/*
 * RHQ Management Platform
 * Copyright (C) 2005-2008 Red Hat, Inc.
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation, and/or the GNU Lesser
 * General Public License, version 2.1, also as published by the Free
 * Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License and the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * and the GNU Lesser General Public License along with this program;
 * if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
package org.rhq.core.domain.resource.group;

import java.io.Serializable;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.OneToMany;
import javax.persistence.PrePersist;
import javax.persistence.PreUpdate;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;

import org.rhq.core.domain.util.StringUtils;

@Entity
@NamedQueries( {
    @NamedQuery(name = GroupDefinition.QUERY_FIND_ALL, query = "" //
        + "SELECT gd " //
        + "  FROM GroupDefinition AS gd "), //
    @NamedQuery(name = GroupDefinition.QUERY_FIND_BY_NAME, query = "" //
        + "SELECT gd " //
        + "  FROM GroupDefinition AS gd " //
        + " WHERE LOWER(gd.name) = LOWER(:name)"), //
    @NamedQuery(name = GroupDefinition.QUERY_FIND_ALL_MEMBERS, query = "" //
        + "SELECT rg " //
        + "  FROM ResourceGroup rg " //
        + " WHERE rg.groupDefinition IS NOT NULL "), //
    @NamedQuery(name = GroupDefinition.QUERY_FIND_MANAGED_RESOURCE_GROUP_IDS_ADMIN, query = "" //
        + "SELECT rg.id " //
        + "  FROM ResourceGroup rg " //
        + " WHERE rg.groupDefinition.id = :groupDefinitionId "),
    @NamedQuery(name = GroupDefinition.QUERY_FIND_MANAGED_RESOURCE_GROUP_SIZE_ADMIN, query = "" //
        + "SELECT COUNT(rg.id) " //
        + "  FROM ResourceGroup rg " //
        + " WHERE rg.groupDefinition.id = :groupDefinitionId "),
    /*
     * the next recalculation interval is defined as:
     * 
     * 1) never, if the interval is 0, or at
     * 2) recalculationInterval + lastCalculationTime, if lastCalculationTime is NOT 0 (i.e. the group has been calculated at least once before), or at
     * 3) modifiedTime + lastCalculationTime, if the group has never been calculated once yet
     */
    @NamedQuery(name = GroupDefinition.QUERY_FIND_IDS_FOR_RECALCULATION, query = "" //
        + " SELECT gd.id " //
        + "   FROM GroupDefinition gd " //
        + "  WHERE gd.recalculationInterval != 0 " //
        + "    AND ( ( gd.lastCalculationTime IS NOT NULL " //
        + "            AND ( gd.lastCalculationTime + gd.recalculationInterval < :now ) ) " //
        + "          OR " //
        + "          ( gd.lastCalculationTime IS NULL " //
        + "            AND ( gd.modifiedTime + gd.recalculationInterval < :now ) ) ) "), //
    @NamedQuery(name = GroupDefinition.QUERY_FIND_ALL_RECALCULATING, query = "" //
        + "SELECT gd " //
        + "  FROM GroupDefinition AS gd " //
        + " WHERE gd.recalculationInterval != 0 ") })
@SequenceGenerator(name = "id", sequenceName = "RHQ_GROUP_DEF_ID_SEQ")
@Table(name = "RHQ_GROUP_DEF")
public class GroupDefinition implements Serializable {
    private static final long serialVersionUID = 1L;

    public static final String QUERY_FIND_ALL = "GroupDefinition.findAll";
    public static final String QUERY_FIND_BY_NAME = "GroupDefinition.findByName";
    public static final String QUERY_FIND_MEMBERS = "GroupDefinition.findMembers";
    public static final String QUERY_FIND_ALL_MEMBERS = "GroupDefinition.findAllMembers_admin";
    public static final String QUERY_FIND_MANAGED_RESOURCE_GROUP_IDS_ADMIN = "GroupDefinition.findManagedResourceGroupIds_admin";
    public static final String QUERY_FIND_MANAGED_RESOURCE_GROUP_SIZE_ADMIN = "GroupDefinition.findManagedResourceGroupSize_admin";
    public static final String QUERY_FIND_IDS_FOR_RECALCULATION = "GroupDefinition.findIdsForRecalculation_admin";
    public static final String QUERY_FIND_ALL_RECALCULATING = "GroupDefinition.findAllRecalculating_admin";

    @Column(name = "ID", nullable = false)
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "id")
    @Id
    private int id;

    @Column(name = "NAME", nullable = false)
    private String name;

    @Column(name = "DESCRIPTION")
    private String description;

    @Column(name = "RECURSIVE")
    private boolean recursive;

    @Column(name = "CTIME")
    private Long createdTime;

    @Column(name = "MTIME")
    private Long modifiedTime;

    @Column(name = "CALC_TIME")
    private Long lastCalculationTime;

    @Column(name = "CALC_INTERVAL")
    private long recalculationInterval;

    @Column(name = "EXPRESSION")
    private String expression;

    @OneToMany(mappedBy = "groupDefinition", cascade = { CascadeType.PERSIST })
    private Set<ResourceGroup> managedResourceGroups;

    /* no-arg constructor required by EJB spec */
    protected GroupDefinition() {
    }

    public GroupDefinition(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "GroupDefinition" + "[" + "id=" + getId() + ", " + "name=" + getName() + "]";
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public boolean isRecursive() {
        return recursive;
    }

    public void setRecursive(boolean recursive) {
        this.recursive = recursive;
    }

    public Long getCreatedTime() {
        return createdTime;
    }

    public void setCreatedTime(Long ctime) {
        this.createdTime = ctime;
    }

    public Long getModifiedTime() {
        return modifiedTime;
    }

    public void setModifiedTime(Long mtime) {
        this.modifiedTime = mtime;
    }

    @PrePersist
    void onPersist() {
        this.modifiedTime = this.createdTime = System.currentTimeMillis();
    }

    @PreUpdate
    void onUpdate() {
        this.modifiedTime = System.currentTimeMillis();
    }

    public Long getLastCalculationTime() {
        return lastCalculationTime;
    }

    public void setLastCalculationTime(Long lastCalculationTime) {
        this.lastCalculationTime = lastCalculationTime;
    }

    public Long getRecalculationInterval() {
        return recalculationInterval;
    }

    public void setRecalculationInterval(Long recalculationInterval) {
        this.recalculationInterval = recalculationInterval;
    }

    public Long getNextCalculationTime() {
        if (getRecalculationInterval() == 0) {
            return 0L; // never recalculate
        } else {
            if (getLastCalculationTime() != null) {
                return getLastCalculationTime() + getRecalculationInterval();
            } else {
                // interval millis after the user saves the changes to the group, to prevent flooding
                return getModifiedTime() + getRecalculationInterval();
            }
        }
    }

    public String getExpression() {
        return expression;
    }

    public List<String> getExpressionAsList() {
        /*
         * should never be empty tokens, but if we return all tokens now (including empty ones) the business logic
         * should remove the empty tokens when the user saves this definition
         */
        return StringUtils.getStringAsList(expression, "\n", false);
    }

    public void setExpression(String expression) {
        this.expression = expression;
    }

    public Set<ResourceGroup> getManagedResourceGroups() {
        return managedResourceGroups;
    }

    public void addResourceGroup(ResourceGroup resourceGroup) {
        if (this.managedResourceGroups == null) {
            this.managedResourceGroups = new HashSet<ResourceGroup>();
        }

        this.managedResourceGroups.add(resourceGroup);

        resourceGroup.setGroupDefinition(this);
    }

    public void removeResourceGroup(ResourceGroup resourceGroup) {
        if (this.managedResourceGroups == null) {
            return;
        }

        this.managedResourceGroups.remove(resourceGroup);

        resourceGroup.setGroupDefinition(null);
    }

    public void setManagedResourceGroups(Set<ResourceGroup> managedResourceGroups) {
        this.managedResourceGroups = managedResourceGroups;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = (prime * result) + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }

        if ((obj == null) || (!(obj instanceof GroupDefinition))) {
            return false;
        }

        final GroupDefinition other = (GroupDefinition) obj;

        if (name == null) {
            if (other.name != null) {
                return false;
            }
        } else if (!name.equals(other.name)) {
            return false;
        }

        return true;
    }
}