/* Gradio API 桥: POST /gradio_api/call/<name> -> event_id -> SSE complete */

export const LS = {
  get: (k: string, d: string | null = null) => localStorage.getItem("celestial_" + k) ?? d,
  set: (k: string, v: string) => localStorage.setItem("celestial_" + k, v),
  del: (k: string) => localStorage.removeItem("celestial_" + k),
}

/* 设备标识: 档案与创建它的设备/浏览器绑定 */
function deviceId(): string {
  let d = LS.get("device")
  if (!d) {
    d = crypto.randomUUID ? crypto.randomUUID() : `${Date.now()}-${Math.random().toString(36).slice(2)}`
    LS.set("device", d)
  }
  return d
}
export const DEVICE = deviceId()

export async function api<T = unknown>(name: string, args: unknown[] = []): Promise<T> {
  const post = await fetch(`/gradio_api/call/${name}`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ data: args }),
  })
  if (!post.ok) throw new Error(`后端未应答 (${post.status})`)
  const { event_id } = await post.json()
  const res = await fetch(`/gradio_api/call/${name}/${event_id}`)
  const text = await res.text()
  let event = ""
  let data: unknown[] | null = null
  for (const raw of text.split("\n")) {
    if (raw.startsWith("event:")) event = raw.slice(6).trim()
    else if (raw.startsWith("data:")) {
      const payload = raw.slice(5).trim()
      if (event === "complete" && payload) data = JSON.parse(payload)
      if (event === "error") throw new Error(payload && payload !== "null" ? payload : "天问服务出错")
    }
  }
  if (data === null) throw new Error("天问服务未应答，请确认 app.py 已运行")
  return data[0] as T
}

/* Windows 后端返回的 FileData url 含反斜杠 */
export const fileUrl = (fd: { url?: string }) => String(fd.url || "").replace(/\\/g, "/")

/* 流式解读 (FastAPI 原生 SSE 路由 /stream/*): 每个事件 data:{"text": 累积全文},
   onText 每次收到当前完整文本; 命中安全护栏时后端直接推送替换后的安全文案。 */
export async function apiStream(path: string, body: object, onText: (text: string) => void): Promise<void> {
  // 90s 断流超时: 防止 LLM 卡死时无限等待
  const ctrl = new AbortController()
  const timer = setTimeout(() => ctrl.abort(), 90000)
  try {
    const res = await fetch(path, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(body),
      signal: ctrl.signal,
    })
    if (!res.ok || !res.body) throw new Error(`流式服务未应答 (${res.status})`)
    const reader = res.body.getReader()
    const decoder = new TextDecoder()
    let buf = ""
    for (;;) {
      const { done, value } = await reader.read()
      if (done) break
      buf += decoder.decode(value, { stream: true })
      const events = buf.split("\n\n")
      buf = events.pop() ?? ""
      for (const evt of events) {
        const dataLine = evt.split("\n").find((l) => l.startsWith("data:"))
        if (!dataLine) continue
        try {
          const o = JSON.parse(dataLine.slice(5).trim())
          if (typeof o.text === "string") onText(o.text)
        } catch { /* 忽略不完整片段 */ }
      }
    }
  } finally {
    clearTimeout(timer)
  }
}