/**
 * toknmtr agent — pusher.
 *
 * POSTs parsed batches to the server's /api/ingest. The ingest endpoint
 * (src/routes/api/ingest/+server.ts) accepts `{ host?, events, toolCalls?, sessions? }` —
 * events are the documented minimal contract; toolCalls/sessions are additional top-level
 * keys the ingest agent reads to populate the tool_calls/sessions tables. Idempotent
 * upsert on the server means re-pushing (e.g. retrying after a failed request) is always
 * safe. Config via env: TOKNMTR_URL, TOKNMTR_TOKEN.
 */
import type { ParsedEvent, SessionMeta, ToolCall } from './parse.ts';
import type { UsageGauges } from './usage.ts';

const URL_BASE = process.env.TOKNMTR_URL ?? 'http://localhost:3001';
const TOKEN = process.env.TOKNMTR_TOKEN ?? '';

/** Max events per ingest request — keeps request bodies (and the server's single
 *  transaction per request) a reasonable size for large backfills. Events carry raw
 *  prompt/response text, so a batch of 500 can run into many MB; 200 keeps each POST
 *  comfortably under the server's BODY_SIZE_LIMIT (see ops/README.md — set it generously,
 *  e.g. BODY_SIZE_LIMIT=64M, on the deployed container). */
const CHUNK_SIZE = 200;

export interface PushBatch {
	host?: string;
	events: ParsedEvent[];
	toolCalls?: ToolCall[];
	sessions?: SessionMeta[];
}

export interface PushResult {
	ok: boolean;
	received: number;
	requests: number;
}

interface IngestResponse {
	ok: boolean;
	events?: number;
	tool_calls?: number;
	sessions?: number;
	received?: number; // older/stub server shape
}

async function postChunk(body: Record<string, unknown>): Promise<number> {
	const res = await fetch(`${URL_BASE}/api/ingest`, {
		method: 'POST',
		headers: {
			'content-type': 'application/json',
			authorization: `Bearer ${TOKEN}`
		},
		body: JSON.stringify(body)
	});
	if (!res.ok) throw new Error(`ingest failed: ${res.status} ${await res.text()}`);
	const parsed = (await res.json()) as IngestResponse;
	return parsed.events ?? parsed.received ?? 0;
}

/**
 * Push a full batch (events + tool calls + session metadata), chunking `events` into
 * groups of CHUNK_SIZE per request. toolCalls/sessions (typically much smaller) are sent
 * once, attached to the first request.
 */
export async function pushBatch(batch: PushBatch): Promise<PushResult> {
	const { host, events, toolCalls = [], sessions = [] } = batch;
	if (events.length === 0 && toolCalls.length === 0 && sessions.length === 0) {
		return { ok: true, received: 0, requests: 0 };
	}

	let received = 0;
	let requests = 0;
	const chunkCount = events.length > 0 ? Math.ceil(events.length / CHUNK_SIZE) : 1;
	for (let i = 0; i < chunkCount; i++) {
		const chunk = events.slice(i * CHUNK_SIZE, (i + 1) * CHUNK_SIZE);
		const body: Record<string, unknown> = { events: chunk };
		if (host) body.host = host;
		if (i === 0) {
			if (toolCalls.length > 0) body.toolCalls = toolCalls;
			if (sessions.length > 0) body.sessions = sessions;
		}
		received += await postChunk(body);
		requests++;
	}
	return { ok: true, received, requests };
}

/** Convenience wrapper for pushing just events (no tool calls / session metadata). */
export async function pushEvents(
	events: ParsedEvent[]
): Promise<{ ok: boolean; received: number }> {
	const result = await pushBatch({ events });
	return { ok: result.ok, received: result.received };
}

/**
 * POST a single subscription-usage gauge reading to the server's /api/usage endpoint.
 * Returns true on a 2xx. Caller decides whether/when to scrape (see agent/usage.ts) — this
 * just ships whatever it's handed. Idempotent on the server (upsert by host + ts_utc).
 */
export async function pushUsageGauges(gauges: UsageGauges): Promise<boolean> {
	const res = await fetch(`${URL_BASE}/api/usage`, {
		method: 'POST',
		headers: {
			'content-type': 'application/json',
			authorization: `Bearer ${TOKEN}`
		},
		body: JSON.stringify(gauges)
	});
	if (!res.ok) throw new Error(`usage push failed: ${res.status} ${await res.text()}`);
	return true;
}