import type { Database } from "bun:sqlite";
import { getAllConfig, getDb } from "../db/index";
import { log, warn } from "../lib/log";
import { getItem, type JellyfinConfig } from "./jellyfin";
import { loadLibrary as loadRadarrLibrary, isUsable as radarrUsable } from "./radarr";
import { type RescanConfig, type RescanResult, upsertJellyfinItem } from "./rescan";
import { loadLibrary as loadSonarrLibrary, isUsable as sonarrUsable } from "./sonarr";

/**
 * Events we care about. Jellyfin's Webhook plugin (jellyfin-plugin-webhook)
 * only exposes ItemAdded as a library-side notification — there is no
 * ItemUpdated or Library.ItemUpdated. File-rewrites on existing items
 * produce zero MQTT traffic, so we can't observe them here; the UI's
 * post-job verification runs off our own ffprobe instead.
 *
 * Payload fields are PascalCase (NotificationType, ItemId, ItemType) — the
 * earlier camelCase in this handler matched nothing the plugin ever sends.
 */
const ACCEPTED_EVENTS = new Set(["ItemAdded"]);
const ACCEPTED_TYPES = new Set(["Movie", "Episode"]);

/** 5-second dedupe window: Jellyfin can fire the same ItemAdded twice when multiple libraries share a path. */
const DEDUPE_WINDOW_MS = 5000;
const dedupe = new Map<string, number>();

function parseLanguageList(raw: string | null | undefined, fallback: string[]): string[] {
	if (!raw) return fallback;
	try {
		const parsed = JSON.parse(raw);
		return Array.isArray(parsed) ? parsed.filter((v): v is string => typeof v === "string") : fallback;
	} catch {
		return fallback;
	}
}

export interface WebhookPayload {
	NotificationType?: string;
	ItemId?: string;
	ItemType?: string;
}

export interface WebhookHandlerDeps {
	db: Database;
	jellyfin: JellyfinConfig;
	rescanCfg: RescanConfig;
	getItemFn?: typeof getItem;
	now?: () => number;
}

export interface WebhookResult {
	accepted: boolean;
	reason?: string;
	result?: RescanResult;
}

/**
 * Parse an incoming webhook payload and, if it describes a relevant Jellyfin
 * library event for a Movie/Episode, re-analyze the item and let rescan's
 * webhook-override flip stale 'done' plans back to 'pending'.
 *
 * Errors from Jellyfin are logged and swallowed: one bad message must not
 * take down the MQTT subscriber.
 */
export async function processWebhookEvent(payload: WebhookPayload, deps: WebhookHandlerDeps): Promise<WebhookResult> {
	const { db, jellyfin, rescanCfg, getItemFn = getItem, now = Date.now } = deps;

	if (!payload.NotificationType || !ACCEPTED_EVENTS.has(payload.NotificationType)) {
		return { accepted: false, reason: `NotificationType '${payload.NotificationType}' not accepted` };
	}
	if (!payload.ItemType || !ACCEPTED_TYPES.has(payload.ItemType)) {
		return { accepted: false, reason: `ItemType '${payload.ItemType}' not accepted` };
	}
	if (!payload.ItemId) {
		return { accepted: false, reason: "missing ItemId" };
	}

	// Debounce: drop bursts within the window, always evict stale entries.
	const ts = now();
	for (const [id, seen] of dedupe) {
		if (ts - seen > DEDUPE_WINDOW_MS) dedupe.delete(id);
	}
	const last = dedupe.get(payload.ItemId);
	if (last != null && ts - last <= DEDUPE_WINDOW_MS) {
		return { accepted: false, reason: "deduped" };
	}
	dedupe.set(payload.ItemId, ts);

	const fresh = await getItemFn(jellyfin, payload.ItemId);
	if (!fresh) {
		warn(`Webhook: Jellyfin returned no item for ${payload.ItemId}`);
		return { accepted: false, reason: "jellyfin returned no item" };
	}

	const result = await upsertJellyfinItem(db, fresh, rescanCfg, { source: "webhook" });
	log(`Webhook: ingested ${payload.ItemType} ${payload.ItemId} is_noop=${result.isNoop}`);
	return { accepted: true, result };
}

/**
 * MQTT-facing adapter: parses the raw payload text, pulls config, calls
 * processWebhookEvent. Exposed so server/services/mqtt.ts can stay purely
 * about transport, and tests can drive the logic without spinning up MQTT.
 */
export async function handleWebhookMessage(rawPayload: string): Promise<WebhookResult> {
	let payload: WebhookPayload;
	try {
		payload = JSON.parse(rawPayload);
	} catch (err) {
		warn(`Webhook: malformed JSON payload: ${String(err)}`);
		return { accepted: false, reason: "malformed JSON" };
	}

	const cfg = getAllConfig();
	const jellyfin: JellyfinConfig = {
		url: cfg.jellyfin_url,
		apiKey: cfg.jellyfin_api_key,
		userId: cfg.jellyfin_user_id,
	};
	if (!jellyfin.url || !jellyfin.apiKey) {
		return { accepted: false, reason: "jellyfin not configured" };
	}

	const radarrCfg = { url: cfg.radarr_url, apiKey: cfg.radarr_api_key };
	const sonarrCfg = { url: cfg.sonarr_url, apiKey: cfg.sonarr_api_key };
	const radarrEnabled = cfg.radarr_enabled === "1" && radarrUsable(radarrCfg);
	const sonarrEnabled = cfg.sonarr_enabled === "1" && sonarrUsable(sonarrCfg);
	const [radarrLibrary, sonarrLibrary] = await Promise.all([
		radarrEnabled ? loadRadarrLibrary(radarrCfg) : Promise.resolve(null),
		sonarrEnabled ? loadSonarrLibrary(sonarrCfg) : Promise.resolve(null),
	]);

	const rescanCfg: RescanConfig = {
		audioLanguages: parseLanguageList(cfg.audio_languages, []),
		radarr: radarrEnabled ? radarrCfg : null,
		sonarr: sonarrEnabled ? sonarrCfg : null,
		radarrLibrary,
		sonarrLibrary,
	};

	return processWebhookEvent(payload, { db: getDb(), jellyfin, rescanCfg });
}

/** Exposed for tests. */
export function _resetDedupe(): void {
	dedupe.clear();
}