/**
 * Reads token usage out of Gemini CLI's own session transcripts.
 *
 * Layout, confirmed on a real machine (18 files spanning June–August 2026):
 * `~/.gemini/tmp/<projectSlug>/chats/session-<timestamp>-<id>.jsonl`. The
 * sibling `~/.gemini/history/<projectSlug>/` directories are a git-based
 * shadow-history of edited files, not chat logs — no JSONL lives there.
 *
 * Each file is a small append-only patch log rather than one JSON object per
 * line of "the same shape": line 0 is a header (`sessionId`, `projectHash`,
 * `startTime`, `lastUpdated`, `kind`); every line after that is either
 * `{"$set": {...}}` (a partial merge — `messages` on session bootstrap,
 * scalar fields like `lastUpdated`/`summary` afterwards) or a bare message
 * object appended directly. Confirmed on the installed CLI's own bundled
 * source (`@google/gemini-cli` `ChatRecordingService.pushMessage`): a bare
 * append is `appendRecord(msg)` with no wrapper, which is why real transcripts
 * mix both shapes. This reader unwraps `$set.messages[]` (only ever seen once
 * per file, holding the single injected `<session_context>` bootstrap
 * message) and reads bare objects that carry `id`/`type` directly.
 *
 * The installed source also revealed a real double-write race, invisible in
 * this machine's own samples (0 duplicate ids across all 18 files) but
 * reachable on any machine: `recordMessage()` first pushes a `type: "gemini"`
 * message with whatever `tokens` value is already queued (often `null`,
 * before the response's usage metadata has arrived), and
 * `recordMessageTokens()` — called separately once usage arrives — re-pushes
 * the SAME message id with `tokens` now filled in if it finds the last
 * message still token-less. `pushMessage()` unconditionally appends a new
 * line every time it is called, even for an id it has already written. So the
 * same `id` can legitimately appear twice: once without tokens, once with.
 * Dedup here keeps, per id, whichever record has the larger `tokens.total`
 * (a record with no tokens contributes 0), which is correct for both that
 * race and an ordinary resumed-session replay. The map is per-file, mirroring
 * `claudeCodeReader.ts`.
 *
 * `tokens` is `{input, output, cached, thoughts, tool, total}`, and the source
 * (`recordMessageTokens`) maps it straight from the GenAI response's own
 * `usageMetadata` — `input = promptTokenCount`, `output = candidatesTokenCount`,
 * `cached = cachedContentTokenCount`, `thoughts = thoughtsTokenCount`,
 * `tool = toolUsePromptTokenCount`, `total = totalTokenCount`. Real data
 * confirms `total = input + output + thoughts + tool` and that `cached` is a
 * SUBSET of `input`: the one real record with nonzero cache had
 * `input: 12121, cached: 4073`, and `total (12344) = input (12121) + output
 * (1) + thoughts (222)` — cached tokens are not added on top of input, they
 * are already inside it. So `inputTokens` here is `input - cached`, the same
 * subtraction `codexReader.ts` and `qwenCodeReader.ts` make for the same
 * reason: this subsystem's `LocalUsageTotals.inputTokens` +
 * `.cacheReadTokens` must sum to the true prompt size without double-counting.
 * No cache-CREATION concept exists in this API family's usage metadata, so
 * `cacheCreationTokens` stays 0.
 *
 * The write path also nests subagent transcripts one level deeper —
 * `chats/<parentSessionId>/<subagentSessionId>.jsonl`, per the same source —
 * so this reader recurses under `chats/` rather than globbing one level, even
 * though no nested subagent file exists on the machine this was verified
 * against.
 *
 * Cost is deliberately `unavailable`. Gemini CLI supports three genuinely
 * different auth modes with unrelated billing (`gemini-api-key`: metered, and
 * the Flash models specifically have a real free tier; `oauth-personal`: free,
 * rate-limited; `vertex-ai`: billed to a GCP project at negotiated rates), and
 * no session record — not the header, not a message — carries which mode was
 * active when it was written. `settings.json` records only the CURRENT mode,
 * which cannot be projected onto historical sessions. Modeling a per-token
 * dollar figure from the public API price list would misrepresent every
 * free-tier or Vertex-billed session as if it were pay-as-you-go. Concretely,
 * on the reference machine even the majority model logged (`gemini-3.5-flash`,
 * 12 of 14 sampled turns) has no entry in `pricing.ts` at all — only the
 * minority model (`gemini-3-flash-preview`) does — so most real traffic would
 * be unpriced regardless.
 */
import type { LocalUsageReader } from "../types/index.js";
export declare function createGeminiCliReader(): Promise<LocalUsageReader>;