/* -------------------------------------------------------------------------- */
/* Copyright 2002-2010, OpenNebula Project Leads (OpenNebula.org)             */
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/* 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                                                   */
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/* 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,          */
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/* See the License for the specific language governing permissions and        */
/* limitations under the License.                                             */
/* -------------------------------------------------------------------------- */

#ifndef VIRTUAL_MACHINE_POOL_H_
#define VIRTUAL_MACHINE_POOL_H_

#include "PoolSQL.h"
#include "VirtualMachine.h"

#include <time.h>

using namespace std;


/**
 *  The Virtual Machine Pool class. ...
 */
class VirtualMachinePool : public PoolSQL
{
public:

    VirtualMachinePool(SqliteDB * db, vector<const Attribute *> hook_mads);

    ~VirtualMachinePool(){};

    /**
     *  Function to allocate a new VM object
     *    @param uid user id (the owner of the VM)
     *    @param stemplate a string describing the VM
     *    @param oid the id assigned to the VM (output)
     *    @param on_hold flag to submit on hold
     *    @return 0 on success, -1 error inserting in DB or -2 error parsing
     *  the template
     */
    int allocate (
        int     uid,
        const  string& stemplate,
        int *  oid,
        bool   on_hold = false);

    /**
     *  Function to get a VM from the pool, if the object is not in memory
     *  it is loade from the DB
     *    @param oid VM unique id
     *    @param lock locks the VM mutex
     *    @return a pointer to the VM, 0 if the VM could not be loaded
     */
    VirtualMachine * get(
        int     oid,
        bool    lock)
    {
        return static_cast<VirtualMachine *>(PoolSQL::get(oid,lock));
    };

    /**
     *  Function to get the IDs of running VMs
     *   @param oids a vector that contains the IDs
     *   @return 0 on success
     */
    int get_running(
        vector<int>&    oids);

    /**
     *  Function to get the IDs of pending VMs
     *   @param oids a vector that contains the IDs
     *   @return 0 on success
     */
    int get_pending(
        vector<int>&    oids);

    //--------------------------------------------------------------------------
    // Virtual Machine DB access functions
    //--------------------------------------------------------------------------

    /**
     *  Updates the template of a VM, adding a new attribute (replacing it if
     *  already defined), the vm's mutex SHOULD be locked
     *    @param vm pointer to the virtual machine object
     *    @param name of the new attribute
     *    @param value of the new attribute
     *    @return 0 on success
     */
    int update_template_attribute(
        VirtualMachine *	vm,
        string&			 	name,
        string&			 	value)
    {
    	return vm->update_template_attribute(db,name,value);
    }

    /**
     *  Updates the history record of a VM, the vm's mutex SHOULD be locked
     *    @param vm pointer to the virtual machine object
     *    @return 0 on success
     */
    int update_history(
        VirtualMachine * vm)
    {
        return vm->update_history(db);
    }

    /**
     *  Updates the previous history record, the vm's mutex SHOULD be locked
     *    @param vm pointer to the virtual machine object
     *    @return 0 on success
     */
    int update_previous_history(
        VirtualMachine * vm)
    {
        return vm->update_previous_history(db);
    }

    /**
     *  Bootstraps the database table(s) associated to the VirtualMachine pool
     */
    static void bootstrap(SqliteDB * _db)
    {
        VirtualMachine::bootstrap(_db);
    };
    
    /**
     *  Dumps the VM pool in XML format. A filter can be also added to the query
     *  Also the hostname where the VirtualMachine is running is added to the
     *  pool
     *  @param oss the output stream to dump the pool contents
     *  @param where filter for the objects, defaults to all
     *
     *  @return 0 on success
     */
    int dump(ostringstream& oss, const string& where)
    {
        int rc;

        oss << "<VM_POOL>";

        rc = VirtualMachine::dump(db,oss,where);

        oss << "</VM_POOL>";
            
        return rc;
    }
    
private:
    /**
     *  Generate context file to be sourced upon VM booting
     *  @param vm_id, ID of the VM to generate context for
     *  @param attr, the template CONTEXT attribute (the first one)
     */
    void generate_context(int vm_id, Attribute * attr);

    /**
     *  Factory method to produce VM objects
     *    @return a pointer to the new VM
     */
    PoolObjectSQL * create()
    {
        return new VirtualMachine;
    };
};

#endif /*VIRTUAL_MACHINE_POOL_H_*/