"""P1-1: 单测 — llm_router 路由/熔断/上下文(双 Claw 共享 #875)。

为什么这个文件存在:
    LLM Router 是 #875 加速带的关键能力,但 #937 副密钥 failover 设计依托
    同一熔断 / 决策路径。锁死关键纯函数 + mock 路径,防止回归。

验证范围:
    1. 上下文注入: set_route_ctx → get_route_ctx 含 tenant/claw/trace
    2. OTel 桥接: set_route_ctx 同步注入 OTel 双 Claw 标签
    3. _is_text_only: 排除 media-only 模型(关键坑:failover 误用图像模型给文本)
    4. _tenant_authorized: 全局 / 私有模型归属校验
    5. _fallbacks: 排除 exclude_ids + 仅纯文本 + is_default desc
    6. 熔断: report_failure ×3 → _fail_count = 3(内存降级)
    7. 熔断: report_success 清零
    8. 熔断: TTL 过期自动清零
    9. RouteDecision 数据类可序列化 / 字段完整
"""
from __future__ import annotations

import os
import sys
import time

import pytest

_HERE = os.path.dirname(os.path.abspath(__file__))
sys.path.insert(0, os.path.join(_HERE, ".."))

from app.core import llm_router as lr  # noqa: E402
from app.core.llm_router import (  # noqa: E402
    SHADOW,
    _is_text_only,
    _tenant_authorized,
    _fallbacks,
    _fail_count,
    _BREAKER_LOCAL,
    report_failure,
    report_success,
    set_route_ctx,
    get_route_ctx,
    RouteDecision,
)


# =====================================================================
# 1. 上下文注入
# =====================================================================

def test_set_route_ctx_default():
    set_route_ctx()
    ctx = get_route_ctx()
    assert ctx["claw_type"] == "web"
    assert ctx["tenant_id"] == ""
    assert "trace_id" in ctx


def test_set_route_ctx_im():
    set_route_ctx(tenant_id="t-1", claw_type="im")
    ctx = get_route_ctx()
    assert ctx["tenant_id"] == "t-1"
    assert ctx["claw_type"] == "im"


def test_set_route_ctx_otel_bridge(monkeypatch):
    """set_route_ctx 应同步注入 OTel 双 Claw 标签"""
    captured = {}

    def fake_set_otel_ctx(*, tenant_id, claw_type):
        captured["tenant_id"] = tenant_id
        captured["claw_type"] = claw_type

    # patch the lazy import target
    import app.core.otel as otel_mod
    monkeypatch.setattr(otel_mod, "set_otel_ctx", fake_set_otel_ctx)
    set_route_ctx(tenant_id="t-9", claw_type="im")
    assert captured == {"tenant_id": "t-9", "claw_type": "im"}


def test_set_route_ctx_otel_silently_swallows_failure(monkeypatch):
    """otel 不可用时静默跳过,不冒泡"""
    import app.core.otel as otel_mod
    def boom(**kw):
        raise RuntimeError("otel down")
    monkeypatch.setattr(otel_mod, "set_otel_ctx", boom)
    # 应不抛
    set_route_ctx(tenant_id="t-x", claw_type="web")


# =====================================================================
# 2. _is_text_only — failover 备选关键判断
# =====================================================================

class FakeModel:
    def __init__(self, capabilities):
        self.capabilities = capabilities


def test_is_text_only_pure_text():
    assert _is_text_only(FakeModel(["text"])) is True


def test_is_text_only_excludes_image():
    """纯图像模型不是文本 failover 备选"""
    assert _is_text_only(FakeModel(["image"])) is False


def test_is_text_only_excludes_mixed_with_media():
    """含 text 但同时有 image → 视为媒体"""
    assert _is_text_only(FakeModel(["text", "image"])) is False


def test_is_text_only_handles_empty():
    assert _is_text_only(FakeModel([])) is False
    assert _is_text_only(FakeModel(None)) is False


# =====================================================================
# 3. _tenant_authorized
# =====================================================================

class FakeModelWithTenant:
    def __init__(self, tenant_id):
        self.tenant_id = tenant_id


def test_tenant_authorized_global_open():
    """全局模型(无 tenant_id)任何人可用"""
    m = FakeModelWithTenant(None)
    assert _tenant_authorized(m, "t-1") is True
    assert _tenant_authorized(m, "") is True


def test_tenant_authorized_private_match():
    m = FakeModelWithTenant("t-1")
    assert _tenant_authorized(m, "t-1") is True


def test_tenant_authorized_private_mismatch():
    m = FakeModelWithTenant("t-1")
    assert _tenant_authorized(m, "t-2") is False


def test_tenant_authorized_no_tenant_blocked():
    """私有模型 + caller 没传 tenant → 拒绝"""
    m = FakeModelWithTenant("t-1")
    assert _tenant_authorized(m, "") is False


# =====================================================================
# 4. _fallbacks: 排除 exclude_ids + 纯文本 + is_default desc
# =====================================================================

class FakeAimModel:
    def __init__(self, id, capabilities, is_default=False, is_enabled=True):
        self.id = id
        self.capabilities = capabilities
        self.is_default = is_default
        self.is_enabled = is_enabled


class FakeDb:
    def __init__(self, rows):
        self._rows = rows
    def query(self, cls):
        rows = self._rows
        class Q:
            def filter(self_inner, *a, **kw):
                return self_inner
            def order_by(self_inner, *a, **kw):
                return self_inner
            def all(self_inner):
                return rows
        return Q()


def test_fallbacks_excludes_exclude_ids():
    db = FakeDb([
        FakeAimModel("a", ["text"], is_default=True),
        FakeAimModel("b", ["text"], is_default=False),
    ])
    out = _fallbacks(db, exclude_ids={"a"}, limit=4)
    assert [m.id for m in out] == ["b"]


def test_fallbacks_excludes_media():
    db = FakeDb([
        FakeAimModel("a", ["text"], is_default=True),
        FakeAimModel("b", ["image"], is_default=True),  # 媒体不算
    ])
    out = _fallbacks(db, exclude_ids=set(), limit=4)
    assert [m.id for m in out] == ["a"]


def test_fallbacks_limit_caps():
    db = FakeDb([
        FakeAimModel(f"m{i}", ["text"], is_default=False) for i in range(10)
    ])
    out = _fallbacks(db, exclude_ids=set(), limit=3)
    assert len(out) == 3


# =====================================================================
# 5. 熔断: 内存降级(无 Redis)
# =====================================================================

def setup_function(_):
    """每个测试前清空内存 breaker 状态"""
    _BREAKER_LOCAL.clear()


def test_breaker_increments_and_reads():
    report_failure("m-1")
    report_failure("m-1")
    report_failure("m-1")
    assert _fail_count("m-1") == 3


def test_breaker_success_clears():
    report_failure("m-2")
    report_failure("m-2")
    assert _fail_count("m-2") == 2
    report_success("m-2")
    assert _fail_count("m-2") == 0


def test_breaker_ttl_expires(monkeypatch):
    """TTL 过期后 _fail_count 返回 0,本地条目清理"""
    report_failure("m-3")
    # 假装时间穿越到未来(after TTL)
    fake_now = time.time() + 1000
    monkeypatch.setattr(lr.time, "time", lambda: fake_now)
    assert _fail_count("m-3") == 0
    assert "m-3" not in _BREAKER_LOCAL


def test_breaker_empty_model_id():
    report_failure("")
    assert _fail_count("") == 0


# =====================================================================
# 6. RouteDecision 数据类
# =====================================================================

def test_route_decision_defaults():
    rd = RouteDecision(capability="text", claw_type="web", tenant_id="t-1")
    assert rd.capability == "text"
    assert rd.claw_type == "web"
    assert rd.tenant_id == "t-1"
    assert rd.models == []
    assert rd.primary is None
    assert rd.shadow is True
    assert rd.matched_legacy is None
    assert rd.reason == ""


def test_route_decision_fields_assignable():
    rd = RouteDecision(capability="text", claw_type="im", tenant_id="t-1")
    rd.models = ["a", "b"]
    rd.primary = "a"
    rd.reason = "explicit"
    rd.matched_legacy = True
    assert rd.models == ["a", "b"]
    assert rd.primary == "a"
    assert rd.reason == "explicit"
    assert rd.matched_legacy is True