"""前向链推理机（InferenceEngine）单元测试。"""
from router_system.inference import InferenceEngine, render_template
from router_system.knowledge import KnowledgeBase, Rule
from router_system.memory import WorkingMemory


def _engine():
    return InferenceEngine(KnowledgeBase())


def test_forward_chain_fires_rules():
    eng = _engine()
    mem = WorkingMemory()
    eng.initialize("求解方程 x^2 - 5x + 6 = 0", "math", "medium", 0.9, mem)
    fired = eng.run("求解方程 x^2 - 5x + 6 = 0", "math", mem)
    assert fired, "数学查询应触发规则"
    # 优先级最高的 math-equation 最先触发
    assert fired[0] == "math-equation"
    # 轨迹包含规则记录
    assert any(t.startswith("rule:") for t in mem.trace)


def test_no_match_terminates():
    eng = _engine()
    mem = WorkingMemory()
    eng.initialize("今天天气怎么样", "general", "medium", 0.5, mem)
    fired = eng.run("今天天气怎么样", "general", mem)
    assert fired == []


def test_max_steps_limit():
    eng = _engine()
    mem = WorkingMemory()
    eng.initialize("求解方程 x^2 - 5x + 6 = 0", "math", "medium", 0.9, mem)
    fired = eng.run("求解方程 x^2 - 5x + 6 = 0", "math", mem, max_steps=1)
    assert len(fired) == 1


def test_blackboard_facts_written():
    eng = _engine()
    mem = WorkingMemory()
    eng.initialize("求解方程 x^2 - 5x + 6 = 0", "math", "hard", 0.95, mem)
    assert mem.get_fact("domain") == "math"
    assert mem.get_fact("difficulty") == "hard"
    assert "init:" in mem.trace[0]


def test_rule_output_renders_section():
    kb = KnowledgeBase()
    # 注入一条带 output 模板的规则
    kb._rules["test-rule"] = Rule(
        id="test-rule", domain="general", priority=10,
        patterns=["测试渲染"], output="领域={facts.domain} 查询={query}",
    )
    eng = InferenceEngine(kb)
    mem = WorkingMemory()
    eng.initialize("测试渲染一下", "general", "easy", 0.6, mem)
    fired = eng.run("测试渲染一下", "general", mem)
    assert "test-rule" in fired
    section = mem.section("test-rule")
    assert section is not None
    assert "领域=general" in section
    assert "查询=测试渲染一下" in section


def test_render_missing_placeholder():
    out = render_template("你好 {query} {facts.缺失字段}", "世界", {})
    assert "你好 世界 [未提供]" == out