feat: 初始提交（仅核心代码，已排除大文件）

src/server/logger.js

@@ -0,0 +1,86 @@
+const fs = require('fs')
+const path = require('path')
+
+const logsDir = path.join(process.cwd(), 'logs')
+if (!fs.existsSync(logsDir)) fs.mkdirSync(logsDir, { recursive: true })
+const logFile = path.join(logsDir, 'app.log')
+if (!fs.existsSync(logFile)) fs.writeFileSync(logFile, '')
+const channelFileCache = new Map()
+let pendingWrites = new Map()
+let flushScheduled = false
+
+const ts = () => new Date().toISOString()
+
+const ensureChannel = channel => {
+  const name = String(channel || '').trim()
+  if (!name) return null
+  if (channelFileCache.has(name)) return channelFileCache.get(name)
+  const file = path.join(logsDir, `${name}.log`)
+  if (!fs.existsSync(file)) fs.writeFileSync(file, '')
+  channelFileCache.set(name, file)
+  return file
+}
+
+const flushPendingWrites = () => {
+  flushScheduled = false
+  if (pendingWrites.size === 0) return
+  const batch = pendingWrites
+  pendingWrites = new Map()
+  batch.forEach((content, file) => {
+    fs.appendFile(file, content, () => {})
+  })
+  if (pendingWrites.size > 0) scheduleFlush()
+}
+
+const scheduleFlush = () => {
+  if (flushScheduled) return
+  flushScheduled = true
+  setImmediate(flushPendingWrites)
+}
+
+const enqueueWrite = (file, line) => {
+  const prev = pendingWrites.get(file) || ''
+  pendingWrites.set(file, prev + line)
+  scheduleFlush()
+}
+
+const log = (msg, channel) => {
+  const line = `${ts()} ${String(msg)}\n`
+  enqueueWrite(logFile, line)
+  const chFile = ensureChannel(channel)
+  if (chFile) enqueueWrite(chFile, line)
+}
+
+const logJSON = (label, obj, channel) => {
+  let s = ''
+  try { s = JSON.stringify(obj) } catch { s = String(obj) }
+  log(`${label} ${s}`, channel)
+}
+
+const getLogs = (limit = 2000, channel) => {
+  let file = logFile
+  const chFile = ensureChannel(channel)
+  if (chFile) file = chFile
+  let content = ''
+  try {
+    const stat = fs.statSync(file)
+    const maxReadBytes = Math.min(stat.size, 512 * 1024)
+    const start = Math.max(0, stat.size - maxReadBytes)
+    const fd = fs.openSync(file, 'r')
+    const buf = Buffer.alloc(maxReadBytes)
+    const bytesRead = fs.readSync(fd, buf, 0, maxReadBytes, start)
+    fs.closeSync(fd)
+    content = buf.subarray(0, bytesRead).toString('utf-8')
+  } catch {}
+  const lines = content.split(/\r?\n/).filter(Boolean)
+  const tail = lines.slice(Math.max(0, lines.length - limit))
+  return tail
+}
+
+const clearLogs = channel => {
+  const chFile = ensureChannel(channel)
+  if (chFile) fs.truncateSync(chFile, 0)
+  else fs.truncateSync(logFile, 0)
+}
+
+module.exports = { log, logJSON, getLogs, clearLogs }