import { isApiError } from "@/lib/errors"

export type UploadFileType = "avatar" | "chat" | "post" | "verification" | "dispute"

function getCookieValue(name: string): string | null {
  if (typeof document === "undefined") return null
  if (!document.cookie) return null

  for (const part of document.cookie.split("; ")) {
    if (part.startsWith(`${name}=`)) return part.slice(name.length + 1)
  }
  return null
}

let csrfReady: Promise<void> | null = null

async function prepareCsrf() {
  if (getCookieValue("__Host-XSRF-TOKEN") && getCookieValue("__Host-XSRF-GUARD")) return

  csrfReady ??= fetch("/healthz", {
    cache: "no-store",
    credentials: "include",
  })
    .then(() => {})
    .finally(() => {
      csrfReady = null
    })
  await csrfReady

  if (!getCookieValue("__Host-XSRF-TOKEN")) {
    await fetch("/api/v1/games?offset=0&limit=1", {
      cache: "no-store",
      credentials: "include",
    })
  }
}

async function readJsonBody(res: Response): Promise<{ json: unknown | null; text: string }> {
  const text = await res.text()
  if (!text) return { json: null, text: "" }

  try {
    return { json: JSON.parse(text) as unknown, text }
  } catch {
    return { json: null, text }
  }
}

function messageFromJson(json: unknown): string | undefined {
  if (typeof json !== "object" || json === null) return undefined
  const value = json as { message?: unknown; msg?: unknown }
  if (typeof value.message === "string") return value.message
  if (typeof value.msg === "string") return value.msg
  return undefined
}

export async function getFileById(fileId: string): Promise<Blob> {
  const res = await fetch(`/api/v1/files?key=${encodeURIComponent(fileId)}`)

  if (res.ok) return await res.blob()

  const text = await res.text()
  let json: unknown = null
  if (text) {
    try {
      json = JSON.parse(text) as unknown
    } catch {
      json = null
    }
  }

  const maybeObj = (typeof json === "object" && json !== null ? json : null) as {
    code?: unknown
    message?: unknown
    msg?: unknown
  } | null

  const code = (typeof maybeObj?.code === "number" ? maybeObj.code : res.status) as number
  const msg =
    typeof maybeObj?.message === "string"
      ? maybeObj.message
      : typeof maybeObj?.msg === "string"
        ? maybeObj.msg
        : text || res.statusText || "Request failed"

  if (res.status === 401 || code === 401) throw new Error("UNAUTHORIZED")

  throw { code, msg }
}

export async function uploadFile(file: File, type: UploadFileType): Promise<string> {
  const formData = new FormData()
  formData.set("type", type)
  formData.set("file", file)

  await prepareCsrf()

  const headers = new Headers()
  const xsrfToken = getCookieValue("__Host-XSRF-TOKEN")
  if (xsrfToken) headers.set("XSRF-TOKEN", xsrfToken)

  const res = await fetch("/api/v1/upload", {
    method: "POST",
    headers,
    body: formData,
    credentials: "include",
  })

  const { json, text } = await readJsonBody(res)

  if (res.ok) {
    if (typeof json === "object" && json !== null) {
      const value = json as { url?: unknown }
      if (typeof value.url === "string") return value.url
    }
    throw { code: 500, msg: "上传响应缺少文件地址" }
  }

  if (res.status === 401) throw new Error("UNAUTHORIZED")
  if (isApiError(json)) throw json

  throw {
    code: res.status,
    msg: messageFromJson(json) ?? (text || res.statusText || "Request failed"),
  }
}