app/api/routes.py

"""
API 路由定义
提供汇率查询和换算接口
"""
from fastapi import APIRouter, HTTPException, Request
from typing import Optional

from app.models import (
    RatesResponse,
    CurrencyRateResponse,
    ConvertRequest,
    ConvertResponse,
    BatchConvertRequest,
    BatchConvertResponse,
    CurrenciesResponse,
    CurrencyInfo,
    ServiceStatusResponse
)
from app.utils.currency_names import CURRENCY_INFO, get_currency_info
from app.utils.logger import logger

router = APIRouter(prefix="/api", tags=["汇率接口"])


def get_exchange_service(request: Request):
    """从应用状态获取 ExchangeRateService 实例"""
    return request.app.state.exchange_service


# ==================== 获取所有汇率 ====================

@router.get("/rates", response_model=RatesResponse)
async def get_all_rates(request: Request):
    """
    获取所有货币汇率
    
    返回缓存中的所有汇率数据，包括基准货币、汇率列表、更新时间等。
    """
    service = get_exchange_service(request)
    cached = service.get_cached_rates()
    
    if not cached:
        logger.warning("API /rates: 没有可用的缓存数据")
        raise HTTPException(
            status_code=503, 
            detail="汇率数据不可用，请稍后重试。"
        )
    
    return RatesResponse(
        success=True,
        base_currency=cached.base_code,
        rates=cached.rates,
        last_update=cached.last_update_utc,
        cached_at=cached.cached_at.isoformat(),
        currencies_count=len(cached.rates)
    )


# ==================== 获取特定货币汇率 ====================

@router.get("/rates/{currency}", response_model=CurrencyRateResponse)
async def get_currency_rate(currency: str, request: Request):
    """
    获取特定货币对基准货币的汇率
    
    - **currency**: 货币代码（如 USD, EUR, JPY）
    """
    service = get_exchange_service(request)
    cached = service.get_cached_rates()
    
    if not cached:
        raise HTTPException(
            status_code=503, 
            detail="汇率数据不可用"
        )
    
    currency = currency.upper()
    
    if currency not in cached.rates:
        raise HTTPException(
            status_code=404, 
            detail=f"未找到货币 '{currency}'"
        )
    
    return CurrencyRateResponse(
        success=True,
        base_currency=cached.base_code,
        currency=currency,
        rate=cached.rates[currency]
    )


# ==================== 两种货币换算 ====================

@router.post("/convert", response_model=ConvertResponse)
async def convert_currency(request: Request, body: ConvertRequest):
    """
    两种货币之间的汇率换算
    
    - **from_currency**: 源货币代码
    - **to_currency**: 目标货币代码
    - **amount**: 换算金额
    
    返回换算结果、汇率和反向汇率。
    """
    service = get_exchange_service(request)
    
    result = service.convert(
        body.from_currency,
        body.to_currency,
        body.amount
    )
    
    if not result:
        raise HTTPException(
            status_code=400, 
            detail="换算失败，请检查货币代码是否有效。"
        )
    
    return result


# ==================== GET 方式的货币换算 ====================

@router.get("/convert/{from_currency}/{to_currency}")
async def convert_currency_get(
    from_currency: str, 
    to_currency: str, 
    amount: float,
    request: Request
):
    """
    两种货币之间的汇率换算（GET 方式）
    
    - **from_currency**: 源货币代码
    - **to_currency**: 目标货币代码
    - **amount**: 换算金额（查询参数）
    
    示例: GET /api/convert/USD/CNY?amount=100
    """
    service = get_exchange_service(request)
    
    result = service.convert(from_currency, to_currency, amount)
    
    if not result:
        raise HTTPException(
            status_code=400, 
            detail="换算失败，请检查货币代码是否有效。"
        )
    
    return result


# ==================== 批量换算 ====================

@router.post("/batch-convert", response_model=BatchConvertResponse)
async def batch_convert(request: Request, body: BatchConvertRequest):
    """
    批量换算：计算某金额对应所有货币的值
    
    - **base_currency**: 基准货币代码
    - **amount**: 换算金额
    
    返回所有货币的换算结果。
    """
    service = get_exchange_service(request)
    
    result = service.batch_convert(body.base_currency, body.amount)
    
    if not result:
        raise HTTPException(
            status_code=400, 
            detail="批量换算失败，请检查基准货币是否有效。"
        )
    
    return result


# ==================== GET 方式的批量换算 ====================

@router.get("/batch-convert/{base_currency}")
async def batch_convert_get(base_currency: str, amount: float, request: Request):
    """
    批量换算（GET 方式）
    
    - **base_currency**: 基准货币代码
    - **amount**: 换算金额（查询参数）
    
    示例: GET /api/batch-convert/USD?amount=100
    """
    service = get_exchange_service(request)
    
    result = service.batch_convert(base_currency, amount)
    
    if not result:
        raise HTTPException(
            status_code=400, 
            detail="批量换算失败，请检查基准货币是否有效。"
        )
    
    return result


# ==================== 获取货币列表 ====================

@router.get("/currencies", response_model=CurrenciesResponse)
async def get_currencies(request: Request):
    """
    获取支持的货币列表（含中英文名称）
    
    返回所有可用货币的代码、名称和符号，按优先级排序。
    """
    service = get_exchange_service(request)
    settings = service.settings
    cached = service.get_cached_rates()
    
    if not cached:
        raise HTTPException(
            status_code=503, 
            detail="汇率数据不可用"
        )
    
    currencies = []
    
    for code in cached.rates.keys():
        info = get_currency_info(code)
        currencies.append(CurrencyInfo(
            code=code,
            name=info.get("name", code),
            name_cn=info.get("name_cn", code),
            symbol=info.get("symbol", "")
        ))
    
    # 按优先级排序
    priority = settings.PRIORITY_CURRENCIES
    currencies.sort(key=lambda x: (
        priority.index(x.code) if x.code in priority else 999,
        x.code
    ))
    
    return CurrenciesResponse(
        success=True,
        currencies=currencies
    )


# ==================== 服务状态 ====================

@router.get("/status", response_model=ServiceStatusResponse)
async def get_status(request: Request):
    """
    获取服务状态
    
    返回缓存状态、上次更新时间、货币数量等信息。
    """
    service = get_exchange_service(request)
    cached = service.get_cached_rates()
    
    return ServiceStatusResponse(
        status="healthy" if cached else "degraded",
        cache_valid=service.is_cache_valid(),
        last_update=cached.cached_at.isoformat() if cached else None,
        currencies_count=len(cached.rates) if cached else 0,
        api_keys_count=len(service.api_keys),
        update_interval_seconds=service.settings.CACHE_UPDATE_INTERVAL
    )


# ==================== 强制刷新缓存 ====================

@router.post("/refresh")
async def refresh_cache(request: Request):
    """
    强制刷新汇率缓存
    
    立即从 API 获取最新汇率数据，不等待定时任务。
    注意：频繁调用可能导致 API 限流。
    """
    service = get_exchange_service(request)
    
    logger.info("收到手动刷新缓存请求")
    success = await service.update_cache()
    
    if success:
        cached = service.get_cached_rates()
        return {
            "success": True,
            "message": "缓存刷新成功",
            "currencies_count": len(cached.rates) if cached else 0,
            "cached_at": cached.cached_at.isoformat() if cached else None
        }
    else:
        raise HTTPException(
            status_code=503,
            detail="刷新缓存失败，请稍后重试。"
        )