import logging
from datetime import datetime, timedelta

from fastapi import APIRouter, Depends, HTTPException, Request
from pydantic import BaseModel

from .. import config, db, security, wechat
from ..user import user_payload


logger = logging.getLogger(__name__)

router = APIRouter(prefix="/api/v1/auth", tags=["auth"])


class WeChatLoginRequest(BaseModel):
    code: str


class BindPhoneRequest(BaseModel):
    code: str
    phone_code: str


class PasswordLoginRequest(BaseModel):
    phone: str
    password: str


class SetPasswordRequest(BaseModel):
    """运营更改单个学员登录密码的入参（需验证老密码）。

    - `old_password`：老密码（`password_hash` 为空时默认 = 手机号后6位）。
    - `new_password`：新密码。
    """

    phone: str
    old_password: str
    new_password: str


# 密码长度约束（设置密码时校验；登录时不校验，避免历史弱密码登不进来）
PASSWORD_MIN_LEN = 8
PASSWORD_MAX_LEN = 64


def get_current_user(request: Request):
    token = ""

    # 1. 优先从 Authorization header 取（小程序 API 调用方式）
    auth = request.headers.get("Authorization", "")
    if auth.startswith("Bearer "):
        token = auth[7:]

    # 2. header 没有则从 cookie 取（webview H5 页面内请求方式）
    if not token:
        token = request.cookies.get("auth_token", "")

    if not token:
        raise HTTPException(status_code=401, detail="缺少 token")

    session = db.fetch_one(
        "SELECT s.user_id AS id FROM auth_sessions s "
        "WHERE s.token=%s AND s.expires_at>NOW()",
        (token,),
    )
    if not session:
        raise HTTPException(status_code=401, detail="token 无效或过期")
    user = db.fetch_one("SELECT * FROM auth_users WHERE id=%s", (session["id"],))
    if not user:
        raise HTTPException(status_code=401, detail="用户不存在")
    return user


def _record_session(user_id):
    """创建会话 token 并写入 auth_sessions。"""
    token = security.create_session_token()
    expires = datetime.now() + timedelta(seconds=config.JWT_TTL_SECONDS)
    db.execute(
        "INSERT INTO auth_sessions (user_id, token, expires_at) VALUES (%s, %s, %s)",
        (user_id, token, expires),
    )
    return token


@router.post("/wechat-login")
def wechat_login(req: WeChatLoginRequest):
    try:
        openid = wechat.code_to_openid(req.code)
    except wechat.WeChatError as exc:
        logger.warning("微信登录 code 换取 openid 失败: %s", exc)
        raise HTTPException(status_code=400, detail=str(exc))

    user = db.fetch_one("SELECT * FROM auth_users WHERE wechat_openid=%s", (openid,))
    if user:
        token = _record_session(user["id"])
        return {"success": True, "is_new": False, "token": token, **user_payload(user)}

    return {"success": False, "need_phone": True, "error": "需要绑定手机号"}


@router.post("/bind-phone")
def bind_phone(req: BindPhoneRequest):
    try:
        openid = wechat.code_to_openid(req.code)
        phone = wechat.get_phone_number(req.phone_code)
    except wechat.WeChatError as exc:
        logger.warning("绑定手机号时获取微信信息失败: %s", exc)
        raise HTTPException(status_code=400, detail=str(exc))

    if not phone:
        raise HTTPException(status_code=400, detail="获取手机号失败")

    encrypted = security.encrypt_phone(phone)
    user = db.fetch_one("SELECT * FROM auth_users WHERE phone_encrypted=%s", (encrypted,))
    if not user:
        return {"success": False, "error": "手机号未匹配，无法登录"}

    db.execute("UPDATE auth_users SET wechat_openid=%s WHERE id=%s", (openid, user["id"]))
    user["wechat_openid"] = openid
    token = _record_session(user["id"])
    return {"success": True, "is_new": True, "token": token, **user_payload(user)}


@router.post("/password-login")
def password_login(req: PasswordLoginRequest):
    """手机号 + 密码登录（与微信登录并列的第二条登录路径，2026-09-22 新增）。

    - 查询靠 `phone_encrypted` 的 HMAC 比对，**库里不存明文手机号**，
      做法与 `bind-phone` 完全一致（同一个 `encrypt_phone`）。
    - 错误文案统一成「手机号或密码错误」，**刻意不区分**「账号不存在」与「密码不对」——
      否则这个接口就成了「哪些手机号是有效学员」的枚举器。
    - 响应结构与 `/wechat-login` 一致，前端两条登录路径可共用后续处理。
    - **未设置密码（`password_hash` 为空）时，默认密码 = 手机号后6位**，便于学员免初始设置直接登录。
    - ⚠️ 与微信登录保持一致，**不校验 `status`**：`暂停` 学员仍然能登录。
    """
    phone = (req.phone or "").strip()
    password = req.password or ""
    if not phone or not password:
        raise HTTPException(status_code=400, detail="手机号与密码均不能为空")

    user = db.fetch_one(
        "SELECT * FROM auth_users WHERE phone_encrypted=%s",
        (security.encrypt_phone(phone),),
    )
    if not user:
        logger.info("密码登录失败：手机号未匹配到账号")
        raise HTTPException(status_code=401, detail="手机号或密码错误")
    stored = user.get("password_hash")
    used_default = False
    if not stored:
        # 未设置密码的账号，默认密码 = 手机号后6位（便于学员免初始设置直接登录）。
        stored = security.hash_password(phone[-6:])
        used_default = True
    if not security.verify_password(password, stored):
        # 日志里区分「默认密码也不对」与「密码错」，方便运营排查；对外文案保持一致。
        # 典型情况：006 迁移还没执行 → password_hash 列取不到 → 这里走默认密码分支。
        reason = "默认密码(手机号后6位)不正确" if used_default else "密码不正确"
        logger.info("密码登录失败：user_id=%s %s", user["id"], reason)
        raise HTTPException(status_code=401, detail="手机号或密码错误")

    token = _record_session(user["id"])
    return {"success": True, "token": token, **user_payload(user)}


def _check_password_input(phone, password):
    """校验一条待设置的账号密码，返回错误原因；空串表示通过。"""
    if not phone:
        return "手机号不能为空"
    if not password:
        return "密码不能为空"
    if len(password) < PASSWORD_MIN_LEN or len(password) > PASSWORD_MAX_LEN:
        return "密码长度需为 %d~%d 位" % (PASSWORD_MIN_LEN, PASSWORD_MAX_LEN)
    if password == phone:
        return "密码不能与手机号相同"
    return ""


@router.post("/set-password")
def set_password(req: SetPasswordRequest, request: Request):
    """
    - **改密码需先验证老密码**：`old_password` 正确才更新；`password_hash` 为空时
      默认老密码 = 手机号后6位（与 `password-login` 的默认密码逻辑一致）。
    - **直接覆盖已有密码**（"重置"就是这个语义），没有二次确认。
    - 手机号必须能匹配到 `auth_users`（用 `encrypt_phone` 比对）；
      匹配不到即报错，**不会新建账号** —— 本系统没有注册流程，用户由运营导入。
    """
    phone = (req.phone or "").strip()
    old_password = req.old_password or ""
    new_password = req.new_password or ""

    err = _check_password_input(phone, new_password)
    if err:
        raise HTTPException(status_code=400, detail=err)

    user = db.fetch_one(
        "SELECT * FROM auth_users WHERE phone_encrypted=%s",
        (security.encrypt_phone(phone),),
    )
    if not user:
        raise HTTPException(status_code=404, detail="手机号未匹配到学员账号")

    # 验证老密码：password_hash 为空时，默认老密码 = 手机号后6位。
    stored = user.get("password_hash")
    if not stored:
        stored = security.hash_password(phone[-6:])
    if not security.verify_password(old_password, stored):
        raise HTTPException(status_code=403, detail="老密码不正确")

    db.execute(
        "UPDATE auth_users SET password_hash=%s WHERE id=%s",
        (security.hash_password(new_password), user["id"]),
    )
    logger.info("设置登录密码：user_id=%s", user["id"])
    return {"success": True, "user_id": user["id"]}


@router.get("/verify")
def verify(user=Depends(get_current_user)):
    return {"success": True, **user_payload(user)}


@router.post("/logout")
def logout(request: Request, user=Depends(get_current_user)):
    from fastapi.responses import JSONResponse

    auth = request.headers.get("Authorization", "")
    if auth.startswith("Bearer "):
        db.execute("DELETE FROM auth_sessions WHERE token=%s", (auth[7:],))
    # 退出登录时解除该用户手机号绑定的微信 openid，下次需重新授权手机号绑定
    db.execute(
        "UPDATE auth_users SET wechat_openid=NULL WHERE id=%s",
        (user["id"],),
    )
    resp = JSONResponse(content={"success": True})
    # 同时清除 webview cookie 登录态
    resp.delete_cookie(key="auth_token", path="/")
    return resp