module TK.SpaceTac {
    /**
     * Get the proportional effect done to a ship's health (in -1,1 range)
     */
    function getHealthDiffShip(plan: AIPlan, ship: Ship): number {
        let chull = ship.getAttribute("hull_capacity");
        let cshield = ship.getAttribute("shield_capacity");
        let hull = ship.getValue("hull")
        let shield = ship.getValue("shield");
        let dhull = 0;
        let dshield = 0;

        plan.effects.forEach(diff => {
            if (diff instanceof ShipValueDiff) {
                if (ship.is(diff.ship_id)) {
                    if (diff.code == "hull") {
                        dhull += clamp(hull + diff.diff, 0, chull) - hull;
                    } else if (diff.code == "shield") {
                        dshield += clamp(shield + diff.diff, 0, cshield) - shield;
                    }
                }
            }
        });

        if (hull + dhull <= 0) {
            return -1;
        } else {
            let diff = dhull + dshield;
            return clamp(diff / (hull + shield), -1, 1);
        }
    }

    /**
     * Evaluate the effect on health for a group of ships
     */
    function getHealthDiffShips(plan: AIPlan, ships: Ship[]): number {
        if (ships.length) {
            let diffs = ships.map(ship => getHealthDiffShip(plan, ship));
            let deaths = sum(diffs.map(i => i == -1 ? 1 : 0));
            return ((sum(diffs) * 0.5) - (deaths * 0.5)) / ships.length;
        } else {
            return 0;
        }
    }

    /**
     * Functions to help scoring a turn plan produced by an AI
     * 
     * Helpers should try to remain in the -1..1 range
     */
    export class AIScoringHelpers {
        /**
         * Sum of other scoring methods
         */
        static sum(...scorings: AIPlanScoring[]): AIPlanScoring {
            return plan => sum(scorings.map(scoring => scoring(plan)));
        }

        /**
         * Scaled version of another scoring method
         */
        static scaled(evaluator: AIPlanScoring, factor: number): AIPlanScoring {
            return (plan: AIPlan) => factor * evaluator(plan);
        };

        /**
         * Negatively score the fleet's remaining power, between -1 and 0
         */
        static remainingPower(plan: AIPlan): number {
            const toggled = isum(imap(plan.battle.iallies(plan.player), ship => sum(ship.getToggleActions(true).map(action => action.getPowerUsage(ship)))));
            const available = isum(imap(plan.battle.iallies(plan.player), ship => ship.getAttribute("power_capacity")));
            const used = sum(cfilter(plan.effects, ShipActionUsedDiff).map(diff => {
                const ship = plan.battle.getShip(diff.ship_id);
                if (ship && ship.isPlayedBy(plan.player)) {
                    const action = ship.actions.getById(diff.action);
                    if (action) {
                        return action.getPowerUsage(ship);
                    } else {
                        return 0;
                    }
                } else {
                    return 0;
                }
            }));
            return available ? (used - toggled - available) / available : 0;
        }

        /**
         * Evaluate the effect on health to the enemy, between -1 and 1
         */
        static healthEnemies(plan: AIPlan): number {
            let enemies = imaterialize(plan.battle.ienemies(plan.player, true));
            return -getHealthDiffShips(plan, enemies);
        }

        /**
         * Evaluate the effect on health to allied ships, between -1 and 1
         */
        static healthAllies(plan: AIPlan): number {
            let allies = imaterialize(plan.battle.iallies(plan.player, true));
            return getHealthDiffShips(plan, allies);
        }

        /**
         * Evaluate the cost of overheating equipments
         */
        static overheat(plan: AIPlan): number {
            return sum(cfilter(plan.effects, ShipActionUsedDiff).map(diff => {
                const ship = plan.battle.getShip(diff.ship_id);
                if (ship && ship.isPlayedBy(plan.player)) {
                    const action = ship.actions.getById(diff.action);
                    if (action) {
                        const cooldown = ship.actions.getCooldown(action);
                        if (cooldown.willOverheat()) {
                            return -Math.min(1, 0.4 * cooldown.cooling);
                        } else {
                            return 0;
                        }
                    } else {
                        return 0;
                    }
                } else {
                    return 0;
                }
            }));
        }

        /**
         * Evaluate the gain or loss of active effects
         */
        static activeEffects(plan: AIPlan): number {
            let result = 0;
            plan.effects.forEach(effect => {
                if (effect instanceof ShipEffectAddedDiff || effect instanceof ShipEffectRemovedDiff) {
                    let target = plan.battle.getShip(effect.ship_id);
                    let enemy = target && !target.isPlayedBy(plan.player);
                    let beneficial = effect.effect.isBeneficial();
                    if (effect instanceof ShipEffectRemovedDiff) {
                        beneficial = !beneficial;
                    }
                    // TODO Evaluate the "power" of the effect
                    if ((beneficial && !enemy) || (!beneficial && enemy)) {
                        result += 1;
                    } else {
                        result -= 1;
                    }
                }
            });
            return clamp(result / plan.battle.ships.count(), -1, 1);
        }
    }
}