'use strict';

const crypto = require('crypto');
const fs = require('fs');
const os = require('os');
const path = require('path');

function orderCurrentTargetLast(targets, currentSourcePath) {
	if (!currentSourcePath) return [...targets];
	const current = path.resolve(currentSourcePath);
	return [...targets].sort((left, right) => {
		const leftIsCurrent = path.resolve(left.sourcePath) === current;
		const rightIsCurrent = path.resolve(right.sourcePath) === current;
		return Number(leftIsCurrent) - Number(rightIsCurrent);
	});
}

/**
 * Apply one rendered frame to explicitly selected Eagle items.
 * Each item gets an independent temporary file because Eagle may consume or
 * defer reading the file passed to setCustomThumbnail.
 */
async function applyThumbnailTargets(options) {
	const targets = options.targets || [];
	// 渲染结果为空时立刻报清楚的原因，否则会在写临时文件时才抛出难懂的参数类型错误。
	if (!options.rendered || !Buffer.isBuffer(options.rendered.buffer)) throw new Error('缩略图渲染结果为空');
	const settleDelayMs = options.settleDelayMs === undefined ? 800 : options.settleDelayMs;
	const cleanupDelayMs = options.cleanupDelayMs === undefined ? 1200 : options.cleanupDelayMs;
	const retryAttempts = options.retryAttempts === undefined ? 3 : options.retryAttempts;
	const delay = (ms) => ms > 0 ? new Promise((resolve) => setTimeout(resolve, ms)) : Promise.resolve();
	const tempPaths = [];
	let success = 0;
	let skipped = Number(options.initialSkipped) || 0;
	let failed = 0;
	for (let index = 0; index < targets.length; index++) {
		if (options.onProgress) options.onProgress(index + 1, targets.length);
		let itemTempPath = null;
		try {
			const target = targets[index];
			const fresh = await options.getItem(target.sourcePath);
			if (fresh.data.customThumbnail === true && target.allowOverwrite !== true) { skipped++; continue; }
			itemTempPath = path.join(os.tmpdir(), 'spineviewer-group-' + fresh.id + '-' + crypto.randomBytes(12).toString('hex') + options.rendered.extension);
			fs.writeFileSync(itemTempPath, options.rendered.buffer);
			tempPaths.push(itemTempPath);
			let applied = false;
			let lastError = null;
			for (let attempt = 0; attempt < retryAttempts && !applied; attempt++) {
				try {
					const accepted = await options.setThumbnail(fresh.id, itemTempPath);
					if (accepted !== true) throw new Error(options.notConfirmedMessage || 'Thumbnail update was rejected');
					applied = await options.waitForApplied(target.sourcePath);
					if (!applied) throw new Error(options.notConfirmedMessage || 'Thumbnail update was not confirmed');
				} catch (error) {
					lastError = error;
					if (attempt < retryAttempts - 1) await delay(settleDelayMs);
				}
			}
			if (!applied) throw lastError || new Error(options.notConfirmedMessage || 'Thumbnail update was not confirmed');
			// The local HTTP API can resolve before Eagle has finished consuming the
			// supplied file. Keep every file alive and serialize requests with a short
			// settling interval so a later request cannot replace an earlier queued job.
			await delay(settleDelayMs);
			success++;
			if (options.onSuccess) options.onSuccess(fresh);
		} catch (error) {
			failed++;
			if (options.onError) options.onError(error);
		} finally { /* temporary inputs are retained until the whole queue settles */ }
	}
	await delay(cleanupDelayMs);
	for (const tempPath of tempPaths) {
		try { if (fs.existsSync(tempPath)) fs.unlinkSync(tempPath); } catch (e) { /* ignore */ }
	}
	return { success, skipped, failed };
}

module.exports = { applyThumbnailTargets, orderCurrentTargetLast };