/**
 * 跨平台验证: 模拟 uni-app 预处理, 把 pages.json 在每个平台上
 * (H5 / MP-WEIXIN / APP-PLUS / MP-HARMONY / etc.) 展开后,
 * 用标准 JSON.parse 验证其合法性.
 *
 * uni-app 预处理规则:
 * - // #ifdef PLATFORM ... // #endif: 当 PLATFORM 匹配当前平台, 保留块; 否则删除 (含注释行)
 * - // #ifndef PLATFORM ... // #endif: 当 PLATFORM 不匹配当前平台, 保留块; 否则删除
 * - 处理嵌套
 *
 * 运行: node scripts/verify-pages-json-cross-platform.js
 */
const fs = require('fs');
const path = require('path');

const PAGES_JSON = path.join(__dirname, '..', 'pages.json');
const raw = fs.readFileSync(PAGES_JSON, 'utf-8');
const lines = raw.split(/\r?\n/);

const PLATFORMS = ['H5', 'MP-WEIXIN', 'APP-PLUS', 'MP-HARMONY', 'MP-ALIPAY', 'MP-BAIDU', 'MP-TOUTIAO', 'MP-QQ', 'MP-KUAISHOU', 'MP-JD', 'MP-360', 'MP-XHS', 'APP', 'APP-NVUE'];

/**
 * 模拟预处理: 给定平台, 返回剥除 // #ifdef / // #ifndef 后的行数组.
 */
function preprocess(platform) {
	const out = [];
	const stack = []; // 每项 { mode: 'ifdef' | 'ifndef', platform, keep }

	for (const line of lines) {
		// 检测 // #ifdef PLAT / // #ifndef PLAT
		const openMatch = line.match(/^\s*\/\/\s*#(ifdef|ifndef)\s+([\w-]+)\b/);
		if (openMatch) {
			const mode = openMatch[1];
			const plat = openMatch[2];
			const keep = mode === 'ifdef'
				? plat === platform
				: plat !== platform;
			stack.push({ mode, platform: plat, keep });
			if (!keep) {
				// 这行也不输出 (块被剥除)
				continue;
			}
			out.push(line);
			continue;
		}
		const closeMatch = line.match(/^\s*\/\/\s*#endif\b/);
		if (closeMatch) {
			const top = stack.pop();
			if (!top) {
				// 不平衡的 #endif, 仍输出 (避免破坏后续)
				out.push(line);
				continue;
			}
			if (!top.keep) continue; // 整块被剥除, // #endif 也不输出
			out.push(line);
			continue;
		}
		// 普通行: 若当前栈顶 keep=false, 不输出
		if (stack.length > 0 && !stack[stack.length - 1].keep) continue;
		out.push(line);
	}

	if (stack.length > 0) {
		console.warn(`[warn] platform=${platform}: 残留未关闭 #ifdef/#ifndef ${stack.length} 个`);
	}
	return out;
}

/**
 * 剥除 // 行注释, 返回纯 JSON 字符串.
 * 注意: 必须先做预处理把 // #ifdef 块剥除, 否则 // 会被当成 JSON 注释.
 */
function stripLineComments(keptLines) {
	const out = [];
	for (const line of keptLines) {
		let lo = '';
		let inS = false, e = false;
		for (let i = 0; i < line.length; i++) {
			const c = line[i];
			if (inS) {
				if (e) e = false;
				else if (c === '\\') e = true;
				else if (c === '"') inS = false;
			} else {
				if (c === '/' && line[i + 1] === '/') break;
				if (c === '"') inS = true;
			}
			lo += c;
		}
		out.push(lo);
	}
	return out.join('\n');
}

let allOk = true;
for (const plat of PLATFORMS) {
	const kept = preprocess(plat);
	const cleanJson = stripLineComments(kept);
	try {
		JSON.parse(cleanJson);
		console.log(`✅ ${plat.padEnd(12)} OK`);
	} catch (err) {
		allOk = false;
		console.log(`❌ ${plat.padEnd(12)} FAIL: ${err.message}`);
		// 输出错误附近 6 行
		const m = err.message.match(/position (\d+)/);
		if (m) {
			const pos = parseInt(m[1]);
			const allLines = cleanJson.split('\n');
			let p = 0;
			for (let k = 0; k < allLines.length; k++) {
				if (p + allLines[k].length + 1 > pos) {
					console.log('     near preprocessed line', k + 1, '(in raw pages.json line', findRawLine(k, plat) + ')');
					for (let j = Math.max(0, k - 3); j <= Math.min(allLines.length - 1, k + 3); j++) {
						console.log('     ', j === k ? '>>>' : '   ', allLines[j]);
					}
					break;
				}
				p += allLines[k].length + 1;
			}
		}
	}
}

function findRawLine(preprocIdx, platform) {
	// 找到 raw 中第 preprocIdx 行对应到哪一行. 用同样的预处理规则计算.
	const stack = [];
	let preIdx = -1;
	for (let k = 0; k < lines.length; k++) {
		const line = lines[k];
		const openMatch = line.match(/^\s*\/\/\s*#(ifdef|ifndef)\s+([\w-]+)\b/);
		if (openMatch) {
			const mode = openMatch[1];
			const plat = openMatch[2];
			const keep = mode === 'ifdef' ? plat === platform : plat !== platform;
			stack.push({ keep });
			if (!keep) continue;
			preIdx++;
			continue;
		}
		if (/^\s*\/\/\s*#endif\b/.test(line)) {
			const top = stack.pop();
			if (top && !top.keep) continue;
			preIdx++;
			continue;
		}
		if (stack.length > 0 && !stack[stack.length - 1].keep) continue;
		preIdx++;
		if (preIdx === preprocIdx) return k + 1;
	}
	return -1;
}

process.exit(allOk ? 0 : 1);