package zw.qantra.tm.domain.services;

import lombok.RequiredArgsConstructor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.io.ClassPathResource;
import org.springframework.http.HttpHeaders;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

import jakarta.mail.internet.MimeMessage;
import zw.qantra.tm.domain.dtos.sms.SmsApiResponse;
import zw.qantra.tm.domain.dtos.sms.SmsBatchRequest;
import zw.qantra.tm.domain.dtos.sms.SmsMessage;
import zw.qantra.tm.rest.RestService;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.Collections;
import java.util.UUID;
import java.util.stream.Collectors;

@Service
@RequiredArgsConstructor
public class NotificationService {
    private static final Logger logger = LoggerFactory.getLogger(NotificationService.class);

    private final RestService restService;
    private final JavaMailSender emailSender;

    @Value("${zss.sms.api.url}")
    private String smsApiUrl;
    @Value("${zss.sms.api.auth}")
    private String smsApiAuth;
    @Value("${sms.debug}")
    private Boolean smsDebug;

    @Async
    public void sendEmail(String to, String subject, String text) {
        sendEmailWithHtml(to, subject, text, null);
    }

    @Async
    public void sendEmailWithHtml(String to, String subject, String htmlContent) {
        sendEmailWithHtml(to, subject, null, htmlContent);
    }

    @Async
    public void sendEmailWithHtml(String to, String subject, String text, String htmlContent) {
        try {
            MimeMessage message = emailSender.createMimeMessage();
            MimeMessageHelper helper = new MimeMessageHelper(message, true, "UTF-8");
            helper.setFrom("noreply@qantra.co.zw");
            helper.setTo(to);
            helper.setSubject(subject);

            if (htmlContent != null) {
                helper.setText(text != null ? text : "", htmlContent);
            } else if (text != null) {
                helper.setText(text);
            }

            emailSender.send(message);
            logger.info("Email sent to {} - Subject: {}", to, subject);
        } catch (Exception e) {
            logger.error("Failed to send email to {}: {}", to, e.getMessage(), e);
        }
    }

    @Async
    public void sendOtpEmail(String to, String username, String otpCode) {
        try {
            // Load and populate the HTML template
            ClassPathResource resource = new ClassPathResource("templates/email-otp.html");
            String htmlTemplate;
            try (BufferedReader reader = new BufferedReader(
                    new InputStreamReader(resource.getInputStream(), StandardCharsets.UTF_8))) {
                htmlTemplate = reader.lines().collect(Collectors.joining("\n"));
            }

            // Simple placeholder replacement
            String htmlContent = htmlTemplate
                    .replace("{{username}}", username != null ? username : "")
                    .replace("{{otpCode}}", otpCode != null ? otpCode : "");

            MimeMessage message = emailSender.createMimeMessage();
            MimeMessageHelper helper = new MimeMessageHelper(message, true, "UTF-8");
            helper.setFrom("noreply@qantra.co.zw");
            helper.setTo(to);
            helper.setSubject("Velocity Pay verification code");
            helper.setText("Your Velocity Pay verification code is: " + otpCode, htmlContent);

            emailSender.send(message);
            logger.info("OTP email sent to {} for user: {}", to, username);
        } catch (Exception e) {
            logger.error("Failed to send OTP email to {}: {}", to, e.getMessage(), e);
        }
    }

    @Async
    public void sendSms(String to, String message) {
        if(smsDebug) {
            logger.info("Sending SMS to {}: {}", to, message);
            return;
        }
        try {
            SmsMessage smsMessage = SmsMessage.builder()
                    .reference(UUID.randomUUID().toString())
                    .message(message)
                    .msisdn(to)
                    .build();

            SmsBatchRequest batchRequest = SmsBatchRequest.builder()
                    .batchReference(UUID.randomUUID().toString())
                    .smsList(Collections.singletonList(smsMessage))
                    .build();

            HttpHeaders headers = new HttpHeaders();
            headers.set("Authorization", smsApiAuth);

            SmsApiResponse response = restService.postWithExternalAuth(
                    smsApiUrl,
                    batchRequest,
                    headers,
                    SmsApiResponse.class
            );

            logger.info("SMS sent to {} - Status: {}, Result: {}", to, response.getStatus(), response.getResult());
        } catch (Exception e) {
            logger.error("Failed to send SMS to {}: {}", to, e.getMessage(), e);
        }
    }
}