package com.rit.whatsapp.service;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

import java.util.HashMap;
import java.util.Map;

@Service
public class WhatsAppMessageService {

    @Value("${whatsapp.api-token}")
    private String apiToken;

    @Value("${whatsapp.phone-number-id}")
    private String phoneNumberId;

    private final RestTemplate restTemplate;

    public WhatsAppMessageService() {
        this.restTemplate = new RestTemplate();
    }

    public void sendMessage(String toPhoneNumber, String messageText) {
        Map<String, Object> payload = new HashMap<>();
        payload.put("messaging_product", "whatsapp");
        payload.put("to", toPhoneNumber);
        payload.put("type", "text");

        Map<String, String> textPayload = new HashMap<>();
        textPayload.put("body", messageText);
        payload.put("text", textPayload);
        
        executePost(payload);
    }

    public void sendInteractiveMessage(String toPhoneNumber, Map<String, Object> interactiveObject) {
        Map<String, Object> payload = new HashMap<>();
        payload.put("messaging_product", "whatsapp");
        payload.put("to", toPhoneNumber);
        payload.put("type", "interactive");
        payload.put("interactive", interactiveObject);

        executePost(payload);
    }

    private void executePost(Map<String, Object> payload) {
        String cleanPhoneId = phoneNumberId != null ? phoneNumberId.trim() : "";
        String cleanToken = apiToken != null ? apiToken.trim() : "";

        String url = "https://graph.facebook.com/v19.0/" + cleanPhoneId + "/messages";

        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);
        headers.setBearerAuth(cleanToken);

        HttpEntity<Map<String, Object>> request = new HttpEntity<>(payload, headers);

        try {
            ResponseEntity<String> response = restTemplate.postForEntity(url, request, String.class);
            System.out.println("Message successfully delivered to WhatsApp.");
        } catch (Exception e) {
            System.err.println("Failed to send message: " + e.getMessage());
        }
    }

    public String uploadMedia(byte[] fileData, String fileName, String mimeType) {
        String cleanPhoneId = phoneNumberId != null ? phoneNumberId.trim() : "";
        String cleanToken = apiToken != null ? apiToken.trim() : "";
        String url = "https://graph.facebook.com/v19.0/" + cleanPhoneId + "/media";

        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.MULTIPART_FORM_DATA);
        headers.setBearerAuth(cleanToken);

        org.springframework.util.MultiValueMap<String, Object> body = new org.springframework.util.LinkedMultiValueMap<>();
        body.add("messaging_product", "whatsapp");
        body.add("file", new org.springframework.core.io.ByteArrayResource(fileData) {
            @Override
            public String getFilename() {
                return fileName;
            }
        });
        body.add("type", mimeType);

        HttpEntity<org.springframework.util.MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(body, headers);

        try {
            ResponseEntity<String> response = restTemplate.postForEntity(url, requestEntity, String.class);
            com.fasterxml.jackson.databind.JsonNode root = new com.fasterxml.jackson.databind.ObjectMapper().readTree(response.getBody());
            return root.get("id").asText();
        } catch (Exception e) {
            System.err.println("Media upload failed: " + e.getMessage());
            return null;
        }
    }

    public void sendDocumentMessage(String toPhoneNumber, String mediaId, String caption, String filename) {
        Map<String, Object> payload = new HashMap<>();
        payload.put("messaging_product", "whatsapp");
        payload.put("to", toPhoneNumber);
        payload.put("type", "document");

        Map<String, Object> doc = new HashMap<>();
        doc.put("id", mediaId);
        if (caption != null && !caption.isEmpty()) doc.put("caption", caption);
        if (filename != null && !filename.isEmpty()) doc.put("filename", filename);
        
        payload.put("document", doc);
        
        executePost(payload);
    }
}