import io
import time
from pathlib import Path

from fastapi import APIRouter, Depends, File, HTTPException, UploadFile, status
from fastapi.responses import FileResponse
from PIL import Image

from app.core.config import settings
from app.core.dependencies import get_current_user
from app.core.logging import get_logger
from app.features.auth.deps import get_auth_service
from app.features.auth.preset_avatars import (
    avatar_url_for_preset_filename,
    list_preset_items,
    preset_filename_for_id,
    preset_file_path,
    safe_avatar_upload_path,
)
from app.features.auth.schemas import (
    AvatarPresetItem,
    ChangePasswordRequest,
    ChangePhoneRequest,
    LoginRequest,
    MockSmsLoginRequest,
    RefreshTokenRequest,
    RegisterRequest,
    ResetPasswordRequest,
    SendSmsRequest,
    SetAvatarPresetRequest,
    SmsLoginRequest,
    SmsRegisterRequest,
    TokenResponse,
    UpdateNicknameRequest,
    UserResponse,
)
from app.features.auth.service import AuthError, AuthService
from app.features.user.models import User

logger = get_logger(__name__)

router = APIRouter(
    prefix="/api/auth",
    tags=["auth"],
    responses={401: {"description": "认证失败"}},
)

AVATAR_DIR = Path("uploads/avatars")
AVATAR_DIR.mkdir(parents=True, exist_ok=True)

# ── helpers ──────────────────────────────────────────────────

_ERROR_STATUS: dict[str, int] = {
    "INVALID_CREDENTIALS": status.HTTP_401_UNAUTHORIZED,
    "INVALID_TOKEN": status.HTTP_401_UNAUTHORIZED,
    "TOKEN_REVOKED": status.HTTP_401_UNAUTHORIZED,
    "TOKEN_EXPIRED": status.HTTP_401_UNAUTHORIZED,
    "USER_NOT_FOUND": status.HTTP_404_NOT_FOUND,
    "PHONE_EXISTS": status.HTTP_400_BAD_REQUEST,
}


def _map_auth_error(e: AuthError) -> HTTPException:
    code = _ERROR_STATUS.get(e.code, status.HTTP_400_BAD_REQUEST)
    return HTTPException(status_code=code, detail=e.message)


def _user_response(user: User) -> UserResponse:
    raw_lang = getattr(user, "language_preference", "zh")
    lang = str(raw_lang).strip().lower() if isinstance(raw_lang, str) else "zh"
    if lang not in ("zh", "en"):
        lang = "zh"
    return UserResponse(
        id=user.id,
        phone=user.phone,
        email=user.email,
        nickname=user.nickname,
        avatar_url=user.avatar_url,
        subscription_type=user.subscription_type,
        created_at=user.created_at.isoformat(),
        language_preference=lang,
    )


def _check_terms(agreed: bool) -> None:
    if not agreed:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="请先阅读并同意用户协议和隐私政策",
        )


def _mock_sms_login_route_enabled() -> bool:
    env = (settings.app_environment or "").lower().strip()
    if env == "production":
        return False
    return bool(settings.mock_sms_login_enabled)


# ── registration & login ─────────────────────────────────────


@router.post(
    "/register",
    response_model=TokenResponse,
    status_code=status.HTTP_201_CREATED,
    summary="手机号密码注册",
    responses={400: {"description": "手机号/邮箱已注册或参数错误"}},
)
async def register(
    request: RegisterRequest,
    service: AuthService = Depends(get_auth_service),
):
    _check_terms(request.agreed_to_terms)
    try:
        result = await service.register(
            phone=request.phone,
            password=request.password,
            nickname=request.nickname,
            email=request.email,
            language=request.language,
        )
    except AuthError as e:
        raise _map_auth_error(e)
    return TokenResponse(
        access_token=result["access_token"],
        refresh_token=result["refresh_token"],
    )


@router.post(
    "/login",
    response_model=TokenResponse,
    summary="手机号密码登录",
    responses={401: {"description": "手机号或密码错误"}},
)
async def login(
    request: LoginRequest,
    service: AuthService = Depends(get_auth_service),
):
    _check_terms(request.agreed_to_terms)
    try:
        result = await service.login(
            phone=request.phone,
            password=request.password,
        )
    except AuthError as e:
        raise _map_auth_error(e)
    return TokenResponse(
        access_token=result["access_token"],
        refresh_token=result["refresh_token"],
    )


@router.post(
    "/refresh",
    response_model=TokenResponse,
    summary="刷新访问令牌",
    responses={401: {"description": "刷新令牌无效/已撤销/已过期"}},
)
async def refresh_token(
    request: RefreshTokenRequest,
    service: AuthService = Depends(get_auth_service),
):
    try:
        result = await service.refresh_tokens(
            refresh_token=request.refresh_token,
        )
    except AuthError as e:
        raise _map_auth_error(e)
    return TokenResponse(
        access_token=result["access_token"],
        refresh_token=result["refresh_token"],
    )


# ── logout ────────────────────────────────────────────────────


@router.post(
    "/logout",
    status_code=status.HTTP_200_OK,
    summary="登出当前设备",
)
async def logout(
    request: RefreshTokenRequest,
    current_user: User = Depends(get_current_user),
    service: AuthService = Depends(get_auth_service),
):
    await service.logout(request.refresh_token, current_user.id)
    return {"message": "登出成功"}


@router.post(
    "/logout/all",
    summary="登出所有设备",
)
async def logout_all_devices(
    current_user: User = Depends(get_current_user),
    service: AuthService = Depends(get_auth_service),
):
    count = await service.logout_all(current_user.id)
    return {"message": f"已登出所有设备，共撤销 {count} 个令牌"}


# ── user profile ──────────────────────────────────────────────


@router.get(
    "/me",
    response_model=UserResponse,
    summary="获取当前用户信息",
)
async def get_me(
    current_user: User = Depends(get_current_user),
):
    return _user_response(current_user)


@router.put(
    "/me/nickname",
    response_model=UserResponse,
    summary="修改昵称",
)
async def update_nickname(
    request: UpdateNicknameRequest,
    current_user: User = Depends(get_current_user),
    service: AuthService = Depends(get_auth_service),
):
    try:
        user = await service.update_nickname(current_user.id, request.nickname)
    except AuthError as e:
        raise _map_auth_error(e)
    return _user_response(user)


# ── avatar ────────────────────────────────────────────────────


@router.post(
    "/me/avatar",
    response_model=UserResponse,
    summary="上传头像",
    responses={400: {"description": "文件类型或大小不符合要求"}},
)
async def upload_avatar(
    file: UploadFile = File(...),
    current_user: User = Depends(get_current_user),
    service: AuthService = Depends(get_auth_service),
):
    allowed_types = ["image/jpeg", "image/png", "image/webp"]

    if file.content_type not in allowed_types:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"不支持的文件类型。仅支持: {', '.join(allowed_types)}",
        )

    file_content = await file.read()

    if not file_content or len(file_content) == 0:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="文件内容为空",
        )

    if len(file_content) > 5 * 1024 * 1024:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="文件大小超过5MB限制",
        )

    logger.debug(
        "上传头像: user_id={} filename={} content_type={} size={}",
        current_user.id,
        file.filename,
        file.content_type,
        len(file_content),
    )

    try:
        AVATAR_DIR.mkdir(parents=True, exist_ok=True)

        image_bytes = io.BytesIO(file_content)
        image_bytes.seek(0)

        header = image_bytes.read(16)
        image_bytes.seek(0)

        is_valid_image = False
        if header.startswith(b"\xff\xd8\xff"):
            is_valid_image = True
        elif header.startswith(b"\x89PNG\r\n\x1a\n"):
            is_valid_image = True
        elif header.startswith(b"RIFF") and b"WEBP" in header[:12]:
            is_valid_image = True
        else:
            logger.warning("无法识别的图片文件头")
            logger.debug("无法识别的文件头 hex={}", header[:12].hex())

        if not is_valid_image:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail=f"无效的图片文件格式。文件头: {header[:12].hex()}",
            )

        image = Image.open(image_bytes)
        logger.debug(
            "头像解码: format={} mode={} size={}",
            image.format,
            image.mode,
            image.size,
        )

        if image.mode != "RGB":
            image = image.convert("RGB")

        width, height = image.size
        size = min(width, height)
        left = (width - size) // 2
        top = (height - size) // 2
        right = left + size
        bottom = top + size
        image = image.crop((left, top, right, bottom))

        if size > 512:
            image = image.resize((512, 512), Image.Resampling.LANCZOS)

        file_extension = "jpg"
        filename = f"{current_user.id}.{file_extension}"
        file_path = AVATAR_DIR / filename

        image.save(file_path, "JPEG", quality=85, optimize=True)

        # 路径固定为 {user_id}.jpg，客户端会缓存；每次写入新文件后 bump URL 以绕过缓存。
        avatar_url = f"/api/auth/avatars/{filename}?v={time.time_ns()}"
        user = await service.update_avatar_url(current_user.id, avatar_url)
        return _user_response(user)
    except HTTPException:
        raise
    except Exception as e:
        logger.exception("头像上传失败: {}", e)
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail="处理图片失败，请重试",
        ) from e


@router.get(
    "/avatar-presets",
    response_model=list[AvatarPresetItem],
    summary="预设头像列表",
)
async def list_avatar_presets():
    return [
        AvatarPresetItem(id=item_id, url=item_url)
        for item_id, item_url in list_preset_items()
    ]


@router.put(
    "/me/avatar/preset",
    response_model=UserResponse,
    summary="使用预设头像",
    responses={400: {"description": "无效的预设编号"}},
)
async def set_avatar_preset(
    request: SetAvatarPresetRequest,
    current_user: User = Depends(get_current_user),
    service: AuthService = Depends(get_auth_service),
):
    filename = preset_filename_for_id(request.preset_id)
    if filename is None:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="无效的预设头像编号",
        )
    path = preset_file_path(filename)
    if path is None or not path.exists():
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="预设头像不可用",
        )
    avatar_url = f"{avatar_url_for_preset_filename(filename)}?v={time.time_ns()}"
    try:
        user = await service.update_avatar_url(current_user.id, avatar_url)
    except AuthError as e:
        raise _map_auth_error(e)
    return _user_response(user)


@router.get(
    "/avatar-presets/{filename}",
    summary="获取预设头像图片",
    responses={404: {"description": "预设不存在"}},
)
async def get_avatar_preset(filename: str):
    path = preset_file_path(filename)
    if path is None or not path.exists():
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="预设头像不存在",
        )
    return FileResponse(path, media_type="image/png")


@router.get(
    "/avatars/{filename}",
    summary="获取头像图片",
    responses={404: {"description": "头像不存在"}},
)
async def get_avatar(filename: str):
    file_path = safe_avatar_upload_path(filename, AVATAR_DIR)
    if file_path is None or not file_path.exists():
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="头像不存在",
        )
    return FileResponse(file_path, media_type="image/jpeg")


# ── SMS verification ──────────────────────────────────────────


@router.post(
    "/sms/send",
    summary="发送短信验证码",
    responses={
        400: {"description": "手机号格式或用途不合法"},
        429: {"description": "发送过于频繁"},
        503: {"description": "短信服务不可用"},
    },
)
async def send_sms_code(
    request: SendSmsRequest,
    service: AuthService = Depends(get_auth_service),
):
    if not request.phone.isdigit():
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="手机号格式不正确",
        )

    valid_purposes = ["register", "login", "reset_password", "change_phone"]
    if request.purpose not in valid_purposes:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"无效的用途，必须是: {', '.join(valid_purposes)}",
        )

    try:
        success, message, expires_in = await service.send_sms_code(
            phone=request.phone,
            purpose=request.purpose,
            ip_address=None,
        )
    except AuthError as e:
        raise _map_auth_error(e)

    if not success:
        if "频繁" in message:
            status_code = status.HTTP_429_TOO_MANY_REQUESTS
        elif "配置" in message or "配置错误" in message or "授权失败" in message:
            status_code = status.HTTP_503_SERVICE_UNAVAILABLE
        else:
            status_code = status.HTTP_500_INTERNAL_SERVER_ERROR
        raise HTTPException(status_code=status_code, detail=message)

    return {"message": message, "expires_in": expires_in}


@router.post(
    "/login/sms",
    response_model=TokenResponse,
    summary="短信验证码登录（新用户自动注册）",
    responses={400: {"description": "验证码错误"}},
)
async def login_with_sms(
    request: SmsLoginRequest,
    service: AuthService = Depends(get_auth_service),
):
    _check_terms(request.agreed_to_terms)
    try:
        result = await service.login_with_sms(
            phone=request.phone,
            code=request.code,
            nickname=request.nickname,
            language=request.language,
        )
    except AuthError as e:
        raise _map_auth_error(e)
    return TokenResponse(
        access_token=result["access_token"],
        refresh_token=result["refresh_token"],
    )


@router.post(
    "/mock/sms-login",
    response_model=TokenResponse,
    summary="[评测] Mock 短信登录（跳过验证码）",
    description=(
        "需 MOCK_SMS_LOGIN_ENABLED=1 且 APP_ENV 非 production。"
        "供 Eval Web 等内网工具联调，勿在生产环境开启。"
    ),
    responses={404: {"description": "未启用或生产环境已禁用"}},
)
async def mock_sms_login_route(
    request: MockSmsLoginRequest,
    service: AuthService = Depends(get_auth_service),
):
    if not _mock_sms_login_route_enabled():
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Not Found")
    _check_terms(request.agreed_to_terms)
    try:
        result = await service.mock_sms_login(
            phone=request.phone,
            nickname=request.nickname,
            language=request.language,
        )
    except AuthError as e:
        raise _map_auth_error(e)
    return TokenResponse(
        access_token=result["access_token"],
        refresh_token=result["refresh_token"],
    )


@router.post(
    "/register/sms",
    response_model=TokenResponse,
    status_code=status.HTTP_201_CREATED,
    summary="短信验证码注册",
    responses={400: {"description": "验证码错误或手机号/邮箱已注册"}},
)
async def register_with_sms(
    request: SmsRegisterRequest,
    service: AuthService = Depends(get_auth_service),
):
    _check_terms(request.agreed_to_terms)
    try:
        result = await service.register_with_sms(
            phone=request.phone,
            code=request.code,
            password=request.password,
            nickname=request.nickname,
            email=request.email,
            language=request.language,
        )
    except AuthError as e:
        raise _map_auth_error(e)
    return TokenResponse(
        access_token=result["access_token"],
        refresh_token=result["refresh_token"],
    )


# ── password & phone management ───────────────────────────────


@router.post(
    "/password/reset",
    summary="通过短信验证码重置密码",
    responses={
        400: {"description": "验证码错误"},
        404: {"description": "用户不存在"},
    },
)
async def reset_password(
    request: ResetPasswordRequest,
    service: AuthService = Depends(get_auth_service),
):
    try:
        await service.reset_password(
            phone=request.phone,
            code=request.code,
            new_password=request.new_password,
        )
    except AuthError as e:
        raise _map_auth_error(e)
    return {"message": "密码重置成功"}


@router.post(
    "/password/change",
    summary="修改密码（需旧密码）",
    responses={400: {"description": "旧密码错误"}},
)
async def change_password(
    request: ChangePasswordRequest,
    current_user: User = Depends(get_current_user),
    service: AuthService = Depends(get_auth_service),
):
    try:
        await service.change_password(
            user_id=current_user.id,
            old_password=request.old_password,
            new_password=request.new_password,
        )
    except AuthError as e:
        raise _map_auth_error(e)
    return {"message": "密码修改成功"}


@router.post(
    "/phone/change",
    response_model=UserResponse,
    summary="更换手机号",
    responses={400: {"description": "验证码错误或手机号已被占用"}},
)
async def change_phone(
    request: ChangePhoneRequest,
    current_user: User = Depends(get_current_user),
    service: AuthService = Depends(get_auth_service),
):
    try:
        user = await service.change_phone(
            user_id=current_user.id,
            new_phone=request.new_phone,
            code=request.code,
        )
    except AuthError as e:
        raise _map_auth_error(e)
    return _user_response(user)