init

render.ts

@@ -0,0 +1,123 @@
+import { readdirSync, statSync, readFileSync, mkdirSync, writeFileSync } from "node:fs"
+import { join } from "node:path"
+
+const IF_PATH_RE = /^<@if\(context\.(.+?)\)>(.*)$/
+const VAR_RE = /<@var\(context\.(.+?)(?::(\w+))?\)>/g
+const DIRECTIVE_RE = /<@(if|elseif|else|endif)(?:\(context\.(.+?)\))?>/g
+
+function resolve(context: Record<string, unknown>, path: string): unknown {
+  const segments = path.split(".")
+  let current: unknown = context
+  for (const seg of segments) {
+    if (current === null || current === undefined || typeof current !== "object") return undefined
+    current = (current as Record<string, unknown>)[seg]
+  }
+  return current
+}
+
+// Each stack frame tracks: did any branch match yet, is the current branch active
+type IfFrame = { matched: boolean; active: boolean }
+
+function processIfBlocks(content: string, context: Record<string, unknown>): string {
+  let result = ""
+  let pos = 0
+  const stack: IfFrame[] = []
+
+  const re = new RegExp(DIRECTIVE_RE.source, "g")
+  let match: RegExpExecArray | null
+
+  function isEmitting(): boolean {
+    return stack.every(f => f.active)
+  }
+
+  while ((match = re.exec(content)) !== null) {
+    const directive = match[1]!
+    const condPath = match[2]
+
+    if (directive === "if") {
+      if (isEmitting()) result += content.slice(pos, match.index)
+      const truthy = !!resolve(context, condPath!)
+      stack.push({ matched: truthy, active: truthy })
+      pos = re.lastIndex
+    } else if (directive === "elseif") {
+      if (stack.length === 0) throw new Error("Unexpected <@elseif> without <@if>")
+      const top = stack[stack.length - 1]!
+      // Emit text before this directive if current branch was active
+      if (isEmitting()) result += content.slice(pos, match.index)
+      if (top.matched) {
+        // A previous branch already matched — skip this one
+        top.active = false
+      } else {
+        const truthy = !!resolve(context, condPath!)
+        top.matched = truthy
+        top.active = truthy
+      }
+      pos = re.lastIndex
+    } else if (directive === "else") {
+      if (stack.length === 0) throw new Error("Unexpected <@else> without <@if>")
+      const top = stack[stack.length - 1]!
+      if (isEmitting()) result += content.slice(pos, match.index)
+      top.active = !top.matched
+      top.matched = true
+      pos = re.lastIndex
+    } else if (directive === "endif") {
+      if (stack.length === 0) throw new Error("Unexpected <@endif> without <@if>")
+      if (isEmitting()) result += content.slice(pos, match.index)
+      stack.pop()
+      pos = re.lastIndex
+    }
+  }
+
+  if (stack.length > 0) {
+    throw new Error("Unmatched <@if> without <@endif>")
+  }
+
+  result += content.slice(pos)
+  return result
+}
+
+function renderContent(content: string, context: Record<string, unknown>): string {
+  const processed = processIfBlocks(content, context)
+  return processed.replace(VAR_RE, (_match, path: string) => {
+    return String(resolve(context, path) ?? "")
+  })
+}
+
+function renderDir(
+  srcDir: string,
+  destDir: string,
+  context: Record<string, unknown>,
+) {
+  mkdirSync(destDir, { recursive: true })
+  const entries = readdirSync(srcDir).sort()
+
+  for (const entry of entries) {
+    const srcPath = join(srcDir, entry)
+    const stat = statSync(srcPath)
+
+    // Check if path segment has an @if directive
+    const ifMatch = entry.match(IF_PATH_RE)
+    let outputName = entry
+    if (ifMatch) {
+      const conditionPath = ifMatch[1]!
+      if (!resolve(context, conditionPath)) continue
+      outputName = ifMatch[2]!
+    }
+
+    // Process @var in the output name
+    outputName = outputName.replace(VAR_RE, (_match, path: string) => {
+      return String(resolve(context, path) ?? "")
+    })
+
+    const destPath = join(destDir, outputName)
+    if (stat.isDirectory()) {
+      renderDir(srcPath, destPath, context)
+    } else {
+      mkdirSync(destDir, { recursive: true })
+      const content = readFileSync(srcPath, "utf-8")
+      writeFileSync(destPath, renderContent(content, context))
+    }
+  }
+}
+
+export { renderDir, renderContent }