"""Tests for v2.0.0 browser fingerprint headers and UA pool enhancements.

Covers: build_browser_headers (Chrome/Edge/Firefox variants, Referer,
Accept modes), get_ua_for_domain (deterministic per-domain, caching,
explicit override), parse_retry_after (numeric/HTTP date/edge cases),
compute_backoff_delay (cap enforcement), UA pool size and diversity.
"""
import sys
import os
sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "scripts"))

from common import (
    FALLBACK_UAS,
    RETRY_BACKOFF_CAP,
    build_browser_headers,
    compute_backoff_delay,
    get_ua_for_domain,
    parse_retry_after,
    reset_domain_ua_cache,
    _ua_index_for_domain,
)


# ----- UA pool -----

def test_ua_pool_has_at_least_12_entries():
    """v2.0.0: expanded from 3 to 12 for diversity."""
    assert len(FALLBACK_UAS) >= 12


def test_ua_pool_covers_multiple_browsers():
    browsers = []
    for ua in FALLBACK_UAS:
        if "Edg/" in ua:
            browsers.append("edge")
        elif "Firefox/" in ua:
            browsers.append("firefox")
        elif "Chrome/" in ua:
            browsers.append("chrome")
    # 至少三种浏览器
    assert "chrome" in browsers
    assert "firefox" in browsers
    assert "edge" in browsers


def test_ua_pool_covers_multiple_platforms():
    platforms = []
    for ua in FALLBACK_UAS:
        if "Windows" in ua:
            platforms.append("windows")
        elif "Macintosh" in ua:
            platforms.append("macos")
        elif "Linux" in ua:
            platforms.append("linux")
    assert "windows" in platforms
    assert "macos" in platforms
    assert "linux" in platforms


# ----- get_ua_for_domain -----

def test_get_ua_for_domain_is_deterministic():
    """同一域名永远返回同一 UA（跨调用一致）。"""
    reset_domain_ua_cache()
    url = "https://example.com/page1"
    ua1 = get_ua_for_domain(url)
    ua2 = get_ua_for_domain(url)
    assert ua1 == ua2
    assert ua1 in FALLBACK_UAS


def test_get_ua_for_domain_same_domain_different_paths():
    """同域名不同路径返回同 UA。"""
    reset_domain_ua_cache()
    ua1 = get_ua_for_domain("https://example.com/a")
    ua2 = get_ua_for_domain("https://example.com/b/c/d")
    assert ua1 == ua2


def test_get_ua_for_domain_explicit_override():
    """显式 user_agent 优先于域名缓存。"""
    reset_domain_ua_cache()
    custom = "MyCustomBot/1.0"
    ua = get_ua_for_domain("https://example.com", user_agent=custom)
    assert ua == custom


def test_get_ua_for_domain_different_domains_may_differ():
    """不同域名可能映射到不同 UA（不一定，但缓存独立）。"""
    reset_domain_ua_cache()
    ua1 = get_ua_for_domain("https://aaa.example.com")
    ua2 = get_ua_for_domain("https://bbb.example.com")
    # 都是合法 UA
    assert ua1 in FALLBACK_UAS
    assert ua2 in FALLBACK_UAS


def test_get_ua_for_domain_invalid_url_returns_default():
    """无效 URL 返回第一个 UA（兜底）。"""
    reset_domain_ua_cache()
    ua = get_ua_for_domain("not-a-url")
    assert ua == FALLBACK_UAS[0]


def test_get_ua_for_domain_caches_across_calls():
    """缓存生效：第二次调用不重新计算。"""
    reset_domain_ua_cache()
    url = "https://cached.example.com"
    ua1 = get_ua_for_domain(url)
    # 直接从缓存取
    from common import _domain_ua_cache
    domain_key = "cached.example.com"
    assert domain_key in _domain_ua_cache
    assert _domain_ua_cache[domain_key] == ua1


def test_ua_index_for_domain_is_stable_across_processes():
    """SHA-256 hash 保证跨进程一致（不像内置 hash 受 PYTHONHASHSEED 影响）。"""
    idx1 = _ua_index_for_domain("example.com", len(FALLBACK_UAS))
    idx2 = _ua_index_for_domain("example.com", len(FALLBACK_UAS))
    assert idx1 == idx2
    assert 0 <= idx1 < len(FALLBACK_UAS)


# ----- build_browser_headers -----

def test_build_headers_chrome_includes_sec_ch_ua():
    """Chrome UA 应生成 Sec-Ch-Ua 系列头。"""
    chrome_ua = FALLBACK_UAS[0]  # Chrome 131 Windows
    headers = build_browser_headers(chrome_ua)
    assert "Sec-Ch-Ua" in headers
    assert "Sec-Ch-Ua-Mobile" in headers
    assert "Sec-Ch-Ua-Platform" in headers
    assert "Windows" in headers["Sec-Ch-Ua-Platform"]


def test_build_headers_firefox_excludes_sec_ch_ua():
    """Firefox UA 不应生成 Sec-Ch-Ua（Firefox 不发送此头）。"""
    firefox_ua = next(ua for ua in FALLBACK_UAS if "Firefox/" in ua)
    headers = build_browser_headers(firefox_ua)
    assert "Sec-Ch-Ua" not in headers
    assert "Sec-Ch-Ua-Mobile" not in headers


def test_build_headers_includes_accept_language():
    """所有浏览器都应有 Accept-Language。"""
    headers = build_browser_headers(FALLBACK_UAS[0])
    assert "Accept-Language" in headers
    assert "en-US" in headers["Accept-Language"]


def test_build_headers_includes_accept_encoding():
    """Accept-Encoding 必须存在；Firefox 不发 br；Chrome/Edge 仅在
    本机安装了 brotli 解压器时才声明 br（v2.2.1 智能声明）。

    未安装 brotli 时声明 br 会导致服务器返回 br 压缩字节而 requests
    无法解压 → 全页乱码。这是 fetch.py 真实环境的 bug 修复。
    """
    # 导入 common 的 brotli 检测状态
    from common import _HAS_BROTLI

    chrome_headers = build_browser_headers(FALLBACK_UAS[0])
    # Chrome/Edge：根据 brotli 可用性决定是否声明 br
    if _HAS_BROTLI:
        assert "br" in chrome_headers["Accept-Encoding"]
    else:
        assert "br" not in chrome_headers["Accept-Encoding"]
    assert "gzip" in chrome_headers["Accept-Encoding"]

    firefox_ua = next(ua for ua in FALLBACK_UAS if "Firefox/" in ua)
    firefox_headers = build_browser_headers(firefox_ua)
    assert "br" not in firefox_headers["Accept-Encoding"]
    assert "gzip" in firefox_headers["Accept-Encoding"]


def test_build_headers_html_mode_includes_upgrade_insecure():
    """HTML 模式下 Upgrade-Insecure-Requests=1。"""
    headers = build_browser_headers(FALLBACK_UAS[0], accept_html=True)
    assert headers["Upgrade-Insecure-Requests"] == "1"


def test_build_headers_json_mode_excludes_upgrade_insecure_navigation():
    """JSON 模式下不发送导航相关头。"""
    headers = build_browser_headers(FALLBACK_UAS[0], accept_html=False)
    assert headers["Upgrade-Insecure-Requests"] == "0"
    assert headers["Sec-Fetch-Mode"] == "cors"
    assert headers["Sec-Fetch-Dest"] == "empty"


def test_build_headers_sec_fetch_dest_document_for_html():
    """HTML 模式 Sec-Fetch-Dest=document。"""
    headers = build_browser_headers(FALLBACK_UAS[0], accept_html=True)
    assert headers["Sec-Fetch-Dest"] == "document"
    assert headers["Sec-Fetch-Mode"] == "navigate"


def test_build_headers_referer_set_when_provided():
    """传入 referer 时设置 Referer 头。"""
    headers = build_browser_headers(FALLBACK_UAS[0],
                                    referer="https://google.com/")
    assert headers["Referer"] == "https://google.com/"


def test_build_headers_no_referer_when_absent():
    """不传 referer 时不设置 Referer 头。"""
    headers = build_browser_headers(FALLBACK_UAS[0])
    assert "Referer" not in headers


def test_build_headers_sec_fetch_site_none_without_referer():
    """无 Referer 时 Sec-Fetch-Site=none（像地址栏直接访问）。"""
    headers = build_browser_headers(FALLBACK_UAS[0], accept_html=True)
    assert headers["Sec-Fetch-Site"] == "none"


def test_build_headers_sec_fetch_site_cross_site_with_referer():
    """有 Referer 时 Sec-Fetch-Site=cross-site。"""
    headers = build_browser_headers(FALLBACK_UAS[0],
                                    accept_html=True,
                                    referer="https://google.com/")
    assert headers["Sec-Fetch-Site"] == "cross-site"


def test_build_headers_edge_includes_edge_brand():
    """Edge UA 的 Sec-Ch-Ua 应包含 Microsoft Edge 品牌。"""
    edge_ua = next(ua for ua in FALLBACK_UAS if "Edg/" in ua)
    headers = build_browser_headers(edge_ua)
    assert "Microsoft Edge" in headers["Sec-Ch-Ua"]


def test_build_headers_macos_platform():
    """macOS UA 的 Sec-Ch-Ua-Platform=macOS。"""
    mac_ua = next(ua for ua in FALLBACK_UAS if "Macintosh" in ua and "Edg/" not in ua)
    headers = build_browser_headers(mac_ua)
    assert "macOS" in headers["Sec-Ch-Ua-Platform"]


def test_build_headers_linux_platform():
    """Linux UA 的 Sec-Ch-Ua-Platform=Linux。"""
    linux_ua = next(ua for ua in FALLBACK_UAS if "Linux" in ua and "Firefox/" not in ua)
    headers = build_browser_headers(linux_ua)
    assert "Linux" in headers["Sec-Ch-Ua-Platform"]


def test_build_headers_user_agent_set():
    """UA 必须设置到 User-Agent 头。"""
    headers = build_browser_headers(FALLBACK_UAS[0])
    assert headers["User-Agent"] == FALLBACK_UAS[0]


def test_build_headers_connection_keep_alive():
    """Connection: keep-alive 支持 HTTP 持久连接。"""
    headers = build_browser_headers(FALLBACK_UAS[0])
    assert headers["Connection"] == "keep-alive"


# ----- parse_retry_after -----

def test_parse_retry_after_numeric_seconds():
    """纯数字格式：秒数。"""
    assert parse_retry_after("30") == 30.0
    assert parse_retry_after("0") == 0.0
    assert parse_retry_after("120") == 120.0


def test_parse_retry_after_decimal():
    """小数秒数。"""
    assert parse_retry_after("1.5") == 1.5


def test_parse_retry_after_empty():
    """空字符串返回 0。"""
    assert parse_retry_after("") == 0.0
    assert parse_retry_after(None) == 0.0


def test_parse_retry_after_http_date_future():
    """HTTP date 格式（未来时间）返回正秒数。"""
    from datetime import datetime, timezone, timedelta
    future = datetime.now(timezone.utc) + timedelta(seconds=60)
    from email.utils import format_datetime
    date_str = format_datetime(future)
    seconds = parse_retry_after(date_str)
    assert 50 < seconds < 70  # 允许一点时间漂移


def test_parse_retry_after_http_date_past():
    """HTTP date 格式（过去时间）返回 0（已过期）。"""
    from datetime import datetime, timezone, timedelta
    past = datetime.now(timezone.utc) - timedelta(seconds=60)
    from email.utils import format_datetime
    date_str = format_datetime(past)
    assert parse_retry_after(date_str) == 0.0


def test_parse_retry_after_garbage():
    """无法解析的值返回 0。"""
    assert parse_retry_after("not-a-date-or-number") == 0.0


def test_parse_retry_after_negative_numeric():
    """负数秒返回 0（不允许负等待）。"""
    assert parse_retry_after("-5") == 0.0


# ----- compute_backoff_delay -----

def test_backoff_caps_at_60_seconds():
    """退避延迟不超过 60s 上限。"""
    # attempt=20 会产生 1.5*2^20 ≈ 1.5M，远超上限
    delay = compute_backoff_delay(20)
    assert delay <= RETRY_BACKOFF_CAP


def test_backoff_increases_with_attempt():
    """退避延迟随 attempt 增加（允许抖动误差）。"""
    # 多次取均值避免抖动干扰
    import random
    random.seed(42)
    delays = [compute_backoff_delay(0) for _ in range(100)]
    avg0 = sum(delays) / len(delays)
    random.seed(42)
    delays = [compute_backoff_delay(3) for _ in range(100)]
    avg3 = sum(delays) / len(delays)
    assert avg3 > avg0


def test_backoff_custom_cap():
    """自定义上限生效。"""
    delay = compute_backoff_delay(20, cap=5.0)
    assert delay <= 5.0


def test_backoff_attempt_zero_positive():
    """attempt=0 时延迟为正。"""
    delay = compute_backoff_delay(0)
    assert delay > 0