"""GNACS 司法辖区路由"""
from fastapi import APIRouter, HTTPException, Query
import database

router = APIRouter()

def serialize(doc):
    if doc is None:
        return None
    result = {}
    for k, v in doc.items():
        if k == "_id":
            result["_id"] = str(v)
        elif isinstance(v, dict):
            result[k] = serialize(v)
        else:
            result[k] = v
    return result

@router.get("/list")
async def list_jurisdictions(
    tier: int = Query(None, description="按监管等级筛选：1=高度成熟，2=中等成熟，3=新兴市场"),
    region: str = Query(None, description="按地区筛选：Americas/Europe/Asia/ASEAN/GCC/Africa/Oceania"),
    limit: int = Query(100, description="返回数量限制")
):
    """列出所有支持的司法辖区"""
    col = database.jurisdictions_col
    query = {}
    if tier is not None:
        query["tier"] = tier
    if region:
        query["region"] = region
    cursor = col.find(query, sort=[("tier", 1), ("code", 1)]).limit(limit)
    jurisdictions = []
    async for doc in cursor:
        jurisdictions.append(serialize(doc))
    total = await col.count_documents(query)
    return {"success": True, "jurisdictions": jurisdictions, "total": total}

@router.get("/check-cross-border")
async def check_cross_border(
    investor_jurisdiction: str = Query(..., description="投资者所在辖区代码，如CN"),
    asset_jurisdiction: str = Query(..., description="资产所在辖区代码，如US")
):
    """检查是否为跨境交易，并返回双重合规要求"""
    col = database.jurisdictions_col
    treaties_col = database.tax_treaties_col

    investor_j = await col.find_one({"code": investor_jurisdiction.upper()})
    asset_j = await col.find_one({"code": asset_jurisdiction.upper()})

    if not investor_j:
        raise HTTPException(status_code=404, detail=f"投资者辖区 {investor_jurisdiction} 不存在")
    if not asset_j:
        raise HTTPException(status_code=404, detail=f"资产辖区 {asset_jurisdiction} 不存在")

    is_cross_border = investor_jurisdiction.upper() != asset_jurisdiction.upper()

    # 查询双边税收协定
    treaty = await treaties_col.find_one({
        "$or": [
            {"source": investor_jurisdiction.upper(), "target": asset_jurisdiction.upper()},
            {"source": asset_jurisdiction.upper(), "target": investor_jurisdiction.upper()}
        ]
    })

    # 综合KYC要求（取两者最高）
    combined_kyc = max(
        investor_j.get("tier", 1),
        asset_j.get("tier", 1)
    )
    # Tier转KYC等级映射
    tier_to_kyc = {0: 1, 1: 2, 2: 3, 3: 3}
    combined_kyc_level = tier_to_kyc.get(combined_kyc, 2)

    result = {
        "is_cross_border": is_cross_border,
        "investor_jurisdiction": serialize(investor_j),
        "asset_jurisdiction": serialize(asset_j),
        "combined_kyc_level": combined_kyc_level,
        "forex_control_applicable": investor_j.get("forex_control", False) or asset_j.get("forex_control", False),
        "fatca_applicable": investor_j.get("fatca_applicable", False) or asset_j.get("fatca_applicable", False),
        "crs_applicable": investor_j.get("crs_participant", False) and asset_j.get("crs_participant", False),
        "tax_treaty": serialize(treaty) if treaty else None,
        "compliance_notes": []
    }

    if is_cross_border:
        notes = []
        if investor_j.get("forex_control"):
            notes.append(f"{investor_jurisdiction}有外汇管制，跨境转账需申报")
        if investor_j.get("fatca_applicable"):
            notes.append("需提交FATCA表格（美国纳税人）")
        if result["crs_applicable"]:
            notes.append("CRS信息自动交换适用，账户信息将共享给税务机关")
        if not treaty:
            notes.append(f"{investor_jurisdiction}与{asset_jurisdiction}之间无双边税收协定，可能面临双重征税")
        else:
            notes.append(f"适用{treaty.get('treaty_code','')}税收协定")
        result["compliance_notes"] = notes

    return {"success": True, "data": result}

@router.get("/{code}")
async def get_jurisdiction_detail(code: str):
    """获取指定辖区的详细信息"""
    col = database.jurisdictions_col
    doc = await col.find_one({"code": code.upper()})
    if not doc:
        raise HTTPException(status_code=404, detail=f"辖区 {code} 不存在")
    return {"success": True, "data": serialize(doc)}