import fs from 'node:fs';
import path from 'node:path';
import { defineConfig, transformWithEsbuild, type Plugin } from 'vite';
import uni from '@dcloudio/vite-plugin-uni';

/** 此路径根据自己项目路径修改；默认为 uniapp 插件市场导入路径；*/
import viteVueUnocss, { unocss, flex, pseudo, border } from './unocss/a-hua-unocss';

const isAlipay = () => process.env.UNI_PLATFORM === 'mp-alipay';

/**
 * 支付宝旧 Babel（CE1000）对箭头函数 / 模板字符串 / ?? / ?. / catch{} 等解析不稳。
 * 仅 mp-alipay 构建时把产物降到 es2015（保留 const/let；esbuild 不支持 const→es5）。
 */
const ALIPAY_ESBUILD_OPTIONS = {
	loader: 'js' as const,
	target: 'es2015',
	sourcemap: false as const,
	supported: {
		arrow: false,
		'template-literal': false,
		'optional-chain': false,
		'nullish-coalescing': false,
		'optional-catch-binding': false,
		'object-rest-spread': false,
		'class-field': false
	}
};

const needsAlipayTransform = (source: string) =>
	source.includes('=>') ||
	source.includes('`') ||
	source.includes('?.') ||
	source.includes('??') ||
	/catch\s*\{/.test(source);

const walkJsFiles = (dir: string, files: string[] = []) => {
	if (!fs.existsSync(dir)) return files;
	for (const name of fs.readdirSync(dir)) {
		const fullPath = path.join(dir, name);
		if (fs.statSync(fullPath).isDirectory()) {
			walkJsFiles(fullPath, files);
		} else if (name.endsWith('.js')) {
			files.push(fullPath);
		}
	}
	return files;
};

const transformAlipayOutputDir = async (root: string) => {
	const files = walkJsFiles(root);
	let changed = 0;
	for (const file of files) {
		const source = fs.readFileSync(file, 'utf8');
		if (!needsAlipayTransform(source)) continue;
		try {
			const result = await transformWithEsbuild(source, file, ALIPAY_ESBUILD_OPTIONS);
			if (result.code && result.code !== source) {
				fs.writeFileSync(file, result.code, 'utf8');
				changed += 1;
			}
		} catch (error: any) {
			console.warn('[alipay-es-compat] skip', file, error?.message || error);
		}
	}
	console.log(`[alipay-es-compat] ${root} transformed ${changed} file(s)`);
};

function alipayEsCompatPlugin(): Plugin {
	return {
		name: 'cashier-alipay-es-compat',
		apply: 'build',
		enforce: 'post',
		async renderChunk(code) {
			if (!isAlipay() || !needsAlipayTransform(code)) return null;
			const result = await transformWithEsbuild(code, 'chunk.js', ALIPAY_ESBUILD_OPTIONS);
			return { code: result.code, map: null };
		},
		async closeBundle() {
			if (!isAlipay()) return;
			const roots = [
				path.resolve(__dirname, 'unpackage/dist/dev/mp-alipay'),
				path.resolve(__dirname, 'unpackage/dist/build/mp-alipay')
			];
			for (const root of roots) {
				await transformAlipayOutputDir(root);
			}
		}
	};
}

export default defineConfig({
	build: isAlipay()
		? {
				target: 'es2015',
				cssTarget: 'chrome61'
			}
		: undefined,
	plugins: [
		uni(),
		alipayEsCompatPlugin(),
		viteVueUnocss({
			presets: [
				unocss(),
				flex(),
				pseudo(),
				border({
					width: 1,
					style: 'solid',
					color: 'currentColor'
				})
			],
			prefix: ['li'],
			exclude: ['node_modules', 'uni_modules'],
			theme: {
				generator: true,
				colors: {
					veryCool: '#37A5FF',
					brand: {
						primary: '#37A5FF',
						DEFAULT: '#942192'
					}
				}
			}
		})
	]
});