixed(2),
        }
      );

      console.log(
        `Lost item notification sent to customer service for rental ${rental.id}`
      );
    } catch (error) {
      console.error(
        "Failed to send lost item notification to customer service:",
        error
      );
    }
  }

  async sendRentalConfirmationEmails(rental) {
    const results = {
      ownerEmailSent: false,
      renterEmailSent: false,
    };

    try {
      // Get owner and renter details
      const owner = await User.findByPk(rental.ownerId, {
        attributes: ["email", "firstName"],
      });
      const renter = await User.findByPk(rental.renterId, {
        attributes: ["email", "firstName"],
      });

      // Create notification data for owner
      const ownerNotification = {
        type: "rental_confirmed",
        title: "Rental Confirmed",
        message: `Your "${rental.item.name}" has been confirmed for rental.`,
        rentalId: rental.id,
        userId: rental.ownerId,
        metadata: { rentalStart: rental.startDateTime },
      };

      // Create notification data for renter
      const renterNotification = {
        type: "rental_confirmed",
        title: "Rental Confirmed",
        message: `Your rental of "${rental.item.name}" has been confirmed.`,
        rentalId: rental.id,
        userId: rental.renterId,
        metadata: { rentalStart: rental.startDateTime },
      };

      // Send email to owner - independent error handling
      if (owner?.email) {
        try {
          const ownerResult = await this.sendRentalConfirmation(
            owner.email,
            ownerNotification,
            rental,
            owner.firstName
          );
          if (ownerResult.success) {
            console.log(
              `Rental confirmation email sent to owner: ${owner.email}`
            );
            results.ownerEmailSent = true;
          } else {
            console.error(
              `Failed to send rental confirmation email to owner (${owner.email}):`,
              ownerResult.error
            );
          }
        } catch (error) {
          console.error(
            `Failed to send rental confirmation email to owner (${owner.email}):`,
            error.message
          );
        }
      }

      // Send email to renter - independent error handling
      if (renter?.email) {
        try {
          const renterResult = await this.sendRentalConfirmation(
            renter.email,
            renterNotification,
            rental,
            renter.firstName
          );
          if (renterResult.success) {
            console.log(
              `Rental confirmation email sent to renter: ${renter.email}`
            );
            results.renterEmailSent = true;
          } else {
            console.error(
              `Failed to send rental confirmation email to renter (${renter.email}):`,
              renterResult.error
            );
          }
        } catch (error) {
          console.error(
            `Failed to send rental confirmation email to renter (${renter.email}):`,
            error.message
          );
        }
      }
    } catch (error) {
      console.error(
        "Error fetching user data for rental confirmation emails:",
        error
      );
    }

    return results;
  }
}

module.exports = new EmailService();