{
	"receiver": "feishu",
	"status": "resolved",
	"alerts": [{
		"status": "resolved",
		"labels": {
			"alertname": "Simple dummy streaming example",
			"grafana_folder": "test"
		},
		"annotations": {
			"description": "Test the large screen alarm"
		},
		"startsAt": "2023-01-12T14:46:00Z",
		"endsAt": "2023-01-12T15:07:00Z",
		"generatorURL": "http://localhost:3000/alerting/grafana/zgbSUF24z/view?orgId=1",
		"fingerprint": "09b095c0ac5a31bc",
		"silenceURL": "http://localhost:3000/alerting/silence/new?alertmanager=grafana\u0026matcher=alertname%3DSimple+dummy+streaming+example\u0026matcher=grafana_folder%3Dtest",
		"dashboardURL": "http://localhost:3000/d/TXSTREZ?orgId=1",
		"panelURL": "http://localhost:3000/d/TXSTREZ?orgId=1\u0026viewPanel=2",
		"values": null,
		"valueString": ""
	}],
	"groupLabels": {
		"alertname": "Simple dummy streaming example"
	},
	"commonLabels": {
		"alertname": "Simple dummy streaming example",
		"grafana_folder": "test"
	},
	"commonAnnotations": {
		"description": "Test the large screen alarm"
	},
	"externalURL": "http://localhost:3000/",
	"version": "1",
	"groupKey": "{}/{}:{alertname=\"Simple dummy streaming example\"}",
	"truncatedAlerts": 0,
	"orgId": 1,
	"title": "[RESOLVED] Simple dummy streaming example (test)",
	"state": "ok",
	"message": "**Resolved**\n\nValue: [no value]\nLabels:\n - alertname = Simple dummy streaming example\n - grafana_folder = test\nAnnotations:\n - description = Test the large screen alarm\nSource: http://localhost:3000/alerting/grafana/zgbSUF24z/view?orgId=1\nSilence: http://localhost:3000/alerting/silence/new?alertmanager=grafana\u0026matcher=alertname%3DSimple+dummy+streaming+example\u0026matcher=grafana_folder%3Dtest\nDashboard: http://localhost:3000/d/TXSTREZ?orgId=1\nPanel: http://localhost:3000/d/TXSTREZ?orgId=1\u0026viewPanel=2\n"
}

public interface AlarmMessage {

    /**
     * Send text alert
     * @param content
     */
    void sendData(String content);
}

@Service
public class FeiShuNotifier implements AlarmMessage {

	private static final String DEFAULT_MESSAGE = " Alert title:#{title} \n Alarm description:#{description} \n panel URL: #{panelUrl} \n Time of occurrence:#{startTime}";

	private final SpelExpressionParser parser = new SpelExpressionParser();

	@Value("${feishu.webhook-url}")
	private String webhookUrl;

	@Value("${feishu.secret}")
	private String secret;

	private Expression message = parser.parseExpression(DEFAULT_MESSAGE, ParserContext.TEMPLATE_EXPRESSION);

	private RestTemplate restTemplate = new RestTemplate();

	@Override
	public void sendData(String content) {
		Map<String, Object> message = createMessage(getText(content));
		HttpHeaders headers = new HttpHeaders();
		headers.setContentType(MediaType.APPLICATION_JSON);
		restTemplate.postForEntity(webhookUrl, new HttpEntity<>(message, headers), Void.class);
	}


	/**
	 * Build a notification message
	 * @param content
	 * @return
	 */
	protected Map<String, Object> createMessage(String content) {
		Map<String, Object> messageJson = new HashMap<>();
		messageJson.put("msg_type", "text");

		Map<String, Object> text = new HashMap<>();
		text.put("text", content);
		messageJson.put("content", text);
		Long timestamp = System.currentTimeMillis() / 1000;
		messageJson.put("timestamp", timestamp);
		messageJson.put("sign", getSign(timestamp));

		return messageJson;
	}

	/**
	 * Build text content
	 * @param body
	 * @return
	 */
	private String getText(String body) {
		JSONObject json = JSON.parseObject(body);
		Map<String, Object> root = new HashMap<>();
		root.put("title", json.getString("title"));
		root.put("description", json.getJSONObject("commonAnnotations").getString("description"));
		JSONObject alertObject = json.getJSONArray("alerts").getJSONObject(0);
		root.put("panelUrl", alertObject.getString("panelURL"));
		root.put("startTime", DateUtil.parseUTC(alertObject.getString("startsAt")).toString(TimeZone.getDefault()));
		StandardEvaluationContext context = new StandardEvaluationContext(root);
		context.addPropertyAccessor(new MapAccessor());
		return message.getValue(context, String.class);
	}

	private String getSign(Long timestamp) {
		try {
			String stringToSign = timestamp + "\n" + secret;
			Mac mac = Mac.getInstance("HmacSHA256");
			mac.init(new SecretKeySpec(stringToSign.getBytes(StandardCharsets.UTF_8), "HmacSHA256"));
			byte[] signData = mac.doFinal(new byte[]{});
			return new String(Base64.encodeBase64(signData, false));
		}
		catch (Exception ex) {
			ex.printStackTrace();
		}
		return "";
	}

}

@RestController
public class WebhookController {

    @Resource
    private FeiShuNotifier feiShuNotifier;

    @RequestMapping("/webhook/receive")
    public void receive(@RequestBody String message) {
        feiShuNotifier.sendData(message);
    }
}