"""Tests for the layered HintGenerator architecture (ADR-009).

Covers ADR-009 acceptance gates:
  - gate 1: HintGenerator Protocol; layers satisfy it (runtime_checkable).
  - gate 2: TemplateHintGenerator is byte-identical to the existing dispatch()
    for all 5 registered kinds (no regression).
  - gate 3: CompositeHintGenerator tries layers cost-first — a tool_not_found
    site is served by the template layer (no LLM call); a style site falls
    through to the judge layer.
  - gate 4: LLMJudgeHintGenerator caches (second identical call = zero
    completions).
  - gate 5: as_collator_hook() matches CollatorConfig.hint_generator's
    (error_kind, error_meta) -> str | None signature.

All CPU-only, no network (LLM layer is a stub).
"""
from __future__ import annotations

from composer_replication.hint_generator import (
    HINT_TEMPLATES,
    CompositeHintGenerator,
    HintGenerator,
    LLMJudgeHintGenerator,
    RawErrorHintGenerator,
    TemplateHintGenerator,
    default_composite,
    dispatch,
)


# --- gate 1: Protocol -------------------------------------------------------

def test_layers_satisfy_protocol():
    assert isinstance(TemplateHintGenerator(), HintGenerator)
    assert isinstance(RawErrorHintGenerator(), HintGenerator)
    assert isinstance(LLMJudgeHintGenerator(), HintGenerator)
    assert isinstance(CompositeHintGenerator([]), HintGenerator)


# --- gate 2: template byte-identity ----------------------------------------

def test_template_layer_byte_identical_to_dispatch():
    tmpl = TemplateHintGenerator()
    meta = {
        "available_tools": ["read", "write"],
        "tool_name": "frobnicate",
        "tool_schema": {"x": "int"},
        "error_message": "boom",
    }
    for kind in HINT_TEMPLATES:
        ctx = dict(meta)
        ctx.setdefault("error_kind", kind)
        expected = dispatch(kind, ctx)
        got = tmpl.generate(kind, meta)
        assert got == expected, f"template layer drifted from dispatch for {kind}"


def test_template_layer_returns_none_for_unknown_kind():
    assert TemplateHintGenerator().generate("totally_unknown_kind", {}) is None


# --- gate 3: cost-ordered composite ----------------------------------------

def test_composite_serves_tool_error_from_template_no_llm():
    calls = {"n": 0}

    def fake_complete(prompt: str) -> str:
        calls["n"] += 1
        return "LLM HINT"

    comp = default_composite(llm_complete=fake_complete)
    hint = comp.generate("tool_not_found", {"available_tools": ["read", "write"]})
    assert hint is not None
    assert "Available tools" in hint  # template output
    assert calls["n"] == 0, "LLM judge must NOT be called for a template-covered site"


def test_composite_falls_through_to_judge_for_uncovered_site():
    calls = {"n": 0}

    def fake_complete(prompt: str) -> str:
        calls["n"] += 1
        return "Be more concise; you repeated the same explanation."

    comp = default_composite(llm_complete=fake_complete, enable_raw_error=False)
    # 'verbose_communication' has no template and no error_message -> judge.
    hint = comp.generate("verbose_communication", {})
    assert hint == "Be more concise; you repeated the same explanation."
    assert calls["n"] == 1


def test_raw_error_layer_covers_unmatched_site_with_message():
    comp = default_composite()  # no LLM
    hint = comp.generate("weird_unmapped_error", {"error_message": "Segfault at 0x0"})
    assert hint is not None
    assert "Segfault at 0x0" in hint


def test_composite_returns_none_when_all_layers_defer():
    comp = default_composite()  # templates + raw-error, no LLM
    # unknown kind + no message -> nothing fires
    assert comp.generate("unknown", {}) is None


# --- gate 4: LLM-judge cache ------------------------------------------------

def test_llm_judge_caches_in_memory(tmp_path):
    calls = {"n": 0}

    def fake_complete(prompt: str) -> str:
        calls["n"] += 1
        return f"hint #{calls['n']}"

    judge = LLMJudgeHintGenerator(fake_complete, cache_dir=str(tmp_path))
    meta = {"error_message": "X"}
    h1 = judge.generate("k", meta)
    h2 = judge.generate("k", meta)  # identical -> cache hit
    assert h1 == h2
    assert calls["n"] == 1, "second identical call must hit cache (zero completions)"


def test_llm_judge_disk_cache_survives_new_instance(tmp_path):
    calls = {"n": 0}

    def fake_complete(prompt: str) -> str:
        calls["n"] += 1
        return "persisted hint"

    j1 = LLMJudgeHintGenerator(fake_complete, cache_dir=str(tmp_path))
    j1.generate("k", {"error_message": "X"})
    # fresh instance, same cache dir -> disk hit, no completion
    j2 = LLMJudgeHintGenerator(fake_complete, cache_dir=str(tmp_path))
    h = j2.generate("k", {"error_message": "X"})
    assert h == "persisted hint"
    assert calls["n"] == 1


def test_llm_judge_disabled_when_no_complete():
    assert LLMJudgeHintGenerator(None).generate("k", {"error_message": "X"}) is None


# --- gate 5: collator-hook signature ---------------------------------------

def test_as_collator_hook_matches_collator_signature():
    comp = default_composite()
    hook = comp.as_collator_hook()
    # CollatorConfig.hint_generator is Callable[[str, dict], str | None]
    out = hook("tool_not_found", {"available_tools": ["read"]})
    assert isinstance(out, str)
    out_none = hook("unknown", {})
    assert out_none is None


def test_as_collator_hook_drops_into_collator_config():
    """The hook is accepted by CollatorConfig without changes."""
    from composer_replication.trainer.data_collator import CollatorConfig

    comp = default_composite()
    cfg = CollatorConfig(hint_generator=comp.as_collator_hook())
    assert cfg.hint_generator is not None
    assert cfg.hint_generator("json_decode", {}) is not None  # template fires