/** One hit zone: what a hit there multiplies, and how much likelier it is to crit. */
export interface HitZoneDef {
    id: string;
    /** Multiplier for a hit in this zone that does not crit. Default `1`. */
    multiplier?: number;
    /** Added to the table's base crit chance for hits in this zone. Default `0`. */
    critChance?: number;
    /** Crit multiplier in this zone; defaults to the table's `critMultiplier`. */
    critMultiplier?: number;
}
/**
 * A serializable hit-zone table: where a hit landed, what that multiplies, and the table's base crit
 * chance and multiplier. A generated gun or a weapon runtime passes its own zones in; the engine has
 * no built-in headshot.
 */
export interface HitZoneTable {
    zones: readonly HitZoneDef[];
    /** Zone used when a caller names one the table does not list. Must appear in `zones`. */
    defaultZone: string;
    /** Base crit chance in `[0,1]`. Default `0`. */
    critChance?: number;
    /** Base crit multiplier. Default `2`. */
    critMultiplier?: number;
}
/** One resolved zone: where the hit landed, whether it crit, and the single multiplier to apply. */
export interface HitZoneResolution {
    zone: string;
    crit: boolean;
    /**
     * The one multiplier this hit earns. A crit *replaces* the zone's normal multiplier instead of
     * compounding with it, so a headshot crit can never silently become zone × crit.
     */
    multiplier: number;
    /** The crit draw, or `null` when the chance was zero and no draw was taken. */
    roll: number | null;
    /** True when the named zone was absent from the table and `defaultZone` was used. */
    fallback: boolean;
}
/** Raised when neither the named zone nor the table's `defaultZone` exists — a data error, not a 1× hit.
 * @capability hit-zone-unknown reject a hit zone table whose named default does not exist
 */
export declare class UnknownHitZoneError extends Error {
    readonly zone: string;
    constructor(zone: string);
}
/** Default crit multiplier for a zone that does not name one. */
export declare const DEFAULT_CRIT_MULTIPLIER = 2;
/** Validate a zone table once at construction: duplicate ids and a missing default fail loudly.
 * @capability hit-zone-validate reject a hit-zone table with duplicate zones or a missing default
 */
export declare function assertHitZoneTable(table: HitZoneTable): void;
/**
 * The multiplier a zone earns for a known crit outcome, without rolling. `resolveHitZone` and a
 * time-to-kill quote both read through this, so a quoted crit uses the same number combat does.
 *
 * @capability hit-zone-multiplier quote a zone's multiplier for a known crit outcome without rolling
 */
export declare function hitZoneMultiplier(table: HitZoneTable, zone: string | undefined, crit: boolean): {
    zone: string;
    multiplier: number;
    fallback: boolean;
};
/**
 * Resolve where a hit landed into one multiplier: roll the crit chance for that zone, and apply the
 * crit multiplier when it lands, otherwise the zone's own multiplier. The injected `rng` keeps the
 * roll reproducible; a zero chance draws nothing, so a deterministic test can force either outcome.
 *
 * @capability hit-zone resolve a hit zone into one damage multiplier, crit by zone with an injected RNG
 */
export declare function resolveHitZone(table: HitZoneTable, zone: string | undefined, rng?: () => number): HitZoneResolution;