import http from 'node:http';

/** One assistant response's token usage, extracted from a session jsonl line. */
interface UsageRecord {
    /** Epoch milliseconds of the message. */
    timestamp: number;
    /** Session id (from the session header line, fallback: file name). */
    sessionId: string;
    /** Working directory of the session (from the session header line). */
    cwd: string;
    provider: string;
    model: string;
    input: number;
    output: number;
    cacheRead: number;
    cacheWrite: number;
    reasoning: number;
    totalTokens: number;
    /** Total cost in USD, as reported by the session log. */
    cost: number;
}
interface ScanResult {
    records: UsageRecord[];
    fileCount: number;
    /** Files whose content was actually parsed in this scan. */
    parsedFiles: number;
    /** Milliseconds the scan took. */
    elapsedMs: number;
}
/**
 * Parse one session jsonl file into usage records.
 * Two sources contribute:
 *   - assistant messages carrying a `usage` object (per-request billing data)
 *   - subagent / trellis_subagent toolResult messages, whose `details` carry
 *     the aggregated token usage of the spawned child agents
 */
declare function parseSessionFile(content: string, fallbackSessionId: string): UsageRecord[];
/**
 * Incremental scanner for the sessions directory. Caches parsed files by
 * (mtimeMs, size) so repeated scans only re-read changed files.
 */
declare class SessionStore {
    readonly dir: string;
    private cache;
    constructor(dir: string);
    scan(): Promise<ScanResult>;
}

type RangeKey = "day" | "week" | "month";
interface BucketTotals {
    input: number;
    output: number;
    cacheRead: number;
    cacheWrite: number;
    reasoning: number;
    totalTokens: number;
    cost: number;
    requests: number;
}
interface TimeBucket extends BucketTotals {
    /** Bucket start, epoch ms (local-time aligned). */
    start: number;
    label: string;
}
interface ModelUsage extends BucketTotals {
    provider: string;
    model: string;
    /** provider/model 组合名，便于展示。 */
    name: string;
    sessions: number;
}
interface FolderUsage extends BucketTotals {
    /** Working directory path. */
    cwd: string;
    /** Short display name (last segment or full path). */
    name: string;
    sessions: number;
}
interface Overview {
    range: RangeKey;
    windowStart: number;
    generatedAt: number;
    summary: BucketTotals & {
        sessions: number;
    };
    buckets: TimeBucket[];
    models: ModelUsage[];
    folders: FolderUsage[];
}
declare const RANGES: Record<RangeKey, {
    bucketMs: number;
    bucketCount: number;
    unit: "hour" | "day";
}>;
declare function isRangeKey(value: string): value is RangeKey;
/**
 * Aggregate usage records into a fixed grid of time buckets plus a
 * per-model ranking, for the given range ending at `now`.
 */
declare function aggregate(records: UsageRecord[], range: RangeKey, now?: number): Overview;

interface StatsServer {
    server: http.Server;
    /** Rescan the sessions directory and update in-memory records. */
    refresh: () => Promise<ScanResult>;
}
declare function createStatsServer(store: SessionStore): Promise<StatsServer>;

export { type BucketTotals, type FolderUsage, type ModelUsage, type Overview, RANGES, type RangeKey, type ScanResult, SessionStore, type StatsServer, type TimeBucket, type UsageRecord, aggregate, createStatsServer, isRangeKey, parseSessionFile };