Initial shared Copilot resources scaffold

install/merge-vscode-settings.mjs

@@ -0,0 +1,248 @@
+#!/usr/bin/env node
+
+import fs from 'node:fs';
+import path from 'node:path';
+
+function usage() {
+  console.error(
+    'Usage: node install/merge-vscode-settings.mjs --target <settings.json> --template <settings.template.jsonc> [--set NAME=value]'
+  );
+}
+
+function parseArgs(argv) {
+  const options = {
+    replacements: {},
+  };
+
+  for (let index = 0; index < argv.length; index += 1) {
+    const arg = argv[index];
+
+    if (arg === '--target') {
+      options.target = argv[index + 1];
+      index += 1;
+      continue;
+    }
+
+    if (arg === '--template') {
+      options.template = argv[index + 1];
+      index += 1;
+      continue;
+    }
+
+    if (arg === '--set') {
+      const assignment = argv[index + 1] ?? '';
+      const equalsIndex = assignment.indexOf('=');
+      if (equalsIndex <= 0) {
+        throw new Error(`Invalid --set assignment: ${assignment}`);
+      }
+      const key = assignment.slice(0, equalsIndex);
+      const value = assignment.slice(equalsIndex + 1);
+      options.replacements[key] = value;
+      index += 1;
+      continue;
+    }
+
+    throw new Error(`Unknown argument: ${arg}`);
+  }
+
+  if (!options.target || !options.template) {
+    usage();
+    throw new Error('Both --target and --template are required.');
+  }
+
+  return options;
+}
+
+function stripJsonComments(input) {
+  let output = '';
+  let inString = false;
+  let escaping = false;
+  let inLineComment = false;
+  let inBlockComment = false;
+
+  for (let index = 0; index < input.length; index += 1) {
+    const char = input[index];
+    const next = input[index + 1];
+
+    if (inLineComment) {
+      if (char === '\n') {
+        inLineComment = false;
+        output += char;
+      }
+      continue;
+    }
+
+    if (inBlockComment) {
+      if (char === '*' && next === '/') {
+        inBlockComment = false;
+        index += 1;
+      } else if (char === '\n' || char === '\r') {
+        output += char;
+      }
+      continue;
+    }
+
+    if (inString) {
+      output += char;
+      if (escaping) {
+        escaping = false;
+      } else if (char === '\\') {
+        escaping = true;
+      } else if (char === '"') {
+        inString = false;
+      }
+      continue;
+    }
+
+    if (char === '"') {
+      inString = true;
+      output += char;
+      continue;
+    }
+
+    if (char === '/' && next === '/') {
+      inLineComment = true;
+      index += 1;
+      continue;
+    }
+
+    if (char === '/' && next === '*') {
+      inBlockComment = true;
+      index += 1;
+      continue;
+    }
+
+    output += char;
+  }
+
+  return output;
+}
+
+function stripTrailingCommas(input) {
+  let output = '';
+  let inString = false;
+  let escaping = false;
+
+  for (let index = 0; index < input.length; index += 1) {
+    const char = input[index];
+
+    if (inString) {
+      output += char;
+      if (escaping) {
+        escaping = false;
+      } else if (char === '\\') {
+        escaping = true;
+      } else if (char === '"') {
+        inString = false;
+      }
+      continue;
+    }
+
+    if (char === '"') {
+      inString = true;
+      output += char;
+      continue;
+    }
+
+    if (char === ',') {
+      let lookahead = index + 1;
+      while (lookahead < input.length && /\s/.test(input[lookahead])) {
+        lookahead += 1;
+      }
+      if (input[lookahead] === '}' || input[lookahead] === ']') {
+        continue;
+      }
+    }
+
+    output += char;
+  }
+
+  return output;
+}
+
+function renderTemplate(input, replacements) {
+  return input.replace(/\{\{([A-Z0-9_]+)\}\}/g, (match, key) => {
+    if (!(key in replacements)) {
+      return match;
+    }
+    return replacements[key]
+      .replace(/\\/g, '\\\\')
+      .replace(/"/g, '\\"');
+  });
+}
+
+function parseJsonc(input, label) {
+  const sanitized = stripTrailingCommas(stripJsonComments(input)).trim();
+  if (!sanitized) {
+    return {};
+  }
+
+  let parsed;
+  try {
+    parsed = JSON.parse(sanitized);
+  } catch (error) {
+    throw new Error(`Failed to parse ${label}: ${error.message}`);
+  }
+
+  if (!isPlainObject(parsed)) {
+    throw new Error(`${label} must contain a JSON object at the root.`);
+  }
+
+  return parsed;
+}
+
+function isPlainObject(value) {
+  return value !== null && typeof value === 'object' && !Array.isArray(value);
+}
+
+function cloneValue(value) {
+  if (Array.isArray(value)) {
+    return value.map((item) => cloneValue(item));
+  }
+  if (isPlainObject(value)) {
+    return Object.fromEntries(
+      Object.entries(value).map(([key, nested]) => [key, cloneValue(nested)])
+    );
+  }
+  return value;
+}
+
+function deepMerge(target, source) {
+  const merged = { ...target };
+
+  for (const [key, value] of Object.entries(source)) {
+    if (isPlainObject(value) && isPlainObject(merged[key])) {
+      merged[key] = deepMerge(merged[key], value);
+      continue;
+    }
+    merged[key] = cloneValue(value);
+  }
+
+  return merged;
+}
+
+function main() {
+  const options = parseArgs(process.argv.slice(2));
+  const templateText = fs.readFileSync(options.template, 'utf8');
+  const renderedTemplate = renderTemplate(templateText, options.replacements);
+  const managedSettings = parseJsonc(renderedTemplate, options.template);
+
+  const targetText = fs.existsSync(options.target)
+    ? fs.readFileSync(options.target, 'utf8')
+    : '{}\n';
+  const currentSettings = parseJsonc(targetText, options.target);
+  const mergedSettings = deepMerge(currentSettings, managedSettings);
+  const output = `${JSON.stringify(mergedSettings, null, 2)}\n`;
+
+  fs.mkdirSync(path.dirname(options.target), { recursive: true });
+
+  if (output === targetText) {
+    console.log(`VS Code settings already up to date: ${options.target}`);
+    return;
+  }
+
+  fs.writeFileSync(options.target, output, 'utf8');
+  console.log(`Merged managed VS Code settings into: ${options.target}`);
+}
+
+main();