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package io.mstream.trader.commons.config;


import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import io.mstream.trader.commons.config.schema.SchemaValidator;
import org.slf4j.Logger;

import javax.inject.Inject;
import java.util.Optional;

import static org.slf4j.LoggerFactory.getLogger;


public class ConfigClient {
    
    private static final Logger LOGGER = getLogger(ConfigClient.class);
    
    private final CuratorFrameworkSupplier curatorSupplier;
    
    private final ObjectMapper mapper;
    
    private final SchemaValidator schemaValidator;
    
    @Inject
    public ConfigClient(
            CuratorFrameworkSupplier curatorSupplier,
            ObjectMapper mapper,
            SchemaValidator schemaValidator
    ) {
    
        this.curatorSupplier = curatorSupplier;
        this.mapper = mapper;
        this.schemaValidator = schemaValidator;
    }
    
    public  Optional read(Class configType) {
        
        try {
            byte[] configBytes = curatorSupplier
                    .get()
                    .getData()
                    .forPath("/");
            
            if (LOGGER.isDebugEnabled()) {
                LOGGER.debug("fetched config: {}", new String(configBytes));
            }
            JsonNode configNode = mapper.readTree(configBytes);
            
            boolean schemaCompliant = schemaValidator.test(configNode);
            
            if (!schemaCompliant) {
                throw new IllegalStateException(
                        "fetched config is not compliant with the config schema"
                );
            }
            
            T config = mapper.treeToValue(configNode, configType);
            return Optional.of(config);
            
        } catch (Exception e) {
            
            String configPath =
                    curatorSupplier
                            .get()
                            .getNamespace();
            
            LOGGER.error(
                    "could not read the config from path: " + configPath,
                    e
            );
            
            return Optional.empty();
        }
    }
}