/*

missileAI.js

Priority-based AI for missiles

Oolite
Copyright © 2004-2013 Giles C Williams and contributors

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

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 for more details.

You should have received a copy of the GNU 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.

*/

"use strict";

this.name = "Oolite Missile AI";

this.aiStarted = function() {
	var ai = new worldScripts["oolite-libPriorityAI"].PriorityAIController(this.ship);

	/* This is probably too effective for standard missile AI, but
	 * might be worth setting separately on ships that use missile
	 * swarms as their main weapon. It makes the missiles avoid each
	 * other a bit, so that the detonation of the first missile won't
	 * destroy the remainder. */
	// ai.setParameter("oolite_flag_autoSpreadMissiles",true);

	/* Launch correction when fired at target in aft arc */ 
	if (this.ship.target && this.ship.target.position.subtract(this.ship.position).direction().dot(this.ship.vectorForward) < -0.8)
	{
		this.oolite_priorityai.setParameter("oolite_flag_launchAdjustMissile",true);
	}

	// prevent deceleration on launch
	this.ship.desiredSpeed = this.ship.maxSpeed;

	ai.setPriorities([
		{
			condition: ai.conditionMissileOutOfFuel,
			behaviour: ai.behaviourMissileSelfDestruct
		},
		{
			preconfiguration: ai.configurationCheckScanner,
			condition: ai.conditionScannerContainsUnspreadMissile,
			configuration: ai.configurationMissileAdjustSpread,
			behaviour: ai.behaviourApproachDestination,
			reconsider: 2
		},
		{
			condition: ai.conditionMissileNeedsLaunchEvasion,
			configuration: ai.configurationMissileAdjustLaunch,
			behaviour: ai.behaviourApproachDestination,
			reconsider: 2
		},
		{
			condition: ai.conditionHasTarget,
			behaviour: ai.behaviourMissileInterceptTarget,
			reconsider: 5
		},
		/* If target cloaks, go to last known location */
		{
			condition: ai.conditionHasInterceptCoordinates,
			behaviour: ai.behaviourMissileInterceptCoordinates,
			reconsider: 1
		},
		/* Target lost. Self-destruct */
		{
			behaviour: ai.behaviourMissileSelfDestruct
		}
	]);
}


/* ECM response function */
this._ecmProofMissileResponse = function()
{
	if (Math.random() < 0.1) //10% chance per pulse
	{
		if (Math.random() < 0.5)
		{
			// 50% chance responds by detonation
			this.ship.AIScript.shipAchievedDesiredRange();
			return;
		}
		// otherwise explode as normal below
	}
	else // 90% chance unaffected
	{
		return;
	}	
	this.ship.explode();
}

