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using XenAdmin.Diagnostics.Problems;
using XenAdmin.Diagnostics.Problems.VMProblem;
using XenAPI;


namespace XenAdmin.Diagnostics.Checks.DR
{
    public class ExistingVmCheck: PoolCheck
    {
        private readonly VM Vm;

        /// <summary>
        /// Check if the specified VM exists and is running on specified pool.
        /// </summary>
        /// <param name="vm">the VM for which to check the running state</param>
        /// <param name="pool">the pool on which to check if the specified VM exists and is running</param>
        public ExistingVmCheck(VM vm, Pool pool)
            : base (pool)
        {
            Vm = vm;
        }

        protected override Problem RunCheck()
        {
            foreach (VM existingVm in Pool.Connection.Cache.VMs)
            {
                if (existingVm.uuid == Vm.uuid)
                {
                    // if the existing VM's version is >= the version in the metadata import, then the used must destroy the VM first 
                    if (existingVm.version >= Vm.version)
                        return new ExistingVmProblem(this, existingVm);
                    
                    // if the existing VM is currently running, then the user must force shutdown this VM first
                    if (VmIsRunning(existingVm))
                        return new RunningVMProblem(this, existingVm, true);
                
                    // warn the user that the existing VM will be replaced 
                    return new ExistingVmWarning(this, existingVm);
                }
            }
            return null;
        }

        private bool VmIsRunning(VM vm)
        {
            return vm.power_state == vm_power_state.Running
                    || vm.power_state == vm_power_state.Paused
                    || vm.power_state == vm_power_state.Suspended;
        }

        public override string Description
        {
            get
            {
                return string.Format(Messages.DR_WIZARD_VM_CHECK_DESCRIPTION, Vm.Name());
            }
        }
    }
}
