/*
 * Copyright 2012-2019 the original author or authors.
 *
 * 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
 *
 *      https://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.
 */

package org.springframework.boot.actuate.health;

import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.Map;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonInclude.Include;

import org.springframework.util.Assert;

Carries information about the health of a component or subsystem. Extends HealthComponent so that additional contextual details about the system can be returned along with the Status. 
 Health instances can be created by using Builder's fluent API. Typical usage in a HealthIndicator would be: 
try {
	// do some test to determine state of component
	return Health.up().withDetail("version", "1.1.2").build();
}
catch (Exception ex) {
	return Health.down(ex).build();
}

Author:
Christian Dupuis, Phillip Webb, Michael Pratt
Since:
1.1.0/**
 * Carries information about the health of a component or subsystem. Extends
 * {@link HealthComponent} so that additional contextual details about the system can be
 * returned along with the {@link Status}.
 * <p>
 * {@link Health} instances can be created by using {@link Builder}'s fluent API. Typical
 * usage in a {@link HealthIndicator} would be:
 *
 * <pre class="code">
 * try {
 * 	// do some test to determine state of component
 * 	return Health.up().withDetail("version", "1.1.2").build();
 * }
 * catch (Exception ex) {
 * 	return Health.down(ex).build();
 * }
 * </pre>
 *
 * @author Christian Dupuis
 * @author Phillip Webb
 * @author Michael Pratt
 * @since 1.1.0
 */
@JsonInclude(Include.NON_EMPTY)
public final class Health extends HealthComponent {

	private final Status status;

	private final Map<String, Object> details;

	
Create a new Health instance with the specified status and details. 
Params:
builder – the Builder to use/**
	 * Create a new {@link Health} instance with the specified status and details.
	 * @param builder the Builder to use
	 */
	private Health(Builder builder) {
		Assert.notNull(builder, "Builder must not be null");
		this.status = builder.status;
		this.details = Collections.unmodifiableMap(builder.details);
	}

	Health(Status status, Map<String, Object> details) {
		this.status = status;
		this.details = details;
	}

	
Return the status of the health.
Returns:
the status (never null)/**
	 * Return the status of the health.
	 * @return the status (never {@code null})
	 */
	@Override
	public Status getStatus() {
		return this.status;
	}

	
Return the details of the health.
Returns:
the details (or an empty map)/**
	 * Return the details of the health.
	 * @return the details (or an empty map)
	 */
	@JsonInclude(Include.NON_EMPTY)
	public Map<String, Object> getDetails() {
		return this.details;
	}

	
Return a new instance of this Health with all details removed. 
Returns:
a new instance without details
Since:
2.2.0/**
	 * Return a new instance of this {@link Health} with all {@link #getDetails() details}
	 * removed.
	 * @return a new instance without details
	 * @since 2.2.0
	 */
	Health withoutDetails() {
		if (this.details.isEmpty()) {
			return this;
		}
		return status(getStatus()).build();
	}

	@Override
	public boolean equals(Object obj) {
		if (obj == this) {
			return true;
		}
		if (obj instanceof Health) {
			Health other = (Health) obj;
			return this.status.equals(other.status) && this.details.equals(other.details);
		}
		return false;
	}

	@Override
	public int hashCode() {
		int hashCode = this.status.hashCode();
		return 13 * hashCode + this.details.hashCode();
	}

	@Override
	public String toString() {
		return getStatus() + " " + getDetails();
	}

	
Create a new Builder instance with an Status.UNKNOWN status. 
Returns:
a new Builder instance/**
	 * Create a new {@link Builder} instance with an {@link Status#UNKNOWN} status.
	 * @return a new {@link Builder} instance
	 */
	public static Builder unknown() {
		return status(Status.UNKNOWN);
	}

	
Create a new Builder instance with an Status.UP status. 
Returns:
a new Builder instance/**
	 * Create a new {@link Builder} instance with an {@link Status#UP} status.
	 * @return a new {@link Builder} instance
	 */
	public static Builder up() {
		return status(Status.UP);
	}

	
Create a new Builder instance with an Status.DOWN status and the specified exception details. 
Params:
ex – the exception
Returns:
a new Builder instance/**
	 * Create a new {@link Builder} instance with an {@link Status#DOWN} status and the
	 * specified exception details.
	 * @param ex the exception
	 * @return a new {@link Builder} instance
	 */
	public static Builder down(Exception ex) {
		return down().withException(ex);
	}

	
Create a new Builder instance with a Status.DOWN status. 
Returns:
a new Builder instance/**
	 * Create a new {@link Builder} instance with a {@link Status#DOWN} status.
	 * @return a new {@link Builder} instance
	 */
	public static Builder down() {
		return status(Status.DOWN);
	}

	
Create a new Builder instance with an Status.OUT_OF_SERVICE status. 
Returns:
a new Builder instance/**
	 * Create a new {@link Builder} instance with an {@link Status#OUT_OF_SERVICE} status.
	 * @return a new {@link Builder} instance
	 */
	public static Builder outOfService() {
		return status(Status.OUT_OF_SERVICE);
	}

	
Create a new Builder instance with a specific status code. 
Params:
statusCode – the status code
Returns:
a new Builder instance/**
	 * Create a new {@link Builder} instance with a specific status code.
	 * @param statusCode the status code
	 * @return a new {@link Builder} instance
	 */
	public static Builder status(String statusCode) {
		return status(new Status(statusCode));
	}

	
Create a new Builder instance with a specific Status. 
Params:
status – the status
Returns:
a new Builder instance/**
	 * Create a new {@link Builder} instance with a specific {@link Status}.
	 * @param status the status
	 * @return a new {@link Builder} instance
	 */
	public static Builder status(Status status) {
		return new Builder(status);
	}

	
Builder for creating immutable Health instances. /**
	 * Builder for creating immutable {@link Health} instances.
	 */
	public static class Builder {

		private Status status;

		private Map<String, Object> details;

		
Create new Builder instance.
/**
		 * Create new Builder instance.
		 */
		public Builder() {
			this.status = Status.UNKNOWN;
			this.details = new LinkedHashMap<>();
		}

		
Create new Builder instance, setting status to given status. 
Params:
status – the Status to use/**
		 * Create new Builder instance, setting status to given {@code status}.
		 * @param status the {@link Status} to use
		 */
		public Builder(Status status) {
			Assert.notNull(status, "Status must not be null");
			this.status = status;
			this.details = new LinkedHashMap<>();
		}

		
Create new Builder instance, setting status to given status and details to given details. 
Params:
status – the Status to use
details – the details Map to use/**
		 * Create new Builder instance, setting status to given {@code status} and details
		 * to given {@code details}.
		 * @param status the {@link Status} to use
		 * @param details the details {@link Map} to use
		 */
		public Builder(Status status, Map<String, ?> details) {
			Assert.notNull(status, "Status must not be null");
			Assert.notNull(details, "Details must not be null");
			this.status = status;
			this.details = new LinkedHashMap<>(details);
		}

		
Record detail for given Exception. 
Params:
ex – the exception
Returns:
this Builder instance/**
		 * Record detail for given {@link Exception}.
		 * @param ex the exception
		 * @return this {@link Builder} instance
		 */
		public Builder withException(Throwable ex) {
			Assert.notNull(ex, "Exception must not be null");
			return withDetail("error", ex.getClass().getName() + ": " + ex.getMessage());
		}

		
Record detail using given key and value. 
Params:
key – the detail key
value – the detail value
Returns:
this Builder instance/**
		 * Record detail using given {@code key} and {@code value}.
		 * @param key the detail key
		 * @param value the detail value
		 * @return this {@link Builder} instance
		 */
		public Builder withDetail(String key, Object value) {
			Assert.notNull(key, "Key must not be null");
			Assert.notNull(value, "Value must not be null");
			this.details.put(key, value);
			return this;
		}

		
Record details from the given details map. Keys from the given map replace any existing keys if there are duplicates. 
Params:
details – map of details
Returns:
this Builder instance
Since:
2.1.0/**
		 * Record details from the given {@code details} map. Keys from the given map
		 * replace any existing keys if there are duplicates.
		 * @param details map of details
		 * @return this {@link Builder} instance
		 * @since 2.1.0
		 */
		public Builder withDetails(Map<String, ?> details) {
			Assert.notNull(details, "Details must not be null");
			this.details.putAll(details);
			return this;
		}

		
Set status to Status.UNKNOWN status. 
Returns:
this Builder instance/**
		 * Set status to {@link Status#UNKNOWN} status.
		 * @return this {@link Builder} instance
		 */
		public Builder unknown() {
			return status(Status.UNKNOWN);
		}

		
Set status to Status.UP status. 
Returns:
this Builder instance/**
		 * Set status to {@link Status#UP} status.
		 * @return this {@link Builder} instance
		 */
		public Builder up() {
			return status(Status.UP);
		}

		
Set status to Status.DOWN and add details for given Throwable. 
Params:
ex – the exception
Returns:
this Builder instance/**
		 * Set status to {@link Status#DOWN} and add details for given {@link Throwable}.
		 * @param ex the exception
		 * @return this {@link Builder} instance
		 */
		public Builder down(Throwable ex) {
			return down().withException(ex);
		}

		
Set status to Status.DOWN. 
Returns:
this Builder instance/**
		 * Set status to {@link Status#DOWN}.
		 * @return this {@link Builder} instance
		 */
		public Builder down() {
			return status(Status.DOWN);
		}

		
Set status to Status.OUT_OF_SERVICE. 
Returns:
this Builder instance/**
		 * Set status to {@link Status#OUT_OF_SERVICE}.
		 * @return this {@link Builder} instance
		 */
		public Builder outOfService() {
			return status(Status.OUT_OF_SERVICE);
		}

		
Set status to given statusCode. 
Params:
statusCode – the status code
Returns:
this Builder instance/**
		 * Set status to given {@code statusCode}.
		 * @param statusCode the status code
		 * @return this {@link Builder} instance
		 */
		public Builder status(String statusCode) {
			return status(new Status(statusCode));
		}

		
Set status to given Status instance. 
Params:
status – the status
Returns:
this Builder instance/**
		 * Set status to given {@link Status} instance.
		 * @param status the status
		 * @return this {@link Builder} instance
		 */
		public Builder status(Status status) {
			this.status = status;
			return this;
		}

		
Create a new Health instance with the previously specified code and details. 
Returns:
a new Health instance/**
		 * Create a new {@link Health} instance with the previously specified code and
		 * details.
		 * @return a new {@link Health} instance
		 */
		public Health build() {
			return new Health(this);
		}

	}

}