"""出厂默认与快照深合并（E4 配置演进）——Task 3 TDD 用例。

覆盖：
- deep_merge 三性质：缺省补齐 / 不动入参 / 兄弟键保留
- TenantConfig.from_snapshot 的站点模型：覆盖生效、未覆盖项继承租户级 brand、
  无 sites 时空元组
"""
from app.platform.defaults import DEFAULT_CONFIG, deep_merge
from app.platform.tenant_config import Site, TenantConfig


# ---------- deep_merge 三性质 ----------

def test_missing_keys_filled_from_defaults():
    snapshot = {"brand": {"title": "X"}}          # 快照缺一大堆键
    merged = deep_merge(DEFAULT_CONFIG, snapshot)
    assert merged["brand"]["title"] == "X"         # 覆盖生效
    assert "color" in merged["brand"]              # 缺省补齐
    assert "wall" in merged and "push" in merged   # 顶层组补齐


def test_snapshot_not_mutated():
    snapshot = {"brand": {"title": "X"}}
    deep_merge(DEFAULT_CONFIG, snapshot)
    assert snapshot == {"brand": {"title": "X"}}


def test_nested_override_keeps_sibling():
    snapshot = {"email": {"sender_name": "【T】"}}
    merged = deep_merge(DEFAULT_CONFIG, snapshot)
    assert merged["email"]["sender_name"] == "【T】"
    assert "notify_emails" in merged["email"]      # 兄弟键保留默认


# ---------- TenantConfig / Site 站点模型 ----------

def test_site_overrides_and_inherits_tenant_brand():
    """站点覆盖项生效；未覆盖项继承租户级 brand（而非出厂默认）。"""
    tenant = TenantConfig.from_snapshot(
        slug="t1",
        name="Tenant 1",
        snapshot={"brand": {"title": "T Co", "welcome": "hi from tenant"}},
        sites=[
            {"slug": "s1", "name": "Site 1", "domains": ["a.com"],
             "brand": {"color": "#ff0000"}},
        ],
    )
    site = tenant.sites[0]
    assert isinstance(site, Site)
    assert site.slug == "s1"
    assert site.name == "Site 1"
    assert site.domains == ("a.com",)
    assert site.brand["color"] == "#ff0000"        # 站点覆盖生效
    assert site.brand["title"] == "T Co"           # 继承租户级 brand
    assert site.brand["welcome"] == "hi from tenant"
    # 站点 brand 是独立副本，不与租户 data 共享可变对象
    assert site.brand is not tenant.data["brand"]


def test_tenant_without_sites():
    """无 sites 时 sites 为空元组，data 正常深合并。"""
    tenant = TenantConfig.from_snapshot(
        slug="t2", name="Tenant 2", snapshot={"ai": {"model": "glm-4-plus"}},
    )
    assert tenant.sites == ()
    assert tenant.status == "active"
    assert tenant.data["ai"]["model"] == "glm-4-plus"       # 覆盖生效
    assert tenant.data["push"]["enabled"] is False          # 缺省补齐


# ---------- characterization：None / 列表整体替换语义 ----------

def test_explicit_none_replaces_and_keeps_sibling():
    """显式 None 整体替换该键；兄弟键保留默认。

    Task 9 的回退契约依赖此语义：快照里显式写 null 表示"清空/未设置"，
    不能被解读为"回落默认值"。
    """
    merged = deep_merge(DEFAULT_CONFIG, {"ai": {"api_key": None}})
    assert merged["ai"]["api_key"] is None            # 显式 None 生效
    assert merged["ai"]["model"] == "glm-4-flash"     # 兄弟键保留默认


def test_list_replaced_wholesale():
    """列表整体替换，不与默认值拼接。"""
    merged = deep_merge(DEFAULT_CONFIG, {"email": {"notify_emails": ["x@y.z"]}})
    assert merged["email"]["notify_emails"] == ["x@y.z"]