import { Mapping, Transformer } from '@walkeros/core';

/** Raw input to the decoder. Origin-agnostic (express, lambda, pubsub, etc). */
interface GA4Request {
    /** Full request URL including query string. */
    url: string;
    /** POST body if present. May be \n- or \r\n-separated multi-event lines. */
    body?: string;
}
/**
 * Parsed GA4 wire payload. One request → one hit → N events.
 * IMPORTANT: dotted GA4 keys (`ep.transaction_id`, `epn.value`) are nested
 * into structured objects at parse time so the mapping engine's getByPath
 * (which splits paths on `.`) can resolve them.
 */
interface GA4Hit {
    /** Hit-level params from the URL query string. v, tid, cid, sid, dl, dt, ul, sr, gcs, gtm, p. */
    hit: GA4HitParams;
    /** One entry per body line (POST) or single entry (GET). */
    events: GA4Event[];
}
/** Hit-level params extracted from URL query. Known keys typed; unknown keys allowed. */
interface GA4HitParams {
    v?: string;
    tid?: string;
    cid?: string;
    sid?: string;
    sct?: string;
    seg?: string;
    _p?: string;
    _z?: string;
    gtm?: string;
    dl?: string;
    dt?: string;
    dr?: string;
    ul?: string;
    sr?: string;
    uid?: string;
    _dbg?: string;
    _s?: string;
    _ss?: string;
    _fv?: string;
    gcs?: string;
    gcd?: string;
    dma?: string;
    dma_cps?: string;
    npa?: string;
    p?: string;
    [other: string]: string | undefined;
}
interface GA4Event {
    /** Event name from `en` param. */
    en: string;
    /**
     * Per-event params with dotted keys nested:
     * raw `ep.transaction_id` → `params.ep.transaction_id`
     * raw `epn.value` → `params.epn.value`
     * raw `up.role` → `params.up.role`
     * raw `upn.score` → `params.upn.score`
     * Standalone keys: `_et`, `_c` stay flat.
     */
    params: GA4EventParams;
    /** Parsed items from pr1, pr2, ..., prN. Empty array if none. */
    items: GA4Item[];
}
interface GA4EventParams {
    /** String event params from ep.<name>. */
    ep: Record<string, string>;
    /** Numeric event params from epn.<name>. Values are coerced via Number(). */
    epn: Record<string, number>;
    /** String user properties from up.<name>. */
    up: Record<string, string>;
    /** Numeric user properties from upn.<name>. */
    upn: Record<string, number>;
    /** Engagement time delta (ms). */
    _et?: number;
    /** Is-conversion flag. */
    _c?: string;
}
/** Parsed product item from one pr<N> param. */
interface GA4Item {
    id?: string;
    name?: string;
    brand?: string;
    category?: string;
    category2?: string;
    category3?: string;
    category4?: string;
    category5?: string;
    variant?: string;
    price?: number;
    quantity?: number;
    coupon?: string;
    discount?: number;
    listName?: string;
    listId?: string;
    listPosition?: number;
    locationId?: string;
    affiliation?: string;
    creativeName?: string;
    creativeSlot?: string;
    promotionId?: string;
    promotionName?: string;
    /** Custom item params from k<N>/v<N> pairs (multi-digit N supported). */
    custom: Record<string, string>;
}
/** Decoder settings. */
interface GA4Settings {
    /**
     * Mapping registry keyed by GA4 event name (`en`).
     * User config replaces matching package defaults at the per-event key.
     * Use `'*'` for the unknown-event fallback.
     * Set a rule's `ignore: true` to drop matching events.
     */
    mapping?: GA4Mapping;
    /**
     * Regex string to filter `tid` values. Default `^G-` (drops Ads `AW-`/DC `DC-`).
     * String at config time, compiled to RegExp once at init.
     */
    tidPattern?: string;
}
/** Per-event mapping rule keyed by GA4 event name. */
type GA4Mapping = Record<string, Mapping.Rule | undefined> & {
    '*'?: Mapping.Rule;
};

declare const transformerGa4: Transformer.Init<Transformer.Types<GA4Settings>>;

/**
 * Default GA4 event-name → walkerOS mapping rules.
 * Users may override or extend these via settings.mapping at config time.
 * The `'*'` key is the fallback for unknown event names.
 *
 * Field naming for `data.map`:
 * - Monetary: `currency` from `ep.currency`, `value`/`total` from `epn.value`,
 *   `tax` from `epn.tax`, `shipping` from `epn.shipping`, `coupon` from
 *   `ep.coupon`.
 * - Promotions read from `firstItem` (synthetic `items[0]` reference exposed by
 *   the mapper), since GA4 encodes promotion info inside item tilde strings.
 */
declare const defaultMapping: GA4Mapping;

export { type GA4Event, type GA4EventParams, type GA4Hit, type GA4HitParams, type GA4Item, type GA4Mapping, type GA4Request, type GA4Settings, transformerGa4 as default, defaultMapping, transformerGa4 };