/**
 * dsh-float-window — Host 半（标准 DSH / cordis 插件）
 *
 * 职责：
 *  1. 把原生浮窗需要的接入信息写成 `%DSH_HOME%\float-window\endpoint.json`
 *     （WebView2 壳读它来连这里；因为壳是独立进程，拿不到 ctx）。
 *  2. 提供 SSE 数据通道 `/dsh-float-window/events`：会话消息 + 计费指标快照。
 *  3. 提供 `/dsh-float-window/cmd`：浮窗 → 宿主的控制命令。
 *  4. 注册 `float_window` 工具，让 Agent 能自己把浮窗调出来 / 收起 / 置顶 / 全屏。
 *
 * 设计原则：宿主内部 API 一律"探测式"使用（ctx.get(...) + try/catch），
 * 任何一个服务缺失都只是少几个指标，绝不能让插件加载失败拖垮 DSH。
 */
import fs from 'node:fs'
import os from 'node:os'
import path from 'node:path'
import { fileURLToPath } from 'node:url'

export const name = 'dsh-float-window'
export const inject = ['webServer']

const HERE = path.dirname(fileURLToPath(import.meta.url))
const REPO = path.resolve(HERE, '..')
const ROUTE = '/dsh-float-window'

function dshHome() {
  return process.env.DSH_HOME || path.join(os.homedir(), '.dsh')
}

/** 会话事件 → 浮窗消息行的宽松映射（不同版本字段不完全一致，宁可少显示也不要报错） */
function toRow(event) {
  if (!event || typeof event !== 'object') return null
  const type = String(event.type || '')
  const text = (v) => (typeof v === 'string' ? v : '')
  if (type === 'tool/call') {
    return { role: 'tool', text: `${event.name || event.tool || 'tool'}(${short(event.args ?? event.input)})` }
  }
  if (type === 'tool/result') return null
  const msg = event.message
  const role = msg?.role || event.role || (type.includes('user') ? 'user' : type.includes('assistant') ? 'assistant' : '')
  if (!role) return null
  let body = ''
  const content = msg?.content ?? event.content ?? event.text
  if (typeof content === 'string') body = content
  else if (Array.isArray(content)) body = content.map((c) => (typeof c === 'string' ? c : text(c?.text))).join('')
  if (!body) return null
  return { role, text: body.length > 4000 ? body.slice(0, 4000) + '…' : body, streaming: /delta|chunk|stream/.test(type) }
}

function short(v, n = 120) {
  try {
    const s = typeof v === 'string' ? v : JSON.stringify(v)
    return s && s.length > n ? s.slice(0, n) + '…' : s || ''
  } catch { return '' }
}

export function apply(ctx) {
  const log = (...a) => { try { (ctx.logger?.info || console.log)('[float-window]', ...a) } catch { } }

  // ---------------------------------------------------------------- endpoint
  const endpointFile = path.join(dshHome(), 'float-window', 'endpoint.json')
  const writeEndpoint = () => {
    try {
      fs.mkdirSync(path.dirname(endpointFile), { recursive: true })
      const data = {
        baseUrl: `http://127.0.0.1:${ctx.webServer.port}`,
        host: ctx.webServer.host,
        pid: process.pid,
        updatedAt: new Date().toISOString(),
      }
      fs.writeFileSync(endpointFile, JSON.stringify(data, null, 2))
      log('endpoint written', data.baseUrl, '->', endpointFile)
    } catch (e) { log('endpoint write failed:', String(e?.message || e)) }
  }
  writeEndpoint()
  ctx.effect(() => () => { try { fs.rmSync(endpointFile, { force: true }) } catch { } })

  // ---------------------------------------------------------------- 会话镜像缓冲
  const MAX_ROWS = 120
  const rows = new Map() // sessionId -> row[]
  let lastSessionId = null

  ctx.on('session/event', (session, event) => {
    try {
      const id = session?.id || session?.sessionId || 'unknown'
      lastSessionId = id
      const row = toRow(event)
      if (!row) return
      const list = rows.get(id) || []
      const last = list[list.length - 1]
      if (row.streaming && last && last.role === row.role && last.streaming) last.text += row.text
      else list.push(row)
      while (list.length > MAX_ROWS) list.shift()
      rows.set(id, list)
    } catch { }
  })

  // ---------------------------------------------------------------- 指标
  function metricsFor(session) {
    const out = { turns: null, steps: null, tps: null, tokens: null, cacheHit: null, contextUsed: null }
    try {
      const proj = ctx.get('sessionProjection')
      const stats = proj?.get?.(session, 'sessionStats') || proj?.peek?.(session, 'sessionStats')
      if (stats) {
        out.turns = stats.turns ?? null
        out.steps = stats.steps ?? null
        if (stats.decodeTokens && stats.decodeMs) out.tps = (stats.decodeTokens / (stats.decodeMs / 1000))
      }
    } catch { }
    try {
      const meter = ctx.get('tokenMeter')
      const m = meter?.measure?.(session)
      if (m) {
        out.tokens = m.totalTokens ?? m.surfaceTokens ?? null
        const u = m.usage || m.providerUsage
        if (u) {
          const read = u.cacheRead ?? u.cache_read ?? 0
          const input = (u.input ?? 0) + read
          if (input > 0) out.cacheHit = read / input
        }
        const capacity = ctx.get('llm')?.resolveModelInfo?.()?.context
        const used = m.surfaceTokens ?? m.totalTokens
        if (capacity && used) out.contextUsed = Math.min(1, used / capacity)
      }
    } catch { }
    return out
  }

  function snapshot() {
    const sessions = (() => { try { return ctx.get('sessions')?.list?.() || [] } catch { return [] } })()
    let session = sessions.find((s) => s?.id === lastSessionId) || sessions[sessions.length - 1] || null
    const id = session?.id || lastSessionId
    return {
      ok: true,
      at: Date.now(),
      sessionId: id || null,
      title: session?.meta?.title || session?.title || null,
      messages: (id && rows.get(id)) || [],
      metrics: session ? metricsFor(session) : { turns: null, steps: null, tps: null, tokens: null, cacheHit: null, contextUsed: null },
      sessions: sessions.slice(-10).map((s) => ({ id: s?.id, title: s?.meta?.title || s?.title || null })),
    }
  }

  // ---------------------------------------------------------------- 路由
  const sseClients = new Set()
  const push = () => {
    if (!sseClients.size) return
    const payload = `data: ${JSON.stringify(snapshot())}\n\n`
    for (const res of sseClients) { try { res.write(payload) } catch { } }
  }
  const tick = setInterval(push, 1000)
  ctx.effect(() => () => clearInterval(tick))

  const handler = async (req, res) => {
    const url = new URL(req.url || '/', 'http://127.0.0.1')
    const cors = {
      'Access-Control-Allow-Origin': '*',
      'Access-Control-Allow-Headers': 'content-type',
      'Access-Control-Allow-Methods': 'GET,POST,OPTIONS',
    }
    if (req.method === 'OPTIONS') { res.writeHead(204, cors); res.end(); return }
    if (url.pathname === `${ROUTE}/events`) {
      res.writeHead(200, { ...cors, 'Content-Type': 'text/event-stream; charset=utf-8', 'Cache-Control': 'no-cache', Connection: 'keep-alive' })
      res.write(': connected\n\n')
      res.write(`data: ${JSON.stringify(snapshot())}\n\n`)
      sseClients.add(res)
      req.on('close', () => sseClients.delete(res))
      return
    }
    if (url.pathname === `${ROUTE}/state`) {
      res.writeHead(200, { ...cors, 'Content-Type': 'application/json; charset=utf-8' })
      res.end(JSON.stringify(snapshot()))
      return
    }
    if (url.pathname === `${ROUTE}/health`) {
      res.writeHead(200, { ...cors, 'Content-Type': 'application/json; charset=utf-8' })
      res.end(JSON.stringify({ ok: true, version: '0.1.0', shell: shellPath() }))
      return
    }
    res.writeHead(404, { ...cors, 'Content-Type': 'text/plain; charset=utf-8' })
    res.end('dsh-float-window: not found')
  }
  ctx.effect(() => ctx.webServer.register({ kind: 'prefix', path: ROUTE, handler }))

  // ---------------------------------------------------------------- 壳进程
  const stateDir = path.join(dshHome(), 'float-window')
  const cmdFile = path.join(stateDir, 'command.json')
  const aliveFile = path.join(stateDir, 'alive.json')

  function shellPath() {
    return path.join(REPO, 'shell', 'run-float.cmd')
  }

  /** 壳每 700ms 写一次心跳，据此判断浮窗是否还活着 */
  function shellAlive() {
    try { return Date.now() - fs.statSync(aliveFile).mtimeMs < 8000 } catch { return false }
  }

  async function spawnShell() {
    const cmd = shellPath()
    if (!fs.existsSync(cmd)) return { ok: false, error: `launcher not found: ${cmd}` }
    try {
      const shell = ctx.get('shell')
      const sp = ctx.get('sandboxPolicy')
      const policy = sp?.resolve?.({ mode: 'danger-full-access' })
      if (shell?.resolve && shell?.run) {
        const spec = shell.resolve({ command: `cmd /c start "" "${cmd}"`, ...(policy ? { sandboxPolicy: policy } : {}) })
        await shell.run(spec)
        return { ok: true, via: 'ctx.shell' }
      }
    } catch (e) { log('ctx.shell launch failed, fallback to spawn:', String(e?.message || e)) }
    try {
      const { spawn } = await import('node:child_process')
      spawn('cmd', ['/c', 'start', '', cmd], { detached: true, stdio: 'ignore', windowsHide: true }).unref()
      return { ok: true, via: 'spawn' }
    } catch (e) { return { ok: false, error: String(e?.message || e) } }
  }

  /** 浮窗已经在跑就投递命令，否则按需拉起 */
  async function controlFloat(action) {
    if (action === 'open' && !shellAlive()) return spawnShell()
    if (action === 'close' && !shellAlive()) return { ok: true, via: 'already closed' }
    try {
      fs.mkdirSync(stateDir, { recursive: true })
      fs.writeFileSync(cmdFile, JSON.stringify({ cmd: action, at: new Date().toISOString() }))
      return { ok: true, via: 'command file' }
    } catch (e) { return { ok: false, error: String(e?.message || e) } }
  }

  // ---------------------------------------------------------------- Agent 工具
  try {
    const tools = ctx.get('tools')
    if (tools?.register) {
      tools.register({
        name: 'float_window',
        description: '控制 DSH 悬浮窗（始终置顶的会话镜像小窗）：open 打开/聚焦，close 关闭，pin 切换固定位置，fullscreen 切换全屏，hide 临时隐藏（抓屏前用）。',
        parameters: {
          action: { type: 'string', required: true, description: 'open | close | pin | fullscreen | hide | status' },
        },
        output: { schema: { type: 'string' }, render: (_a, v) => [{ type: 'text', text: v }] },
        async execute(args) {
          const action = String(args?.action || 'open')
          if (action === 'status') {
            const s = snapshot()
            return `float-window: alive=${shellAlive()} session=${s.sessionId || 'none'} messages=${s.messages.length} turns=${s.metrics.turns ?? '?'} steps=${s.metrics.steps ?? '?'}`
          }
          if (action === 'hide') { broadcast({ type: 'cmd', cmd: 'hide' }); const r = await controlFloat('hide'); return `float-window: hide (${r.via || r.error})` }
          const r = await controlFloat(action)
          return r.ok ? `float-window: ${action} ok (${r.via})` : `float-window: ${action} failed: ${r.error}`
        },
      })
      log('tool float_window registered')
    } else {
      log('tools service not available; agent trigger disabled')
    }
  } catch (e) { log('tool registration failed:', String(e?.message || e)) }

  const broadcast = (msg) => {
    const payload = `data: ${JSON.stringify(msg)}\n\n`
    for (const res of sseClients) { try { res.write(payload) } catch { } }
  }
  const pushHidden = () => broadcast({ type: 'cmd', cmd: 'hide' })

  // 抓屏前隐藏的对外门面：交给宿主的共享对象。
  // 注意 cordis 要求先 provide 再 set，否则会抛 "cannot set property ... without provide"
  // （实测：漏了 provide 会让整个插件树加载失败、DSH 起不来）。这里做成可选的，
  // 拿不到 provide 就退化成只广播 SSE 命令。
  try {
    ctx.provide?.('floatWindow')
    ctx.set?.('floatWindow', { hide: pushHidden, show: () => broadcast({ type: 'cmd', cmd: 'show' }), snapshot, endpoint: () => endpointFile })
  } catch (e) { log('floatWindow facade skipped:', String(e?.message || e)) }

  // ---------------------------------------------------------------- DSH 设置入口
  // 注册一个设置命名空间，DSH 的「设置 → 插件」会把它渲染成一张卡片。
  // schemastery 是从 profile 的 node_modules 解析的；link: 安装的插件解析不到时
  // 只跳过这一步（浮窗自己的设置面板照常可用）。
  ; (async () => {
    try {
      const settings = ctx.get('settings')
      if (!settings?.register) { log('settings service absent; skip settings entry'); return }
      let z = null
      try { z = (await import('@deepseek-ai/schemastery')).default } catch { }
      if (!z) { log('schemastery not resolvable; skip settings entry'); return }
      const schema = z.object({
        topmost: z.boolean().default(true).description('始终置顶'),
        posLock: z.boolean().default(false).description('固定位置'),
        sizeLock: z.boolean().default(false).description('锁定尺寸'),
        exclude: z.boolean().default(true).description('抓屏时隐藏本窗'),
        opacity: z.number().min(0.3).max(1).default(0.92).description('不透明度'),
        scale: z.number().min(0.8).max(1.5).default(1).description('界面缩放'),
        backdrop: z.union(['opaque', 'translucent', 'acrylic', 'mica', 'blur']).default('opaque').description('背景效果'),
      })
      const scope = settings.register('dsh-float-window', schema)
      const scope2 = scope
      ctx.effect(() => {
        const stop = scope2.watch?.((next) => {
          try { broadcast({ type: 'settings', value: next?.value ?? next }) } catch { }
        })
        return () => { try { stop?.() } catch { } }
      })
      log('settings namespace registered')
    } catch (e) { log('settings registration failed:', String(e?.message || e)) }
  })()

  log('ready; endpoints:', `${ROUTE}/events`, `${ROUTE}/state`, `${ROUTE}/health`)
}