/**
 * Smart preloading service for upcoming tracks
 * Automatically queues downloads for the next few tracks in the queue
 *
 * TRACES: UR-004, UR-011 | DR-006, DR-015
 */

import { invoke } from '@tauri-apps/api/core';
import { auth } from '$lib/stores/auth';

interface PreloadResult {
	queuedCount: number;
	alreadyDownloaded: number;
	skipped: number;
}

interface PreloadOptions {
	/** Enable debug logging */
	debug?: boolean;
	/** Override user ID (defaults to current session user) */
	userId?: string;
}

/**
 * Trigger preloading for upcoming tracks in the queue
 * This should be called after playback starts or advances to the next track
 */
export async function preloadUpcomingTracks(options: PreloadOptions = {}): Promise<void> {
	const { debug = false, userId: overrideUserId } = options;

	try {
		// Get current user ID
		const userId = overrideUserId || auth.getUserId();

		if (!userId) {
			if (debug) console.log('[Preload] No active user session, skipping preload');
			return;
		}

		if (debug) console.log('[Preload] Triggering preload for user:', userId);

		const result = await invoke<PreloadResult>('player_preload_upcoming', {
			userId,
			downloadBasePath: '/downloads' // This parameter is currently unused in the backend
		});

		if (debug) {
			console.log('[Preload] Result:', {
				queued: result.queuedCount,
				alreadyDownloaded: result.alreadyDownloaded,
				skipped: result.skipped
			});
		}

		// Log meaningful results
		if (result.queuedCount > 0) {
			console.log(`[Preload] Queued ${result.queuedCount} track(s) for background download`);
		}
	} catch (error) {
		// Fail silently - preloading is a background optimization
		// Don't interrupt the user's playback experience
		console.warn('[Preload] Failed to preload upcoming tracks:', error);
	}
}

/**
 * Update smart cache configuration
 */
export async function updateCacheConfig(config: {
	queuePrecacheEnabled?: boolean;
	queuePrecacheCount?: number;
	albumAffinityEnabled?: boolean;
	albumAffinityThreshold?: number;
	storageLimit?: number;
	wifiOnly?: boolean;
}): Promise<void> {
	await invoke('player_set_cache_config', { config });
}

/**
 * Get current cache configuration
 */
export async function getCacheConfig(): Promise<{
	queuePrecacheEnabled: boolean;
	queuePrecacheCount: number;
	albumAffinityEnabled: boolean;
	albumAffinityThreshold: number;
	storageLimit: number;
	wifiOnly: boolean;
}> {
	return await invoke('player_get_cache_config');
}