#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import asyncio
import os
import logging
import time
from contextlib import asynccontextmanager
from fastapi import FastAPI, HTTPException, Request
from playwright.async_api import async_playwright

# 配置日志
logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s - %(name)s - %(levelname)s - %(message)s"
)
logger = logging.getLogger("headPickerService")

TARGET_PAGE = os.getenv("TARGET_PAGE")
TARGET_API = os.getenv("TARGET_API")
FINGERPRINT_HEADER = os.getenv("FINGERPRINT_HEADER")

playwright_instance = None
browser = None

# [新增] 全局内存缓存池，存储 JS 脚本
RESOURCE_CACHE = {}

@asynccontextmanager
async def lifespan(app: FastAPI):
    global playwright_instance, browser
    playwright_instance = await async_playwright().start()
    browser = await playwright_instance.chromium.launch(
        headless=True,
        args=[
            "--no-sandbox",
            "--disable-setuid-sandbox",
            "--disable-dev-shm-usage",
            "--disable-software-rasterizer",
        ]
    )
    yield
    await browser.close()
    await playwright_instance.stop()


app = FastAPI(
    title="Web Header Signature Service",
    description="API service for dynamic header signature generation via headless browser",
    version="1.0.0",
    lifespan=lifespan
)


@app.middleware("http")
async def log_request_time(request: Request, call_next):
    start_time = time.time()
    response = await call_next(request)
    process_time = (time.time() - start_time) * 1000
    logger.info(f"{request.method} {request.url.path} - {response.status_code} - {process_time:.2f}ms")
    return response


async def get_fingerprint():
    page = await browser.new_page()
    try:
        # [新增] 拦截无用资源，极大提升加载速度
        async def route_intercept(route):
            request = route.request
            url = request.url
            resource_type = request.resource_type

            # 1. 丢弃无用资源
            if resource_type in ["image", "stylesheet", "media", "font", "other"]:
                await route.abort()
                return

            # 2. 强缓存 JS 文件
            if resource_type == "script":
                if url in RESOURCE_CACHE:
                    logger.debug(f"Cache hit for script: {url}")
                    await route.fulfill(
                        status=200,
                        headers=RESOURCE_CACHE[url]["headers"],
                        body=RESOURCE_CACHE[url]["body"]
                    )
                    return
                
                # 缓存未命中，去真实抓取
                try:
                    logger.debug(f"Fetching script: {url}")
                    response = await route.fetch()
                    body = await response.body()
                    RESOURCE_CACHE[url] = {
                        "headers": response.headers,
                        "body": body
                    }
                    await route.fulfill(response=response, body=body)
                    return
                except Exception as e:
                    pass  # 抓取失败，降级给底层处理

            await route.continue_()
        
        await page.route("**/*", route_intercept)

        fingerprint_future = asyncio.Future()

        async def handle_request(request):
            if TARGET_API in request.url and not fingerprint_future.done():
                headers = request.headers
                if FINGERPRINT_HEADER in headers:
                    fingerprint_future.set_result(headers[FINGERPRINT_HEADER])

        page.on("request", handle_request)
        
        # [修改] 并发执行 goto 和 wait_for。拿到结果就立刻返回，不再死等 goto 结束
        goto_task = asyncio.create_task(page.goto(TARGET_PAGE, wait_until="domcontentloaded"))
        
        fingerprint = await asyncio.wait_for(fingerprint_future, timeout=15)
        return fingerprint
    except asyncio.TimeoutError:
        logger.error("Timeout while waiting for header generation.")
        return None
    except Exception as e:
        logger.error(f"Unexpected error during generation: {str(e)}")
        return None
    finally:
        await page.close()


@app.get("/")
async def root():
    return {"status": "ok", "message": "Web Header Signature Service is running"}


@app.get("/health")
async def health():
    return {"status": "healthy"}


@app.get("/fingerprint")
async def get_fingerprint_endpoint():
    try:
        fingerprint = await get_fingerprint()
        if fingerprint:
            return {
                "status": "success",
                "data": {
                    FINGERPRINT_HEADER: fingerprint
                }
            }
        else:
            logger.error("Failed to generate signature (returned None)")
            raise HTTPException(status_code=500, detail="Failed to generate signature")
    except Exception as e:
        logger.error(f"Service error during request: {str(e)}")
        raise HTTPException(status_code=500, detail=f"Service error: {str(e)}")


if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)