"""FastAPI 路由"""
from __future__ import annotations

import platform
from pathlib import Path
from typing import List

from fastapi import APIRouter, File, HTTPException, UploadFile

from app import __version__
from app.config import settings
from app.core import get_engine
from app.models import HealthResponse, InvoiceResult, PathRecognizeRequest
from app.services.recognize_service import recognize_file, recognize_path

router = APIRouter()


# ---------- 路径白名单 ----------

def _parse_allowed_dirs() -> List[Path]:
    """解析 ALLOWED_DIRS 配置为绝对路径列表"""
    if not settings.allowed_dirs.strip():
        return []
    sep = ";" if platform.system() == "Windows" else ":"
    roots: List[Path] = []
    for raw in settings.allowed_dirs.split(sep):
        raw = raw.strip().strip('"').strip("'")
        if not raw:
            continue
        try:
            p = Path(raw).resolve()
            if p.is_dir():
                roots.append(p)
        except Exception:
            pass
    return roots


def _check_path_allowed(file_path: Path) -> None:
    """校验路径在白名单内（路径遍历攻击防护）

    resolve 后必须是某个 allowed_dir 的子路径。
    """
    roots = _parse_allowed_dirs()
    if not roots:
        raise HTTPException(
            status_code=403,
            detail="路径接口未启用：在 .env 配置 ALLOWED_DIRS 后重启服务",
        )
    try:
        abs_path = file_path.resolve()
    except Exception as e:
        raise HTTPException(status_code=400, detail=f"路径无效: {e}")

    for root in roots:
        try:
            abs_path.relative_to(root)
            return
        except ValueError:
            continue

    raise HTTPException(
        status_code=403,
        detail=f"路径不在白名单内（允许: {', '.join(str(r) for r in roots)}）",
    )


# ---------- 路由 ----------

@router.get("/health", response_model=HealthResponse, summary="健康检查")
def health():
    engine_ok = True
    try:
        get_engine()
    except Exception:
        engine_ok = False
    return HealthResponse(
        status="ok" if engine_ok else "degraded",
        version=__version__,
        engine_ready=engine_ok,
    )


@router.post("/recognize/invoice", response_model=InvoiceResult, summary="识别发票（上传文件）")
async def recognize_invoice(file: UploadFile = File(..., description="发票图片或 PDF")):
    """识别发票并返回结构化字段

    支持：PNG/JPG/JPEG/BMP/WEBP/TIFF/PDF
    """
    content = await file.read()
    max_bytes = settings.max_upload_mb * 1024 * 1024
    if len(content) > max_bytes:
        raise HTTPException(status_code=413, detail=f"文件超过 {settings.max_upload_mb}MB 限制")
    if not content:
        raise HTTPException(status_code=400, detail="文件为空")

    return recognize_file(file.filename or "unknown", content)


@router.post("/recognize/invoice/by-path", response_model=InvoiceResult, summary="识别发票（服务器本地路径）")
def recognize_invoice_by_path(req: PathRecognizeRequest):
    """传入服务器本地路径识别发票（避免重复上传大文件）

    **安全**：路径必须在 .env 的 ALLOWED_DIRS 白名单内才会被执行。
    防止任意文件读取 / 路径遍历攻击。
    """
    p = Path(req.file_path)
    _check_path_allowed(p)

    if not p.exists():
        raise HTTPException(status_code=404, detail=f"文件不存在: {p}")
    if not p.is_file():
        raise HTTPException(status_code=400, detail=f"不是文件: {p}")

    return recognize_path(p, delete_after=False)


@router.post("/recognize/text", summary="仅做字段抽取（不上传文件）")
def recognize_text(raw_text: str):
    """对已有的 OCR 文本做字段抽取（便于接入其他 OCR 引擎）"""
    from app.services import extract_invoice

    fields = extract_invoice(raw_text)
    return {"fields": fields}