import pytest
from app.services import ai_tree_builder as atb


class _FakeProvider:
    def __init__(self, raw):
        self._raw = raw

    async def generate_json(self, *, system_prompt, messages, max_tokens):
        return self._raw, None, None


@pytest.mark.asyncio
async def test_generate_next_node_assigns_id_when_model_omits_it(monkeypatch):
    """The SYSTEM_PROMPT never asks the model for an id (Finding 1). The server
    must assign one to every generated node, or the advance protocol — which keys
    on node_id — can never record an answer and the walk stalls on question 1."""
    monkeypatch.setattr(
        atb, "get_ai_provider",
        lambda *a, **k: _FakeProvider('{"node_type":"question","text":"Plugged in?"}'),
    )
    node = await atb.generate_next_node("printer down", "printer", [])
    assert node["node_type"] == "question"
    assert node.get("id"), "generated node must carry a server-assigned id"


@pytest.mark.asyncio
async def test_generate_next_node_depth_cap_node_has_id(monkeypatch):
    """The depth-cap escalate node must also carry an id (it is persisted as
    current_node_id and may be appended to walked_path)."""
    walked = [{"node_type": "question", "id": f"n{i}", "text": "?", "answer": "no"}
              for i in range(atb.MAX_DEPTH)]
    node = await atb.generate_next_node("x", "printer", walked)
    assert node["node_type"] == "escalate"
    assert node.get("id")


@pytest.mark.asyncio
async def test_generate_next_node_generation_failed_node_has_id(monkeypatch):
    """When both generation attempts fail, the fallback escalate node carries an id."""
    monkeypatch.setattr(
        atb, "get_ai_provider",
        lambda *a, **k: _FakeProvider("not json at all"),
    )
    node = await atb.generate_next_node("x", "printer", [])
    assert node["node_type"] == "escalate"
    assert node["reason_category"] == "generation_failed"
    assert node.get("id")


# ---------------------------------------------------------------------------
# Answer labels: the button text must match the question (live-walk defect:
# "Microsoft account or local account?" rendered with Yes/No buttons).
# ---------------------------------------------------------------------------

def test_system_prompt_requires_answer_labels():
    """The prompt must mandate yes_label/no_label on question nodes — the prompt
    forcing label-less '<yes/no question>' output is the root cause of the
    question/button mismatch."""
    assert "yes_label" in atb.SYSTEM_PROMPT and "no_label" in atb.SYSTEM_PROMPT


@pytest.mark.asyncio
async def test_generated_question_passes_labels_through(monkeypatch):
    monkeypatch.setattr(
        atb, "get_ai_provider",
        lambda *a, **k: _FakeProvider(
            '{"node_type":"question",'
            '"text":"Is Jane\'s Windows account a Microsoft account or a local account?",'
            '"yes_label":"Microsoft account","no_label":"Local account"}'
        ),
    )
    node = await atb.generate_next_node("login issue", "account_login", [])
    assert node["yes_label"] == "Microsoft account"
    assert node["no_label"] == "Local account"


@pytest.mark.asyncio
async def test_question_missing_labels_gets_yes_no_defaults(monkeypatch):
    monkeypatch.setattr(
        atb, "get_ai_provider",
        lambda *a, **k: _FakeProvider('{"node_type":"question","text":"Is the printer powered on?"}'),
    )
    node = await atb.generate_next_node("printer down", "printer", [])
    assert node["yes_label"] == "Yes"
    assert node["no_label"] == "No"


def test_validate_node_rejects_hard_floor_text_in_labels():
    node = {"node_type": "question", "text": "How should we proceed?",
            "yes_label": "Edit the registry", "no_label": "Wait"}
    with pytest.raises(atb.UnsafeNodeError):
        atb.validate_node(node)


def test_validate_node_rejects_indistinct_or_malformed_labels():
    base = {"node_type": "question", "text": "Which network is the laptop on?"}
    with pytest.raises(atb.UnsafeNodeError):
        atb.validate_node({**base, "yes_label": "Wi-Fi", "no_label": "wi-fi "})
    with pytest.raises(atb.UnsafeNodeError):
        atb.validate_node({**base, "yes_label": 1, "no_label": "Ethernet"})


def test_build_context_prefers_answer_label_over_raw_answer():
    """The LLM context must show what the tech actually chose — 'Q? -> yes' is
    ambiguous for an alternatives question and degrades the next generation."""
    ctx = atb._build_context("login issue", "account_login", [
        {"node_type": "question", "id": "n1",
         "text": "Microsoft account or local account?",
         "answer": "yes", "answer_label": "Microsoft account"},
    ])
    assert "-> Microsoft account" in ctx
    assert "-> yes" not in ctx


def test_normalize_walked_path_preserves_question_labels():
    walked = [
        {"node_type": "question", "id": "n1", "text": "Wi-Fi or Ethernet?",
         "answer": "yes", "answer_label": "Wi-Fi",
         "yes_label": "Wi-Fi", "no_label": "Ethernet"},
        {"node_type": "resolved", "id": "n2", "text": "Fixed."},
    ]
    tree = atb.normalize_walked_path(walked)
    n1 = tree["nodes"]["n1"]
    assert n1["yes_label"] == "Wi-Fi" and n1["no_label"] == "Ethernet"


def test_validate_node_rejects_hard_floor_text():
    node = {"node_type": "instruction", "id": "n1", "text": "Open regedit and change the key", "next": "generate"}
    with pytest.raises(atb.UnsafeNodeError):
        atb.validate_node(node)


def test_validate_node_accepts_safe_instruction():
    node = {"node_type": "instruction", "id": "n1", "text": "Restart the printer.", "next": "generate"}
    assert atb.validate_node(node)["node_type"] == "instruction"


def test_depth_cap_forces_escalate():
    walked = [{"node_type": "question", "id": f"n{i}", "text": "?", "answer": "no"} for i in range(atb.MAX_DEPTH)]
    node = atb.escalate_if_depth_exceeded(walked)
    assert node is not None and node["node_type"] == "escalate"


def test_normalize_walked_path_builds_valid_tree():
    walked = [
        {"node_type": "question", "id": "n1", "text": "Powered on?", "answer": "no"},
        {"node_type": "instruction", "id": "n2", "text": "Power it on.", "answer": "ack"},
        {"node_type": "resolved", "id": "n3", "text": "Fixed."},
    ]
    tree = atb.normalize_walked_path(walked)
    assert isinstance(tree, dict) and tree.get("id") == "n1"
    # untraversed 'yes' branch of n1 became a needs_review stub
    assert any(n["node_type"] == "needs_review" for n in tree["nodes"].values())


def test_normalize_walk_ending_on_question_has_no_none_branches():
    walked = [
        {"node_type": "question", "id": "n1", "text": "Powered on?", "answer": "no"},
    ]
    tree = atb.normalize_walked_path(walked)
    n1 = tree["nodes"]["n1"]
    assert n1["yes_next"] is not None and n1["no_next"] is not None
    # both branches must reference real nodes present in the tree
    assert n1["yes_next"] in tree["nodes"] and n1["no_next"] in tree["nodes"]


def test_normalize_preserves_escalate_reason_category():
    walked = [
        {"node_type": "question", "id": "n1", "text": "On?", "answer": "no"},
        {"node_type": "escalate", "id": "n2", "text": "Beyond L1.",
         "reason_category": "exhausted_safe_steps"},
    ]
    tree = atb.normalize_walked_path(walked)
    assert tree["nodes"]["n2"]["reason_category"] == "exhausted_safe_steps"


def test_normalize_empty_walk_returns_needs_review_root():
    tree = atb.normalize_walked_path([])
    assert tree["id"] in tree["nodes"]
    assert tree["nodes"][tree["id"]]["node_type"] == "needs_review"