/*
 * Copyright 1999-2015 dangdang.com.
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * </p>
 */

package io.elasticjob.cloud.scheduler.env;

import io.elasticjob.cloud.event.rdb.JobEventRdbConfiguration;
import io.elasticjob.cloud.reg.zookeeper.ZookeeperConfiguration;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import lombok.Getter;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.dbcp.BasicDataSource;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.Properties;

/**
 * 启动环境对象.
 *
 * @author zhangliang
 */
@Slf4j
public final class BootstrapEnvironment {
    
    @Getter
    private static BootstrapEnvironment instance = new BootstrapEnvironment();
    
    private static final String PROPERTIES_PATH = "conf/elastic-job-cloud-scheduler.properties";
    
    private final Properties properties;
    
    private BootstrapEnvironment() {
        properties = getProperties();
    }
    
    private Properties getProperties() {
        Properties result = new Properties();
        try (FileInputStream fileInputStream = new FileInputStream(PROPERTIES_PATH)) {
            result.load(fileInputStream);
        } catch (final IOException ex) {
            log.warn("Can not load properties file from path: '{}'.", PROPERTIES_PATH);
        }
        setPropertiesByEnv(result);
        return result;
    }
    
    private void setPropertiesByEnv(final Properties prop) {
        for (EnvironmentArgument each : EnvironmentArgument.values()) {
            String key = each.getKey();
            String value = System.getenv(key);
            if (!Strings.isNullOrEmpty(value)) {
                log.info("Load property {} with value {} from ENV.", key, value);
                prop.setProperty(each.getKey(), value);
            }
        }
    }
    
    /**
     * 获取Framework的Hostname和Port.
     *
     * @return Framework的Hostname和Port
     */
    public String getFrameworkHostPort() {
        return String.format("%s:%d", getMesosConfiguration().getHostname(), getRestfulServerConfiguration().getPort());
    }
    
    /**
     * 获取Mesos配置对象.
     *
     * @return Mesos配置对象
     */
    public MesosConfiguration getMesosConfiguration() {
        return new MesosConfiguration(getValue(EnvironmentArgument.USER), getValue(EnvironmentArgument.MESOS_URL), getValue(EnvironmentArgument.HOSTNAME));
    }
    
    /**
     * 获取Zookeeper配置对象.
     * 
     * @return Zookeeper配置对象
     */
    // TODO 其他zkConfig的值可配置
    public ZookeeperConfiguration getZookeeperConfiguration() {
        ZookeeperConfiguration result = new ZookeeperConfiguration(getValue(EnvironmentArgument.ZOOKEEPER_SERVERS), getValue(EnvironmentArgument.ZOOKEEPER_NAMESPACE));
        String digest = getValue(EnvironmentArgument.ZOOKEEPER_DIGEST);
        if (!Strings.isNullOrEmpty(digest)) {
            result.setDigest(digest);
        }
        return result;
    }
    
    /**
     * 获取Restful服务器配置对象.
     *
     * @return Restful服务器配置对象
     */
    public RestfulServerConfiguration getRestfulServerConfiguration() {
        return new RestfulServerConfiguration(Integer.parseInt(getValue(EnvironmentArgument.PORT)));
    }
    
    /**
     * 获取Mesos框架配置对象.
     *
     * @return Mesos框架配置对象
     */
    public FrameworkConfiguration getFrameworkConfiguration() {
        return new FrameworkConfiguration(Integer.parseInt(getValue(EnvironmentArgument.JOB_STATE_QUEUE_SIZE)), Integer.parseInt(getValue(EnvironmentArgument.RECONCILE_INTERVAL_MINUTES)));
    }
    
    /**
     * 获取作业数据库事件配置.
     *
     * @return 作业数据库事件配置
     */
    public Optional<JobEventRdbConfiguration> getJobEventRdbConfiguration() {
        String driver = getValue(EnvironmentArgument.EVENT_TRACE_RDB_DRIVER);
        String url = getValue(EnvironmentArgument.EVENT_TRACE_RDB_URL);
        String username = getValue(EnvironmentArgument.EVENT_TRACE_RDB_USERNAME);
        String password = getValue(EnvironmentArgument.EVENT_TRACE_RDB_PASSWORD);
        if (!Strings.isNullOrEmpty(driver) && !Strings.isNullOrEmpty(url) && !Strings.isNullOrEmpty(username)) {
            BasicDataSource dataSource = new BasicDataSource();
            dataSource.setDriverClassName(driver);
            dataSource.setUrl(url);
            dataSource.setUsername(username);
            dataSource.setPassword(password);
            return Optional.of(new JobEventRdbConfiguration(dataSource));
        }
        return Optional.absent();
    }
    
    /**
     * 获取作业数据库事件配置Map.
     *
     * @return 作业数据库事件配置Map
     */
    // CHECKSTYLE:OFF
    public HashMap<String, String> getJobEventRdbConfigurationMap() {
        HashMap<String, String> result = new HashMap<>(4, 1);
        // CHECKSTYLE:ON
        result.put(EnvironmentArgument.EVENT_TRACE_RDB_DRIVER.getKey(), getValue(EnvironmentArgument.EVENT_TRACE_RDB_DRIVER));
        result.put(EnvironmentArgument.EVENT_TRACE_RDB_URL.getKey(), getValue(EnvironmentArgument.EVENT_TRACE_RDB_URL));
        result.put(EnvironmentArgument.EVENT_TRACE_RDB_USERNAME.getKey(), getValue(EnvironmentArgument.EVENT_TRACE_RDB_USERNAME));
        result.put(EnvironmentArgument.EVENT_TRACE_RDB_PASSWORD.getKey(), getValue(EnvironmentArgument.EVENT_TRACE_RDB_PASSWORD));
        return result;
    }
    
    /**
     * 获取该framework的mesos角色.
     * 
     * @return 角色的可选值.
     */
    public Optional<String> getMesosRole() {
        String role = getValue(EnvironmentArgument.MESOS_ROLE);
        if (Strings.isNullOrEmpty(role)) {
            return Optional.absent();
        }
        return Optional.of(role);
    }
    
    private String getValue(final EnvironmentArgument environmentArgument) {
        String result = properties.getProperty(environmentArgument.getKey(), environmentArgument.getDefaultValue());
        if (environmentArgument.isRequired()) {
            Preconditions.checkState(!Strings.isNullOrEmpty(result), String.format("Property `%s` is required.", environmentArgument.getKey()));
        }
        return result;
    }
    
    /**
     * 环境参数.
     * 
     * @author zhangliang
     */
    @RequiredArgsConstructor
    @Getter
    public enum EnvironmentArgument {
        
        HOSTNAME("hostname", "localhost", true),
        
        MESOS_URL("mesos_url", "zk://localhost:2181/mesos", true),
        
        MESOS_ROLE("mesos_role", "", false),
        
        USER("user", "", false),
        
        ZOOKEEPER_SERVERS("zk_servers", "localhost:2181", true),
        
        ZOOKEEPER_NAMESPACE("zk_namespace", "elastic-job-cloud", true),
        
        ZOOKEEPER_DIGEST("zk_digest", "", false),
        
        PORT("http_port", "8899", true),
        
        JOB_STATE_QUEUE_SIZE("job_state_queue_size", "10000", true),
        
        EVENT_TRACE_RDB_DRIVER("event_trace_rdb_driver", "", false),

        EVENT_TRACE_RDB_URL("event_trace_rdb_url", "", false),

        EVENT_TRACE_RDB_USERNAME("event_trace_rdb_username", "", false),

        EVENT_TRACE_RDB_PASSWORD("event_trace_rdb_password", "", false),
    
        RECONCILE_INTERVAL_MINUTES("reconcile_interval_minutes", "-1", false);
        
        private final String key;
        
        private final String defaultValue;
        
        private final boolean required;
    }
}