import threading
from time import monotonic

import httpx
from flask import Flask

from upload.backend.session import add_file, cleanup, configure, create_session, get_files
from upload.backend.session import state as session_state
from upload.backend.upload_refs.blueprint import create_upload_refs_blueprint


def build_app(transport, **config):
    app = Flask(__name__)
    app.config['TESTING'] = True
    app.config['UPLOAD_HTTPX_TRANSPORT'] = transport
    app.register_blueprint(create_upload_refs_blueprint({
        'vmUploadPrefix': 'https://vm.test/buffer/',
        'httpxTransport': transport,
        'pullRetries': 3,
        'pullRetryDelay': 0,
        **config,
    }))
    return app


def test_session_limit_accepts_exact_boundary_and_rejects_overflow():
    sid = create_session()
    previous = session_state.MAX_SESSION_BYTES
    configure(max_session_bytes=10)
    try:
        assert add_file(sid, 'exact.bin', b'x' * 10) is True
        assert add_file(sid, 'overflow.bin', b'x') is False
        assert len(get_files(sid)) == 1
    finally:
        configure(max_session_bytes=previous)
        cleanup(sid)


def test_upload_refs_rejects_actual_oversize_and_deletes_buffer():
    storage = {'oversize': b'123456789'}
    deleted = []

    def handler(request):
        if request.method == 'GET':
            return httpx.Response(200, content=storage['oversize'])
        if request.method == 'DELETE':
            deleted.append(request.url.path)
            storage.clear()
            return httpx.Response(204)
        return httpx.Response(405)

    transport = httpx.MockTransport(handler)
    app = build_app(transport, maxFileBytes=8)
    sid = create_session()
    try:
        with app.test_client() as client:
            response = client.post('/api/upload_refs', json={
                'session': sid,
                'files': [{
                    'name': 'oversize.txt',
                    'size': 8,
                    'url': 'https://vm.test/buffer/oversize',
                }],
            })
        assert response.status_code == 200
        assert response.get_json()['added'] == 0
        assert get_files(sid) == []
        assert deleted == ['/buffer/oversize']
        assert storage == {}
    finally:
        cleanup(sid)


def test_upload_refs_retries_transient_pull_and_deletes_after_success():
    attempts = []
    deleted = []

    def handler(request):
        if request.method == 'GET':
            attempts.append(request.url.path)
            if len(attempts) == 1:
                return httpx.Response(503)
            return httpx.Response(200, content=b'retry-content')
        if request.method == 'DELETE':
            deleted.append(request.url.path)
            return httpx.Response(204)
        return httpx.Response(405)

    transport = httpx.MockTransport(handler)
    app = build_app(transport)
    with app.test_client() as client:
        response = client.post('/api/upload_refs', json={'files': [{
            'name': 'retry.txt',
            'size': 13,
            'url': 'https://vm.test/buffer/retry',
        }]})
    assert response.status_code == 200
    data = response.get_json()
    assert data['added'] == 1
    assert len(attempts) == 2
    assert deleted == ['/buffer/retry']
    cleanup(data['session'])


def test_session_ttl_removes_session():
    previous = session_state.TTL_SECONDS
    configure(ttl_seconds=0.05)
    sid = create_session()
    try:
        deadline = monotonic() + 1
        while monotonic() < deadline and get_files(sid) is not None:
            threading.Event().wait(0.01)
        assert get_files(sid) is None
    finally:
        configure(ttl_seconds=previous)
        cleanup(sid)