"""可替换的 PDF 查询/下载接口；模拟接口返回原始测试 PDF，保留其真实身份。"""
import hashlib
from pathlib import Path

import httpx
from fastapi import FastAPI, HTTPException
from fastapi.responses import FileResponse


def create_mock_report_app(pdf_path):
    source = Path(pdf_path).resolve()
    if not source.is_file() or source.suffix.lower() != '.pdf':
        raise ValueError('模拟报告接口需要已有的测试 PDF 文件')
    sha = hashlib.sha256(source.read_bytes()).hexdigest()
    app = FastAPI(title='主通风机测定报告模拟接口')

    @app.get('/api/main-fan/reports')
    async def reports(mine_code: str, shaft_id: str):
        return {'code': 200, 'data': [{
            'file_id': 'fixture-' + sha[:16], 'filename': source.name, 'sha256': sha,
            'download_path': '/api/main-fan/report-files/' + sha + '.pdf',
            'requested_mine_code': mine_code, 'requested_shaft_id': shaft_id,
            'is_mock': True, 'binding': 'test_fixture_not_mine_report',
            'note': '复用既有测试PDF原件；不改写封面、矿名或设备身份，不能视为目标矿的正式报告。'}]}

    @app.get('/api/main-fan/report-files/{name}')
    async def download(name: str):
        if name != sha + '.pdf':
            raise HTTPException(404, '报告文件不存在')
        return FileResponse(source, media_type='application/pdf', filename=source.name)

    return app


class ReportClient:
    def __init__(self, http):
        self.http = http

    async def list(self, mine_code, shaft_id):
        params = {'mine_code': mine_code, 'shaft_id': shaft_id}
        response = await self.http.get('/api/main-fan/reports', params=params)
        response.raise_for_status()
        body = response.json()
        if str(body.get('code')) not in {'0', '200'} or not isinstance(body.get('data'), list):
            raise ValueError('报告列表接口没有返回成功的文件数组')
        return body['data'], {'method': 'GET', 'path': '/api/main-fan/reports', 'params': params}, body

    async def download(self, record, target):
        path = record.get('download_path', '')
        if not path.startswith('/api/main-fan/report-files/') or '..' in path:
            raise ValueError('报告下载路径不在已配置的文件接口内')
        partial = target.with_suffix('.part')
        target.parent.mkdir(parents=True, exist_ok=True)
        size, digest = 0, hashlib.sha256()
        try:
            async with self.http.stream('GET', path) as response:
                response.raise_for_status()
                if 'pdf' not in response.headers.get('content-type', '').lower():
                    raise ValueError('报告下载未返回 PDF')
                with partial.open('wb') as stream:
                    async for chunk in response.aiter_bytes():
                        size += len(chunk)
                        if size > 50 * 1024 * 1024:
                            raise ValueError('报告文件超过50MB')
                        digest.update(chunk)
                        stream.write(chunk)
            if not size or not partial.read_bytes()[:5] == b'%PDF-':
                raise ValueError('报告文件为空或不是PDF原件')
            sha = digest.hexdigest()
            if record.get('sha256') and sha != record['sha256']:
                raise ValueError('报告实际内容hash与接口声明不一致')
            partial.replace(target)
            return sha
        finally:
            partial.unlink(missing_ok=True)


def mock_report_client(pdf_path):
    return httpx.AsyncClient(transport=httpx.ASGITransport(app=create_mock_report_app(pdf_path)),
                             base_url='http://mock-report.local', timeout=30)