"""HTTP 客户端：JSON 请求、线上站点之间出声的 fallback、token 显示辅助。"""

import base64
import json
import os
import sys
import time
import urllib.error
import urllib.parse
import urllib.request
from datetime import datetime, timezone

from creds import bucket_name_for, get_bucket, load_creds, resolve_api_url, save_creds
from errors import ApiError, WpError
from sites import ONLINE_URLS, SITES, site_label


TOKEN_REFRESH_MARGIN = 3600

DEFAULT_TIMEOUT = 30
WRITE_TIMEOUT = 120
DEFAULT_BATCH = 50


def mask(token):
    if not token:
        return "(无)"
    if len(token) <= 16:
        return token[:4] + "…"
    return token[:8] + "…" + token[-4:]


def jwt_payload(token):
    """不验签地读出 JWT payload，仅用于显示有效期。"""
    try:
        part = token.split(".")[1]
        part += "=" * (-len(part) % 4)
        return json.loads(base64.urlsafe_b64decode(part.encode("ascii")))
    except Exception:
        return {}


def token_expiry(token):
    exp = jwt_payload(token).get("exp")
    return int(exp) if isinstance(exp, (int, float)) else None


def fmt_ts(ts):
    if not ts:
        return "未知"
    return datetime.fromtimestamp(ts, tz=timezone.utc).astimezone().strftime("%Y-%m-%d %H:%M")


def note(msg):
    print(msg, file=sys.stderr)


def http_json(api_url, method, path, token=None, body=None, query=None, timeout=DEFAULT_TIMEOUT):
    """发一个 JSON 请求，返回解析后的响应体（dict）。

    网络层失败抛 urllib 的异常（由 Client 决定是否 fallback）；
    HTTP 层失败抛 ApiError，带上服务端 message。
    """
    # 路径里可能有巴利词（parivāsa），urllib 只接受 ASCII，必须先百分号编码
    url = api_url + "/" + urllib.parse.quote(path.lstrip("/"), safe="/")
    if query:
        url += "?" + urllib.parse.urlencode({k: v for k, v in query.items() if v is not None})
    data = None
    headers = {"Accept": "application/json", "User-Agent": "wikipali-write-skill"}
    if body is not None:
        data = json.dumps(body, ensure_ascii=False).encode("utf-8")
        headers["Content-Type"] = "application/json"
    if token:
        headers["Authorization"] = "Bearer " + token
    req = urllib.request.Request(url, data=data, headers=headers, method=method)
    try:
        with urllib.request.urlopen(req, timeout=timeout) as resp:
            raw = resp.read().decode("utf-8", "replace")
            status = resp.status
    except urllib.error.HTTPError as exc:
        raw = exc.read().decode("utf-8", "replace")
        status = exc.code
        payload = safe_json(raw)
        message = payload.get("message") if isinstance(payload, dict) else None
        raise ApiError(status, message or f"HTTP {status}", url=url, body=payload or raw)
    payload = safe_json(raw)
    if not isinstance(payload, dict):
        raise ApiError(status, f"响应不是 JSON：{raw[:200]}", url=url, body=raw)
    if not payload.get("ok", False):
        raise ApiError(status, payload.get("message") or "请求失败", url=url, body=payload)
    return payload.get("data")


def safe_json(raw):
    try:
        return json.loads(raw)
    except ValueError:
        return None


class Client:
    """按站点收发请求，并在线上地址之间做出声的 fallback。"""

    def __init__(self, api_url, source, creds, allow_fallback=True):
        self.api_url = api_url
        self.source = source
        self.creds = creds
        self.bucket_name = bucket_name_for(api_url)
        self.bucket = get_bucket(creds, self.bucket_name, api_url)
        self.allow_fallback = allow_fallback and api_url in ONLINE_URLS

    # -- 凭据 ---------------------------------------------------------------

    @property
    def user_token(self):
        token = (self.bucket.get("user") or {}).get("token")
        if not token:
            raise WpError(
                "尚未登录。请自己执行（Claude Code 里用 ! 前缀）：\n"
                "    ! python3 " + os.path.join(os.path.dirname(os.path.abspath(__file__)), "wp_login.py")
            )
        return token

    @property
    def model(self):
        model = self.bucket.get("model") or {}
        if not model.get("token"):
            raise WpError("尚未取得模型身份 token。请先跑：python3 wp.py ensure-model --name <模型名>")
        return model

    def save(self):
        save_creds(self.creds)

    # -- 请求 ---------------------------------------------------------------

    def fallback_order(self):
        """同版本的另一域名 → 另一版本的同域名 → 其余。绝不含 local。"""
        cur = next((s for s in SITES if s["url"] == self.api_url), None)
        if not cur:
            return []
        others = [s for s in SITES if s["key"] != "local" and s["url"] != self.api_url]
        others.sort(
            key=lambda s: (
                0 if s["version"] == cur["version"] else 1,
                0 if s["domain"] == cur["domain"] else 1,
            )
        )
        return [s["url"] for s in others]

    def call(self, method, path, token=None, body=None, query=None, timeout=DEFAULT_TIMEOUT):
        urls = [self.api_url] + (self.fallback_order() if self.allow_fallback else [])
        last = None
        for idx, url in enumerate(urls):
            try:
                data = http_json(url, method, path, token=token, body=body, query=query, timeout=timeout)
            except (urllib.error.URLError, TimeoutError, OSError) as exc:
                # 仅网络层不可达才换站点；HTTP 错误是服务端的明确答复，不该被掩盖
                last = exc
                reason = getattr(exc, "reason", exc)
                if idx + 1 < len(urls):
                    note(f"⚠ {url} 连接失败（{reason}），改用 {urls[idx + 1]}")
                continue
            if url != self.api_url:
                # fallback 成功后本次会话都用它，但不写回凭据文件
                note(f"⚠ 本次请求实际发往 {url}（{site_label(url)}）")
                self.api_url = url
            return data
        raise WpError(f"所有可用站点都连不上，最后一次错误：{last}")

    def api_note(self):
        src = {"cli": "--api", "env": "环境变量", "creds": "凭据文件", "default": "内置默认"}[self.source]
        return f"{self.api_url}（{site_label(self.api_url)}，来源：{src}）"


def make_client(args, allow_fallback=True):
    creds = load_creds()
    api_url, source = resolve_api_url(getattr(args, "api", None), creds)
    return Client(api_url, source, creds, allow_fallback=allow_fallback)