from __future__ import annotations

from typing import Any

import pytest

from agent_lab.application.events import (
    ConfirmationPolicy,
    EventDefinition,
    EventExecutionContext,
    EventKernel,
    EventRegistry,
    EventRequest,
    EventSource,
    EventStatus,
    ResultPolicy,
    RiskLevel,
)
from agent_lab.application.tools import (
    ToolDefinition,
    ToolExecutionContext,
    ToolRegistry,
)
from agent_lab.domain.events import ToolCallEvent
from agent_lab.domain.messages import ChatMessage


def _definition(
    name: str = "example.lookup",
    **overrides: Any,
) -> EventDefinition:
    values: dict[str, Any] = {
        "name": name,
        "description": "Look up an example value.",
        "parameters": {
            "type": "object",
            "properties": {"query": {"type": "string"}},
            "required": ["query"],
        },
        "handler": lambda request: {
            "event": request.name,
            "query": request.arguments["query"],
        },
    }
    values.update(overrides)
    return EventDefinition(**values)


def test_registry_registers_flat_definitions_and_filters_enabled_catalog():
    registry = EventRegistry(
        [_definition("example.lookup"), _definition("device.inspect")]
    )

    assert [item["name"] for item in registry.catalog()] == [
        "example.lookup",
        "device.inspect",
    ]
    assert registry.catalog(["device.inspect"]) == [
        {
            "name": "device.inspect",
            "description": "Look up an example value.",
            "parameters": {
                "type": "object",
                "properties": {"query": {"type": "string"}},
                "required": ["query"],
            },
        }
    ]
    assert registry.tool_schema("example.lookup")["function"]["name"] == (
        "example.lookup"
    )
    assert registry.tool_schema("missing") is None


def test_registry_rejects_duplicate_definition_names():
    with pytest.raises(ValueError, match="duplicate event definition: example.lookup"):
        EventRegistry([_definition(), _definition()])


def test_tool_registry_public_api_remains_compatible():
    registry = ToolRegistry(
        [
            ToolDefinition(
                name="compat.lookup",
                description="Look up compatibility data.",
                parameters={
                    "type": "object",
                    "properties": {"query": {"type": "string"}},
                    "required": ["query"],
                },
                handler=lambda event: {
                    "tool": event.name,
                    "query": event.arguments["query"],
                },
                argument_resolver=lambda event, context: {
                    "query": context.history[-1].content
                },
            )
        ]
    )
    event = ToolCallEvent(
        id="call-1",
        name="compat.lookup",
        arguments={"query": "provider"},
        raw_arguments='{"query":"provider"}',
    )

    assert registry.available_tools() == [
        {
            "name": "compat.lookup",
            "description": "Look up compatibility data.",
            "parameters": {
                "type": "object",
                "properties": {"query": {"type": "string"}},
                "required": ["query"],
            },
        }
    ]
    assert "- compat.lookup: Look up compatibility data." in (
        registry.chat_event_system_message(["compat.lookup"])
    )
    assert registry.tool_schema("compat.lookup")["function"]["name"] == (
        "compat.lookup"
    )
    assert registry.handle(
        event,
        ToolExecutionContext(history=[ChatMessage(role="user", content="history")]),
    ) == {"tool": "compat.lookup", "query": "history"}
    assert registry.execute(event) == {"tool": "compat.lookup", "query": "provider"}


@pytest.mark.asyncio
async def test_kernel_executes_complete_deterministic_arguments_without_fallback():
    fallback_calls: list[str] = []

    async def fallback(*args: Any) -> dict[str, Any]:
        fallback_calls.append("called")
        return {"query": "fallback"}

    registry = EventRegistry(
        [_definition(resolver=lambda request, context: {"query": "deterministic"})]
    )

    result = await EventKernel(registry, argument_fallback=fallback).execute(
        EventRequest(id="event-1", name="example.lookup"),
        enabled_names=["example.lookup"],
    )

    assert result.status is EventStatus.SUCCESS
    assert result.arguments == {"query": "deterministic"}
    assert result.payload == {"event": "example.lookup", "query": "deterministic"}
    assert result.used_fallback is False
    assert fallback_calls == []


@pytest.mark.asyncio
async def test_kernel_calls_fallback_once_when_required_arguments_are_incomplete():
    fallback_calls: list[dict[str, Any]] = []

    async def fallback(
        definition: EventDefinition,
        request: EventRequest,
        context: EventExecutionContext,
    ) -> dict[str, Any]:
        fallback_calls.append(dict(request.arguments))
        return {"query": "resolved once"}

    registry = EventRegistry([_definition(resolver=lambda request, context: {})])

    result = await EventKernel(registry, argument_fallback=fallback).execute(
        EventRequest(id="event-1", name="example.lookup"),
        enabled_names=["example.lookup"],
    )

    assert result.status is EventStatus.SUCCESS
    assert result.arguments == {"query": "resolved once"}
    assert result.used_fallback is True
    assert fallback_calls == [{}]


@pytest.mark.asyncio
async def test_kernel_does_not_fallback_when_definition_disallows_it():
    fallback_calls = 0

    async def fallback(*args: Any) -> dict[str, Any]:
        nonlocal fallback_calls
        fallback_calls += 1
        return {"query": "not allowed"}

    registry = EventRegistry(
        [
            _definition(
                resolver=lambda request, context: {},
                fallback_allowed=False,
            )
        ]
    )

    result = await EventKernel(registry, argument_fallback=fallback).execute(
        EventRequest(id="event-1", name="example.lookup"),
        enabled_names=["example.lookup"],
    )

    assert result.status is EventStatus.INVALID_ARGUMENTS
    assert result.error == "missing required arguments: query"
    assert result.used_fallback is False
    assert fallback_calls == 0


@pytest.mark.asyncio
async def test_provider_resolved_arguments_are_not_rewritten_or_fallen_back():
    resolver_calls = 0
    fallback_calls = 0

    def resolver(*args: Any) -> dict[str, Any]:
        nonlocal resolver_calls
        resolver_calls += 1
        return {"query": "rewritten"}

    async def fallback(*args: Any) -> dict[str, Any]:
        nonlocal fallback_calls
        fallback_calls += 1
        return {"query": "fallback"}

    registry = EventRegistry([_definition(resolver=resolver)])

    result = await EventKernel(registry, argument_fallback=fallback).execute(
        EventRequest(
            id="event-1",
            name="example.lookup",
            arguments={"query": "provider value"},
            source=EventSource.PROVIDER_RESOLVED,
        ),
        enabled_names=["example.lookup"],
    )

    assert result.status is EventStatus.SUCCESS
    assert result.arguments == {"query": "provider value"}
    assert resolver_calls == 0
    assert fallback_calls == 0


@pytest.mark.asyncio
async def test_provider_resolved_missing_arguments_return_invalid_without_fallback():
    fallback_calls = 0

    async def fallback(*args: Any) -> dict[str, Any]:
        nonlocal fallback_calls
        fallback_calls += 1
        return {"query": "fallback"}

    result = await EventKernel(
        EventRegistry([_definition()]), argument_fallback=fallback
    ).execute(
        EventRequest(
            id="event-1",
            name="example.lookup",
            arguments={},
            source=EventSource.PROVIDER_RESOLVED,
        ),
        enabled_names=["example.lookup"],
    )

    assert result.status is EventStatus.INVALID_ARGUMENTS
    assert result.error == "missing required arguments: query"
    assert fallback_calls == 0


@pytest.mark.asyncio
@pytest.mark.parametrize(
    ("event_request", "enabled_names", "expected_status", "expected_error"),
    [
        (
            EventRequest(id="event-1", name="missing"),
            ["missing"],
            EventStatus.UNKNOWN,
            "unknown event",
        ),
        (
            EventRequest(id="event-1", name="example.lookup"),
            [],
            EventStatus.DISABLED,
            "event disabled",
        ),
        (
            EventRequest(
                id="event-1",
                name="example.lookup",
                arguments={"query": 42},
                source=EventSource.PROVIDER_RESOLVED,
            ),
            ["example.lookup"],
            EventStatus.INVALID_ARGUMENTS,
            "invalid argument type for query: expected string",
        ),
    ],
)
async def test_kernel_normalizes_lookup_and_validation_failures(
    event_request: EventRequest,
    enabled_names: list[str],
    expected_status: EventStatus,
    expected_error: str,
):
    result = await EventKernel(EventRegistry([_definition()])).execute(
        event_request,
        enabled_names=enabled_names,
    )

    assert result.status is expected_status
    assert result.error == expected_error


@pytest.mark.asyncio
async def test_kernel_normalizes_handler_exceptions():
    def fail(request: EventRequest) -> dict[str, Any]:
        raise RuntimeError("boom")

    result = await EventKernel(
        EventRegistry([_definition(handler=fail)])
    ).execute(
        EventRequest(
            id="event-1",
            name="example.lookup",
            arguments={"query": "value"},
            source=EventSource.PROVIDER_RESOLVED,
        ),
        enabled_names=["example.lookup"],
    )

    assert result.status is EventStatus.HANDLER_ERROR
    assert result.error == "event handler failed: boom"


@pytest.mark.asyncio
async def test_kernel_rejects_boolean_for_json_number_arguments():
    definition = _definition(
        parameters={
            "type": "object",
            "properties": {"query": {"type": "number"}},
            "required": ["query"],
        }
    )

    result = await EventKernel(EventRegistry([definition])).execute(
        EventRequest(
            id="event-1",
            name="example.lookup",
            arguments={"query": True},
            source=EventSource.PROVIDER_RESOLVED,
        ),
        enabled_names=["example.lookup"],
    )

    assert result.status is EventStatus.INVALID_ARGUMENTS
    assert result.error == "invalid argument type for query: expected number"


@pytest.mark.asyncio
async def test_definition_metadata_survives_registration_and_result_creation():
    definition = _definition(
        result_policy=ResultPolicy.TEMPLATE_FOLLOW_UP,
        confirmation_policy=ConfirmationPolicy.REQUIRED,
        risk_level=RiskLevel.HIGH,
        idempotency_key_fields=("session_id", "event_id"),
        concurrency_class="device-write",
        conflict_keys=("device",),
        timeout_seconds=1.5,
        terminal=True,
    )
    registry = EventRegistry([definition])

    result = await EventKernel(registry).execute(
        EventRequest(
            id="event-1",
            name="example.lookup",
            arguments={"query": "value"},
            source=EventSource.PROVIDER_RESOLVED,
        ),
        enabled_names=["example.lookup"],
    )

    registered = registry.definition("example.lookup")
    assert registered is definition
    assert result.result_policy is ResultPolicy.TEMPLATE_FOLLOW_UP
    assert result.confirmation_policy is ConfirmationPolicy.REQUIRED
    assert result.risk_level is RiskLevel.HIGH
    assert result.idempotency_key_fields == ("session_id", "event_id")
    assert result.concurrency_class == "device-write"
    assert result.conflict_keys == ("device",)
    assert result.timeout_seconds == 1.5
    assert result.terminal is True


def test_kernel_source_has_no_builtin_event_name_branches():
    from pathlib import Path

    source = Path("src/agent_lab/application/events/kernel.py").read_text()

    assert "handoff_note" not in source
    assert "mock_search" not in source
    assert "mock_ticket" not in source