import { ISystem, System, Component, Components } from '../engine/system';
import { IEntity, State, DoSet, IAction } from '../engine/state';
import { IHudWindow } from '../../client/engine/ui';

interface IStat {
    name: string;
    current: number;
    min: number;
    max: number;
    regen: number;
}

interface IStatsComponent {
    [key: string]: IStat;
}

const clampStat = (stat: IStat) => {
    stat.current = Math.max(stat.current, stat.min);
    stat.current = Math.min(stat.current, stat.max);
};

const tickStat = (stat: IStat, delta: number) => {
    stat.current += stat.regen * delta;
    clampStat(stat);
    // console.log(stat.name + ' ' + Math.floor(stat.current));
};

export interface IDamageAction extends IAction {
    type: 'DAMAGE';
    entityId: string;
    stat: string;
    amount: number;
}

export const DoDamage = (entity: IEntity, stat: string, amount: number): IDamageAction => {
    return {
        type: 'DAMAGE',
        entityId: entity.id,
        stat,
        amount
    };
};

@Components('stats')
export class Stats extends System {
    add(entity: IEntity) {
        super.add(entity);
        this.dispatch(DoSet(entity.id, 'stats', Object.assign({}, entity.stats)));
        this.update(entity, 'stats');
    }
    HandleDamage(a: IDamageAction) {
        const entity = this.entities[a.entityId];
        const stat = entity.stats[a.stat];
        if (stat === undefined) return;
        const before = stat.current;
        stat.current -= a.amount;
        clampStat(stat);
        const after = stat.current;
        const dealt = before - after;
        const newStats = Object.assign({}, entity.stats) as IStatsComponent;
        newStats[a.stat] = stat;
        // TODO - it might be optimal to capture all 'dirty' stats and do a batch update after all actions are handled
        this.dispatch(DoSet(entity.id, 'stats', newStats));
    }
    tick(delta) {
        this.actions({
            DAMAGE: this.HandleDamage
        });

        Object.keys(this.entities).forEach(id => {
            const entity = this.entities[id];
            const newStats = Object.assign({}, entity.stats) as IStatsComponent;

            Object.keys(newStats).forEach(k => {
                const stat = newStats[k];
                tickStat(stat, delta);
            });
            this.dispatch(DoSet(entity.id, 'stats', newStats));

            // TODO - move this out of here and make it only happen for the the player entity
            const hw = window as IHudWindow;
            hw.hud.updateStats(entity.stats['health'].current);
        });
    }
}