"""Tests unitaires du graphe LangGraph.

Ces tests sont FOURNIS COMPLETS — ils servent de spécification.
Ils doivent tous passer une fois react_agent.py implémenté.
Le LLM est entièrement mocké : Ollama n'est pas nécessaire.

Lancer : uv run pytest tests/unit/test_agent.py -v
"""

from unittest.mock import MagicMock, patch

import pytest
from langchain_core.messages import AIMessage, HumanMessage

from src.agents.react_agent import AgentState, agent_node, should_continue


# ── Helpers ───────────────────────────────────────────────────────────────────

def make_state(messages: list, iterations: int = 0) -> AgentState:
    return AgentState(messages=messages, iterations=iterations)

def ai_with_tools() -> AIMessage:
    return AIMessage(content="", tool_calls=[
        {"name": "search_product", "args": {"name": "laptop"}, "id": "c1", "type": "tool_call"}
    ])

def ai_final(content: str = "Voici la réponse.") -> AIMessage:
    return AIMessage(content=content)


# ── Tests should_continue ─────────────────────────────────────────────────────

class TestShouldContinue:

    def test_returns_tools_when_tool_calls_present(self) -> None:
        state = make_state([HumanMessage("test"), ai_with_tools()])
        assert should_continue(state) == "tools"

    def test_returns_end_when_no_tool_calls(self) -> None:
        from langgraph.graph import END
        state = make_state([HumanMessage("test"), ai_final()])
        assert should_continue(state) == END

    def test_returns_end_at_max_iterations(self) -> None:
        from langgraph.graph import END
        state = make_state([HumanMessage("test"), ai_with_tools()], iterations=20)
        assert should_continue(state) == END

    def test_continues_below_max_iterations(self) -> None:
        state = make_state([HumanMessage("test"), ai_with_tools()], iterations=5)
        assert should_continue(state) == "tools"


# ── Tests agent_node ──────────────────────────────────────────────────────────

class TestAgentNode:

    def test_increments_iterations(self) -> None:
        with patch("src.agents.react_agent.get_llm") as mock:
            mock.return_value.bind_tools.return_value.invoke.return_value = ai_final()
            result = agent_node(make_state([HumanMessage("test")], iterations=2))
        assert result["iterations"] == 3

    def test_appends_response_to_messages(self) -> None:
        response = ai_final("Réponse test")
        with patch("src.agents.react_agent.get_llm") as mock:
            mock.return_value.bind_tools.return_value.invoke.return_value = response
            result = agent_node(make_state([HumanMessage("test")]))
        assert response in result["messages"]

    def test_returns_messages_and_iterations_keys(self) -> None:
        with patch("src.agents.react_agent.get_llm") as mock:
            mock.return_value.bind_tools.return_value.invoke.return_value = ai_final()
            result = agent_node(make_state([HumanMessage("test")]))
        assert "messages" in result
        assert "iterations" in result

    def test_binds_tools_to_llm(self) -> None:
        with patch("src.agents.react_agent.get_llm") as mock:
            mock_llm = MagicMock()
            mock_llm.bind_tools.return_value.invoke.return_value = ai_final()
            mock.return_value = mock_llm
            agent_node(make_state([HumanMessage("test")]))
        mock_llm.bind_tools.assert_called_once()
        assert len(mock_llm.bind_tools.call_args[0][0]) > 0


# ── Tests build_agent ─────────────────────────────────────────────────────────

class TestBuildAgent:

    def test_graph_compiles(self) -> None:
        from src.agents.react_agent import build_agent
        assert build_agent(use_memory=False) is not None

    def test_graph_has_agent_and_tools_nodes(self) -> None:
        from src.agents.react_agent import build_agent
        app = build_agent(use_memory=False)
        ids = list(app.get_graph().nodes.keys())
        assert "agent" in ids
        assert "tools" in ids

    def test_mermaid_is_generated(self) -> None:
        from src.agents.react_agent import build_agent
        mermaid = build_agent(use_memory=False).get_graph().draw_mermaid()
        assert "agent" in mermaid
        assert "tools" in mermaid