#!/usr/bin/env python3

import json
import os
import re
import secrets
import sys
import urllib.error
import urllib.request
from pathlib import Path

API_BASE = "https://api.cloudflare.com/client/v4"
ENV_FILE = Path("/tmp/huggingclaw-cloudflare-proxy.env")
DEFAULT_ALLOWED = [
    "api.telegram.org",
    "web.whatsapp.com",
]


def cf_request(method: str, path: str, token: str, body: bytes | None = None, content_type: str = "application/json"):
    req = urllib.request.Request(
        f"{API_BASE}{path}",
        data=body,
        method=method,
        headers={
            "Authorization": f"Bearer {token}",
            "Content-Type": content_type,
        },
    )
    with urllib.request.urlopen(req, timeout=30) as response:
        payload = json.loads(response.read().decode("utf-8"))
    if not payload.get("success"):
        errors = payload.get("errors") or [{"message": "Unknown Cloudflare API error"}]
        raise RuntimeError(errors[0].get("message", "Unknown Cloudflare API error"))
    return payload["result"]


def slugify(value: str) -> str:
    cleaned = re.sub(r"[^a-z0-9-]+", "-", value.lower()).strip("-")
    cleaned = re.sub(r"-{2,}", "-", cleaned)
    if not cleaned:
        cleaned = "huggingclaw-proxy"
    return cleaned[:63].rstrip("-")


def derive_worker_name() -> str:
    explicit = os.environ.get("CLOUDFLARE_WORKER_NAME", "").strip()
    if explicit:
        return slugify(explicit)
    space_host = os.environ.get("SPACE_HOST", "").strip()
    if space_host:
        base = space_host.replace(".hf.space", "")
        return slugify(f"{base}-proxy")
    return "huggingclaw-proxy"


def render_worker(secret_value: str, allowed_targets: list[str], allow_proxy_all: bool) -> str:
    allowed_json = json.dumps(allowed_targets)
    allow_all_js = "true" if allow_proxy_all else "false"
    secret_json = json.dumps(secret_value)
    return f"""addEventListener("fetch", (event) => {{
  event.respondWith(handleRequest(event.request));
}});

const PROXY_SHARED_SECRET = {secret_json};
const ALLOW_PROXY_ALL = {allow_all_js};
const ALLOWED_TARGETS = {allowed_json};

function isAllowedHost(hostname) {{
  const normalized = String(hostname || "").trim().toLowerCase();
  if (!normalized) return false;
  if (ALLOW_PROXY_ALL) return true;
  return ALLOWED_TARGETS.some(
    (domain) => normalized === domain || normalized.endsWith(`.${{domain}}`),
  );
}}

async function handleRequest(request) {{
  const url = new URL(request.url);
  const targetHost = request.headers.get("x-target-host");

  if (PROXY_SHARED_SECRET) {{
    const providedSecret = request.headers.get("x-proxy-key") || "";
    if (providedSecret !== PROXY_SHARED_SECRET) {{
      return new Response("Unauthorized", {{ status: 401 }});
    }}
  }}

  let targetBase = "";
  if (targetHost) {{
    if (!isAllowedHost(targetHost)) {{
      return new Response("Target host is not allowed.", {{ status: 403 }});
    }}
    targetBase = `https://${{targetHost}}`;
  }} else if (url.pathname.startsWith("/bot")) {{
    targetBase = "https://api.telegram.org";
  }} else {{
    return new Response("Invalid request.", {{ status: 400 }});
  }}

  const targetUrl = targetBase + url.pathname + url.search;
  const headers = new Headers(request.headers);
  headers.delete("cf-connecting-ip");
  headers.delete("cf-ray");
  headers.delete("cf-visitor");
  headers.delete("x-real-ip");
  headers.delete("x-target-host");

  const proxiedRequest = new Request(targetUrl, {{
    method: request.method,
    headers,
    body: request.body,
    redirect: "follow",
  }});

  try {{
    return await fetch(proxiedRequest);
  }} catch (error) {{
    return new Response(`Proxy Error: ${{error.message}}`, {{ status: 502 }});
  }}
}}
"""


def write_env(proxy_url: str, proxy_secret: str) -> None:
    ENV_FILE.write_text(
        "\n".join(
            [
                f'export CLOUDFLARE_PROXY_URL="{proxy_url}"',
                f'export CLOUDFLARE_PROXY_SECRET="{proxy_secret}"',
            ]
        )
        + "\n",
        encoding="utf-8",
    )


def main() -> int:
    existing_url = os.environ.get("CLOUDFLARE_PROXY_URL", "").strip()
    existing_secret = os.environ.get("CLOUDFLARE_PROXY_SECRET", "").strip()
    api_token = os.environ.get("CLOUDFLARE_API_TOKEN", "").strip()

    if existing_url:
      if existing_secret:
        write_env(existing_url, existing_secret)
      print(f"☁️ Using configured Cloudflare proxy: {existing_url}")
      return 0

    if not api_token:
        return 0

    account_id = os.environ.get("CLOUDFLARE_ACCOUNT_ID", "").strip()
    try:
        if not account_id:
            accounts = cf_request("GET", "/accounts", api_token)
            if not accounts:
                raise RuntimeError("No Cloudflare account available for this token.")
            account_id = accounts[0]["id"]

        subdomain_info = cf_request(
            "GET",
            f"/accounts/{account_id}/workers/subdomain",
            api_token,
        )
        subdomain = (subdomain_info or {}).get("subdomain", "").strip()
        if not subdomain:
            raise RuntimeError(
                "Cloudflare Workers subdomain is not configured. Enable workers.dev in your Cloudflare account first."
            )

        worker_name = derive_worker_name()
        allowed_raw = os.environ.get("CLOUDFLARE_PROXY_DOMAINS", "").strip()
        allow_proxy_all = not allowed_raw or allowed_raw == "*"
        allowed_targets = DEFAULT_ALLOWED if not allowed_raw or allow_proxy_all else [
            value.strip() for value in allowed_raw.split(",") if value.strip()
        ]
        proxy_secret = existing_secret or secrets.token_urlsafe(24)
        worker_source = render_worker(proxy_secret, allowed_targets, allow_proxy_all)

        cf_request(
            "PUT",
            f"/accounts/{account_id}/workers/scripts/{worker_name}",
            api_token,
            body=worker_source.encode("utf-8"),
            content_type="application/javascript",
        )

        proxy_url = f"https://{worker_name}.{subdomain}.workers.dev"
        write_env(proxy_url, proxy_secret)
        print(f"☁️ Cloudflare proxy ready: {proxy_url}")
        return 0
    except urllib.error.HTTPError as error:
        detail = error.read().decode("utf-8", errors="replace")
        print(f"☁️ Cloudflare proxy setup failed: HTTP {error.code} {detail}")
        return 1
    except Exception as error:
        print(f"☁️ Cloudflare proxy setup failed: {error}")
        return 1


if __name__ == "__main__":
    raise SystemExit(main())