/*
 * This file is part of ComputerCraft - http://www.computercraft.info
 * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
 * Send enquiries to dratcliffe@gmail.com
 */
package dan200.computercraft.core.lua;

import dan200.computercraft.ComputerCraft;
import dan200.computercraft.api.lua.ILuaContext;
import dan200.computercraft.api.lua.ILuaTask;
import dan200.computercraft.api.lua.LuaException;
import dan200.computercraft.core.computer.Computer;
import dan200.computercraft.core.computer.MainThread;

import javax.annotation.Nonnull;

class LuaContext implements ILuaContext
{
    private final Computer computer;

    LuaContext( Computer computer )
    {
        this.computer = computer;
    }

    @Override
    public long issueMainThreadTask( @Nonnull final ILuaTask task ) throws LuaException
    {
        // Issue command
        final long taskID = MainThread.getUniqueTaskID();
        final Runnable iTask = () -> {
            try
            {
                Object[] results = task.execute();
                if( results != null )
                {
                    Object[] eventArguments = new Object[results.length + 2];
                    eventArguments[0] = taskID;
                    eventArguments[1] = true;
                    System.arraycopy( results, 0, eventArguments, 2, results.length );
                    computer.queueEvent( "task_complete", eventArguments );
                }
                else
                {
                    computer.queueEvent( "task_complete", new Object[] { taskID, true } );
                }
            }
            catch( LuaException e )
            {
                computer.queueEvent( "task_complete", new Object[] { taskID, false, e.getMessage() } );
            }
            catch( Exception t )
            {
                if( ComputerCraft.logComputerErrors ) ComputerCraft.log.error( "Error running task", t );
                computer.queueEvent( "task_complete", new Object[] {
                    taskID, false, "Java Exception Thrown: " + t,
                } );
            }
        };
        if( computer.queueMainThread( iTask ) )
        {
            return taskID;
        }
        else
        {
            throw new LuaException( "Task limit exceeded" );
        }
    }
}