#!/usr/bin/env node
// Documentation-only tool. Install pinned packages in a separate temporary directory;
// UML_RENDER_TOOLS points there. No app dependencies or remote rendering service.
import { createRequire } from 'node:module';
import { readFile, readdir, mkdir, writeFile } from 'node:fs/promises';
import path from 'node:path';
import { fileURLToPath, pathToFileURL } from 'node:url';

const tools = process.env.UML_RENDER_TOOLS;
// 工具依赖放在独立目录，避免给应用运行依赖增加文档渲染包。
if (!tools) throw new Error('Set UML_RENDER_TOOLS to the documentation tool directory; see docs/architecture/uml/README.md');
const require = createRequire(path.join(path.resolve(tools), 'package.json'));
const { createCanvas } = require('@napi-rs/canvas');
const { DOMImplementation, XMLSerializer, DOMParser } = require('@xmldom/xmldom');
const sharp = require('sharp');

// PlantUML's official JS engine uses DOM construction and Canvas text metrics.
// Supply a real XML DOM and native Canvas metrics, not approximate text widths.
globalThis.PLANTUML_VIZ = require('@viz-js/viz');
globalThis.window = globalThis;
globalThis.XMLSerializer = XMLSerializer;
globalThis.DOMParser = DOMParser;
const document = new DOMImplementation().createDocument(null, 'root', null);
const element = document.createElement.bind(document);
const elementNS = document.createElementNS.bind(document);
function measurementCanvas() {
  // PlantUML 的文本布局需要真实字体宽高，统一用本机 Canvas 测量而非固定字符宽度。
  const canvas = createCanvas(1, 1);
  const context = canvas.getContext('2d');
  const measure = context.measureText.bind(context);
  context.measureText = text => {
    const metrics = measure(text);
    // PlantUML uses this height for line spacing. Font-wide ascent/descent
    // keeps adjacent class fields from colliding when glyphs lack descenders.
    return {
      ...metrics,
      width: metrics.width,
      actualBoundingBoxAscent: metrics.fontBoundingBoxAscent || metrics.actualBoundingBoxAscent,
      actualBoundingBoxDescent: metrics.fontBoundingBoxDescent || metrics.actualBoundingBoxDescent,
    };
  };
  return canvas;
}
document.createElement = tag => tag === 'canvas' ? measurementCanvas() : element(tag);
document.createElementNS = (namespace, tag) => {
  // 为无浏览器 DOM 补齐样式与 getBBox，满足官方渲染引擎的 SVG 文本布局需求。
  const node = elementNS(namespace, tag);
  node.style = {};
  node.getBBox = () => {
    const context = measurementCanvas().getContext('2d');
    context.font = `${node.getAttribute('font-size') || 14}px ${node.getAttribute('font-family') || 'Arial'}`;
    const metrics = context.measureText(node.textContent || '');
    return {
      width: metrics.width,
      height: metrics.actualBoundingBoxAscent + metrics.actualBoundingBoxDescent,
      x: 0,
      y: -metrics.actualBoundingBoxAscent,
    };
  };
  return node;
};
document.body = element('body');
document.documentElement.appendChild(document.body);
globalThis.document = document;
const { renderToString } = await import(pathToFileURL(require.resolve('@plantuml/core')));
const root = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..');
const source = path.join(root, 'docs/architecture/uml');
const output = path.join(source, 'rendered');
await mkdir(output, { recursive: true });
for (const filename of (await readdir(source)).filter(name => name.endsWith('.puml')).sort()) {
  // 每张图独立渲染并检查错误文本；错误图不能被当作正常产物覆盖已有预览。
  const text = await readFile(path.join(source, filename), 'utf8');
  const rendered = await new Promise((resolve, reject) => renderToString(text.split('\n'), resolve, reject));
  const xml = new DOMParser().parseFromString(rendered, 'image/svg+xml');
  const labels = Array.from(xml.getElementsByTagName('text'), node => node.textContent).join('\n');
  if (xml.documentElement.tagName !== 'svg' || /syntax error|error line|assumed diagram type|an error has occurr/i.test(labels)) {
    throw new Error(`${filename}: renderer returned an error diagram\n${labels}`);
  }
  // Explicit opaque paper keeps arrows/labels legible in dark Markdown viewers.
  const paper = xml.createElementNS('http://www.w3.org/2000/svg', 'rect');
  for (const [key, value] of Object.entries({ x: '0', y: '0', width: '100%', height: '100%', fill: '#FFFFFF' })) paper.setAttribute(key, value);
  xml.documentElement.insertBefore(paper, xml.documentElement.firstChild);
  const svg = new XMLSerializer().serializeToString(xml);
  // 同时保存可缩放 SVG 和通用 PNG；写完读取 PNG 元数据确认生成尺寸。
  const stem = filename.slice(0, -5);
  await writeFile(path.join(output, `${stem}.svg`), svg);
  // High-resolution PNG is the universally visible Markdown preview; SVG keeps zoomable text.
  const png = sharp(Buffer.from(svg), { density: 192 });
  await png.png().toFile(path.join(output, `${stem}.png`));
  const metadata = await sharp(path.join(output, `${stem}.png`)).metadata();
  console.log(`${filename} -> SVG + PNG (${metadata.width}×${metadata.height})`);
}