// DSH 动态 Cordis 插件 —— 文件拖拽上传（Host 半）
// 本文件是 cordis_define 的 code.host 函数体：直接整文件复制使用。
// 职责：接收 Client 上传的 base64 文件内容，写入系统临时目录下的 dsh-file-drop/ 目录（便于系统自动清理）。
return {
  apply(ctx) {
    harness.handle('drop-upload', async (args) => {
      const fs = ctx.get('fs')
      const shell = ctx.get('shell')
      const sessions = ctx.get('sessions')
      const sandboxPolicy = ctx.get('sandboxPolicy')

      const isObj = (v) => v !== null && typeof v === 'object'
      const session = sessions !== undefined && isObj(args) && typeof args.sessionId === 'string'
        ? sessions.get(args.sessionId)
        : undefined

      let policy = undefined
      if (sandboxPolicy !== undefined) {
        policy = sandboxPolicy.resolve(session !== undefined ? { session } : {})
      }
      let root = policy !== undefined && typeof policy.workspaceRoot === 'string'
        ? policy.workspaceRoot
        : (session !== undefined && typeof session.header.cwd === 'string' ? session.header.cwd : undefined)
      if (typeof root !== 'string' || root === '') return { ok: false, error: 'Cannot resolve workspace root' }
      const execPolicy = policy !== undefined && policy.mode !== undefined
        ? { mode: policy.mode, workspaceRoot: root }
        : undefined
      // 平台探测（沙箱里没有 process.platform）：Windows 的 workspace/cwd 以盘符或 UNC 开头。
      // DSH 在 Windows 上挂载 pwsh shell 栈、在 POSIX 上挂载 bash 栈，命令方言与路径分隔符都要跟随。
      const isWindows = /^[A-Za-z]:[\\/]/.test(root) || /^[\\/]{2}/.test(root)
      const sep = isWindows ? '\\' : '/'

      const files = isObj(args) && Array.isArray(args.files) ? args.files : []
      if (files.length === 0) return { ok: false, error: 'No files to save' }
      if (files.length > 6) return { ok: false, error: 'Too many files (max 6)' }
      if (fs === undefined) return { ok: false, error: 'Filesystem service unavailable' }

      if (shell === undefined) return { ok: false, error: 'Shell service unavailable' }
      let dropDir = ''
      try {
        // 一条命令完成：取系统临时目录 → 创建 dsh-file-drop 子目录 → 输出绝对路径。
        // POSIX（Linux/macOS）：$TMPDIR 缺省 /tmp；Windows：%TEMP%（与 Node os.tmpdir() 同源）。
        // workspace-write 模式下系统临时目录与 /tmp 都在沙箱可写根集合内，与 fs 围栏的 writableRoots 一致。
        const makeCommand = isWindows
          ? '$dir = Join-Path ([System.IO.Path]::GetTempPath()) "dsh-file-drop"; New-Item -ItemType Directory -Force -Path $dir | Out-Null; Write-Output $dir'
          : 'base="${TMPDIR:-/tmp}"; base="${base%/}"; dir="$base/dsh-file-drop"; mkdir -p "$dir" && printf %s "$dir"'
        const spec = shell.resolve({
          command: makeCommand,
          workdir: root,
          sandboxPolicy: execPolicy,
        })
        const made = await shell.run(spec)
        if (made.exitCode !== 0) {
          return { ok: false, error: 'Failed to create dsh-file-drop directory (exit ' + String(made.exitCode) + ')' }
        }
        dropDir = isObj(made.stdout) && typeof made.stdout.text === 'string' ? made.stdout.text.trim() : ''
        if (dropDir === '') return { ok: false, error: 'Failed to resolve system temp directory' }
      } catch (err) {
        return { ok: false, error: 'Failed to create dsh-file-drop directory: ' + messageOf(err) }
      }

      const saved = []
      for (const item of files) {
        const base = sanitizeName(isObj(item) && typeof item.name === 'string' ? item.name : '')
        if (base === '') {
          saved.push({ name: '', ok: false, error: 'Invalid file name' })
          continue
        }
        if (isObj(item) && item.binary === true) {
          saved.push({ name: base, ok: false, error: 'Binary files are not supported' })
          continue
        }
        const b64 = isObj(item) && typeof item.contentBase64 === 'string' ? item.contentBase64 : ''
        if (b64 === '') {
          saved.push({ name: base, ok: false, error: 'Empty content' })
          continue
        }
        let content = ''
        try {
          content = atob(b64)
        } catch (err) {
          saved.push({ name: base, ok: false, error: 'Invalid content encoding' })
          continue
        }
        let name = base
        let n = 2
        while (n < 100) {
          try {
            const probe = await fs.resolve(dropDir + sep + name)
            const st = await fs.stat(probe)
            if (st === undefined) break
          } catch (err) {
            break
          }
          name = suffixName(base, n)
          n += 1
        }
        try {
          const target = await fs.resolve(dropDir + sep + name)
          await fs.writeText(target, content, undefined, undefined, execPolicy)
          saved.push({ name, path: dropDir + sep + name, size: content.length, ok: true })
        } catch (err) {
          saved.push({ name, ok: false, error: 'Write failed: ' + messageOf(err) })
        }
      }

      const okCount = saved.filter((f) => f.ok === true).length
      return { ok: okCount > 0, okCount, files: saved }
    })

    function sanitizeName(name) {
      let out = String(name).replace(/\\/g, '/')
      const idx = out.lastIndexOf('/')
      if (idx !== -1) out = out.slice(idx + 1)
      out = out.replace(/[\u0000-\u001f\u007f]/g, '')
      // Windows 文件名非法字符与保留设备名（CON/PRN/AUX/NUL/COM1-9/LPT1-9），替换保证三大平台都可落盘。
      out = out.replace(/[<>:"|?*]/g, '_')
      if (/^(con|prn|aux|nul|com[1-9]|lpt[1-9])(?:\.|$)/i.test(out)) out = '_' + out
      out = out.trim()
      if (out === '.' || out === '..' || out === '') return ''
      if (out.length > 80) {
        const dot = out.lastIndexOf('.')
        if (dot > 0) out = out.slice(0, Math.max(1, 80 - (out.length - dot))) + out.slice(dot)
        else out = out.slice(0, 80)
      }
      return out
    }

    function suffixName(name, n) {
      const dot = name.lastIndexOf('.')
      if (dot > 0) return name.slice(0, dot) + '-' + n + name.slice(dot)
      return name + '-' + n
    }

    function messageOf(err) {
      if (err !== null && typeof err === 'object' && typeof err.message === 'string') return err.message
      return String(err)
    }
  },
}